INTERNATIONAL POTASH INSTITUTE (IPI)

LITHUANIAN INSTITUTE OF AGRICULTURE (LIA)

POTASSIUMAND

PHOSPHORUS:FERTILISATION EFFECT

ON SOIL AND CROPS

LITHUANIA, 2000

INTERNATIONAL LITHUANIAN INSTITUTE OFPOTASH INSTITUTE (IPI) AGRICULTURE (LIA)

POTASSIUM AND PHOSPHORUS:FERTILISATION EFFECT ON SOIL AND CROPS

Proceedings of the Regional IPI WorkshopOctober 23-24, 2000

LITHUANIA

Dotnuva-Akademija,2000

UDK 631.8 (06)Po-219

ORGANISING COMMITTEE:

Chairman: Prof. AdolfKrauss (International Potash Institute)Secretary: Dr. Sigitas Lazauskas (Lithuanian Institute of Agriculture)Members: Prof. IossiffBogdevitch (Belorussian Research Institute for

Soil Science and Agrochemistry)Prof. Aldis Karklins (Latvian University of Agriculture)Dr. Vytas MaJauskas (Lithuanian Institute of Agriculture)Prof. Albinas iuliauskas (Lithuanian University of Agriculture)

The publication sponsored by:The Lithuanian State Science and Studies FoundationThe Ministry of Agriculture of the Republic of Lithuania

ISBN 9986-527-67-8 Q Lithuanian Institute of Agriculture, 2000

PREFACE

The International Potash Institute (IPI) and the Lithuanian Institute of Agriculture(LIA) held a Regional Workshop on "Potassium and Phosphorus: Fertilisationeffect on soil and crops" in Dotnuva-Akademija, Lithuania on 23-24 October, 2000.Researchers from II countries presented 37 scientific papers which are publishedin this book. Research topics cover nutritional status of soil, trends in fertiliser useand nutrient balances, effect on yield and quality of crops. The organisers of theworkshop are grateful to all contributors and strongly believe, that this book will beof interest for a wide circle of researchers, advisors, students and managersworking within agriculture, environment, soil and fertiliser trade.Organisers of the workshop also want to express their gratitude to the sponsors ofthe workshop and this book:

Lithuanian State Science and Studies FoundationMinistry of Agriculture of the Republic of LithuaniaKutinsko firma "ARVI"UAB "Baltkalis"UAB "Kemira-Lifosa"AB "Lifosa"AB Taupomasis Bankas, Kedainiqj skyriusUAB "Agrokoncemas"

Organisers

3

CONTENTS

Adolf Krauss. Potassium, integral part for sustained soil fertility ...................... 7

lossif Bogdevitch, Galina Pirogovskaya. Problem of balanced fertili-zation and soil fertility maintenance in Belarus ............................................... 20

Gosek Stanislaw. Potassium balance and development of fertilizationand soil K status in Poland ............................................................................... 32

Stanislav Torma. Nitrogen, phosphorus and potassium balance in cropproduction of Slovak Republic in recent decade (1989-1999) .......................... 37

Janusz Igras, Mariusz Fotyma, Jerzy Kopitiski. Phosphorus balancein Polish agriculture .......................................................................................... 43

Stanislav Torma. The mineral fertilisers consumption and main cropsyield in Slovakia in 1989-1998 ........................................................................ 50

Andrzej Sapek, Stefan Pietrzak. Potassium and phosphorus farm-gatebalance in livestock farms as a basis for fertiliser recommendation .................. 56

Barbara Sapek. Potassium and phosphorus balance in a long-termgrassland experim ents ....................................................................................... 61

Jonas Ma'vila, Jonas Arba iauskas, Zigmas Vai~vila,Tomas Adomaitis. The need of agricultural crops for potassium fertili-sers in Lithuanian soils .................................................................................... 69

Anne Falk Ogaard. Ability of some Norwegian soils to supply grassw ith potassium ....................................................................................................... 77

Jfinis Vigovskis, Aivars Jermugs. Balance of phosphorus in soil at longapplication of fertilisers and lim ing .................................................................. 81

Zigmas Vai~vila, Kristinas Matusevi ius, Jonas Malvila,Leonas Eitminaviiius. Amount of phosphorus in the soils of Lithuaniaand its role in optimization of agricultural crops nutrition ................................. 85

Liudmila Tripolskaja. The influence of organic fertilizers on phosphoricregime in the soddy - podzolic sandy loam soil ............................................... 92

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Natalia Mikhailovskaia, Larisa Jurko. Influence of potassium andphosphorus fertilizers on biological nitrogen fixation efficiency ...................... 98

Augra Arlauskien6, Stanislava Mailjttnien6. Effect of variouspreceding crops on the accumulation of phosphorus and potassiumin a heavy loam soil and cereal yield ................................................................... 103

Benediktas Jankauskas. Efficiency of phosphorus and potassiumon the acid and lim ed dytric albeluvisols ............................................................. 110

Vincas Kup~inskas, Audrius Stogkus. Effect of N, P and K fertilisercombinations on the productivity of the crop rotation and soil properties ............ 118

Henning Hogh-Jensen and Jan K. Schjorring. Shoot nutrient indicesas indicators of nitrogen, phosphorus and potassiuf deficiencies in grassland....124

Stephan Gorbanov, Svetla Kostadinova. The effect of phosphorusand potassium fertilization on the yield and grain quality of winter wheat .......... 132

Alfonsas gvedas, Zofija Jankauskient. The relationship betweenavailable phosphorus and potassium concentration and flax yield andeffi cacy of phosphorus fertiliser ........................................................................... 138

Alfonsas Svedas, Daiva JanugauskaitO. Rye yield in relation to PKfertilisation and their content in the soil ............................................................... 145

Peteris Berzins, Aija Antonija, Skaidrite Bumane. Effectivenessof phosphorus and potassium on pastures depending on their content in soil ....... 153

Vladislav B. Minin and Anatoly Osipov. Impact of liming and soilreaction on crop's P and K accumulation from acid soil ...................................... 157

Virgilijus Paltanavi~ius, Vytautas Liakas, Giedrius Narkevi ius,Albinas Siuliauskas. Comparison of the efficiency of the differentform s of potassium fertilizers .............................................................................. 160

Annbjorg Overli, Bernt Hoe[ and Bjorn Molteberg. Grain yieldresponse of spring barley to seed placed phosphorus and nitrogen in Norway..... 164

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Virgilijus Paltanavi~ius, Arnoldas tepeM, Vytautas Liakas,Albinas Siuliauskas. Comparison of the efficiency of differentform of phosphorus fertilizers .............................................................................. 166

Ramdane Dris. Influence of phosphorus nutrition on fruit crops quality ............ 170

Dalia Feizien . The influence of fertilisation on different backgroundsof soil tillage on amount and concentration of phosphorus in grain production ... 175

Ona Bundinien6. Nutrient changes in crop production and soil withapplication of different cropping system s ............................................................ 181

Antanas Antanaitis, Jonas Maivila, Jadvyga Lubyt6,Zigmas Vai~vila. The interrelation of the amount of potassiumdetermined by different methods in glacial lacustrine soils of Lithuania ............. 187

Irena Krigtaponyt6. Effect of fertilisation systems on the balanceof nutrients and soil agrochem ical properties ....................................................... 195

Livija Zarina. Soil potassium and phosphorus in different croprotation by influence of fertilisation system ......................................................... 202

Sigitas Lazauskas, Vytas Magauskas. Prospects of balancedpotassium and phosphorus fertilisation in Lithuania ............................................ 206

Panasin V.I., SIobozhaninova V.D., Novikova S.I. Agrochemicalaspects of the dynamics of phosphorus in soils of Kaliningrad oblast .................. 212

Jonas Gutauskas, Alvyra Slepetiene. Long term effectsof potassium and phosphorus surplus in pasture ecosystem ................................. 218

Virgilijus Paltanavi~ius. Influence of multi-nutrient fertilizerson the yield and quality of spring barley and rape ................................................ 223

Anne-Kristin Loes, Hugh Riley, Sissel Hansen, Steinar Dragland.Chopped clover mulch in organic vegetable production contains largeamounts of easily available P and K .................................................... 227

6

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

POTASSIUM, INTEGRAL PART FOR SUSTAINED SOIL FERTILITY

Adolf KraussInternational Potash Institute

More people need more and better food, but land and water become scarceThree major challenges confront future agricultural production:* a continuously growing global pojulation needs more food, i.e. it requires higher

production;" increasing urbanization demands more food in general and more meat, vegetables and

fruits in particular, i.e. more diverse diet and thus a diverse crop spectrum;" higher purchasing power of the urban population will ask for better quality.Concerning the future demand for food, experts expect that the global demand for cerealswill grow till 2020 to 3.4 billion tons. However, production of cereals will increase fromcurrently 1.87 billion tons only to 2.59 billion t in 2020 (Rosegrant et al., 1995), whichleaves a gap of about 0.8 billion tons. Demand for meat is expected to increase fromcurrently 160 million t to 280 million tons in 2020. Most of the demand will occur indeveloping countries. In this context, the area with vegetables and fruits increased forinstance in China 4 and 8 times, respectively, which reflects the driving demand fromurbanization. In contrast, the area under cereals remains almost unchanged.Most of the projected increase in crop production has to come from higher yields and lessdue to area extension because land reserves to cultivate crops are almost exhausted,especially in Asia. To the contrary, loss of land for urbanization, industrial purpose andcivic needs will continue, leaving less land for crop production. The global per capitaavailability of land will further decrease from currently 0.24 ha to 0.17 ha within the next20 years, in Asia from 0.15 ha to merely 800 m2 .Assuming that the global area with cereals remains fairly constant at around 700 millionha, it would imply that the global cereal yield has to be increased from currently 3 t/ha toalmost 5 t/ha within the next 20 years to match the expected demand. However, if, asshown in figure 1 the current trend in cereal yield persists it will fail to achieve the goal of5 t/ha in 2020. There are considerable regional differences in cereal yield. The EuropeanUnion (EU) is well above the global average. Cereal yields in Central Eastern EuropeCEE developed fairly well before the economic reform but experienced a substantialsetback during the post-reform period. The same applies to the former USSR whereby theyield in Lithuania lately increased in contrast to Russia, which shows a rather drasticdecline.Fertilizers feed the world, but fertilizer use went out of balanceIn general, there is a fairly good relationship between fertilizer use and crop yield,because 35-40% of the yield increase can be attributed to fertilizer (Figure 2). Numerousfield trials of FAO and the fertilizer industry showed that with one kg fertilizer, grainyield of cereals increased by about 10 kg/ha. However, fertilizer use went out of balancewith respect to the ratio between the applied nutrients and the balance between input byfertilizers and nutrient output by crops. This refers in particular to potassium.

7

Figure 1: Regional cereal yieldshistoric evolution and current trend

required yieldgrain yield tlha to meet future demand

EU(15)

5

4 N o"CFE3 rc

c rrre

rend

global Mo- 7FLt

1 USSR -Russia

0 1 1 1 11960 1970 1980 1990 2000 2010 2020 2030

cere. 070500 year data ase FAOSTAT '98

Figure 2: Relationship between regional fertilizer useand cereal yield

mean 1996-98 total NPK use by crops; cereal yield

grain yield tlha

6 5 WEu

EAsia

3 C gCAmn

Oceania. sla SAsia

0 50 100 150 200 250NPKuse18 o300 kglha NPK

FAOSTAT98

Considering the global fertilizer use, it shows that use of N is steadily increasing. Incontrast, P and K use in particular lags seriously behind at a level still lower than thatachieved 10 years ago. In consequence, the NK ratio depreciated from 1:0.4 in the earlyeighties to currently 1:0.27 (Figure 3). On the other hand, a good crop absorbs about 100-200 kg/ha N, 40-80 kg/ha P205 and 100-400 kg/ha K20 (Gething, 1991). This means thatplants take up potassium in the same or even higher quantity than nitrogen.

8

Figure 3: Evolution of global fertilizer use

million t nutrient NK ratio (N=1)90 0.5

N 0.470

60 ,. NK ratio- 0.3

40 P205 0.2

30 - -0.1A

20K20

10 1'' . . . 01 1182 85/86 89190 93194 98199

WKun01 FAO 20002O0

Most of the growth in N use happens in developing countries, To the contrary, fertilizeruse in developed countries decreases due to economic constraints, set-a-side programsand ecological considerations. In West Europe for instance, use of N declined since thelate eighties by about 13%, and P and K use by about 30%. Even worse is the situation inCentral/Eastern Europe and the countries of the Former Soviet Union, FSU (Figure 4).Fertilizer use in this region almost collapsed after the economic reform in the early 90ies.A quick recovery to a pre-reform level appears to be less realistic when the currenteconomic situation of the farmers prevails, i.e. lack of funds, unclear land titles, lack ofadvice.

Figure 4: Fertilizer nutrient consumptionFormer Soviet Union, FSU

historic and projected consumption

million t nutrients14

12

2

081102 85186 8990 93/94 989100' 02/03

"prefiminary figureIFA 2000

9

Within the Baltic States, Lithuania has currently (1998/99) the highest fertilizerconsumption of around 140'000 t with the closest NK ratio of 1:0.46, followed by Latvia(35'000 t and NK 1:0.33) and Estonia (32'000 t and NK 1:0.12).Nutrient balance in FSU became negativeThe change in fertilizer use had a considerable impact on the nutrient balance. During thepre-reform period, use of N, P and K in the FSU exceeded substantially the removal bycrops (Figure 5). This indicates build-up of soil fertility. Currently, it appears thatfertilizer use irrespective to the nutrient is far below the nutrient removal by crops. Thenutrient balance became strongly negative in the post-reform period, indicating heavilysoil nutrient mining. This refers to all 3 major nutrients.

Figure 5: Fertilizer use in relation to nutrient removal by cropsFSU

mean of 3 yearsmillion t million t million t

N P205 K207_

fertili..r ..

t I-- t

bI

2 2

*35 0 *5 60 65 65 70 75 *0 55 60 05 65 70 75 *0 *5 0 05000 data source: FAO

The current situation in the Baltic States is comparable to those for the whole FSU. InLithuania nutrient removal by crops exceeds use of fertilizers to arable crops by 35,000 tin N, 2 F400 t in P2O5 and 25'200 t in K20. This indicates soil mining for all 3 nutrients.The situation in Latvia and Estonia is similar to Lithuania.The post-reform fertilizer use pattern in Central/Eastern Europe compares very much withthe situation in FSU. Vostal (1997), calculating the balance for arable land of the CzechRep., show for the period of 1991-95 for all 3 major nutrients a negative balance of -10.2kg/ha N - 13.6 kg/ha P205 and even - 51.2 kg/ha K20. The share of organic manure on thenutrient input in Czech Rep. increased in the last 10 years from 40 to 67%. However, atthe same time, the K content of manure decreased from 4.40 to 4.14 kg K20/t in cattleslurry, from 2.40 to 1.48 kg/t in pig slurry and from 3.97 to 3.37 kg/t in poultry slurry. Thereason is seen in changes in the livestock management and feeding technology, but usingfeed with lower K contents due to less potash use cannot be excluded.Soil K is subject to dynamic processesSoil K is partitioned into 4 major fractions: (i) K contained in soil solution, (ii),exchangeable or readily available K, (iii) the non-exchangeable fraction, and (iv) thelattice K or reserves (Figure 6). All fractions are interrelated through exchange processes.Soil K removed from solution through plant uptake or leaching is replenished with K

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desorbed from the exchange sites. Adding K with fertilizers initiates the reverse process,namely absorption of K.

Figure 6: K dynamics in soilsK input

fertilaer simplified modelK manture

uptake , a

K In soill et~mn, e

solutionr

eslly .fract , 1 ,

a vble available available

Kleaching Knuss 0498

un50199

The nutrient requirement of a good crop is considerable. Maximum uptake occurs at thefinal harvest for N and P, but for K during anthesis at the peak of vegetative development.Johnston et al. (1998) summarized daily uptake rates of a range of crops from thetemperate zone and show that the daily uptake varies around 5, 0.5 and 5 kg/ha for N, Pand K, respectively. To provide 5 kg K per ha and day by diffusion to the roots, therequired K concentration in the soil solution should range in moist soils from around 100pM in light soils to 200 pM in heavy soils. The drier the soil and the less dense the rootsystem, the higher is the needed K concentration (Figure 7). Winter wheat has a maximumroot length density of 12.2 cm/cm3 , sugar beet and potato of 2.6 and 1.9 cm/cm 3,respectively. Therefore, the latter needs a better K supply than cereals.

Figure 7: Soil K concentration needed in soil solutionto sustain an uptake rate of 5 kg K per ha per day

as affected by root lenght density, soil texture and soil moisture

uM Kin ubjM K .MIktm, A K.asiaa

7.0 450 3

a) rot length density b) sol texture C) soil moistuire80eeczs se

4WO 300 'C03:0 - 5C

acee

3 3 150

Lv iJHOt"

0000 after JOH4N$TON at *1., 199

II

Mobility of K in soils depends on diffusion and is restricted to a few mm. By removing Kfrom soil solution, the plant root creates a concentration gradient. K moves along thisgradient to the root surface. The steeper the gradient, the better is the diffusive flux of K.With increasing K supply the diffusive flux of K in soil solution increases as well (Gdth,1992). As shown in figure 8 the K flux also improves with the soil moisture. On the otherhand, a generous K supply can to certain extend compensate less diffusive K flux in driersoils. Furthermore, heavy textured soils have a lower flux rate than light textured soils,i.e. they require a higher K supply for the same flux rate. With depletion of theexchangeable fraction, the K release rate from this fraction decreases as well (table 1).This restricts the replenishment of solution K. There is also a substantial decrease in theK release from the non-exchangeable or slowly available fraction. K uptake of plants andthus plant growth declines rapidly with decreasing K release (Cheng Mingfang et al.,1999). Also Grimme (1974) showed, as the contribution from non-exchangeable Kincreases, the yield declines.

Figure 8: K diffusive fluxes ays affected bysoil water content and the K status of the soil

K flux rate ug Kfcm2Id140

120

10 45 Vol % water

80

25 Vol %

....... -40 -- m -,a ' - -

2014 Vol %

5 10 is 20 25 30 35

K content mg K201100 g soil*oIOT after OATH, 1992

0199

Table 1: K release and K adsorption of soils as affected bycropping intensity

selected soils from North China

cropping exch K release non-xch release K adsorptlointensity mglkg rat. exch K rate adsorbed n rate

K mg/kg non-exch mg/kg mg/kgmminmglkgmin K

mg/kg/min

low 171 9.4 314 0.52 608 1.46

medium 144 5.1 87 0.14 1276 2.07

high 164 4.8 60 0.10 1818 2.75

.i9 after Cheng Migfang i aL., 1999

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Furthermore, depleted soils possess a much higher K fixation capacity than soils wellsupplied with K (Tributh et al., 1987). To rehabilitate K depleted soils is costly.Experiments with Indian soils showed that it requires up to 5 times more units of K toincrease the soil K by one unit in contrast to soils with a good K status where 1.2 units ofK was enough to increase the soil K content (Srinivasa Rao & Khera, 1995). This alsoindicates the consequences for the soils in CEE and FSU if the insufficient K supplycontinues.Potassium is the key nutrient in yield physiologyPotassium is a versatile nutrient involved in plants in many metabolic processes such asenzyme activation, osmotic control of the water economy, carbohydrate production andpartitioning and the anion/cation balance. K has a motor function in cycling nutrients forgrowth, i.e. nitrogen from the roots to the shoot and carbon from the source (shoot) to thesink (roots, storage organs like grains, tubers). K travels as counter-ion together with NO3in the xylem to the shoot (Marschner ct al., 1996). Lack of potassium however, restrictsthe NO3 transport, which leads to nitrate reduction in the roots and accumulation of aminoacids (Figure 9). This may signal via a feedback effect to the root to restrict further Nuptake, which in turn lowers the N fertilizer use efficiency. More N remains in therhizosphere that might be leached or volatilized. The plant cannot be forced to take upmore N ifK is in short supply-

Figure 9: K nutrition and nutrient cycling in plants

good yield and quality poor yield and quality

rapid N metabolism C accumulation

K+C1 K+Cj

K+lJ K-J

quick N transfer N-accumulation-

efficIen N uptake restricted N uptakeat at

adequate K supply insufficient K

rfnlO1 after MARSCHNER at al., 1996

Insufficient K supply prevents full exploitation of yield potential of cropsThe benefit of balanced fertilization on crop yield and thus, farm income is welldocumented. Results from more recent trials of the IPI program in Central/Eastern Europeshow for instance:* Up to 36% higher potato yields in Poland with balanced fertilization including

NPK+S+Mg compared to NP (Figure 10).* 8% higher beet and up to 17% higher sugar yield in Czech Rep. with NPK+S+Mg.* 18% higher beet and 20% higher sugar yield in Hungary (NP versus NPK+Mg+S).

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* 29% higher yield of beans and 11% higher yield of potato tubers in Bulgaria.* up to 23% higher yields in maize, 8% in sugar beet, 29% in potato and 18% in tomato

with NPK in Romania.* 51% higher wheat yield and Rb 761/ha more income in Russia with NPK.

Figure 10: Effect of balanced fertilizationon yield of potato tubers

IPI trials Poland 1999tuber yield tlha

40

38 - NPK+S+Mg

36 -

34 ,, .-

32

KO 80 160 240

kglha K20 IPI Reportpot.to03 20000300

As indicated earlier, the response of a particular crop to potassium varies with genotypicaldifferences in the root characteristics and thus the spatial soil exploitation.The genotypical differences in root length density also imply that the losses in opportunityyield at declining soil K status is larger in leafy crops than in cereals. Kerschberger &Richter (1987), summarizing results from 650 field trials in Germany, found that at thelowest levels of exchangeable K, root crops lost 38% and grain crops 18% of potentialyield (Figure 11).The value of lost opportunity yield due to unbalanced fertilization is considerable.Nikolova & Samalieva (1998) estimate that the economic loss for Bulgaria amounts toapproximately 135'000 t wheat, 28'000 t maize and 53'000 t sunflower seeds or theequivalent of almost 30 million US$ in local prices. Prokoshev (1998) calculated for 17administrative regions of Russia a loss of some 1.24 million t cereals, 150,000 t sugar beetand about 300'000 t potato tubers due to omitting of potash or the equivalent of 680billion roubles (prices for 1996).Potassium is the quality factor in crop productionThe involvement of K in quality formation can be seen in its function to stimulatetransport of soluble assimilate such as amino acids and sugars to storage organs likegrains, tubers, roots and to activate its conversion into starch, protein oil/fat, vitamins, etc.This pivotal role of K is irrespective to crop type and region where the crop is cultivated.

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Figure 11: Loss in opportunity yield at different levels ofsoil K status

lost yield opportunities (%)100

s0 -leafy crops-

70

60 advancing soil K mining -60very high high adequate low very low

soil K statusafter KERSCHBERGER & RICHTER, 1987

Some examples from the IPI program:" Farmers in India report a 10-15% premium in procurement price for wheat and

soybean with potash because seeds are more bold and shiny. At the same time,balanced nutrition with potash increased the protein yield in wheat by 37.5%.

" Balanced use of potash in India more than doubled oil yield in rape seed, andincreased by 38% in soybean and by 57% in groundnut.

" Potatoes in Poland had a 47% higher starch yield at balanced fertilization." Green tea in China receiving K, especially in combination with S and Mg, had a

higher content of amino acids and caffeine and thus a better quality than at the NPcontrol. A comparable effect was observed in the content of aromatic components inoolong tea and in black tea (Wu Xun et al., 1997).

" Cabbage and carrots in Russia not only had higher yields at balanced fertilization, thestorage loss was considerably reduced as well.

* Up to 17% higher sugar yield with sugar beet in Iran (Tehrani & Malakouti, 1997).* And last but not least, sugar beet in Hungary responded very well to potash with

respect to root yield, sugar content and sugar yield. Addition of S and Mg to NPKincreased yield and quality furthermore (Figure 12) (Kulcsar & Debreczeni, 1997).

Concerning beet quality, OEHLUND (1999) calculated that to produce one ton of sugarfrom low quality beet, e.g. 80% extractability and 13% sugar content as typical ofunbalanced fertilization, would need around 10 t of roots. But with high quality beethaving 95% extractability and 17% sugar content, less than 7 tonnes would suffice. Thesaving in energy required to transport and extract 3 t less high quality beet is obvious.

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Figure 12: Effect of balanced fertilization with potashon yield and quality of sugar beet in Hungary

mean of 2 locations

beet UhN % sugar (adjumted) sugar tha

80 15 10

145

70

14

60 13.5 -a

13

50 -7

40 125 6NP NPK NPK+S~g 12 NP NPK NPK+S+Mg NP NPK NPK+S+Mg

beetl01 from KULCSAR & DEBRECZENI, 1997

Potassium is the crop insurance against yield loss on adverse soil and climaticconditions. Early wilting at drought is typical for K deficiency. Inadequate stomataregulation restricts the photosynthesis and ultimately yields. Wyrwa et al. (1998) found inPoland that yield of triticale grown on K depleted soils under drought conditions lost morethan 50% yield. Application of 100 kg/ha K20 increased the yield to a level, which was onlyabout 17% less than the yield of plants well supplied with water (Figure 13). Thebeneficial effect of K can be ascribed both to improved K mobility (higher K flux) in thesoil and control of the water household of the plant.

Figure 13: Effect of potassium supply on yield of triticale asaffected by drought (Wyrwa etal, 1998)

results from Poland

grain yield tha10

optim.m drought

6

4

2

00 100

K supply kg/ha K(20from WYRWA et al., 1998

16

Plant receiving inadequate K show often frost damage, which, at the cellular level, isrelated in some respect to water deficiency. The results from Grewal & Singh (1980) thatfrost damage of the foliage of potato is inversely related to the K content of leaves refer tothis relationship.... and potassium strengthen the plant to resist to pests and diseasesThe NK ratio plays a particular role in the host/pathogen relationship. Perrenoud (1990)reviewed almost 2450 literature references on this subject and concluded that the use ofpotash decreased the incidence of fungal diseases in 70% of the cases. The correspondingdecreases for other pests were bacteria 69%, insects and mites 63% and viruses 41%.Simultaneously, K increased the yield of plants infested with fungal diseases in 42% ofthe cases, with bacteria in 57%, with insects and mites in 36% and with viruses in 78%(Figure 14).

Figure 14: Effect of potassium on pests and disease incidenceand yield

yield increaselless Incidence (%)150

yield

100

50 M

0

,incidence ,

-100fungal bacteria pests viruses

from PERRENOUD, 1990

Probable explanations for the beneficial effect of K on the host/pathogen relationshipfocus on the following mechanisms:* At insufficient K and/or excessive nitrogen, low molecular soluble assimilates like

amino acids, amide and sugars accumulate in the plant cells. Correspondingly,Noguchi & Sugawara (1966) found in leaf sheaths of rice that the content of soluble Nincreased from 0.18 at adequate K to 0.45% at NP only. Similarly, soluble sugarincreased from 1.52% to 2.43% at NP. The concentration of soluble assimilates in aplant cell is an important factor for the development of invading pathogens such asobligate parasites to complete their life cycle. The host cell must survive the invasionby the parasite if the latter is to develop. Ample N and low K supply such anenvironment, i.e. longevity of cells, high turnover of assimilates and high content oflow molecular organic compounds.

17

o The NK ratio in fertilization affects also the host's anatomy and morphology. As ageneral observation, plants excessively supplied with N have soft tissue with littleresistance to penetration by fungal hyphae or sucking and chewing insects. Excessivegrowth due to unbalanced N supply can also create microclimatic conditions, forinstance lodging cereals, favourable for fungal diseases. Insufficient K causes a paleleaf colour, which is particularly attractive to aphids, which not only compete forassimilates but transmit viruses at the same time. Wilting, commonly observed with Kdeficiency, is another attraction to insects.

" As a 3rd possible mechanism seems that insufficient K and/or excessive N affects thehost/pathogen coincidence. Changing the growth dynamics through inadequatefertilizer management can keep host plants longer in a susceptible growth stage, whichgives invading pathogens a higher chance to attack the plant.

ConclusionThe particular behavior of potassium in soil as a fairly immobile nutrient depending ondiffusive and exchange processes and its versatility in the plant deserve more attention inmanaging the nutrient supply of cultivated crops. However, the "discreet" action of K, i.e.the absence of spectacular effects on yield when omitted earmarks the nutrient as the oneto be sacrificed first at economic shortcomings like currently in FSU and CEE. Lack ofprice incentives for higher crop quality as often observed, support this unacceptableattitude. Soils, especially those with a good texture may buffer insufficient K fertilizationfor a while by replenishing solution K with K from the non-exchangeable or slowlyavailable reserves. But, with continuous soil K mining as observed in FSU and CEE, thesoils exhaust on K reserves. Unbalanced nutrition as widely practiced mines the soil, itdeprives the soil's capacity to buffer adverse conditions and ultimately, it is a threat to theenvironment. The declining replenishment from K reserves of course restricts yieldformation as explained earlier.Agriculture in the Baltic States and in CEE is too important to their economies to beneglected. It contributes 7% to the GDP (EU 1.7%) and employs 22.5% (EU 5.1%) of thetotal work force (figures for 1996, Agrafocus, 1998). Also in view of the intendedmembership in the European Union, the agriculture in this region has to be productiveand competitive but based on sustainable soil fertility. Unbalanced nutrition with respectto nutrient input and output and also with respect to the ratio between the nutrients cannotsupport sustainability. There is need to change the political frame for agriculture towardsa better price/cost ratio in production, access to credits, etc. to enable the farmers toreplenish with fertilizers the part of soil fertility removed with the harvested crop. Thereis also need for education not only to improve the knowledge of the farmer but also toinform politicians and decision-makers on the consequences of continuous soil nutrientmining due to unbalanced fertilization.

References1. Agrafocus (1998): The monthly report for European agribusiness executives. November 1998,

Belgium.2. Cheng Mingfang, Jin Jiyun and Huang Shaowen (1999): Release of native and non-

exchangeable soil potassium and adsorption in selected soils of North China. Better CropsInternational, Vol. 13 (2), pp. 3-5.

3. FAO: Food and Agriculture Organisation, Rome, Italy, Production Yearbooks, FertilizerYearbooks, several issues.

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4. Gath, S. (1992): Dynamik der Kaliumanlieferung im Boden. Report of the Institut forLandeskultur, Justus-Liebig-University Giessen, Germany.

5. Gething, P. (1991): Potash Facts. 123 pp. International Potash Institute, Basel, Switzerland.6. Grewal, J.S. and Singh, S.N. (1980): Effect of potassium nutrition on frost damage and yield

of potato plants on alluvial soils of the Punjab (India). Plant Soil 57: 105-110.7. Grimne, H. (1974): Potassium release in relation to crop production. In: Proc. 1 0 th Congress

Intern. Potash Institute, Budapest, Hungary, pp. 131-136.8. IFA (2000): International Fertilizer Industry Association Paris, France9. Johnston, A.E., Barraclough, P.B., Poulton, P.R. and Dawson, C.J. (1998): Assessment of

some spatially variable soil factors limiting crop yield. Proceedings No. 419, TheInternational Fertilizer Society, York, UK.

10. Kerschberger, M. and Richter, D. (1987): Neue Versorgungsstufen (VST) fur den pflan-zenverfligbaren K-Gehalt (DL-Methode) auf Ackerbbden. Richtlinien der Dflngung 1I, 14-18.

11: Kulcsar, L. and Debreczeni, K. (1997): Einfluss der Kali- und Magnesiumdolngung aufErtragshohe und Qualitat von Zuckerriiben. IPI Report, preliminary results.

12. Marschner, H., Kirkby, E.A. and Cakmak, 1. (1996): Effect of mineral nutritional status onshoot-root partitioning of photo-assimilates and cycling of mineral nutrients. J. Exp. Botany47: 1255-1263.

13. Nikolova, M. and Sanalieva, A. (1998): Economic potential of fertilizer use in Bulgaria withparticular reference to potassium. In: Proc. of the 11' Int. Symposium on Codes of goodfertilizer practice and balanced fertilization, September 27-29, 1998, Pulawy, Poland, pp.416-422.

14. Noguchi, Y. and Sugawara, T. (1966): Potassium and japonica rice. International PotashInstitute, Basel, Switzerland, 102 pages.

15. Ohlund, K. (1999): Economy of sugar beet nutrition in Central Europe. BETA-IMPHOS-IPI Workshop on 'Balanced plant nutrition in sugar beet cropping systems for high yield andquality', Budapest, Hungary, 1-2 September 1999.

16. Perrenoud, S. (1990): Potassium and plant health. IPI Research Topics No. 3, InternationalPotash Institute, Basel, Switzerland.

17. Prokoshev, V. (1998): IPI Coordinator for FSU, pers. comm.18. Rosegrant, M.W., Agcaoili-Sombilla, M. and Perez, N.D. (1995): Global food projections to

2020: Implications for investment. In: Food, agriculture, and the environment discussionpaper 5, International Food Policy Research Institute.

19. Srinivasa Rao Ch. and Khera, M.S. (1995): Consequences of potassium depletion underintensive cropping. Better crops, Vol. 79, pp. 24-27.

20. Tehrani, M.M. and Malakouti, M.L. (1997): Effects of K and micronutrients on increase ofsugar content of beets in Iran. In: Proc. IPI Regional Workshop on 'Food security in theWANA region, the essential need for balanced fertilization', Bornova, lzmir, Turkey, 26-30May 1997, pp. 220-223.

21. Tributh, H., von Boguslawski, E., von Lieres, A., Steffens, D. and Mengel, K. (1987): Effectof potassium removal by crop on transformation of illitic clay minerals. Soil Sci. 143: 404409.

22. Vostal, J. (1997): quoted by Klir, J., Vostal, J. and Lipavsky, J. (1998): Plant nutrientbalances in Czech agriculture. In: Proc. of the I th Int. Symposium on Codes of good fertilizerpractice and balanced fertilization, September 27-29, 1998, Pulawy, Poland, pp. 428-434.

23. Wu Xun, Ruan Jianyun and Wu Binghua (1997): Potassium and magnesium for better teaproduction. Tea Res. Institute Hangzhou, China, and Intern. Potash Institute Basel,Switzerland, 32 pages (Engl./Chinese).

24. Wyrwa, P., Diatta, J.B. and Grzebisz, W. (1998): Siring triticale reaction to simulateddrought and potassium fertilization. In: Proc. of the I I Int. Symposium on Codes of goodfertilizer practice and balanced fertilization, September 27-29, 1998, Pulawy, Poland, pp. 255-259.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

PROBLEM OF BALANCED FERTILIZATION AND SOIL FERTILITYMAINTENANCE IN BELARUS

lossif Bogdevitch, Galina PirogovskayaBelorussian Research Institute for Soil Science and Agrochemistry,

SummaryIt is a necessity to maintain the land productivity on the appropriate high level, due to theimportant role of agriculture in economy of Belarus. But the yield levels declined byabout 20 to 40% since the beginning of the 90's. One of the main factors for this is thesharp decline in fertilizer consumption. The present insufficient and unbalancedfertilization leads to the declining of production, poor crop quality and soil fertilitydepletion. The soil tests indicated a fall in P- and K- content on 70-75 % of agriculturalland. It is very important to prevent a reduction of soil fertility level. The application ofN, P and K fertilizers is profitable. But poor financial status of farmers is the majorobstacle for efficient use of fertilizers and manure. There is a need for development ofhelpful agricultural politics, economical and ecological relevant fertilization strategies.

Key words: nitrogen, phosphorus, potassium, soil testing, fertilizers, efficiency, cropresponse, and net return.

IntroductionThe low-yield sod-podzolic and swampy soils of Belarus are relatively poor in availableplant nutrients. Therefore fertilizer application is very important in order to meet therequirements of agricultural crops and to develop the soil fertility status. As a result of thelarge scale water engineering, liming and the intensive use of fertilizers over the period1965-1990 the productivity of arable land has increased from 1.5 to 4.3 tons per hectarein grain equivalent. The significant improvement of soil fertility status was also achieved.The transition period to market economy is accompanied with severe economicdifficulties. The economic crisis strongly affected the agricultural sector. As a result thedisparity of commodity circulation in different branches the reduction of agriculturalproduction in Belarus on gross output during the period 1991-1996 accounted for 25%.Many collective farms could not even compensate current production expenditure.Farmers were forced almost to stop the use of yield increasing means of production,especially fertilizers, plant protection chemicals and modern means of agriculturalmechanization. The lower input of fertilizers in addition with reduced livestock andsmaller amount of manure leads to depletion of soil reserves. Since 1996 there is apositive trend of a renewed increase in fertilizer use and very slow improvement ofagricultural market conditions and cropping management. But the problems of requiredagriculture production output and soil fertility maintenance still are not settled.

MethodsYield and fertilizer consumption data were collected from official statistics. Thecalculation of nutrient balance sheets (inputs-outputs) on national level has been done

20

according to the BRISSA methodic [6]. Data on soil fertility status are based on theresults of the soil test monitoring conducted by State Agrochemical Service. The soilfertility in Belarus is commonly evaluated in terms of the properties monitored every 4-5years (pH value, P20 5, K20, CaO, MgO and organic matter contents as standard practiceand also B, Cu and Zn contents as required). Economic efficiency parameters of fertilizerapplication in this paper were calculated using the crop response data of BRISSA long-term experiments and current prices of fertilizers and crop production on 01.09.2000. Theprices are given in US dollars according to official transfer rate of National Bank ofBelarus.

ResultsAgriculture plays an important role in the economy of Belarus. A share of about 27 % ofGNP is apportioned to agriculture and the share of employees in agriculture and forestryreaches about 19 % of total employees. An agriculture area about 9 mill. ha has toproduce food for 10 mill. people and for the export, to compensate the expense of theimported energy sources - gas and fuel for agricultural sector. Significant area about 0.26mill. ha, that had been extremely contaminated after Chernobyl accident, was excludedfrom agricultural use. The agricultural production is conducted on the moderatelycontaminated land of 1.35 mill. ha with "PCs deposition of 37-1480 'B"".n Some part ofthis land, 0.55 mill. ha, is simultaneously contaminated with °Sr as well (5.5 -111 kBq/n9).

The total area of agricultural land in public sector is about 7.4 million ha including 5.1million ha of arable land. The cooperative farm workers and private farmers have aboutof 1 million ha of agricultural land in a private property.The consumption of fertilizers and farm manure had been strongly declined during thetransition period. At the period 1991-95 the average amount of nutrients applied perI hectare of arable land and grassland quickly decreased. The strongest decline of Pfertilizer rates was observed in 1995 -only 12 kg of P205 per hectare of arable land and Ikg/ha on improved meadows and pastures had been applied. The low rates of N and Kfertilizers were also applied (Table 1).

Table 1. Fertilizer application in Belarus, kg/ha, manure - tlha

Meadows and pastureYear Arable land (improved)

N P205 K20 Manure N P205 K2O1981-85 76 45 95 13.3 62 14 661986-90 88 66 105 14.4 74 27 751991 85 66 111 13.0 75 31 851992 74 54 103 13.3 60 18 721993 65 34 92 12.0 56 7 641994 41 17 59 11.0 35 2 361995 29 12 44 9.2 32 I 251996 42 15 56 8.9 39 2 301997 51 23 73 8.4 40 3 361998 55 26 77 8.2 41 2 381999 51 22 84 7.9 34 2 47

Balanced fertilization, or adequate supply of nutrients from fertilizers and soil in therequired ratio, is one of the main prerequisites for efficient utilization of the fertilizernutrients. The continued high application of only one element, especially nitrogen,

21

disturbs the nutrient balance and leads to the depletion of soil P and K reserves as well asto poor utilization of the fertilizer nitrogen. The fertilizers applied in Belarus areunbalanced mainly in respect of nutrient ratio, especially N to P. The NP ratio in fertilizeruse on arable land decline in the past 10 years from a well balanced value of 1:0.75 to1:0.43. The NP ratio of fertilizers applied on grassland for the same period declined fromvalue of 1: 0.36 to 1:0.06. The fertilizers applied on grassland were strongly unbalancedin the last six years.The yields of main agricultural crops declined on 20-40% of the level of 1986-1990.Presently the average yields of cereals are around 2 t/ha, potatoes - about 11 t/ha, sugarbeets - about 28 tlha, perennial grass hay - about 2-3 tons/ha.Elaboration of an annual nutrient balance is advantageous for the control of the utilizationand losses of nitrogen, phosphorus and potassium on farms. On this basis farmers are ableto increase or reduce the amount of nutrients brought with fertilizers. The savings may beallotted to other purposes, reducing the risk of environment pollution [9, 10].The main aim of the soil surface balance is to estimate the net loading of the soil withnutrients. The nitrogen balance appears to be the most complex and difficult for objectiveassessment. It is important to calculate the most significant sources of N that has to berecorded as inputs [7]. The nutrient inputs via atmospheric deposition were calculatedusing the nutrient contents and the measurements of precipitation on lysimeter experimentof BRISSA. The annual input of nitrogen with precipitation varied from 11.0 to 60 kg/ha.A mean value of about 19.6 kg/ha could be accepted as a basis for the precipitationassessment as a nitrogen source. This experimental estimation is very close to the value oftotal N-input with precipitation for Poland (22.7 kg/ha) [3]. The mean inputs of K20 andP20 5 with precipitation may be estimated as 7.5 and 0.3 kg/ha respectively. The nitrogeninput with symbiotic N-fixation by legume rhizobial bacteria was estimated basing on theassumptions that each ton of DM yield of legume grains (pea, lupine) is equivalent tofixation of 50 kg N. The amount of N fixed by clover and clover/grass mixture wasassumed as 8 kg N per I ton of DM hay yield. Non-symbiotic N-fixation by soilmicroorganism has been supposed in average as 10 kg of N per hectare. The nutrientinputs with crop seeds per hectare were assumed as 3 kg of N, 1.3 kg of P205 and 1.5 kg ofK20. The total amount of nitrogen that was leached down significantly increased onsandy soil when compared with loess and loam soils. It was also noticed that N leachinglosses increased by increased N applications. The mean annual value of 8.5 kg/ha hasbeen assumed for the leaching N losses on arable land of Belarus. The N-losses with solidflow as result of soil water erosion are rather low - in average about 1.1 kg/ha. Theleaching losses of potassium are much higher. The mean experimental value of K2017.7 kg/ha has been estimated for leaching losses and 0.6 kg/ha for surface runoff losses onarable land. The leaching and erosion losses of phosphorous are insignificant.The nutrient balance on a national scale of arable land is shown in table 2. The nutrientinput with manure usually is calculated using official statistic data on manure applicationand the published manure characteristics [6]. The mean nutrient input with I tone offarmyard manure was considered as 3.5 kg of N, 1.8 kg of P205 and 3.2 kg of K20. Thesignificant part of the nutrient input is coming from cattle followed the pigs breeding. Themean manure loading (7.9 tons/ha) on arable land is comparatively low. It is significantlylower than the soil capacity to involve the manure nutrients into biological cycle withoutthe risk for environment. The arable land of Belarus could accept the 2-3 times highermean rates of manure in the case of good management and the even manure distribution.The total number of livestock has decreased twice since 1990. Animal density per

22

agriculture land is important for the balance between amount of animals in farm and theamount of land available for spreading manure on. The average data of animal density inBelarus is very low: 0.52 heads of cattle per hectare, including 0.21 dairy cows perhectare of agriculture land and 0.60 pigs/ha of arable land. However the animal breedingis not uniformly distributed between the farms and the agricultural districts. There aresome collective farms with high density of animal breeding, especially the farms wherethe concentration of pigs reaches up to 108 000 animals per farm with 3-5 thousandshectares of agricultural land. In such cases the manure rates could exceed about 5 to 10times the ecological friendly loading. In general 6% of cattle and 41% of pigs in thecountry are concentrated on big farms.

Table 2. Development of nutrient balance, kg/ha, on arable soils in Belarus

1986-1990 1 1991-1995 1996 1997 1998Arable land

N input with fertilizer 88.0 58.8 42.0 51.0 55.0N input with manure 50.4 41.0 31.2 29.4 28.7N balance (surplus) 40.6 23.1 14.3 17.1 27.3% of utilization 52 57 62 60 52P205 input with fertilizer 65.0 34.0 15.0 23.0 26.0P205 input with manure 25.9 20.9 16.0 15.0 14.8P2O5 balance (surplus) 58.0 27.8 7.0 12.5 15.5% of utilization 37 51 78 68 63K 20 input with fertilizer 105.0 79.0 56.0 73.0 77.0K20 input with manure 46.1 37.1 28.5 27.0 26.2K20 balance (surplus) 47.6 27.8 4.8 16.1 29.0%of utilization 59 63 75 68 58

Meadows and pastureN input with fertilizer 74.0 37.9 24.0 23.2 35.7N input with manure 2.3 1.6 1.5 1.2 3.6N balance (surplus) 45.0 24.2 12.1 13.5 20.4% of utilization 39 48 60 58 52P20, input with fertilizer 27.4 9.6 1.0 1.7 2.4P205 input with manure 1.3 0.9 0.8 0.7 1.9P205 balance (surplus) 12.1 -3.5 -10.7 -10.7 -10.1%of utilization 58 132 609 496 320K20 input with fertilizer 75:2 42.4 18.1 25.5 29.4K20 input with manure 2.2 1.5 1.4 1.2 3.5K20 balance (surplus) 16.3 4.1 -16.2 -10.5 -8.1% of utilization 71 76 130 107 100

The nitrogen fertilizer applications had been significantly decreased after 1990 and meanrates on the arable land were moderate, 42 - 55 kg/ha N in 1996-1998. The inputs ofnitrogen from manure also decreased up to two times at the period 1990-1998 due toreduced stock of animals. There is a strong decreasing trend in nitrogen uptake, whichcorrelate with decrease of crop yields in the last decade. The surplus of nitrogen in theperiod of 1986-1990 was moderate and amounted about 40 kg N pre I ha of arable land.

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At last decade the surplus of nitrogen was below 30 kg/ha N, but the utilization (recovery)fraction of nitrogen was rather low, it did not exceed 60%. The increasing trend innitrogen surplus at last 3 years, on the background of the low crop yields, pose sometreats for the environment.The total consumption of phosphorus in mineral and organic fertilizers in the followingperiod more than halved in comparison to the 1986-1990 period. Since 1996 there is aslight trend for increasing the consumption of P fertilizers. The balance of phosphoruswas positive during the all analyzed period. The phosphorus surplus strongly decreased atlast years up to 7-15.5 kg/ha P205 . The utilization fraction of phosphorus sufficientlyincreased from 37 % in 1986-1990 to 78-63 % in 1996-1998. The balance of phosphorusinfluenced the soil fertility in respect to this element. We assume that positive P balanceon arable land is overestimated due to discrepancy of statistical data of fertilizer andmanure used. Because the negative balance of phosphorous on arable land has beenrevealed by results of soil tests, which indicated a fall in available P content in the lasttesting cycles. So the negative effect of phosphorus surplus on the environment could beexpected only at some farms with high density of animal breeding in the long-termperspective.Republic of Belarus is characterized traditionally by the high level of using K fertilizers.Over the period 1986-90 the annual rate of K applied on arable land was 105 kg/ha K2Oresulting in total input 160 kg/ha and a positive balance of K20 48 kg/ha. The applicationof potassium fertilizers was reduced in 1995 up to 44 kg K20 per ha. The potassiumbalance based on statistic data was still positive - about 5 kg/ha. However the realnegative balance was revealed by results of soil tests, which indicated a fall inexchangeable potassium content in the 82 districts of Belarus at last testing cycle. Themain amount of fertilizers and almost all manure are directed to the arable land. Meadowsand pastures are very poor fertilized. In spite of lower N fertilizer inputs on grassland,the N surplus 12-20 kg/ha was calculated. The P and K budgets were negative and the fallin available phosphorus and potassium has been revealed by soil tests everywhere.The extensive testing program to monitor the soil fertility is used in Belarus. Every testingcycle has been performed using the same methodical background, which gives thecomparable results. Available P and K for plants is extracted from the soils (0.2 M HCIsolution in the ratio 1:5 soil/solution for mineral horizon and 1:50 for organichorizon).The soil fertility in respect to phosphorus was improving constantly until 1993(Table 3).The share of the soils of very low and low phosphorus classes decreased from 90.9 % ofthe total area of arable land in 1970 to 20.8 % in 1993 i.e. more than four times.Consequently the share of the soils in high and very high classes increased from 3.6 % to24.8 % respectively. Since 1994 there is a slight trend of decreasing the soil fertilitymanifested in increasing the share of poor soils (to 21.6 %) and decreasing the share ofrich soils (to 23.2 %). For a quantitative analysis the average content of availablephosphorus in soils, expressed in P205 mg/kg soil was calculated. The calculations weremade weighing the middle values for each soil phosphorus class by the percentage shareof this class in the agricultural land. The average content of phosphorus for the arableland has been decreased from 190 to 183 mg/kg soil. The decrease of P content in arablesoil was observed in 80 districts of all 118 districts in Belarus. The soils of meadows andpastures are significantly poorer in available phosphorus.

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Table 3. Development of P content in soils of Belarus

% of tested area AverageYears according to classes mg PO/kg soil P2O,

<60 61-100 101-0 151-250 251-400 >400 mAmble land

1970 57,9 23,0 10,0 5,5 3,6 771980 21,9 26,2 22,9 21,2 7,8 1241985 15,5 23,4 23,6 26,0 11,5 1411989 10,0 17,7 22,0 30,0 15,6 4,7 1731993 6,8 14,0 20,0 34,4 19,8 5,0 1901997 7,0 13,6 20,6 34,3 19,8 4,7 1881999' 7,2 14,4 21,4 33,9 19,4 3,8 183

Meadows and pasture1975 52,3 23,9 9,4 5,9 8,5 841985 43,9 26,1 13,6 10,2 6,2 921989 35,4 26,7 16,2 13,4 5,8 2,5 1081993 29,3 28,2 17,8 15,5 6,7 2,5 1161997 29,8 23,8 20,0 16,2 7,2 3,0 1161999* 31,7 25,2 19,6 15,0 6,2 2,3 110

Estimation for 45 tested districts of 118 total

Development of K status of agricultural soils is shown in table 4. It can be seen that shareof soils with very low content of available K decreased from 70.7 to 10.8% and theaverage content of K has increased almost three times for the period of 1970-1993. Butduring the last six years the negative trend of splitting soil K reserves is observed.

Table 4. Development of K content in soils of Belarus

% of tested areaYears according to classes mg K20/kg soil Average KO

<80 81-140 1141-200 201-300 301-400 >400 mg/kgAmble land

1970 70.7 19.9 5.2 2.6 1.6 671980 23.8 36.7 23.3 12.8 3.4 1371985 18.3 31.4 25.4 18.4 6.5 1561989 13.7 27.1 26.4 22.0 10.8 1721993 10.8 24.9 27.2 25.6 11.5 1821997 12.9 27.9 26.2 23.0 7.2 2.8 1751999 13.6 28.1 26.4 22.2 7.0 2.7 172

Meadows and pasture1975 53.8 24.5 9.7 6 1 59 1041985 53.3 29.5 10.5 4.8 1.9 941989 50.5 29.2 11.4 6.2 2.7 1001993 40.2 31.7 15.3 8.9 3.9 1151997 36.9 33.8 15.8 9.6 2.5 1.4 1131999 39.9 33.7 14.5 8.5 2.2 1.2 109

Fertilizer use efficiency could be markedly increased when they are applied inconjunction with organic manure. Organic manures not only improve the soil physical andbiological properties enhancing the fertilizer use efficiency but also reduce losses ofapplied nutrients. Predominantly light-textured soils of Belarus are poor in organic and

25

inorganic colloids, have poor water retention capacities and low natural nutrient content.The improvement of soil fertility requires the long-term application of organic amendments.The organic matter content in arable soils in period 1965-1975 was very low - 1.77-1.78% (Table 5). The accumulation of organic matter in soil with minimal positivebalance started from 1975 when the share of perennial grasses in cropping structure wasdoubled and reached 16.9%. The ratio of acreage of perennial grasses where organicresidues were accumulated in soil to the area of row crops where the decomposition ofhumus was higher than accumulation has increased from 1:0.5 in 1965 to 1:1 in 1975.The average rate of organic manure applied was also increased from 6.9 to 9.8 t/ha forthat period. Maximum positive O.M. balance (surplus 1.02 tons/ha per year) wasobserved in 1990, when the manure application rate reached the value 14.4 t/ha and theshare of perennial grasses on arable land increased to 25.4%. The significant amount ofpeat has been applied to soil as a component of farm manure and as organic amendmentat the period of 1975-1990.

Table 5. Organic matter balance on arable land of Belarus

1965 1975 1985 1990 1995 1999

Organic matter content in soil, % 1,77 1,78 2,04 2,18 2,26 2,29O.M. balance +/- tons/ha per year - 0,07 0,80 1,02 0,58 0,27Manure applied, tons/ha 6,9 9.8 13,3 14,4 9,2 7,9Share of peat in manure, % - 48 47 37 5 3Share of perennial grasses incropping structure, % 8,5 16,9 24,1 25,4 24,3 23,7Ratio perennial grasses/row crops 0,5 1,0 1,4 1,5 2,8 2,4Estimated share of crop residualsin O.M. accumulated, % 38 40 41 46 55 55

There was a strong decline in use of peat stuff as organic fertilizer at last decade and thesurplus of O.M. in soil balance has decreased about four times. It seems that role of greenmanure, especially perennial grass residuals in O.M. balance will be progressivelyincrease in forthcoming years.To be highly productive the soils have to be in the optimum reaction range. The valuesmentioned in the paper refer to measurements in IM KCI solution suspension. The soilacidity test data of arable land are shown in table 6.It is known that reaction values under pH 4.5-5.0 are very harmful to plants by causingthe toxicities of AL, Fe, Mn and nutrient deficiency. The share of this strongly andmoderate acid soils decreased from 66.8 to 5.6% for the period 1970-1999. Intensiveliming resulted in rising to pH range 5.6-7.0 on area of 78.7 % of arable land where thesoil reaction seems to be satisfactory for good yields of most crops.The ecological aspects should be taken also into consideration for the planning andperformance of liming. It was found that rising the pH value of sandy loam soil above 6.5and clay loam soil above 7.0 causes the deficiency of some micronutrients especially Mn.From this point of view we have about 12 % of overlimed soils on arable land. The soilreaction also influences the availability of dissolved nuclides and their uptake in plants. Itwas found in BRISSA experiments that liming of sod-podzolic soils changed pH valuefrom 5.0 to 6.5-7.0 and as result 37Cs and 90Sr contamination of perennial grassesreduced about 2 times. It is known, that liming may reduce radionuclides transfer in 3 and

26

more times on highly acidic soils (pH = 4.0-4.5). In general the main share of arable andmeadowland of Belarus have the soil reaction pH close to optimum values. The limingwith minimal rates of dolomite should be continued to maintain the optimal range of soilreaction.

Table 6. Liming influence on the soil reaction of arable land

% of tested area CaCO3Years according to classes of soil pH (KCI) applied, 106

<4,5 4,6-5,0 5,1-5,5 5,6-6,0 6,1-7,0 > 7,0 tons per year

1970 33,2 33,6 16,2 7,9 9,1 3,11975 20,2 29,2 20,6 12,5 17,5 5,81980 9,4 21,4 24,8 21,4 21,0 2,0 5,31985 5,4 14,4 23,3 26,9 27,8 2,2 5,51989 3,2 8,6 17,9 29,0 38,6 2,7 5,21993 1,9 6,3 15,6 29,5 44,2 2,6 3,31997 1,4 4,5 12,8 27,5 50,7 3,1 2,61999" 1 ,3 4,3 12,5 27,1 51,6 3,2 2,3

* Estimation for 45 tested districts of 118 total

The K-fertilizer application system in combination with NP-fertilizers, manure and liminghas. been elaborated on soils contaminated after Chernobyl accident [4]. Theeconomically and ecologically acceptable rates of potash were found to ensure the stablelevel of soil fertility and minimization of the radionuclides uptake in crops and pastures.It was found, that for wheat grain yield on soil with optimal level of exchangeablepotassium supply, sufficient dose of K20 was 90 kg/ha. At the same time the increase ofK fertilizer dose from 90 to 120 kg/ha results in decrease of caesium-137 specific activityof grain on 30 %, and strontium-90 on 24 %. There is a reverse correlation betweenradionuclides and K content in grain. The most reliable reverse correlation (R= 0.92) wasfound between the K content and radiocaesium activity in wheat grain (Fig.).

6,0 -y=-17,8K+14,8

g 40____ R=492S4,0I--

0,0-

0,5 0,6 0,6 0,7 0,7 0,8

K-content in grain, %

Figure. Relationship between K content and "Cs accumulation in wheat grain

The correlation coefficient between the potassium content and 'Sr activity of wheat grainwas significantly lower (R= - 0,47). The application of balanced NP-fertilizers incomplex with higher K rate has ensured a decrease of radiocaesium uptake on 58 %,radiostrontium - on 38 %. Thus, the optimization of winter wheat nutrition providessufficient response to fertilizers and reduction of radionuclides accumulation.

27

The recommended fertilizer rates were differentiated for various soil types, levels ofK-content and density of land contamination. The final K20 soil content achieved 200-300 mg kg- ', resulted in decreasing the ..7Cs content in agricultural production in 1,5-2,5

times and the °Sr content - in 2 times [1]. Soil fertility status provides considerableinfluence on the 9°Sr transfer from soil to plants, as seen from Table 7.

Table 7. Transfer of 90Sr to perennial grasses in dependence on fertility levels of sod-

podzolic loamy sand soil (Gomel region, Khoiniki, 1997)

Soil Selected soil properties Deposition 90Sr transferFertility PH CaO I P, 0, K20 Humus of 90Sr factor

level KCI mgkg 1 % l3 q M -2 m2kg -1 10-3

Average 5.88 684 120 103 1.83 49 2.30

Good 6.28 812 500 193 2.27 69 1.44

High 6.86 980 1000 432 3.90 76 0.53

Rational fertilizer application is the significant source of farmer income and it is

profitable. The economic efficiency values of fertilizer use based on the crop responseachieved in the long-tem field experiments are given in Table 8.

Table 8. Economics of fertilizer use on sod-podzolic clay loam and sandy loam soils

Application Value of extra Net returnCrop Nutrient Cost* yield $ ha' $ ha' Per 1 $

kg ha' USD ha' invested

NitrogenWinter wheat 90 36.3 201.0 164.7 4.5

Winter rye 60 20.1 63.7 43.6 2.2

Spring barley 60 20.5 81.8 61.3 3.0

Potato 60 47.9 240 192.1 4.0

Sugar beets 90 56.0 180 124.0 2.2

Grasses (hay) 90 26.9 75.9 49.0 1.8Phosphorus

Winter wheat 60 33.9 78.0 44.0 1.3

Winter rye 40 22.1 29.5 7.4 0.3

Spring barley 40 21.2 32.0 10.7 0.5

Potato 60 49.5 150.0 100.5 2.0

Sugar beets 60 40.3 64.8 24.5 0.6

Grasses (hay) 30 14.6 12.5 -2.2 -0.2

Potassium

Winter wheat 100 13.6 84.7 71.0 5.2

Winter rye 90 10.0 36.5 26.4 2.6

Spring barley 90 8.9 38.9 30.1 3.4

Potato 120 45.6 247.2 201.6 4.4

Sugar beets 150 42.2 150.0 107.8 2.6

Grasses (hay) 90 9.1 30.4 21.3 2.3*The costs include the transportation and application of fertilizer, harvesting and storage of

extra yield with price on 01.09.2000.

28

The average unit response to N fertilizer at optimal rates and good managementbackground were: 15.3 kg of winter wheat grain, 11.8 kg of winter rye, 14.5 kg of barley,40 kg of potato, 50 kg of sugar beet and 25 kg of perennial grass hay. The average yieldresponse per I kg of P205 were: 8.6 kg of winter wheat, 8.2 kg of winter rye, 8.5 kg ofspring barley, 25 kg of potato, 27 kg of sugar beet and 12 kg of perennial grass hay. Theyield response per 1 kg of K20 were: 5.8 kg of winter wheat, 4.5 kg of winter rye, 4.6 kgof spring barley, 20.6 kg of potato, 25 kg of sugar beet and 10 kg of hay. The total cost ofnutrient application including the harvesting and storage of extra yield strongly dependedof crops. For example the total cost of application of I tone of N under winter wheat was403 USD, but for potato - 798 USD. The total expenditure for use of I tone of P20 5 wasrespectively 565 and 825 USD. The cheapest was the total cost of use of I tone of K20 -136 USD for winter wheat and 380 for potato.It is known that N fertilizer have an immediate effect on crop growth, which impressfarmers, while the immediate effect of K fertilizer usually is not visible. But it does notfollow that applying N is more profitable than applying K fertilizer. As can be seen fromTable 8, the net return per I USD invested in use of K fertilizer as high as the net returnof N fertilizer use. The profitability rate of N and K fertilizers applied on fertile clay loamsoils under winter wheat and potato was in the range 400-520 %. Phosphorus fertilizersare the most expensive, but its application is profitable in the first year of P acting for allcrops (30-130%) with the exception for perennial grasses. The crop response to fertilizersin the practice of many collective farms is significantly lower than in field experimentsdue to poor plant protection and crop management. The average rate of profitability ofNPK fertilizes use in public sector of agriculture was about 100% in 1998-1999.The various approaches are being tried to minimize nutrient losses and to increasefertilizer use efficiency. One of them is introduction of slow-release fertilizers. The slow-release concept relies on delaying the availability of soluble N to the plants until theplants have the strong root system which can compete with loss mechanisms andbiological immobilization for the fertilizer N. Two new types of urea and ammoniumsulfate had been proposed by BRISSA scientists [8]. The release rate had been tailored tothe needs of main crops, so the plants could develop in the efficient way to ensure highyields. Numeral field trials showed that yield response of cereals crop to slow-releaseurea was higher on 44-115% than the yield response to standard urea (Table 9).The leaching losses of N from the slow-release urea applied on sandy soils was on 33-47% lower than losses from the standard urea. The coating urea with cheap localmaterials like organic components from peat provides the minor difference in cost offertilizers. Thus I tone of N in slow-release urea delivered to farmer costs about 112USD, while I tone of N in standard urea costs about 95 USD. The profitability of slow-release N fertilizers, produced at Grodno plant is evident and the large-scale usage ofthese fertilizers is expected.Losses of potassium from the rooting zone of soils are a financial loss to the farmer andthe magnitude of such losses is important if it affects the quality of water intended forhuman consumption. At least potash has no known deleterious effect on the quality ofnatural waters. Even in area of intensive arable production of UK water taken from riversonly occasionally had K concentrations approaching 10 mg/I [5]. It was found in ourexperiments that losses of potassium due to leaching on sod-podzolic loamy sand andsandy soils in average for 15 years were in limits 18.6 to 33.2 kg/ha i. e. from 16.2 to29.0 % of total quantity of applied K-fertilizers.

29

Table 9. Effect of slow-release urea applied on sod-podzolic soils (1988-99)

Response,Yield on PK Crop response kg production

Crop Trials treatment, due to N, t/ha per IkgNt*ha N,0 **N, Ns, Nir

Sandy soilWinter rye, N80 4 1.67 0.30 0.66 3.8 8.2Barley, N80 4 1.09 0.39 0.69 4.9 8.6

Oat, N 0 2 1.30 0.52 0.77 6.5 9.6Potato, Ns0 3 24.30 2.60 5.40 32.5 67.5Grasses (hay), N, 20 2 5.26 1.66 1.88 13.8 15.7

Clay loam soilBarley, N, 0 2 5.16 0.40 0.72 5.0 9.0

Oat, Ngo 2 4.55 1.00 1.44 12.5 18.0Potato, N80 2 26.5 4.30 6.80 53.8 85.0Grasses (hay), N 20 7 5.64 1.90 3.06 15.8 25.5*Nst - Urea standard; * Nr - Urea slow-release.

One of the methods of K-fertilizer efficiency increase is the development and applying of

slow-release potassium fertilizers. The development of such fertilizers is carried out by

the way of addition of modifying components, some binder substances and plant growth

stimulators, mainly on the basis of natural and plant raw. The slow-release potassium

chloride showed almost doubled effect on yield increase of main agricultural crops

comparatively with the effect of standard KCI (Table 10).

Table 10. Effect of slow-release K-fertilizer applied on sod-podzolic sand soil (1990-99)

Response,Yield on NP Crop response kg production

Crop Trials treatment, due to Ko, t/ha_____ _____ per Ilk K Otlha *K,, **Ks, Kt Ks,

Winter rye 4 1.84 0.16 0.40 1.8 4.6

Barley 3 1.23 0.25 0.62 3.1 7.8

Oat 2 1.42 0.38 0.59 4.2 6.6

Potato 3 24.50 2.40 4.20 22.4 39.3Clover grass 3 16.90 1.70 4.80 18.9 53.3*K ,- KCI standard; ** K,, - KCI slow-release.

Application of slow-release K-fertilizer at the rates of 90-120 kg K20 ha " provided the

reduction of average annual losses of potassium on 40%. The production of slow-release

potassium chloride on the industrial scale seems to be promising.

The most important task in agriculture remains balanced fertilization with differentiation

of fertilizer rates that would be most suitable to crop requirements and soil tests. In the

areas of poor P and K supplies the deficiency of P and K nutrients cause yield reduction

in a short term as can be seen from the national average yields. Practically nowadays P

and K applications are intended mainly to provide annual plant needs for this nutrients.

Soil P and K build-up requirements are neglected by most of farmers.

The aim of our recommendations is to regulate nutrient balance aiming for target yields

and to increase soil fertility [2]. If soil P or K contents are close to optimum, the

30

phosphorus or potash fertilizer recommendations are calculated so as to replace thenutrients removed in targeted crop yields. For soils with low fertility status therecommendations are increased for P by 120-200% and for K by I10 to 140% of cropremoval in the rotation. Soils with above optimum P or K content should receive lessphosphorus or potash fertilizer (0-60% of crop removal).

ConclusionThe present consumption of fertilizers is insufficient, it endangers the soil fertility and itcauses the yield reduction. The one-side use of unbalanced N-fertilization results innegative effects of decreasing the reserves of available P- and K forms in soil and therebyincreasing the environmental hazards caused by N-fertilizer surplus.Scientific background to make rational choices on the doses and ratios of fertilizers to beapplied that will lead to maximum returns from their spending has been established inBelarus. To obtain the necessary crop yields and to assure that soil fertility is maintainedand gradually improved the annual fertilizer doses should be increased to about 250 kgNPK in proper ratios.Rational fertilizer application is one of the strongest sources to support the financial statusof farmers. The national policy for the subsidiary or economic stimulation of mineralfertilizer use has to be improved.

ReferencesI. Bogdevitch I. (1999). Soil conditions of Belarus and efficiency of potassium fertilizers.

Essential role of potassium in diverse cropping systems. Proceedings of Workshop organizedby International Potash Institute at the 16 World Congress of Soil Science, Montpellier,France, 20-26 August 1998. IPI, Basel, Switzerland: 21-26.

2. Bogdevitch I.M., Lapa V.V., Dembicki M.F. et al.(1993): Methodic of elaboration ofcomputer aided system of fertilization of agricultural plants. Minsk, Belorussian ResearchInstitute for Soil Science and Agrochemistry, -52 p. (Rus.)

3. FilipekT., Badora A. et al., 1999. Dynamics of the use and acidification pressure of nitrogenand N-fertilizers in Polish agriculture. Nitrogen Cycle and Balance in Polish agriculture.Falenty IMUZ Publisher, 116-125.

4. Guide for Agricultural Practice on Lands Contaminated by Radionuclides in the Republic ofBelarus for 1997-2000 edited by l.M Bogdevitch. (1997): Minsk, Ministry of Emergency ofBelarus, 76 pp. (Rus.).

5. Johnston A.E. and Goulding K.W.T., 1992.Potassium Concentrations in Surface andGroundwater and Loss of Potassium in Relation to Land Use. Potassium in Ecosystems,Proceedings of the 23d Colloquium of the International Potash Institute, 135-158.

6. Lapa V., Limantova E., RybikO. et al., 1990. Methodic of balance of nutrients calculation inBelarus agriculture. Minsk, 1-20 (Rus.).

7. Oenema 0., 1999. Nitrogen cycling and losses in agricultural systems; identification ofsustainability indicators. Nitrogen Cycle and Balance in Polish agriculture. Falenty IMUZPublisher, 25-43.

8. Pirogovskaya G.V., Bogdevitch I.M., Lapa V.V. et al.(1999): Recommendations forapplication of new types of fertilizers with biological active amendments for main crops.Minsk, Academy of Agrarian Sciences of Republic of Belarus, 28 pp. (Rus.).

9. Sapek A., Sapek B., 1993. Assumed non-point water pollution based on the nitrogen budgetin Polish Agriculture. Water Sci. Technol. 28, 483-488.

10. SapekA., Sapek B., Pietrzak S. (1997): Proposals for action aimed to abate the non-pointwater pollution as a result of agricultural sources. In: Sustainable agriculture and rural areadevelopment, IMUZ, Falenty, 55-66.

31

Regional IPI/LIA Workshop, Lithuania. 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

POTASSIUM BALANCE AND DEVELOPMENT OF FERTILIZATION ANDSOIL K STATUS IN POLAND.

Gosek StanislawInstitute of Soil Science and Plant Cultivation, Czartoryskich 8.24 - 100 Putawy. Poland

SummaryThe paper presents the balance of potassium in Poland for the years 1975 - 1997. It wasmade according to the OECD methodology, as the soil surface balance. The input are theamount of potassium in mineral and organic fertilizers, and the output data - the amountof this element accumulated in crop yield. Until 1989 the balance was positive, which wasreflected in the increasing of the available potassium content in the soils. Since 1989 yearthe balance was negative due to the dramatic decline in the consumption of mineralfertilizers and slowly decline of manure consumption. There is the lag in infuence of thisnegative potassium balance on the content of this nutrient in the soil, which since 1993year shows slight but steady decreasing trend.

Key words: Potassium balance, potassium fertilizers consumption, available potassiumcontent.

IntroductionPoland covers the area of ca 31 million ha, of which 18,5 million ha is farmland (3). Theproductive farmland supports a population of ca 38,7 million people, what made about0,48 ha per person.It seems to be quite reasonable subsistence area, but the natural farming conditions aremuch poorer in comparison to Western Europe. This is due to the prevalency of light,sandy soils, and the unfavourable climatic conditions. The agricultural landscapeoriginates from the period of glaciation. Post-glacial soils are very heterogeneous.The most common soil types in Poland are; brown soils, acid brown soils, grey brownpodsolic soils, rusty soils and podsolic soils. Much smaller area is covered by fertilechemozem soils, rendzina soils, black soils and alluvial soils.The soils classified as very light cover 31,7%, light 34,1%, medium 23,7% and as heavyones 10,5% of arable land.(2). The specific feature of the soil classification system inPoland is to distinguish so called complexes of agricultural soil usefulness (1). Thecomplex is a group of soils differing with respect to types, families and texture, whichhave similar agricultural properties, and may be utilised in a similar way. The best singlecharacteristic of the soil complex is its potential productivity expressed in the yield ofindicatory cereal species.Polish soils are commonly acid and poor in plant nutrients. Infertile and acid soils accountfor 40-60% of arable land, and only 16-34% of soils can be rated as highly fertile.(5)The most limiting factor in Poland is, undoubtedly, soil acidity, but low availablepotassium content follows suit. The poor soil fertility status with respect to potassium canbe explained by soil texture and mineralogy, as well as, by insufficient consumption ofpotassium fertilizers. As a result of combined soil and climate ratings the average value ofthe agricultural production area accounts for 57 - 64 point only (3).

32

According to the last inventory made in 1996 year the total number of farm holdings inPoland is ca 3,07 million, mostly in the private sector and only 2000 farms in public sector.67% of private farm holdings exceed I ha each, are classified as agricultural plots. Withrespect to numbers, most of the individual farms fall in the I - 7 ha category (68,2%) andonly 8,5% of farms exceed 15 ha. The average size of an individual farm in Poland isabout 7 ha.Most individual Polish farms are economically very weak. From the total agriculturalpopulation only 1/3 make their living exclusively from agricultural activity, and about30% of the farms are selling the products on the market, and the rest provide subsistencyonly. It has a big impact on the farmer's purchasing power which concerns fertilizers as well.The processes of economic transformations, which have started in 1990, also influencedcrop production. The most striking changes in land utilisation are the increase in cereals,with decrease the area under potato and fodder crops. Basic data are presented in table 1.The average crop yields in 1993 - 1997, except sugar beet, are lower than in formerdecade. The main reason is insufficient fertilizer consumption which has decreasedroughly by half.

Table 1. Land utilisation and crop production before and after the economic transformation

Characteristics Average for the years 1985 - 1990 Average for the years 1993 - 1997Area in ha*0 /or Yield kg / ha Area in ha*103 or% Yield kg / ha

Agric. area 18771 31,7 18572 30,9Grassland 4055 5490 4085 4830Arable land 14456 (100%) - 14287 (100%)Cereals 57,5 3007 59,9 2810Potato 13,9 18700 10,7 17330Sugar beet 2,9 34400 2,9 36070Oil seed rape 3,5 2490 2,7 1960Fodder crops 16,4 - 9,7others 4,8 3,7Set-aside land 1,0 10,4* global crop production in cereal units/ha

Materials and methodsThe nutrient balances in the OECD country-members are prepared according to theuniform methodology as so called soil surface balances. The input data are the amount ofpotassium in mineral and organic fertilizers from Statistical Yearbooks, and the outputdata the amount of this element accumulated in crop yield.The uptake of potassium was calculated from the statistical data concerning the area andyield of the arable crops and grassland and the research data on the content of potassiumin the plant products. Until 1977 all soils in Poland were monitored in 10 year intervalsfor the pH and the content of available nutrients, including potassium (5). The data foravailable potassium content in Polish soils were delivered by Dr Strqczyfiski and MgrBoguszewska, what made possible elaborate this publication.

Results and discussionConsumption of potassium by Polish agricultural in the years 1975 - 1997 shows Figure 1.In 1989/1990 in consequences of economic revolution in Poland the subsidy for fertilizerswas lifted, and most of the state farms simply collapsed. The consumption of potassiumfertilizers decreased by almost 75%. (4) Due to the decreasing profitability of animalproduction the stock of animals was limited and there was a serious drop in farmyard

33

manure production. The total consumption of potassium in mineral and organic fertilizersin the following years halved in comparison to the 1980 - 1989 period. In the wholeperiod 1975 - 1989 the amounts of potassium in organic and mineral fertilizers werealmost equal, but afterwards farmyard manure becomes the main source of potassium.

kgK201ba/year i manure

180

160 -mineral

140 inu140too806040

20

Figure 1. Consumpt of potassium in mineral and organicyears

fertilizers

The soil surface potassium balance (Fig.2) is calculated as difference betweenfertilizers and potassium uptake by plants. Almost constant uptake of potassium duringwhole analyzed period 23 years can be explained by conflicting processes of increasingthe individual crop yields and the changes in the share of crops in land utilization structure.

kgK20ha/year $input180 0output

140

1201008060

200

-20.40

Figure 2. The soil surface potassium balance yea"

The most striking changes in this period are:- the substantial increase in the share of cereals in the arable land structure- introducing and gaining importance since 1987 by a new syntetic species-triticale- dramatic drop in the area of potato- appearing in the last decade the fallow and set aside lands

The balance of potassium was positive until 1989 and negative thereafter. In the last decadethe integrated balance difference was minus 20 - 30 kilograms per ha per year (Fig.2).

34

The balance of potassium influenced the soil fertility in respect to this element (Fig.3).

% of soil mg K20/100Ig soil80 • 157060 .145040 133020 - I12I00 I1

"v. low, low -- high, v. High - mgK20 years

Figure 3. Development of soil fertility with respect to potassium

For the proper interpretation of the data concerning the availability indices of soilpotassium three reservations have to be made:1. The data on Figure 3 are presented as 6-year moving averages (1970-1975, 1971-1976 and

so on). The number of soil samples analyzed by Agrochemical Laboratories each yeardiffers quite substantially and therefore the moving averages are most comparable.

2. Until 1977 all soils in Poland were monitored in 10 years intervals for the content ofavailable potassium in central planning system. It was full representativness andcomparability of the results from one period to another. Since 1977 year the samplesare taken and analyzed on farmer's commitment only, and the results of analysisconstitute the base for fertilizer recommendation. The problem, is that only betterfarmers are interested in soil analysis and fertilizer recommendations. Therefore thedata are not necessarily representative for the whole country.

3. Until 1986 there-class system of soil classification in respect to available potassium contentwas in force in Poland. In this year it was decided to introduce five class system.

Both classifications are hardly comparable. It was necessary to use the special algorithmto recalculate the data from the old system to the new one, and both sets of data can be tosome extent inconsistent. Even recognizing these reservations quite consistent conclusionscan be drawn from the data presented on Figure 3.The soil fertility in respect to potassium was slowly improving until 1988 - 1993. Since1994 there is a visible trend of decreasing available potassium content. The calculationswere made weighing the middle values for each soil potassium class by the percentageshare of this class in the agricultural land.

Table 2. Soil classes for the available potassium content until 1986

C mg K 0 100'g soil for the soil categorytent Light Medium Heavy

Low Till 7,0 Till 9,0 Till 14,0Medium 8,0- 12,0 10,0- 15,0 15,0-20,0High From 13,0 From 16,0 From 21,0

35

Table 3. Soil classes for the available potassium content since 1986

Class of K content mg K20 100'g soil for the soil categoryVery light Light Medium Heavy

Very low Till 2,5 Till 5,0 Till 7,5 Till 10,0Low 2,5-7,5 5,1 - 10,0 7,6- 12,5 10,1 - 15,0Medium 7,6- 12,5 10,1 - 15,0 12,6 - 20,0 15,1 -25,0High 12,6- 17,5 15,1 -20,0 21,1 -25,0 25,1 -30,0Very light From 17.6 From 20,1 From 25,1 From 30,1Optimum consumption of potassium fertilizers in Poland has been calculated on theassumption that the whole Poland is one big, single farm managed by the educatedfarmer, who sticks precisely to official fertilizer recommention system NAW - 3. Thefarmer was supposed to grow all crops covered by Statistic Yearbook for 1996 oncorresponding areas and recorded the respective yields. The soil fertility in respect topotassium on this farm corresponds to the figures for the whole country. Substituing theseinput data into fertilizer recommendations program the optimum doses of K werecomputed for each crop and avaraged for the total area in Poland. Consumption anddemand for potassium fertilizers are presented in Table 4.

Table 4. Consumption and demand for potassium fertilizers in Poland until 2008

Consumption or demand for the yearsSpecification 1996/97 1998/99 2002/03 2007/08

Optimum consumption according 989 1002 1100 1223to NAW Kt KODemand Kt KO 376 459 605 731Demand kg K20 ha ' agricultural land 20 25 33 40Coefficient demand/consumption 0,38 0,46 0,55 0,60

Demand for K-fertilizers in 1996,97 was lower than the recommended consumption, andthe coefficient demand/consumption was only 0,38.This coefficient must increase to the target value 0,60 in years 2007/08.

Conclusions1. In the last decade due to the transformation of Polish economy, the consumption of

potassium fertilizers decreased to ca 1/3 of the previous amount.2. Soil surface potassium balance shows the serious deficit of about - 30 kg K2O/ha/year

which is reflected in the declining soil fertility with respect to K and lower crop yield.3. For balanced K-fertilization it is most essential to increase the total consumption of

potassium by 2010 to 90 kg K 20/halyear including 55 kg K20 in mineral fertilizers.

ReferencesI. Fotyma M., Gosek S.: Potassium balance elements as a basis of fertilization with this

element (In Polish) Roczniki Gleboznawcze 37 (1) 1986 P. 191 -2032. Fotyma M., Gosek S.: The soil potassium resources and the efficiency of potassium

fertilizers in Poland Country Report 1. International Potash Institute Basel. 1992 P. 3-51.3. Fotyma M., Gosek S.: Development of potash fertilizer input and the consequences for soil

fertility and crop production in Poland. Fertilizers and Fertilization Nr 1 (2) 2000 Pulawy P.7-50.4. Gosek S., Fotyma M.: Long term potassium balance in Poland. Bibliotheca Fragmenta

Agronomica T3/98. Pulawy 1998-P 443-453.5. Strqczyfiski S., Obojski 1995. Dynamika odczynu i zawarto~ci makro- i mikroskladnik6w w

zaleznotci od kategorii agronomicznej gleb. Zesz. Problemowe Post. Nauk Rolniczych 421 a.1995 P.355 -359.

36

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

NITROGEN, PHOSPHORUS AND POTASSIUM BALANCE IN CROPPRODUCTION OF SLOVAK REPUBLIC IN RECENT DECADE (1989-1999)

Stanislav TormaSoil Science and Conservation Research Institute, Bratislava, regional work station

SummaryIn the paper there is presented the nitrogen, phosphorus and potassium balance in theagricultural soils in Slovakia during the period 1989-1999 and its economicquantification. It was gone out from the amount of applied mineral and organic fertilisersand nutrients uptake with grown plants for the balance calculation. Because of variablesoil-ecological conditions of Slovakia it was no possible objective to include to thebalance the non-symbiotic nitrogen fixation and nutrient deposition with rainfall in theitem inputs and the nutrient losses with leaching and erosion in the item output. It wasfound out that nitrogen balance in agricultural soils is keeping up in the level to - 15-25 kg N.ha " in recent five years in comparison to the beginning of the nineties, when thepositive nitrogen balance reached the level 70 kg. If there is included the symbiotic fixednitrogen with legumes in the balance, the balance of this nutrient comes to the zero, e.g.nitrogen input from the fertilisers and from the air is at the same level as its output withharvested crops. Phosphorus balance is negative 10-15 kg P2O5ha -I and the greatestdeficit was reached at the potassium balance - up to 50 KO.ha" . The economiccalculation shows that approximately 750-950 Slovak crowns are lost from each hectareof agricultural soils, it means more than 2.5 milliard Slovak crowns from Slovakianagricultural soils annually.

Keywords: nitrogen, phosphorus and potassium balance; economical calculation

IntroductionThe nutrient balance in crop production provides the important information not only forthe farmers, but for the economic and ecological experts, as well. The balance is aninformation base about the soil and about potential possibilities of its next utilization.Every year comes to reduction of agricultural soils area and naturally to reduction ofarable land area, too. Therefore if there is necessary to know the nutrients movement fromthe soil and into the soil and to make the needful measures on this base to keep the soilfertility. The nutrients input into the soil with mineral and organic fertilisers and thenutrients output from the soil with the harvested crops are the most important factors ofeach nutrients balance. However, if is also necessary to remember on the soil itself and itsproduction ability. Many processes overshoot in the soil and they secure the next input oroutput of nutrients. To these factors belong nitrogen fixation, nutrients fixation into andrelease from the organic substances, potassium fixation and release with clay minerals.There is a great amount of nutrients lost by water erosion and by leaching, especiallynitrates but on the sandy soil potassium, too.It is not a simple problem to determine the objective nutrients balance. It is very difficultto fix the exact amount of nutrients in above mentioned processes. The next problem is

37

the nutrients amount which is taken up from the soil with weeds. This amount is notnegligible at present farming in Slovakia.The aim of this paper is to give a preview about the nitrogen, phosphorus and potassiumbalance in Slovak Republic in recent decade (1989-1999). In the same time we have triedto calculate the economic impact to which comes with strongly reduced mineral fertilisersconsumption.

Materials and MethodsThere were regarded the nutrients from mineral and organic fertilisers as the nutrientsinput for the calculation of nutrients balance in crop production of Slovakia. In the part ofnutrients output there were regarded the nutrients which were taken up with the main andby-product of the harvested crops.The amount of mineral and organic fertilisers were taken from the Statistic Yearbooks ofSlovak Republic in period 1989-1999. The data about the nutrients content in main andby-products and the ratio between these products were taken from the software,,N.hrstoffvergleiche" (Kerschberger et al., 1997). There was regarded 92-94 per cent oftotal agricultural area of Slovakia in various years, e.g. 2.232-2.276 mil. ha. Theremaining area (6-8 per cent) is presented by gardens, orchards, hops-gardens and by thesecrops which sown area is smaller than 0.1 per cent of total agricultural area of Slovakia.The economic calculation of nutrients balance was worked out on the base of the actualprice of mineral fertilisers in given years. There was taken the price of ammonium nitratefor the nitrogen, the superphosphate for the phosphorus and the potassium chloride for thepotash.

Results and DiscussionThe nutrients balance in crop production from the nation-wide point of view brings therelative great inaccuracy due to heterogeneity of soil and climatic conditions of the wholerepublic. Only the mineral fertilisers consumption and the reached crop yields can betaken as the correct data. The same can be not said about the organic fertilisersconsumption and about other mentioned parameters. There is the similar situation withphosphorus and potassium that get into the mean position due to various pH value anddifferent soil structure.The working-out of the nutrients balance is both a difficult and complicated process andresponsible work, too. On its results can be made many significant decisions in variousbranches of the national economy. However it is necessary to say that even at theachievement of the highest level of balance preparing it is not possible to find just it asthe only right one. There is always the supposition that there exists so many nutrientbalances how many authors.The simple nutrients balance in the crop production in the Slovak Republic (e.g. nutrientsapplied in fertiliser and farm manure less nutrients removed in harvested crops) was till 1990mostly positive. It means that there was added more nutrients into the soil than there wastaken up from the soil with harvested crops (Bielek, 1998, Torma and Jambor, 2000).After 1990 when the mineral fertilisers consumption was strongly reduced the nutrientsbalance gradually became to be negative. There is the absolute difference between thebalances in period 1989-1990 and 1998-1999 70-80 kg of pure nutrients per hectare incase of nitrogen and phosphorus but in the case of potassium the difference has reachedduring the 10 years almost 100 kg per hectare. The figure 1 presents the simple nutrientsbalance in crop production in the Slovak Republic in kg pure nutrients per hectare ofagricultural soils.

38

kg pure nutrientsper ha of farm

land8060 . ... . ON 0P205 *K20

-20 T- ---- ---- ---- ----40 - -----

-60 1

1989 1990 1992 1994 1996 1998 1999

Figure I. Nitrogen, phosphorus and potassium balance inthe agricultural soils of Slovakia

If there is appreciated the balance of individual nutrients it is evident that the balance ofall three nutrients has become worse after 1990. The highest negative influence on thissituation has the reduced mineral fertilisers consumption. The consumption has gonedown from 250 kg to 50 kg of pure nutrients per hectare during 10 years period. From this50 kg almost 40 kg is introduced by nitrogen. The relative mineral fertilisers consumptionin Slovakia during recent 10 years is presented in Table I

Table 1. The relative mineral fertilisers consumption in Slovakia (comparison 1991-1998with 1989-1990) (in %, 1989-1990 = 100 %)

1989-1990 1991-1992 1993-1994 1995-1996 1997-1998NPK-consumption 100 39.6 18.1 20.0 23.0N-consumption 100 56.7 32.5 35.2 40.4P-consumption l0 30.7 10.3 11.8 13-7K-consumption 100 27.5 8.3 9.4 10.8

The production of organic fertilisers is also endangered. The development of farm animalnumber is unfavourable (Table 2). For example the number of cattle has gone down from1.6 million to 700 thousand heads, the number of sheep from 621 thousand to the half andthe same can be said about the number of pigs. The great cattle unit per 100 hectare hasgone down from 85 to 32 during 10 years. In spite of this the nutrients balance can be sawas a acceptable balance till 1992 . However in the next years there was no increase inmineral fertilisers consumption and therefore the balance has began to fall into thenegative levels. There is relatively stable nitrogen balance on the level minus 15-25 kgand phosphorus balance on the level 10-15 kg per hectare since 1994 up till now. Theleast favourable situation is at potassium balance which reaches the negative valuesnearly 50 kg potassium per each hectare of agricultural soil in Slovakia. There is removednearly three times more potassium from the soil than there is applied into the soil withfertilisers.

39

Table 2. Evolution of farm animals number (in thousand heads)

Animal 1989 1993 1994 1995 1996 1997 1998Cattle 1623 993 916 929 892 803 705of which cows 559 386 359 355 335 310 284Horses 15 11 11 10 10 10 10Sheep 621 411 397 428 419 417 326of which ewes 357 286 279 296 284 280 159Pigs 2709 2179 2037 2076 1985 1810 1593of which sows 182 166 157 160 152 139 170Cattle number units per100 ha of farm land 85.0 43.3 40.4 40.7 39.3 39,1 31.8

There is not included the symbiotic fixed nitrogen with the legumes in the nitrogenbalance (Fig. 2). It is to see that the nitrogen balance without this nitrogen reaches aboutminus 15-25 kg per hectare during recent 6 years. The nitrogen balance including thefixed nitrogen will come to zero, e.g. nitrogen input with the fertilisers and from the air isat the same level as its output with harvested crops

kg N per ha offarm land

150 120 rOorganic fertilisers

120 ] ----------- *mineral fertilisers90 -l - ---- offlake

60

30

1989 1990 1992 1994 1996 1998 1999Figure 2. Nitrogen balance in the agricultural soils of

Slovakia

It is to seen from the Figures 3 and 4 how the phosphorus and potassium fertilisersconsumption has gone down and how the balance of these nutrients has gradually becomeinto the negative level.According to calculation of the nutrients amount that is lost each year from the soil on thefinancial expression there is gone to the sum that reaches average 2.5 milliard Slovakcrowns annually. Table 3 presents the financial expression of the negative nutrientsbalance of agricultural soils in Slovakia.From the Table 3 it is evident that we are annually poorer by 2.5 milliard Slovak crowns.However this number is not the final because in it there are not included the financiallosses caused by lower crops yields. There are also not included the nutrients lossescaused by water erosion while 55 per cent of agricultural soils in Slovakia (e.g. more than1.3 million ha) is endangered by erosion. From this area is washed into the water sourcesannually about 2.65 mil. ton of soil (Vilcek et al., 1999). According to Bedma (ex. Jambor

40

and Ilavska, 1998) there is washed away in such lost soil in average 0,5-15 kg N, 0,01-0,20 kg P205 and 0,5-12 kg K2O from each hectare. It makes for the whole republic 650-19.500 ton of nitrogen, 13-260 ton of phosphorus and 650 -15.600 ton of potassium.

kg P205 per haof fam land

120 -0 organic fertilisers

90 - ------------ mineral fertilisers

O~offake60 ---------------30

1989 1990 1992 1994 1996 1998 1999

Figure 3. Phosphorus balance in the agricultural soilsof Slovakia

kg K20 per haof famn land

1501 98 19Oorganic fe19i6isers

120 Fg 4. Ps an in th ag- mineral fertilisers

90 -- - - offtake

3 0

1989 1990 1992 1994 1996 1998 1999

Figure 4. Potassium balance in the agricultural soils ofSlovakia

Table 3. The financial expression of the nutrients balance of the agricultural soils inSlovakia in recent decade (in million Slovak crowns)

Year N P2O K20 Sum1994 844.136 528.498 981.525 2334.1591996 854.286 559.728 1229.488 2643.5031998 624.672 506.274 1111.391 2242.3371999 843.138 678.389 1225.607 2748.034

41

It is necessary to apply more mineral and organic fertilisers, to increase the sown area oflegumes, to keep the right crop rotation and to make some measures against the watererosion to avoid such huge nutrient losses. To tell the truth there are really greatpossibilities especially in last mentioned measure in Slovakia.

ConclusionThe strong reduction of mineral fertilisers consumption since 1992 has caused that thesimple nutrients balance (the difference between nutrients input with fertilisers andnutrients output with harvested crops) in agricultural soils in Slovakia has become into thevery unfavourable situation, especially in case of potassium. The potassium losses reachabout 50 kg K2O per hectare per year. The negative nitrogen balance reaches about 15-25kg per hectare and negative phosphorus balance reaches approximately 10-15 kg P2O5 perhectare. The financial expression documents that the nutrients losses from the agriculturalsoils in Slovakia reach more than 2.5 milliard Slovak crowns annually.By increase on fertilisers consumption (in both mineral and organic forms), by increase oflegumes sown area and by measures against water erosion the huge losses could bereduced.

ReferencesL. Bielek, P.: Dusik v pol'nohospodrskych p6dach Slovenska. VUPU Bratislava, 1998, 255 pp.

(in Slovak).

2. Jambor, P.-llavska, B.: Metodika protierozneho obrabania pody. VUPU Bratislava, 1998,70pp.

3. Kerschberger, M. - Franke, G. - Hess, H.: Anwenderbroschtire Dtingung,,Nahrstoffvergleiche". PC-Program f[r die Berechnung von Nahrstoffvergleichen nachDtingeverordnung. ThOringer Landesanstalt fhr Landwirtschaft Jena, 1997. Statisticalyearbook of Slovak Republic. 1989-1999.

4. Torma, S. - Jambor, P.: Hnojenie draslikom v Slovenskej republike. Country Report 2: Vyvojspotreby draselnych hnojiv ajeho dosledky pre urodnost pod a rastlinnu vyrobu v Slovenskejrepublike. International Potash Institute, Basel - Vyskumny ustav podoznalectva a ochranypody Bratislava, 2000, 64 p. (in Slovak).

5. Vilcek, J. et al.: Podno-ekologicke parametre usporiadania a vyuzivania polnohospodarskekrajiny. VUPOP Bratislava, 1998, 142 pp. (in Slovak).

42

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

PHOSPHORUS BALANCE IN POLISH AGRICULTURE

Janusz Igras, Mariusz Fotyma, Jerzy KopitiskiDep. of Plant Nutrition and Fertilization, Institute of Soil Science and Plant Cultivation

SummaryThe paper deals with the balances of phosphorus in Polish agriculture on soil surface andfarm gate scale. The maps of balances are presented on the background of the Vistula,Odra and coastal rivers catchments with using kriging method. Phosphorus surplus wasfound sustainable on the superior area of the country, however great areas of south-east,south west and central parts of Poland show negative balance.

Key words: soil surface phosphorus balance, farm gate phosphorus balance, soil fertility

IntroductionThe circulation of mineral elements originating from agricultural production is the base ofqualification of factors as a potential source of environmental pollution. The recognizingof inflow and outflow of mineral elements from farms is necessary to maintenance ofagroecosystem (3). The basic element of distinguishing of sustainability is balance ofmineral nutrients. Balance can be prepared on different levels - field, farm, regional ornational scale and by different methods. Onema (7) presents three principle methods ofpreparing of mineral nutrients balances: farm gate balance, soil surface balance andsystem- balance.In the first kind of balance nutrients contained in fertilizers, manure, forage concentrates,etc. that enter the farm via the farm gate are recorded as inputs. Further, only nutrientscontained in crops, milk, meat, manure, etc. that leave the farm via the farm gate arerecorded as outputs. The difference between recorded inputs and outputs is the nutrientsurplus or deficit, expressed in kg nutrient per ha per year. Difference between inflow andoutflow of mineral nutrients expressed excess or deficit of them and determine power ofcharge or impoverishments of ecosystem.The prime aim of the soil surface balance is to estimate the net loading of the soil withnutrients. With a soil surface balance, all nutrients that enter the soil via the soil arerecordered as inputs. The output side of the balance shows only the output via harvestedcrops. This method is recommended by PARCOM (9) and OECD (8) to executing ofinternational comparisons.System budgeting is the most detailed way of analyzing nutrient flows as farm level.Essential to system budgeting is that it analyzes both the internal nutrient flows and pools,and the exchanges of nutrients with the wider environment. The external exchanges provideinformation on the output of nutrients via both, useful produce and losses.Balances presented by different authors have often mixed character and comparingobtained results from this regard is difficult. The mixed phosphorus balance for Polandpresents Szponar at all (11). The very important principle for balance preparation iscorrect estimation of all elements, both after inflow and outflow. The general ideas ofsoil surface and farm gate balances for all macronutrients are presented in other report ofauthors (2). In this paper only the balances of phosphorus in Polish agriculture on soil

43

surface and farm gate scale are presented using methodics in many cases different thanthe paper prepared by Szponar et all (It). Final results show two versions (simplified andenlarged) of soil surface balance and one farm gate balance recommended by OECD (8).

Material and MethodsBasic part of our investigations determined estimation of 10 favoured of elements ofphosphorus balance in temporary (years 1996, 1997, 1998) and spatial frame (for areas offormer provinces). Elements of balance and the way of their calculation are introduced intable 1. The numerical elements of phosphorus balance are given as an average fromyears 1996 - 1998 only for area of all Poland (Table 2), from attentions on limitedvolume of the report. The phosphorus balances on soil surface and farm gate scale arepresented in form of maps, on background of rivers draining area of Poland to Baltic Sea,using kriging method.

Table 1. Elements of phosphorus balance

Mark Element of Methodology of phosphorus balance elements calculationI balance

Sorg Manure From model SFOM (Standard Figures handicap Organic Manures)(4), quantity of animals in groups, data from Annual Yearbooks

Smin Fertilizer Quantity of phosphorus in mineral ferilizres, data from AnnualYearbooks

S Import animal Quantity of phosphorus in imported animal products from masses ofproducts importation (data from Annual Yearbooks) and standard contents of

phosphorus in animal products (5), accounts on provinces inproportion to numbers of population.

S - Export animal Quantity of phosphrus in exported animal products as above,products accounts on provinces in proportion to quantities of animals.

S,,, Crop offtake Quantity of phosphorus uptake with crops, areas and yields fromAnnual Yearbooks, and standard contents of phosphorus in crops (1).

Sipr Import plant Quantity of phosphorus in imported vegetable products from massesproducts of importation (Annual Yearbooks) and standard contents of

phosphorus in vegetable products (I), accounts on provinces inproportion to quantities of animals and numbers of population.

SW Export plant Quantity of phosphorus in exported vegetable products, accounts onproducts provinces in proportion to total vegetable production.

Si Seeds and Quantity of phosphorus in seeds and seed-potatoes, quantity oftubers material in proportion to harvests of cereals and of potato, standard

content of phosphorus in in seeds and seed-potatoesSkon Food Quantity of components received in food by people, number of

consumption population and consumption of products (10), standard contents ofcomponents in products from Annual Yearbooks.

Slud Sold Quantity of components sailing from agriculture with raw productsagricultural intended on processing on food: Sud = Sko, + Sofl*0.3products I

Results and discussionValues of elements of phosphorus balance as a total and superficial one are presented intable 2 and balances in table 3. Values of elements of phosphorus balance andconsistently, their surplus or deficit show considerable territorial differentiation. The

44

following maps (Fig. 1-3) present the isopleths of phosphorus balances on the field andfarm gate scale interpolated with using kriging method, basing on the data from 49 formerprovinces. The maps of balances are presented on the background of the Vistula, Odraand coastal rivers catchments draining area of Poland to Baltic Sea.

Table 2. Values of elements of phosphorus balance in Poland (averages for 1996-1998)

Values of phosphorus balance in Gg/18444 l0 ha and (kg/ha)Sr S I S S S S S Si S'ud95.4 133.8 1.0 3.0 1 235 29.6 6.9 19.0 51.65.2 7.3 0.1) 0.2) 12.7 (1.6) (0.4) .0 2.8)

Table 3. Phosphorus balance in Poland (averages for 1996-1998)

Surface soil balance Farm gate balance (OECD)simplified enlarged Frate. ce OECd)

( ,Sr Sin S - ) (S Sr+ S in S mug- (Sr jn+Sl p S '1a )t SeorSiud)

P Gg/18444 10 ha -5.4 13.5 103P (kg/ha) -0.29) (0.7) (5.6)

Vt. 'V Z7.( <, DAM3

S A> KzItnia slY, )\\ O WARSZAWA ' .)

._. / Zlewnia OdryK) I. (r .- >. \t

//

tx -t-'" 'a " 0 \ "H - '-- " ) ' c' ,/ ' x /-

Figure 1. Simplified phosphorus balance on soil surface kg P/ha45

70,

I "r7 it /t

( /If

Figure 2. Enlarged phosphorus balance on soil surface kg P/ha

The greatest values inroduced as a input in all kinds of balances determined mineral and

organic fertilizers. Phosphorus balance on soil surface level both simplified and enlarged

was sustainable in years 1986-1988 which seemingly shows on correct managing of this

element. Phosphorus balance was found sustainable on the superior area of the country,

however great areas of south-east south west and central parts of Poland show negative

balance (Fig. 1). It is an alarming occurrence with not satisfying phosphorus status in

most of Polish soils. The phosphorus surplus or deficit should be collated with soil

fertility. According to the last calculations (6) 12 % Polish soils show very low, 27 %

low, 26 % medium, 16 % high and 19% very high content of available phosphorus (Fig. 4).

According to fertilizer recommendation only on soils with about medium content of

phosphorus can use phosphorus doses which can be uptakeo by crops (sustainable

balance of phosphorus). On soils with very low content of phosphorus doses should be

about 50 %, and on soils with low content about 25 % higher from the uptake by crops

(positive balance). On soils with very high content doses of phosphorus about 50 %

smaller than uptaken by crops, and on soils with high content with 25 % smaller can be

46

used. These soils account for smaller area than poor soils. Optimum surplus ofphosphorus for conditions of Poland wolud be about several kg P per hectare.

" a i , r .. i . •y i

-o

A- I

Figure 3. Farm gate phosphorus balance kg P/ha

Phosphorus balance at farm gate scale, calculated in aspect of its potential losses from allagriculture was a little positive, however surplus of this element was slight. Only inWielkopolska region with intensive agricultural production and north-east part of Polandsurplus of phosphorus was close to 5 kg P/ha. Potential surpluses of phosphorus at thismethod of calculation mostly result from losses in animal production. Losses in animalproduction reach mostly in fodder production i.e. in chain field (import) - feeding trough,as animals metabolism losses and as losses in managing of food - animal products e. inchain - animal - household. Possibilities of limitation of phosphorus losses from animalproduction is depended on places their losses in fodder production and can limit byimprovement techniques of gathering of fodders and improvement of effectivityimmediate pasturage of animals on green lands.From available statistical data balances of phosphorus till 1998 were prepared for 49provinces. At present balances prepared in a province arrangement will not be sufficiently(detailed, and for district - arrangement lacking indispensable statistical data.

47

.........

morza ewid PrzJinor4*

Zlewi'aILI

ijo

Figure 4. The share of polish soils in % arable land about low and very lowphoshorus content

Conclusions1. Phosphorus balance at farm gate scale, calculated in respect to its potential losses

from all agriculture was a little positive, however surplus of this element was slight.2. Phosphorus surplus was found sustainable in years 1986-1988 on the larger area of

the country, however great areas of south-east, south west and central parts of Polandshow negative balance. It is an alarming occurrence with phosphorus status in most ofPolish soils.

48

ReferencesI. Fotyma M., Mercik S., 1995: Agricultural Chemistry, PWN Warszawa, Ed. II.2. Fotyma M., Igras J., Kopifiski J., Glowacki M., 2000: Nitrogen, phosphorus and

potassium balance in Polish agriculture. Pam. Put. 120/11, P 91-101.3. Iserman K., 1991: Nitrogen and phosphorus balances in agriculture, Helsingor,

Denmark : Proceedings from International Conference on nitrogen, phosphorus andorganic matter, P 1-20.

4. Jadczyszyn T., Maqkowiak Cz., Kopifiski J., 2000: Model SFOM - a tool forsimulating quantity and quality of organic fertilizers produced at the farm. Pam. Put.12011, P 169-175.

5. Kerschberger M., Franke G., Hess H., 1997: Anleitung und Richtwerte furNahrstoffvergfleiche nach Dungeverordnung, Jena: Thuringer Landesanstalt furLandwirtschafl, P 74.

6. Obojski J., Strqczyfiski S., 1995.: Reaction and soil makro and micronutients ferilityIUNG Pulawy Ed.

7. Oenema 0., 1999: Nitrogen cycling and losses in agricultural systems, IMUZ Falenty:Nitrogen cycle and balance in Polish agriculture, P 25-43.

8. OECD (Organisation for Economic Co-operation and Development), 1998: Towardssustainable development, Paris, France, Environmental indicators, P 129.

9. PARCOM (Oslo and Paris convention for the prevention of marine pollution), 1995:Guideleines for calculating mineral balances, PRAM 95/7/6 - E. Oviedo, P 9.

10. Schulz D., (edited), 1999: Nitrogen emission from the sector of human nutrition withsubsequent effluents and waste disposal, Berlin : Nitrogen reduction programme, P 27-29.

11. Szponar L., Pawlik - Dobrowolski J., Domagala R., Twardy S., Traczyk L., 1997:Nitrogen, phosphorus and potassium balance in Polish agriculture, Warszawa, Ed.iZ 80, P 10-27.

49

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUMAND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

THE MINERAL FERTILISERS CONSUMPTION AND MAIN CROPS YIELD INSLOVAKIA IN 1989-1998

Stanislav TormaSoil Science and Conservation Research Institute, Bratislava, regional work station

SummaryMineral fertilisers consumption in Slovakia is on the level of 18-23 % in comparison withperiod 1989-90. It means that in recent six years were applied only 42-57 kg NPK perhectare of farm land, while in 1989-90 it was 240 kg. Nitrogen fertilisers create 66-71 %from this amount and phosphorus and potassium together only 29-34 %. The yields ofmain grown crops (cereals, potatoes, sugar beet, annual and perennial fodder crops) didnot decrease with similar tendency. Cereals and fodder crops yields have been decreasedonly by 10-30 %, while potatoes yield has been increased by 10 % and sugar beet yieldeven by 10-15 %. This can be caused by relatively high rations of nitrogen fertilisers andby still sufficient supply of available forms of phosphorus and potassium in the soils.

Key words: mineral fertilisation, crop yields, nutrient soil supply

IntroductionIn present social conditions, when inputs into the agricultural production increase fasterthan is the growth of prices of products, the optimisation of plant nutrition introduces thesubstantial economical and ecological factor.There is evident decrease of reached crop yields in recent years, when the organic andmineral fertilisers consumption went strongly down. The natural nutrient supply in thesoil is limited and the nutrient balance became into the negative values without adequatereturn of withdrawn nutrients. The experimental works show and the practical expe-riences demonstrate that fertilisation omission causes the yield decrease even to the lowerlevel than it was at the beginning of the fertilisation. This tendency overshoots most oftenquick in the low fertile soils. It is necessary to give the attention to the fertilisation,because on the other side can come (and it is coming yet) to the decrease of availablenutrient supply in the soils. The next soil saturation with the nutrients will be verycomplicated and expensive in the future.At present, first of all in the future, purpose of fertilisation will be focused on productionprocesses stabilisation and optimisation in crop production and soil quality parametersstabilisation - as a natural resource (sustainable agriculture).

Material and MethodsThe aim of this paper was to evaluate the development of mineral fertilisers consumptionand reached yields of most grown crops in the recent decade in Slovakia and to presentthe assumes of the next development of crop yield formation. The data about the yields ofindividual crops and mineral fertilisers consumption were taken from StatisticalYearbooks of Slovak Republic, whereby the calculation for the new regions adminis-tration was made as average from the data about farm land, arable land and fertilisersconsumption of districts before 1996.

50

Results and DiscussionFertilisers used to be very important intensification factor with marked yield-formingeffect in period of beginning of agriculture chemisation in Slovakia. Fertilisation share atyield increase reached, e.g. in 1973 about 30 % - most of all observed factors, thatincluded agrotechnics, crop assortment, plant protection, soil fertility and weatherconditions. In 1990 it was 25 % from the factors that were controlled by man. It is evidentthat the fertilisers have greater influence in the lower fertile soils than in the more fertileones. According to Hueg (Hrasko, 1998) the cereals yield in conditions of USA have beenincreased in low fertile soils by 61 %, while in more fertile soils only by 38 % in period of40 years.The recent period is characterised with decrease of mineral fertilisers consumption allover the world. For example in Western Europe countries the NPK consumption has beendecreased from 175 kg in 1989 to 118 kg per ha of farm land in 1996 (Uebel, 1998). Butwhile in these countries came into the foreground the ecological aspects, the NPKconsumption decrease in Central and Eastern Europe countries is developed byunfavourable economical situation.Also in Slovakia came after the economic changes to the strong decrease of mineral andorganic fertilisers consumption. Mineral fertiliser consumption in kg of pure nutrients perha of farm land in period 1950-1998 is presented in Figure 1.

kg purenutrients per haof farm land

300200 - ------ K20

200 - -------

100 -

50-

0 - C . . . . .O. . . . . . . 0 O

Figure I. Mineral fertilisers consumption in Slovakia from1981 to 1999

From data it is obvious, particularly after 1950 fertilisers consumption rose up rapidly,with culmination in period 1980-1988, when practically during all the decade fertiliserrates reached up to 250 kg pure nutrients NPK per hectare. This was almost 18-foldincrease, when compared to fifties. However yields did not rise in the same ratio. Mostmarkedly increased yields of small grain cereals (3-4-fold), but it should be noticed thatbesides fertilisation positively participated also new crop varieties, plant protection andnew agrotechnical technologies. But these factors could have the positive influence on theyield formation only at sufficient nutrients reserves in the soil.At the end of eighties the process of fertiliser rations reduction was started. Differentiatedsystem of fertilisation by means of computing technique was implemented, wherebybesides assumed yields were respected nutrient soil supplies (according to AgrochemicalSoil Testing) and other criteria. After 1990 came to the drastic limitation of mineral

51

fertilisers consumption, when the consumption decreases from the average ration239,7 kg NPK per ha of farm land in 1990 to 41,6 kg NPK in 1993. The reason wasmainly the financial situation of agricultural farms and the fact that soils are suppliedenough with nutrients, especially with potassium.With fertilisers application is narrowly linked the soil supply with nutrients. Thefertilisation is one of the most effective measures to the nutrients content increase. Thereis necessary to apply 7-15 kg of phosphorus and 5-23 kg of potassium per ha to reach thenutrient content higher by I mg per kg of soil in dependence of soil type and soilstructure. Fertilisation is at the same time one of the most expensive measures. And evenin present economic situation the majority of farms has to very carefully appreciate allinputs into the production or into the soil. There is most often saving in the inputs into thesoils, but from the point of view long-term aspect is such access not respectable. For thesaving of soil fertility it is necessary to give back to the soil as minimum so muchnutrients as was taken up by crop yield and leached or washed out with water erosion.The last results of the Central Control and Testing Institute of Agriculture document thedefinite decrease of potassium and phosphorus content in the soils (Kotvas 1998). Forexample the share of arable land with high phosphorus content has been decreased from36 % to 11,2 % in period for 5 years, whereby almost one half of observed arable land hasmedium content and one quarter of arable land has low and very low phosphorus content.The changes in potassium content are a little bit more favourable concerning to thenatural potassium reserves in the soils. In spite of this more than 10 % of the arable landhas low and very low potassium content and the share with high potassium content hasbeen decreased by 20 %.

The development of the chosen crops yieldThe high yield of agricultural crops can be reached only at optimal conditions of plantgrowth. The soil and its heterogeneous properties, the plant nutrition level, climaticconditions, agrotechnics and plant species are the unit that determines the yield. Each ofthe mentioned parameters can be ultimate for the assumed yield decrease.According to Andres (Bujnovsky, 1996) the optimal nutrient supply in the soil has thegreater influence on the yield than higher fertiliser rations at lower nutrient content in thesoil. The fertilisers influence on the more fertile soils has relative low effect. Kandera(1994) mentioned that the limiting factor of winter wheat yield on the Chemozem is thefactor of year and only than nitrogen application.On the next figures is presented the development of hectare yield of cereals and nextchosen crops in 1989-1998. There is inserted the trend flowline together with thecoefficient of correlation in the case of cereals. These parameters confirm the decrease ofmentioned crops yield since 1990.The tendency of cereals yield decrease can be characterised by parabolic curve and it canbe confirmed that in recent years the decrease has been stopped and the yields are morestable but on the lower level than in the eighties. Certainly, not only fertilisation is thereason of this decrease. The other factors enter into this matter of fact, e.g. availablenutrients supply in the soils, conditions of their taking with plant root systems, utilisationof nutrient in process of photosynthesis, insufficient use of pesticides, increasing soilacidity, insufficient application of farmyard manure (negative carbon balance) andanother factors that are in conflict with good agronomic practice.

52

t.ha- 16.00

3 000

2.001 -

1989 1991 1993 1995 1997 1999F -- winter wheat - spring barleyinter Eet -oats

Figure 2.Cereals yield in Slovakia in recent decade(1989-1999)

t.ha-I potatoes, t.ha-l foddersugar beet crops45 -35

40 -3035\ --- - - I -.. . . . .- 25

4520. 1515 1010 .

----- --------------- i + +t+

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999isugar beet =potatoes -C-annual fodder -*--perennial fodder

Figure 3. Sugar beet, potatoes and fodder crops yield inSlovakia in recent decade (1989-1999)

The similar course is presented in the case of perennial fodder crops, when the yield hasbeen decreased from 9 tons in 1989 to 6 tons per ha in 1998. The annual fodder crops andpotatoes yields are during the observed period very variable and it can be said that greaterinfluence on their yield formation have the climatic conditions than fertilisers application.The sugar beet yield has been increased since 1990.The present status of fertilisation and crops yieldAfter 1990, when was recorded the decrease of mineral fertilisers consumption to 17 % ofprevious status during three years, the consumption was stabilised and it ranges between43,5-57,0 kg NPK per ha of farm land till 1998, whereby since 1993 it graduallyincreased and only in 1998 decreased by 6 kg again. It is clear that the fertilisation in thelevel of 50 kg NPK per ha of farm land does not respond to soil and plant requests. Butthere is one fact to mention; nitrogen creates in average 67 % of fertilisers amount andphosphorus and potassium together only one third.

53

t.ha-I

3.00 -

2.001.00

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999

--,"winter rape - sunflower ---- corn maize

Figure 4. Oil crops and corn maize yield in Slovakia inrecent decade (1989-1999)

The plants take up with their yields more nutrients than is applied with the fertilisers. Atpresent time it is fanned with negative nutrient balance. Kotvas (1998) calculated thisnegative balance for 24,3 kg of nitrogen, 26,3 kg of phosphorus and 90,2 kg of potassiumin 1997, e.g. 140,8 kg NPK per hectare of production area. The greatest deficit ofnutrients per hectare of soil is at sugar beet (-277 kg NPK per ha) and corn maize growing(-240 kg NPK per ha). At the same time this author accentuates that the arable land wasfertilised only on 66,9 %, e.g. on one third of arable land in Slovakia fertilisers were notapplied at all.Such farming with high negative nutrients balance leads to soil fertility plundering and togreat losses. For example in Czech Republic the losses caused by limited fertilisationwere estimated on almost 5 milliard Czech crowns (Collective, 1999). According to thepreliminary calculations (Torma and Jambor, 2000) the losses caused only by higherpotassium uptake than potassium inputs into the soil reaches more than one milliardSlovak crowns annually (depending on various fertilisers costs in individual years), e.g.almost 10 milliard Slovak crowns for period since 1991. In this sum are not included thelosses caused by negative nitrogen and phosphorus balance, as well as the losses causedby significantly lower crop yields.In spite of great decrease of mineral fertilisers consumption in 1993-1998 when compare1989-1990, the decrease of main crops yield in Slovakia does not correspondend withfertilisation reduction.Wheh compared the two-years average values of fertilisers consumption and crops yieldand as initial period will be taken the period 1989-1990 (last years with NPK rations morethan 200 kg per ha of farm land), the decrease of fertilisers consumption in 1993-1998reached 80 % of initial period (nitrogen consumption decreased ,,only" by 60-70 %),while the winter wheat jield decreased by 18 %, spring barley by 30 %, annual foddercrops by 20 %, perennial:fodder crops by 25-30 % and oil crops by 15-28 %. On the otherside sugar beet and corn maize yields increased by 12-15 % or 15-25 % respectively andpotatoes yield almost by l0 % in observed period.This fact can be explained with relative high nitrogen rations and with sufficient availablephosphorus and potassium supply in the soils as well. It is necessary to see that after

54

1990-91 the fertilisation was concentrated mainly on the arable land and the grass landwas practically not fertilised. One should not forget that in the market economy arefertilised (mainly with nitrogen) especially good market crops (winter rape, sugar beet,sunflower and potatoes as well), while other crops have to use old soil power.

Table 1. Relative mineral fertilisers consumption and main crops yields (comparison1991-1998 and 1989-1990) (in %, 1989-1990 = 100 %)

1989-1990 1991-1992 1993-1994 1995-1996 1997-1998NPK consumption 100 39.6 18.1 20.0 23.0N'consumption 100 56.7 32.5 35.2 40.4Winter wheat 100 95.1 82.5 81.4 82.9Spring barley 100 91.6 73.5 68.5 74.6Sugar beet 100 92.6 105.5 115.0 112.9Potatoes 100 90.8 100.5 108.7 107.7Annual fodder crops 100 92.9 78.3 86.1 88.8Perennial fodder crops 100 90.1 75.6 75.3 71.2Oil rape 100 90.1 76.0 84.7 85.7Sunflower 100 106.6 85.9 87.3 72.7Corn maize 100 108.7 96.1 116.9 125.8

ConclusionsThe present status of mineral fertilisers consumption is not satisfactory and shows withlow yields of grown agricultural crops. In addition, the content of available forms ofphosphorus and potassium in the soils is decreasing, too. It is farmed with negativenutrients balance. For conservation of present crops yield level and present soil supply ofphosphorus and potassium it is necessary to apply 50-70 kg P2O5 and 65-100 kg ofpotassium per hectare of arable land. But the situation is on the level under 10 kg ofphosphorus and potassium per ha.

References1. Bujnovsky, R.: K hodnoteniu vztahu hnojenie - agrochemicke vlastnosti pody - podna urodnost -

uroda. In: Ochrana pody - vyzva pre buducnost). VUPU, Tale, 1996, p. 19 1-20 3. (in Slovak).2. Collective: Plant nutrition, quality of production and processing. MZLU Bmo, 1999, 234 p.3. Hrasko, J.: Zmeny niektorych parametrov produkcnosti pody na Slovensku. In: Trvalo

udrzatelna urodnost pody a protierozna ochrana). VUPU, Nitra, Sielnica, 1998, p. 25-30. (inSlovak).

4. Kandera, M.: Moznosti spresnenia davok dusika pri hnojeni ozimnej psenice. Agrochemia(Bratislava) 34, 1994, p. 114-117. (in Slovak).

5. Kotvas, F.: lntenzita hnojenia a zivinovy potencial slovenskych pod. Rolnicke noviny25.11.1998, (in Slovak).

6. Statistical yearbook of Slovak Republic. Bratislava, 1993, 1994, 1995, 1996, 1997, 1998.7. Torma, S. - Jambor, P.: Hnojenie draslikom v Slovenskej republike. Country Report 2: Vyvoj

spotreby draselnych hnojiv ajeho dosledky pre urodnost pod a rastlinnu vyrobu v Slovenskejrepublike. International Potash Institute, Basel - Vyskumny ustav podoznalectva a ochranypody Bratislava, 2000, 64 p. (in Slovak).

8. Uebel, E.: Current fertiliser use in central/eastern Europe (CEE) and the arisingconsequences for soil fertility and crop production. In: Proceedings of the I 1h CIECSymposiums on Codes of Good Fertiliser Practice and Balanced Fertilisation. lUNG Pulawy,1998, p. 409-415.

55

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

POTASSIUM AND PHOSPHORUS FARM-GATE BALANCE IN LIVESTOCKFARMS AS A BASIS FOR FERTILISER RECOMMENDATION

Andrzej Sapek, Stefan Pietrzak

Institute for Land Reclamation and Grassland Farming at Falenty, Poland

AbstractThe ,,farm gate" phosphorus and potassium balance was made in 12 livestock farms beingthe demonstration farms in Baltic Agriculture Runoff Action Program. The calculatedmean surplus amounted about to 25 kg ha-' P and 60 kg ha- K. Most soils in thesedemonstration farms have very high soil P and K test. An important source of phosphorussurplus is purchased fodder. The surplus of potassium resulted from over-fertilisationwith this nutrient. The high P and K surplus is not only a risk to the environment, but alsoan economic loss for farmers. This loss may be rather acute in the case of overuse ofphosphorus fertilisers. The ,,farm gate" balance method is a good tool to improve fertiliserrecommendation system in the direction to protect environment and increase the farmer'sbenefit.

Key words: phosphorus, potassium, nutrient balance, livestock farms, fertiliser

IntroductionIncreasing demand for food production results in expanding use of artificial fertilisers thatproduces some strains to the environment. Contemporary nutrient-management systemsmust not only address efficient crop-production criteria, but also must reduce nutrientlosses to the environment and preserve the natural resources. Thus, the nutrient useshould be more efficient and balanced as well as respects both the crop and animalproduction. The ultimate nitrogen management systems have found broad implementationand the effects of nitrogen dispersion into environment are well recognised. Themanagement system of the two following main nutrients - phosphorus and potassiumrequires more attention.The old farming communities tended to be self-sufficient in that enough feed wasproduced locally and recycled to meet animal requirements. Next, increased fertiliser usein crop production fragmented farming systems, creating specialised crop and animaloperations. Since farmers did not need to rely on manures as nutrient sources, they couldspatially separate grain and animal production. Thus, animal farmers are no more made todepend on fodder produced themselves and base on imported from outside farm. Thechange of farming system from cropping to intense animal production can create apotential phosphorus and potassium surplus, since inputs of these both nutrients becomedominated by feed rather than fertiliser.Phosphorus (P) is an essential element for plant and animal growth and its input has longbeen recognised as necessary to maintain profitable crop and animal production.However, the increasing P inputs into agriculture results in its accumulating in soils anddispersing into the environment that caused the eutrophication of other ecosystems,particularly the surface waters. The rapid growth and intensification of crop and animal

56

farming has created regional and local imbalance in P inputs and outputs. On average,only 30 per cent of the fertiliser and feed P input to farming systems is output in crop andanimal products [5].Potassium (K) is an essential element for plant growth, but not so important to animalgrowth. The increasing K inputs into agriculture results in its dispersing into theenvironment, though the negative effect of this dispersing is not clear determined up tonow. It is only supposed that K dispersion could reinforce the eutrophication of terrestrialecosystems in some conditions. The outputs of K from farm with animal products arenegligible. The bulk amounts of K from feed consumed by animal are eliminating fromthe body with urine and are left on farm. Thus the K surplus in animal farms tends to betoo large and seems to create some economic questions, but also some can causegroundwater pollution in some cases [1, 4].The aim of presented study was to use the ,,farm gate" nutrient balance to identify thesurplus of phosphorus and potassium in different livestock farms.

Methods and study areaThe ,,farm gate" nutrient balance was adopted to improve the fertiliser managementsystem to increase the farmers' benefit and decrease the nutrient dispersion into theenvironment [2]. Such balance is based on one-year calculation and comprises thenutrient inputs to farm with purchased fertilisers, fodder, seeds, animal etc., but also withprecipitation and biological fixation in the case of nitrogen; and the nutrient outputs withsold plant and animal products. Surplus is the difference between inputs and outputs andis the amount of nutrient not used in the course of production during the year in question.However, nutrient surplus is supposed to be the amount of nutrient that creates a potentialrisk to environment, due to its dispersion or/and accumulation in farm soils. Theefficiency of P inputs is considered as per cent of total outputs to total inputs.The balance of phosphorus and potassium was made in 12 demonstration farmsestablished in activity of Baltic Agriculture Runoff Action Program (BAAP). Twelvefarms were selected in three gminas (counties) located in three regions - ToruAi(PR),Plock (SB) and Lomza (KL), where the activities of BAAP project are implemented.In all these farms, the animal production prevails. Dairy is the main production in six,swine in four, and mixed in two farms. In the soils of all farms, very high soil P testprevails. Similarly, high and very high soil K test predominates in these demonstrationfarms.

ResultsThe mean P inputs with purchased fodder were only slightly lower than with fertilisers(Table 1). But, there are observed great differences between farms. In two farms, P inputswith fodder exceeded 50 P kg/ha, since in five farms this kind of P inputs was negligible.The mean P inputs in P kg/ha with fertilisers was about 2.4 times greater than the nationalmean [3] and the differences between farms were lesser. Only on farm 12.PR no Pfertilisers have been applied, because this farmer volunteers in avoiding the P fertilisationon demonstration purpose. His action is under control. The P outputs with animalproducts were slightly higher than with plant products. The P mean surplus was about 25P kg/ha, but this surplus exceeded 50 P kg/ha in three farms. The mean P efficiency wasabout 30%, and is slightly higher than the national mean (25.6%). But in two farms, witha high P surplus, this efficiency was below 10%.

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The main K inputs were with fertilisers, these inputs with fodder have secondaryimportance (Table 2). The part of animal products in K outputs had also small weight.The mean use of K fertilisers in term K kg/ha was in demonstration farms 4 times higherthan the national mean; in spite of the K efficiency was the same as the national mean.The main K outputs were with plant products. In two farms the K surplus exceeded100 K kg/ha, where the K efficiency is below 10%.

Table 1. Phosphorus balance in demonstration farms (1999)

Inputs, P kg ha" Out uts, P kg ha- Surplus Effi-Farm Are, AU Ferti- Purchased Other Total Plant Animal Total P kg ciency,No ha ha" lisers fodder inputs products products outputs ha -1 %

I. SB 47.0 0.31 34.8 1.8 0.3 36.9 8.5 1.6 10A 26.8 27.42. SB 57.0 1.06 11.5 11.3 0.5 23.3 3.1 4.7 7.8 15.5 33.53. SB 41.0 0.81 26.1 35.1 0.1 61.3 2.2 2.8 5.0 56.3 8.24. SB 51.7 0.76 8.9 11.0 0.1 20.0 6.8 4.5 11.3 8.7 56.55. KL 24.0 1.00 23.8 0.7 0.2 24.7 3.0 2.7 5.7 19.0 23.16. KL 26.0 0.64 26.1 1.0 0.4 27.5 5.1 2.5 7.6 19.9 27.67. KL 24.5 1.80 19.7 2.6 0.0 22.3 0.0 4.9 4.9 17.4 22.08. KL 14.0 1.37 8.6 12.0 0.4 21.0 1.0 4.0 5.0 16.0 23.89. PR 34.8 1.29 17.3 53.1 0.0 70.4 1.3 3.4 4.7 65.7 6.710. PR 15.4 1.34 13.1 0.1 0.0 13.2 1.9 2.2 4.1 9.1 31.111. PR 20.5 3.10 17 58.1 0.0 75.1 4.2 13.3 17.5 57.6 23.312. PR 25.9 0.68 0 11.7 0.3 12.0 2.7 5.1 7.8 4.2 65.0Mean 31.8 1.18 17.24 16.5 0.2 34.0 3.3 4.3 7.6 26.4 29.0

SD 14.3 0.73 9.56 20.6 0.2 22.2 2.5 3.1 3.9 21.2 169

Table 2. Potassium balance in demonstration farms (1999)

Fr Area, AU Inputs, K kg hat Outputs, K kg ha t Surplus Effi-

No. ha ha"t Ferti- Purchased Other Total Plant Animal Total K kg ciency,lisers fodder inputs products Products outputs ha" %

. SB 47.0 0.31 95.3 2.3 0.1 97.6 23.6 0.4 24.0 73.6 24.62. SB 57.0 1.06 30.9 13.6 0.1 44.6 8.7 3.5 12.2 32.4 27.43. SB 41.0 0.81 50.2 13.4 0.1 63.4 3.4 1.3 4.7 58.9 7.44. SB 51.7 0.76 17.2 12.6 0.1 29.9 10.6 2.2 12.8 17.0 42.95. KL 24.0 1.00 46.2 1.4 0.0 47.6 4.1 4.5 8.6 39.0 18.26. KL 26.0 0.64 59.1 2.0 1.3 62.3 22.5 2.2 24.7 37.6 39.67. KL 24.5 1.80 36.4 3.0 0.0 39.4 0.0 8.6 8.6 30.8 21.88. KL 14.0 1.37 115.2 12.9 4.3 132.3 7.3 5.0 12.3 120.0 9.39. PR 34.8 1.29 99,8 49.0 0.0 148.2 6.6 3.4 10.0 138.7 6.710. PR 15.4 1.34 65,3 0.1 0.0 65.4 0.0 3.9 3.9 61.5 6.011, PR 20.5 3.10 48,4 50.9 0.0 107.3 20.4 8.3 29.4 77.9 27.412. PR 25.9 0.68 47,9 17.7 0.1 65.7 15.7 2.3 18.0 47.7 27.4Mean 318 1.18 59.3 14.9 0.5 75.3 10.2 3.8 14.1 61.3 21.6

SD 14.3 0.73 29.7 17.4 1.2 37.7 8.4 2.5 82 36.7 12.5

The calculated regressions displayed connection between animal density versus P and Kinputs with purchased fodder. The use of mineral fertilisers was positive correlated withK surplus and negative with P and efficiency. The amount of P in purchased fodder hadimpact on the P load in sold animal products and P surplus. The amount of K in sold plantproducts was connected with K efficiency. The P and K surplus was consequentlynegative correlated with the efficiency of these nutrients (Table 3).

58

Table 3. Significance of correlation coefficients for factors of phosphorus (P) andpotassium (K) balance

AnimalFarm area ni Purchased Purchased Sold plant Sold animal Surplus

ha AU/ha fertilisers fodder products products

PurchasedfertilisersPurchased P*fodder K* K**Sold plantproductsSold animal P***products K* K***

p***Surplus K*** K4

Efficiency ()P* (-)P**(-)K* K* -K

Significant: - by a - 0.05, - = 0.01, - = 0.001

DiscussionThe described nutrient balances were done in farms representing slightly better farmingskill, economic conditions and farm area than bulk of farm giving about 80% of the dairyand meat market production in Poland. One can suppose that they represent the livestockfarming systems in Poland that exist and would develop in next few years. Therefore, arespective nutrient management system should be developed to meet the demand of suchfarms.The nutrient inputs to animal farms comprise not solely fertilisers but also purchasedfodder including concentrates usually enriched in phosphate up to the content of 0.5% Por more. The purchased fodder could be the dominant nutrient sources in some farms,where the field area is too small to produce enough foodstuffs for the held herds.However, this fact is seldom considered in fertiliser strategy in Poland. The calculated Pbalances showed that the highest found P surpluses resulted from P inputs with purchasedfodder. This regularity is not obvious in the case of K, which relative inputs with fodderare evidently less than with fertilisers.The nutrient efficiency in animal farms depends mostly on the system of manuremanagement. The bulk amount of nutrient comprised in crops or pasture herbage is usedthere as foodstuff or bedding in livestock production and is returned to fields or grasslandin the form of manure. Each fertiliser recommendation system is based on some averagenutrient content in different kind of manure. That may create some unwanted effects tofarm economy and/or to environment quality.Nutrients comprised in manures are causally distributed within farm. Some fields aretreated with greater quantity of manure and/or more often. The same, but in smallerdimension takes place in the case of mineral fertilisers. As effect phosphorus, and insmaller extent potassium, is accumulating in soil often to the level exceeding the needs ofgrowing plants and shaping same risk to environment, particularly the accumulation ofphosphorus.

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The classical fertiliser recommendation systems cannot face these questions. The reasonsare: (i) nutrient content in manures differ much from the average data used in thissystems; (ii) the P and K surplus resulting from purchased fodder may only be eliminatedby decreasing the livestock density; (iii) the soil P and K tests are elaborated for narrowdifferences in soil properties, some soil can have high P and K leaching potential; (iv) wehave no knowledge how far we are allowed to surpass the very high or even high soil Ptest. Therefore, an environmentally sound P fertiliser recommendation system forlivestock farms should be based on the ,,farm gate" nutrient balance, and if the P surplussurpasses 5 kg ha" P the commercial P fertiliser should be avoided for several years on allfields with high and very high soil P test. The threshold number for K should be alsodefined.The decrease of P and K surplus has not only an environmental meaning, but alsoeconomic one. The surplus of P and K in farm with soil rich in available forms of thesenutrients means that farmers are losing a genuine quantity of money for buying P or Kfertilisers. In the case of P the price of 1 kg P in fertilisers is about 1.5 USD in Poland.Thus some demonstration farmers are missing up to 90 USD per hectare each year.

ConclusionThe permanent use of commercial fertilisers in livestock farms results often in over-accumulation of P that would produce some risk of eutrophication of surface waters andsurrounding terrestrial ecosystems. The question of K accumulation in soils is not soevident, as potassium is much more easily leached from soils than phosphorus, and the Kimpact on environment is only slightly recognised. The fertiliser recommendation systembased on field scale may effect in odd distribution of nutrient in farm scale. The farm gatebalance is a tool that could be helpful in avoiding over-fertilisation. The nutrient surplusin farm scale is not only a risk to environment, but also an economic loss for farmer. Thisloss may be rather acute in the case of overuse of phosphorus fertilisers.

AcknowledgementsThis study was carried out in Baltic Agriculture Runoff Action Program.

References1. Dewes, T. Zusammensetzung und Eigenschaflen von Sickerwasser aus Stallmiststapeln.

Z.Pflanzenemaehrung, Bodenk. 1997 - Vol. 160. - P. 97-101.2. lsermann,K. Nitrogen and phosphorus balance in agriculture - A comparison of several

Western European countries. International Conference on Nitrogen, Phosphorus and OrganicMatter, May, 13-15, 1991, Helsingor [Denmark]. 1991.

3. Sapek, A. and Sapek, B. Phosphorus balance in food chain in Poland. In: Aktualus MedziaguApykaitos Klausimai, edited by Drebickas, V.Vilnius:Vilniaus Pedagoginis Universitas.1999. P. - 269-274.

4. Sapek B. Farm as a source of soil, water and air pollution with nitrogen, phosphorus andpotassium. Bibliotheca Fragmenta Agronomica. 1998 - Vol. 3/98. P. 124 -144.

5. Sharpley, AN., Daniel, T.C., Sims, J.T., Lemunyon, J.L., Stevens, R.G., and Parry, R.Agricultural phosphorus and eutrophication, USDA ARS. 1999. P. 1-37.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

POTASSIUM AND PHOSPHORUS BALANCE IN A LONG-TERMGRASSLAND EXPERIMENTS

Barbara SapekInstitute for Land Reclamation and Grassland Farming at Falenty

SummaryThe aim of this study, in which a balance of nutrients was made in the field scale, was toassess a deficiency or a surplus of potassium and phosphorus, the latter being a possiblesource of ground water pollution, and to evaluate the utilization of nutrients by meadowvegetation. Results 'were confronted with the differentiated pH of the meadow soil - aconsequence of liming - and from the view of an effect of nitrogen fertilization on theresults of this balance. The investigation has been carried out on the basis of long-termgrassland experiments situated in Mazowieckie voivodship on light, acidic mineral soils.The soils from 3 experiments were differed with the clay minerals and organic carboncontent as well as pH. The fertilizationof NPK was uniform on each experiments: 80kg/ha P20, 150 kg/ha K20 (180 kg/ha K2O from 1991) and two levels of N fertilization -120 kg/ha (N,) and 240 kg/ha (N,2). The liming was performed once, at the beginning ofexperiments, using the calcium carbonate, according to criterion of hydrolytic acidity:lHh (Ca,) and 2Hh (Ca2). It was confirmed that the K fertilization of a permanentgrassland on a light mineral soil at a rate of 150 - 180 kg/ha KO does not fulfill therequirements of 3-cut plants for this nutrient. The plants take it up additionally from thesoil pool in the amount of 10-30% of that introduced with fertilizers and precipitation. Pfertilization of the same soils at a rate of 80 kg/ha P205 is accompanied by the formationof t he nutrient surplus, unused by plants. The surplus, depending on the type of soil, Ndoses and pH, averages 10-50% of that amount of P, which is introduced with fertilizersand precipitation. Fertilization with a higher N dose decreases P surplus. Fertilizationwith N at a rate of 120 kg/ha and maintenance of the meadow soil pH in the range 5 - 6creates the most favorable conditions to limit surplus and losses of the studied nutrientsand provides their effective utilization by plants. Nutrient balances are necessary tocorrect the NPK doses actually used in farms in order to enhance nutrient utilization inagricultural production.

Key words: potassium and phosphorus balance, permanent grassland, long-term experiments,soil pH, nitrogen dose.

IntroductionA balance method may be helpful in activities focused on limiting the surplus nutrientdispersion into the natural environment and their losses due to emissions to theatmosphere or leaching below the root zone of plants. The method allows to limit waterresources pollution by nutrients and to keep their management according to the principlesof sustainable development of agriculture. Balances of nutrients are made, according tothe needs, in different scales - of the country, region, watershed, a farm and a field [4, 5,7,9, 10, 11, 15].

61

The aim of this study, in which a balance of nutrients was made in the field scale, was toassess a deficiency or an surplus of potassium and phosphorus, the latter being a possiblesource of ground water pollution, and to evaluate the utilization of nutrients by meadowvegetation. Results were confronted with the differentiated pH of the meadow soil - aconsequence of liming - and from the view of an effect of nitrogen fertilization on theresults of this balance.

Material and methodsPotassium and phosphorus balance was done from the results of three meadowexperiments - in Baniocha (B), in Janki (1) and in Laszczki (L) established in 1981 in thenow Masovian province. Experiments were set up with a random blocks method in 4repetitions on acidic mineral soils of different organic carbon content (B - 2.5% Corg,J - 1.9% C,, L - 3.8% Corg), different clay particles (< 0.02 mm) content (B - 9.0%,J - 18.4%, L - 22.4%) and pH in I M KCI (B and ) - 4.5, L - 4.3). Liming was performedonce, in the beginning of the experiment by applying calcium carbonate (49.8% CaO) onthe sodded meadow surface. Two lime doses used were calculated according to thecriterion of hydrolytic acidity : lHh (Cal Baniocha - 5.75, Janki - 2.3 and Laszczki - 3.6 tCaO ha" ) and 2Hh (Ca 2 Baniocha - 11.4, Janki - 4.6, and Laszczki 7.2 t CaO ha'). Twolevels of nitrogen fertilization in the form of ammonium nitrate were used: 120 (N,) and240 (N2) kg ha" and a constant phosphorus (80 kg P205 ha-') and potassium (150 kgK20 ha-') fertilization was applied. Since 1991 the potassium dose has been increased to180 kg ha-' (149.4 kg K ha-'). In the B experiment, once in the autumn 1990, animalmanure in the amount of 15 t ha " was used to increase retention capacity of the soil.Detailed data on the experiment can be found in an earlier paper [12]. An average uptakeof N, P and K by crops in the years 1981 - 1995 are given in Table I and soil pH and theamount of total nitrogen in t/ha N in 1995 (after 14 years of experiment duration inBaniocha and Laszczki and 15 years of that in Janki) are given in Table 2.

Table 1. Mean annual uptake of potassium and phosphorus with the yield from theexperiments (Baniocha - B, Janki - Ji" , Laszczki - L) in 1982 - 1995

kg/ haNutrient Experiment Treatments

Ca0 Cal C212N, N, N, N, N, N2

Potassium B 136,9 154,0 152,4 156,1 122,8 156,5J 150,9 158,7 155,7 158,1 154,6 164,1L 176,3 177,7 183,2 177,3 175,8 175,9

Phosphorus B 16,2 21,0 17,4 20,3 13,3 20,81 23,0 25,9 24,8 27,1 23,8 27,7L 29,3 34,1 31,3 34,6 29,3 33,8

I/Janki experiment - 1981-1995

Simplified potassium and phosphorus balances [Farrugia et al. 1997] were madeaccording to the following equation:I) A = A + AA.where:

62

A - the amount of nutrient introduced to soil with fertilizer and atmospheric precipitation(Afr + A,), Atom - the amount of nutrient withdrawn from soil with the plant crop,AA0 - balance difference [(+) nutrient surplus, (-) nutrient deficiency - an uptake fromthe soil pool],AA, /year - an annual average of the balance difference.

Examples of a simplified K and P balance considering all its components are given for theBaniocha experiment. This was selected because the soil properties there made it mostsusceptible to leaching and losses of nutrients [12].The simplified nutrient balance (equation I) does not account for the nutrient content insoil - its accumulation or loss. The balance difference A A. informs only whether therewas a surplus of nutrient unused by plants (+) or its deficiency (-), which means anadditional uptake from the soil pool.Table 2. pH and total nitrogen content (t N,,, /ha) in soil surface layer (0-10 cm) from

grassland experiments in 1995

TreatmentsExperi- Cao Ca1 C111 a2

ment NE N N[ NN N, N,pH NM0, pH Nt, pH Ntot pH N... pH N101 pH N,.,

t/ha tlha t/ha t/ha t/ha t/haBaniocha 3.9 3.22 3.6 3.36 5.9 4.06 5.4 3.36 6.3 3.22 5.8 3.78Janki 3.8 4.14 3.4 4.14 4,5 4.00 4,0 4.00 6.2 4.29 4,5 3.55Laszczki 3.7 3.30 4.1 3.56 5.2 4.32 4.5 3.30 6.9 3.30 6.4 3.17I/ mean values for 4 repetitions of experimentN,., before the start of experiment (1981):B - 2.42 t/ha; I - 2.26 t/ha; L - 4.00 t/ha

The amounts of K and P introduced to the soil in Baniocha experiment with 15 t ofmanure were calculated upon the data given in Maqkowiak [1986]. The average amountsof nutrients introduced annually to soil with precipitation were calculated frommeasurements made in the Department of Soil and Water Chemistry of LMUZ in Falentysince 1988 (Table 3). Presented amounts of K and P are expressed in kg of purecomponent per ha.

Table 3. Input of NPK load (kg/ha /year) with the deposition

Skladnik x SD V% -+t..005 S.N 18,14 4,0 22,0 9,83P 0,28 0,18 62,8 0,15K 3,08 1,2 380 109I/ Mean values in 1988-1995

Results and discussionIn the Baniocha experiment, a surplus of potassium, in relation to its amounts introducedto soil with fertilizer and precipitation, occurred on only two fertilizer objects CaoN1 andCa2N (Table 4). Greater surplus (19.3 kg/ha/year) occurred at the larger lime dose. Onthe remaining objects plants took up potassium additionally from the soil pool (negativebalance differences), the least amounts on limed soil fertilized with N, dose of nitrogen.Fertilization with 240 kg N/ha resulted in an additional uptake of 11.3 - 13.8 kg K/ha a

63

year from soil, which was accompanied by the greatest removal of potassium in crops(Table 1, 4).In the remaining two experiments balance differences were always negative, the greatestin Laszczki (from 37.2 to 46.7 kg K/ha) accompanied by the greatest removal ofpotassium with crops (Table 1, 5). Mostly negative potassium balance shows, that underexperimental conditions the applied dose of 150 kg K 20/ha elevated later to 180 kgK20/ha was insufficient to cover plant requirements for potassium. In the Laszczkiexperiment plants took up additionally from the soil pool 40 - 50 kg K/ha and in the Jankiexperiment - from 20 - 30 kg K/ha (Table 5). Additional uptake of potassium from thesoil pool - from ca 10% in Baniocha experiment to ca. 30% in Laszczki increasedproportionally to the removal of the element with crop (Table 1, 6).Simplified phosphorus balance in the Baniocha experiment showed a surplus of theelement in all fertilization objects (Table 7). On average it amounted annually from 15.6 -22.3 kg P/ha.

Table 4. Simplified balance of potassium on Baniocha experiment in 1982-1995

kg/ha

Balance components TreatmentsCa, Ca, Ca 2

N, N 2 N, N, N NInputFertilizers, Knaw:

mineral (ammonium nitrate) 1868 1868 1868 1868 1868 1868Farmyard manure 87,2 87,2 87,2 87,2 87,2 87,2Load with deposit, K.,d 43,1 43,1 43,1 43,1 43,1 43,1Sum - E K 1998 1998 1998 1998 1998 1998

OutputUptake with yield, Kpr 1902 2156 2134 2186 1719 2191

Balance difference - A K +94 - 158 - 136 - 188 +279 - 193Annual mean, A K.fyear +6,7 - 11,3 - 9,7 - 13,4 + 19,9 - 13,8(+)potassium surplus, (-)potassium defficiency (uptake from the soil pool)

Table 5. Mean annual differences between the potassium and phosphorus input in to thesoil with fertilizer and deposition and uptake by the herbage (kg/halrok) in 1982 - 1995

kg/ha/rok

Nutrient Experi Treatments-ment Ca, Ca, Ca2

N, N, N, N2 N, N2Potassium B + 6,7 - 11,3 - 9,7 - 13,4 + 19,9 - 13,8(A K,/rok) J - 15,0 -22,7 - 19,7 -22,2 - 18,7 -28,1

L - 39,8 - 41,2 - 46,7 - 40,9 - 39,4 - 37,2

Phosphorus B +20,4 + 15,6 + 19,1 +16,3 +23,3 +15,7(A P0/rok) J +12,1 +9,3 + 10,3 +8,1 +11,3 +7,4

L + 5,9 + 1,0 +3,8 +0,5 +5,9 + 1,4

Baniocha - B, Janki - J, Laszczki - L - experiment Janki (J) - 1981-1985

(+)nutrient surplus, (-)nutrient losses

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Smaller surplus followed the use of the larger nitrogen dose (N2), which is a result ofgreater phosphorus removal with crops (Table 1). In Janki and in Laszczki the largestphosphorus surplus was found in soil fertilized with 120 kg N/ha, not limed (pH 3.8 and3.7) or limed with a double dose of lime (pH 6.2 and 6.9) Table 2, 5). The greatest, nearly100% apparent recovery of phosphorus in relation to the amount introduced to soil withfertilizers and precipitation appeared in Laszczki experiment on soil limed with thesmaller lime dose and fertilized with 240 kg N/ha (Table 2, 6).

Table 6. Mean proportional uptake of nutrient in relation to its quantity introdused in tothe soil with fertilizer and deposit in 1982-1995

Treatments K PN, N N, N

BaniochaCa0 95,2 107,9 44,3 57,4Ca1 106,8 109,4 47,6 55,5Ca2 86,0 109,6 36,3 57,0

JankiCal 111,0 116,7 65,5 73,6Ca1 114,5 116,3 70,6 77,0Ca, 113,7 120,7 67,7 78,9

LaszczkiCa0 129,1 129,8 83,3 97,1Ca 134,2 129,9 89,2 98,6Ca2 128,8 127,3 83,3 96,1

I/quantity of nutrient introdused in to the soil with fertilizer and deposit = 100%

So far the problem of potassium introduced to soil as a result of fertilization has notreached the extent it has in the case of nitrogen or phosphorus [7, 10, 11]. In thepresented 14 years studies the potassium surplus, in relation to the amount introduced tosoil with fertilizers and precipitation. appeared in only two fertilization objects - CaoNtand Ca2N, in the Baniocha experiment. Simplified potassium balance made in thisexperiment for the first 6 years was, except for one case, also negative. Liming limitedhere the potassium uptake from the soil pool, which certainly resulted then from the largercalcium supply from fertilizers in soil [12]. Smaller but also negative mean differencesfrom the 14 year long experiment resulted from the increased potassium dose (from 150to 180 kg/ha K20). In the remaining cases potassium balance was usually negative. Fullpotassium balance considering changes in the content of this element in soil should bemade. This would allow to explain whether the nutrient is exhausted in soil otherwise richin potassium.Bailey [1985] in the glass-house experiments demonstrated that the use of calciumcarbonate may decrease the requirements of grass vegetation for potassium. Barszczewski[1998] studying the behavior of potassium, calcium and magnesium in a similar soil(experiment situated in Falenty) of a permanent sprinkled meadow showed also anegative potassium balance at a nitrogen dose of 360 kg/ha even at potassium fertilizationrate of 200 kg/ha K20. Negative potassium balance (67.8 kgtha/year) was alsodemonstrated by Okruszko et al. [1993] on a 24 years old grassland on peat soil in spite ofpotassium fertilization at a rate of 100 kg/ha K20.

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One should ask if and how long the negative potassium balance can be maintainedwithout negative consequences to soil and, moreover, whether increasing potassium dosesis a proper solution to the problem. It seems that more attention should be paid to theequilibrated supply of other nutrients for plants [2].Potassium balance for Poland in the country scale based upon productive data and thedistinction of areas (acc. to the administrative division) of variable threat of pollution bypotassium revealed the mean surplus and dispersion of this nutrient ranging from 6.2 -14.1 kg K/ha/year [13]. The balance made by Szponar et al. [1996] for the whole countryshowed an average annual surplus of potassium equal to 17.7. kg/ha K20 (14.7 kg/ha K).Both balances point to a relatively small dispersion of the nutrient into the environment.High potassium concentration that appears in ground waters, particularly from a farmyardand its vicinity, suggest, however, a possibility of its losses due to leaching [14] andincline to further studies on preservation of this element in the natural environment,having especially in mind its chemical properties different from those of nitrogen andphosphorus.

Table 7. Simplified balance of phosphorus on Baniocha experiment in 1982-1995

kg/haBalance components Treatments

I Ca2N, N, N1 N2 N, N

InputFertilizers, Pf :mineral (ammonium nitrate) 488,3 488,3 488,3 488,3 488,3 488,3Farmyard manure 19,6 19,6 19,6 19,6 19,6 19,6Load with deposit, P, 4,0 4,0 4,0 4,0 4,0 4,0Sum-I P 512 512 512 512 512 512OutputUptake with yield, P, ,, 227 294 244 284 186 292Balance difference - A P. + 285 +218 +268 +228 +326 +228Annual mean - A P./rok, A +20,4 + 15,6 + 19,1 +16,3 +23,3 +15,7P/year

(+)phosphorus surplus

Phosphorus is another nutrient systematically introduced to the environment in the formof both mineral and organic fertilizers of animal origin. Evident eutrophication of surfacewaters and other ecosystems and the resulting negative consequences point to the need forbalancing this element [11]. A positive phosphorus balance was found in all threeexperiments. Positive balance differences were the smaller (Laszczki<Janki<Baniocha)the larger was the phosphorus removal with crops (Laszczki>Janki>Banioha) (Table 1, 7)and were inversely proportional to the dry weight yield [12]. The greatest phosphorussurplus found in soil fertilized with 120 kg N/ha, not limed (pH 3 and 3.7) or limed withthe double lime dose (pH 6.2 and 6.9) (Table 2, 5) shows, that too acidic soil pH as wellas ,overliming" both create conditions unfavorable for the phosphorus uptake by plants.Similar balance differences were obtained for the first 6 years of experiments, particularlyfor the limed objects [12].

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Balancing of phosphorus might be expected at a larger nitrogen dose (which wouldincrease its removal with crops) in a soil, an surplus acidity of which was neutralized witha rational dose of calcium carbonate. One may assume that the dose of 80 kg/ha P2O5used in experiments is a rational dose for meadow soils of the properties similar to thosein the Laszczki experiment, previously limed acc. to the lHh dose. In the remainingexperiments that dose resulted in too high phosphorus surplus in soil.Due to the admittedly low mobility of phosphorus in soils one may assume that its surplustends to accumulate there. The still open question is if accumulation of phosphorusinvolves all its surplus or which part of the element moves out of the root zone or isleached with the surface runoff. A full phosphorus balance considering changes ofphosphorus content in soil during 14 years of the experiment is required to answer thisquestion.Comparatively, phosphorus balance in a grassland on peat soil showed after 24 years ofexperiment a surplus of the nutrient equal to 42.4 kg P/ha [9]. Balance for the wholecountry made in 1993/1994, which considered both plant and animal production [10]showed an annual phosphorus dispersion into the environment amounting 4.3 kg/ha P.Data cited in Iserman [1991] gave the phosphorus dispersion in Ireland equal to 2.8 kg/haP and in Germany (formerly Western Germany) - 6.0 kg/ha. A possibility of phosphorusleached from soils is evident from the results of Gelbrecht and Driescher [1998], whoshowed increasing concentrations of phosphorus (60-350 pg/I) in water of wetlandsdrained in the past. Presented results demonstrate the need for explanation of the fate ofdispersed phosphorus and further studies on the topic.

Conclusions1. Potassium fertilization of a permanent grassland on a light mineral soil at a rate of 150- 180 kg/ha K2O does not fulfill the requirements of 3-cut plants for this nutrient. Theplants take it up additionally from the soil pool in the amount of 10-30% of thatintroduced with fertilizers and precipitation.2. Phosphorus fertilization of the same soils at a rate of 80 kg/ha P205 is accompanied bythe formation of the nutrient surplus, unused by plants. The surplus, depending on thetype of soil, nitrogen doses and pH, averages 10-50% of that amount of phosphorus,which is introduced with fertilizers and precipitation. Fertilization with a higher nitrogendose decreases P surplus.3. Fertilization with nitrogen at a rate of 120 kg/ha and maintenance of the grassland soilpH in the range 5 - 6 creates the most favorable conditions to limit surplus and losses ofthe studied nutrients and provides their effective utilization by plants.4. Nutrient balances are necessary to correct the NPK doses actually used in farms inorder to enhance nutrient utilization in agricultural production.

AcknowledgementsAuthor is indebted to Mrs. Danuta Kalifiska MSc. Eng. for help in making nutrientbalances.

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ReferencesI. Bailey J.S. Potassium - sparing effect of calcium in perennial ryegrass. J. Plant Nutr. -1989.-

V. 12(8).- P. 1019-1027.2. Bailey J.S. Sustainable fertiliser use. The Fertiliscr Society. 1993. Proceedings.- 1993. No. -

P. 345 44s.3. Barszczewski J. The behavior of potassium, calcium and magnesium in a soil-plat system of a

permanent sprinkled meadow (in Polish).Doctoral thesis. 1999.4. Farruggia A., Decau M.L., Vertes F., Delaby L. 1997. En prairie, la balance aztde a I dchelle

de ]a parcelle. Fourrages. 1997.- V. 151.- P.281-296.5. Fotyma M. Mineral nitrogen content in soil as an index of environmental consequences of

fertilization. In: Nitrogen surplus in agruiculture - a human health risk. (in Polish)Miqdzynarodowa Konferencja, Warszawa 9-10,01 1997 r. Wydawnictwo IMUZ, Falenty. -P.35-40

6. Gelbrech J., Driescher E. Phosphorus in subsurface water- a potential eutrophication source ofsurface waters. W: Phosphorus in agriculture and water quality protection., Sielinko nearPoznah, December 2-3 1997, Institute for Land Reclamation and Grassland Farming (IMUZ),Falenty.- 1998.- P. 66-72.

7. Iserman K. Nitrogen and phosphorus balances in agriculture - A comparison of severalwestern European countries. Int. Conf. on Nitrogen, Phosphorus and Organic Matter. May13-15 Helsingor, Denmark. 1991. - P. 1-20.

8. Maqkowiak C. Organic fertilizers in farms and their impact on environment.(in Polish) ODR.1987.

9. Okruszko H., Gotkiewicz J., Szuniewicz J. 1993. Changes in the content of mineralcomponents of peat soil affected by a long term meadow utilization. (in Polish). WiadomogciIMUZ. 1993.- V. XVII, No. 3. - P. 139-152.

10. Sapek A. Phosphorus cycle in Polish agriculture. W: Phosphorus in agriculture and waterquality protection., Sielinko near Poznat, December 2-3 1997, Institute for Land Reclamationand Grassland Farming (IMUZ), Falenty.- 1998a.- P. 8-18.

11. Sapek A. Phosphorus in agriculture and water quality protection. W: Phosphorus inagriculture and water quality protection., Sielinko near Poznafi, December 2-3 1997, Institutefor Land Reclamation and Grassland Farming (IMUZ), Falenty. 1998b. - P. 5-7.

12. Sapek B. Studies on liming of a permanent grassland on mineral soil. (in Polish). Pracahabilitacyjna. Wydawnictwo IMUZ, Falenty. 1993..- 93PP.

13. Sapek B., Kalifiska D., Sapek A., Pietrzak S. An assessment of water pollution by potassiumfrom agricultural sources based upon selected productive data. (in Polish). MateriatyKonferencyjne. ,,Ochrona i wykorzystanie rolniczej przestrzeni produkcyjne Polski. IUNGPulawy. 1997.- P.261-268.

14. Sapek B. Farm as a source of soil, water and air pollution with nitrogen, phosphorus andpotassium. In: Bibliotheca Fragmenta Agronomica. Proc. Int. Symp. CIEC, PFS andWorkshop IMPHOS, IPI. September 27-30, 1998, Putwy. 1998 - No 3/98. - P. 124-144.

15. Szponar L., Pawlik-Dobrowolski J., Domagala R., Twardy S., Traczyk I. Nitrogen,phosphorus and potassium balance in Polish agriculture. (in Polish). Prace IZZ. 1996.- P. 80,5-102.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

THE NEED OF AGRICULTURAL CROPS FOR POTASSIUM FERTILISERS INLITHUANIAN SOILS

Jonas Maivila, Jonas Arba~iauskas, Zigmas Vai~vila, Tomas AdomaitisAgrochemical Research Centre of Lithuanian Institute of Agriculture

SummaryHaving summarised the research data of total and available potassium it was determinedthat the lowest content of total potassium (K2O) was in dero-podzolic - Iv (haplicarenosols) and gleyic derno-podzolic sandy soils - JP,1 (gleyic arenosols) 1,45-2,47%, thehighest (2,74-4,61%) in sod-gleyic - VG, (gleyic combisols) clay loamy and clay soils.There are 7,6% soils in Lithuania with a very small amount of potassium, 3,54% withsmall, 33,4% with medium and 23,6% with sufficient content of potassium (over150mg/kg of available potassium).The amount of potassium in the soil decreased because of intensive fertilization bynitrogen and phosphorus and the uptake of potassium by plants, so the rates of potassiumfertilizers should be increased to achieve the stability of potassium in the soil. Accordingto the research data (elementary plot testing methods and experiments of fertilization incrop rotation) the yield of agricultural crops in moraine soil depended on the amount ofavailable potassium in the soil. A significant dependence of the yield on the amount ofpotassium was obtained in the tests with winter wheat, rye, barley, potatoes and perennialgrasses of the first year of use. However, in glacial lacustrine silty medium loamy soilwith a low status of potassium (76-89 mg/kg) the yield of winter wheat and sugar beetwas not increased by fertilization with potassium fertilizers (on NP background). It isdeemed that the above mentioned crops could uptake the reserve (four times larger thanin moraine soil) of unexchangeable potassium.

Key words: total, available potassium and unexchangeable potassium, fertilizers, sandyloam, silty loam.

IntroductionAccording to research data, potassium as well as nitrogen and phosphorus are veryimportant for plants: in the process of metabolism potassium stimulates the accumulationof proteins. If amount of potassium is sufficient, chlorophyll better absorbs energy fromthe sunlight. It has a positive influence on assimilation; also it facilitates the transpor-tation of sugars. Potassium stimulates the synthesis of pectin and vitamins (thiamine,riboflavin and others), intensifies the hydration of cell colloids, decreases the viscosity,improves the metabolism, permeability, and regulates the ratio of non-protein potassiumcompounds and proteins. One of the main properties of potassium is the capability topenetrate in tissues of a plant. It depends on property of cell's membrane to be pervious topotassium ions, it is very important for various physiological processes [ 2, 5, 6 1.On the other hand, this property of membrane to let pass the potassium easier than otherelements and to make it possible for potassium to move freely in tissues of plant notmaking any stable compounds which would let us discuss the importance of potassium,that is the reason to consider that this element is investigated insufficiently.

69

During the period of 1967-2000 a great number of investigations has been done fordetermination of total and available potassium and it changes in soil.In our opinion, presented research data contribute to the solving further problems ofpotassium and its influence on plants.

Materials and methodsThe total amount of potassium (K20) in Lithuanian soils was determined during theperiod 1971-1985 by melting the soil samples with the anhydrous soda (Na2CO,) in theplatinum vessels. This research data was received from the State Land ManagementInstitute and was summarised in Agrochemical Research Centre. The significance of theavailable K20 in soil for agricultural plants was determined by elementary plot testingmethod (1585 plots) and field crop rotation experiments (24 experiments) carried outduring the period of 1973-1993. Changes of available K20 were discussed when themultifactor experiments of various fertilization NPK rates were carried out in Radviligkisdistrict, Sk~miai in sod-gleyic sandy loam soil during the period 1971-1998 and in,iauliai district, Naisiai, crop rotation experiment (seven field crop rotation). There arepresented 13 different treatments of various NPK fertilization rates for comparison of theinfluence of the amount of KO on the yield in sod-gleyic sandy loam and in sod- gleyicsilty medium loamy soils. In this case, available K20 was determined by A-L (Egner-Rim-Domingo) and Scofild's methods, unexchangeable potassium - by Pchiolkin's method.There was a sequence crop rotation:

1) grasses of the first year of use2) grasses of the second year of use3) winter crops: rye - in derno-podzolic and gleyic derno-podzolic soils, wheat - in

sod-gleyic soils4) potatoes - in demo-podzolic and gleyic derno-podzolic soils and sugar beets - in

sod-gleyic soils5) spring barley.

Yield data was obtained by growing varieties of agricultural plants used at that time.Statistical reliability of research was evaluated by limit of the least essential difference(LSD,,). Dependence of the yield of agricultural plants and efficiency of fertilizers onavailable K20 and fertilizers rate is expressed by the correlative ratio.

Results and discussionFrom the summarised research data it was established that the lowest content of totalpotassium was in demo-podzolic and gleyic demo-podzolic sandy soils (Table 1). Contentof the total potassium in the humus layer was 1,45 - 2,47% and in subsoil 1,45-2,82%.Insignificant quantity of total potassium was in West Lithuanian gleyic demo-podzolicloamy soil, as well as in sandy soil; although in subsoil the amount of total potassium was2,37-3,35%. The largest amount of total potassium was in Middle Lithuanian plain in sod-gleyic clay loamy and clay soils: in humus layer 2,85-4,61% and in subsoil 2,66-4,92%.However, the main source for plant nutrition is available potassium.According to the research data (Agrochemical Research Centre) 7,6% of Lithuanian soilshave very small, 35,4% - small, 33,4% - medium amount and 29,8% (more than 150mg/kg) sufficient amount of available potassium (Table 2).Agricultural plants usually accumulate potassium better than phosphorus and easier getinto the deeper layers. That is why, using fertilization, a less amount of availablepotassium accumulates on the surface horizons.

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Table I. Amount of total potassium in the soils of Lithuania (SLMI 1971-1985)Soil r pe

Sod-podzolic Sod-podzolic Sod-podzolic Sod- Sod- Sod-gley Alluvial(JV) and sod- slightly (Jiv ) gleyic (JP'v) gelyic gleyic (VG2) (A.K)

podzolic and medium (p / P;p) (VGI) (VG0) light sand,Sampling gleyic (JPv) (J2 v) podzolized sandy clay loam loam sandydepth cm sandy sandy loam and (West loam and and loam (p / p) loam and

(ps; s, / s; light loam Lithuania) light (p2 m / lightps s; / s/p) (ps; p / p; p) loam p2 ;m) loam

(East (ps ;p / p) (ps ;p/Lithuania ) I S;p)

Amount of total (K20) %0-10 "2.01 232 2M (9)2.74 51 2.63 2.36

1,60-2,16 1,85-2,71 1,51-2,81 2,47-3,14 2,85-4,52 2,32-2,84 2,22-2,5411-20 192 152 2.06 23§ 3.54 271 2.19

1,45-2,47 1,81-2,87 1,61-2,15 2,46-3,17 2,74-4,61 2,32-2,86 2,01-2,5321-30 1 7.L 2.25 9 4.00 25 228

1,60-2,16 2,00-3,32 1,92-3,0 2,46-2,88 3,27-4,92 2,67-3,13 2,18-2,4431-40 U 278 I 2M 4.07 l9 215

1,60-2,16 2,25-3,52 1,80-2,70 2,41-3,15 3,24-4,85 2,81-3,18 2,00-2,4341-50 L9 Zt 27 2.90 33 L 3-Q 225

1,75-2,82 2,18-3,54 1,82-3,01 2,36-3,24 3,08-4,77 2,72-3,66 2,00-2,5251-60 S 2.85 2.67 2.82 3.7 2.29 2.15

1,46-2,15 2,04-3,75 1,05-3,10 2,35.3,24 2,86-5,05 2,51-3,03 2,00-2,4261-70 1.97 2.96 2.73 269 32 2.82 2.15

1,45-2,30 2,58-3,54 2,33-3,23 2,36-3,24 2,96-4,18 2,32-3,11 2,00-2,4271-80 2.97 . 2. 358 2.89 2.10

1,45-2,15 2,41-3,54 2,37-3,02 2,36-3,24 2,94-4,18 2,70-3,03 1,88-2,4281-90 U 2.8 2.68 2.59 3.57 292 2.5

1,60-2,30 2,56-3,32 2,37-3,02 2,36-3,02 2,84-4,32 2,72-3,16 1,72-2,4391-100 1.94 271 2.67 2.53 2 2.75 1.98

1,60-2,45 2,42-3,32 2,40-3,35 2,21-2,70 12,66-4,12 1261-300 1170-2,23*numerator - average amount of total potassium (K 20)denominator- limits of deviations

Table 2. Available potassium in the soils of Lithuania

Amount of potassium in soils (mg/kg)

Year of Investigated (% from the investig ated area)Area investigation area, ha Very Small Average Sufficient

small(0-50) (51-100) (101-150) (> 150)

East 1985-1993 1097220 8,9 32,3 32,9 25,9Lithuania 1968-1976 1018300 6,8 28,0 35,3 29,9Middle 1985-1990 1387953 6,3 39,5 33,5 20,7Lithuania 1968-1976 1246804 2,9 36,0 35,5 25,6West 1986-1993 823070 7,9 32,8 33,9 25,4Lithuania 1968-1976 703579 3.5 22,7 36,7 37,1

Lithuania 1985-1993 3308243 7,6 35,4 33,4 23,6in total 1968-1975 2968683 4,4 30,1 35,7 29,8

In the long term experiment in Radviligkis district, Sk&miai using various fertilizationNPK rates in sod-gleyic sandy loam soil the amount of accumulated potassium (K 2O) inplants varied from 69,7 to 225,8 kg/ha (Table 3). In major treatments, including the

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control treatment the amount of accumulated potassium in plants was higher than thatgiven with fertilizers and a marked decrease of available potassium was found out. Itdepends not only on the rates of potassium fertilization, but also on the ratio withphosphorus and especially - with nitrogen fertilizers. When only potassium or potassiumand phosphorus fertilizers were used during the period of 27 years the amount ofavailable K20 increased, in the treatments where potassium and larger amount of nitrogenand phosphorus were used the amount of available K20 decreased due to accumulation ofpotassium in plants.

Table 3. The influence of mineral fertilizers on the change of available potassium in sod-gleyic loamy soils (Radviligkis district, Skemiai)

Fertilization rates Accumulated Compensation Amount of K20 in soil mglkga potassium potassium

N PO, K 20 (K2 0) in bfrtis changeyield kg/ha by fertilizers 1971 1998 over 27 years annual

0 0 0 69,7 0 104 74 -30 -1,110 0 96 97,8 98,1 126 128 +2 +0,070 0 192 101,9 188,4 112 180 +68 +2,520 96 0 76,4 0 116 77 -39 -1,440 96 96 107,2 89,5 111 121 +20 +0,740 96 192 131,8 145,6 111 166 +55 +2,030 192 0 84,2 09 113 66 -47 -1,740 192 96 109,8 87,4 112 115 +3 +0,110 192 192 131,9 145,5 102 166 +64 +2,37

144 0 0 102,1 0 104 73 -28 -1,04144 0 96 145,3 66,0 102 117 +15 +0,56144 0 192 172,1 111,5 114 173 +41 +1,52144 96 0 110,4 0 112 64 -48 -1,78144 96 96 157,0 61,1 107 92 -15 -0,56144 96 192 212,1 90,5 105 136 +31 +1,15144 192 0 116,7 0 126 61 -65 -2,41144 192 96 184,3 52,0 110 80 -30 +1,11144 192 192 198,8 96,5 99 131 +32 +1,18

228 0 0 113,4 0 128 63 -65 -2,41228 0 96 152,0 63,2 101 107 +6 +0,22228 0 192 175,7 109,2 97 142 +45 +1,67228 96 0 111,1 0 110 61 -49 -1,81228 96 96 164,3 58,4 96 95 -1 -0,03228 96 192 194,4 98,7 108 113 +5 +0,18228 192 0 110,9 0 122 68 -54 -2,00228 192 96 161,5 59,4 128 85 -43 -1,59228 192 192 225,8 85,0 109 112 +3 +0,11

Then, intensifying fertilization by nitrogen and phosphorus, the amount of availablepotassium in the soil decreased and if we want to stabilise the amount of availablepotassium, it is necessary to increase the potassium fertilization rates. Using fertilizationN 44P96 in the field crop rotation (without manure fertilization) positive changes wereachieved in sandy loam soils using potassium fertilization 160-190 kg/ha annually.When in the field crop rotation manure fertilization was used, the need of mineralpotassium fertilizers decreased. In sod-gleyic sandy loam soils (district Siauliai, Naisiai)

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positive changes of available potassium were determined when annual amount ofavailable potassium was 98,2kg/ha with manure and fertilization with on average 90kg/haof active ingredient of potassium fertilizers.Similar changes of potassium due to fertilization were also obtained in the farms wherethe agrochemical research was carried out. The research data of available potassiumduring the period of 1985-1993 in comparison with the data during the period of 1968-1975 show that twenty years ago there were more than 6,2% soils with sufficient amountof potassium, 2,3% - medium amount and less than 3,0% - very small, 5,3% - smallamount of potassium. It indicates that the amount of available potassium in the soildecreased because the losses of potassium due to the uptake of potassium by plants werelarger than applied with fertilizers, and through potassium leaching to deeper layers.The authors do not have a unanimous opinion about the influence of available K20 oncrop yield. Many authors indicate that the crop yield depends on the amount of availablepotassium [9, I1, 13, 14]. Other authors note that the influence on crop yield depends notonly on the amount of available K2O, but also on granulometric and mineralogicalcomposition, humidity, soil, reaction and other properties, defining the availability ofpotassium to plants [1, 2, 10, 12] and some authors [4, 8] indicate other forms ofpotassium in the soil which take part in plant nutrition.Research data (1967-1993) from Agrochemical Research Centre were analysed byelementary plot testing methods and it was determined that the crops yield depended onthe amount of available potassium in the soil. However the mathematical analysisrevealed less significant correlation in comparison with available phosphorus (Table 4).

Table 4. The dependence of the yield of agricultural crops fertilized by moderate nitrogenand phosphorus fertilizers on the amount of available potassium in the soil (1967-1993)

Amount of K2O in soil, m o/kg Coefficient of<50 51- 101- 151- > r'a+bx+cx' regressive Ratio of Criterion of

Soil too is 200 200 equation coela- correlation

Yield t/ha a I b c11 t

Winter wheat

VG 2,26 3,46 13,57 3,71 4,00 1,50 0,0300 -0,89.1O4 0,56 8.0Rye

JP( 2,07 2,98 3,08 3,27 3,18 1,01 0,0254 -0,58.104 0,51 6,6J.' 2,44 2,69 3,19 3,77 3,99 1,01 0,0198 -0,19.104r 0,61 8,4

BarleyJP1' 1,69 2,77 3,10 3,55 3,51 1,62 0,0167 -0,34104 0,43 7,1VG, 2,55 3,14 3.28 3,48 3,56 2,13 0,0157 -0,40.10 0,41 7,4Jiv 1,65 2,12 2.69 3,08 3,48 0,74 0,0211 -0,43-104 0,46 6,6

Sugar beets

VG, 21,0 28,9 32,3 3,57 39,0 S18,0 10,0943 1-0,30.10" 0,48 6,2Potatoes without fertilization by manure

Jp v 13.6 16,2 18.1 18.5 21,1 13.6 10.0352 -0,80.10 ' 0.52 4,4Jv 11,6 13,9 16,6 20,2 21,8 1,29 0.1334 -0.66-10" 0,67 7,9

Potatoes fertilized by manureJP v 14,2 20,7 24,2 25,2 25,7 13,6 0,1095 -0,24.10-3 0,57 4,4

J0 12.8 17, 22,6 25t 28,3 11,8 0,0820 0,33-10"4 0,53 4,5

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There was established a significant influence of available potassium on the yield of winterwheat and rye, potatoes and the perennial grasses of the first year of use; a little lesseffect was on the yield of barley. The lowest yield of all the tested crops was establishedin the soils with a very low amount (to 50 mg/kg) of available potassium. When theamount of potassium increased to 51-100 mg/kg, a significant yield increase wasobtained. Although in the other group (100-150 mg/kg) the yield increase was 10% forrye, 12% sugar beets, 17% potatoes. When the amount of potassium was over 150 mg/kgin the soil, the yield of all the tested crops increased also, but not so significantly, exceptthe yield of sugar beets.Similar research data about the influence of available potassium on the yield of agriculturalcrops were obtained in the four-course crop rotation (Table 5). In these experiments the roleof available potassium was much more obvious for potatoes and sugar beets.

Table 5. The influence of available potassium on the yield of agricultural crops in thecrop rotation

Soil

Treatments i, JPlV I VG,Agricultural of Amount of K 0 in soil, mpzkg

crops fertilizing 051- 101-151- < 101 151100 1150 1200 100 150 200

Yield of the main production, t/haWinter wheat N60P45 3,91 4,16 4,72Rye NoP45 3,08 3,66 3,64Barley N45P45 3,06 3,44 3,18 2,84 3,59 4,36Sugar beets N12oP75 26,6 38,6 40,6Potatoes N9oPo 13,6 15,7 18,3Grasses of I 's year of use P45 6,23 6,33 6,14Annual mixture crops NoP45 3,51 5,40 5,65Feed units in average N498PW 4540 4900 5120per ha N71 ,2P6 7,5 580 6967 7782

The yield of potatoes without manure fertilization in gleyic derno-podzolic sandy loamand loam soils increased by 4,7 t/ha when the amount of K20 was increased from 100 to200 mg/kg, the yield of sugar beets increased by 14,0 t/ha in sod -gleyic loamy soil.According to Agrochemical Research Centre data in sod-gleyic loamy soil when the soilreaction was almost neutral or alkaline, the yield of agricultural plants increasedconstantly, while the amount of available potassium increased to 200 mg/kg and more,while in demo-podzolic and gleyic demo-podzolic soils the yield was the largest when theamount of available potassium was about 150 mg/kg.It should be noted that all the discussed research data were obtained from the experimentsin moraine origin soils. Investigations carried out in glacial lacustrine sod-gleyic siltymedium loam soils revealed specific features of potassium influence on crops yield.When the amount of available potassium was 76-89 mg/kg, the yield of winter wheat andsugar beets was not increased by potassium fertilizers (Table 6).The research data in Table 7 help to find out the reasons why in this case the increase ofwinter wheat and sugar beet yield was not obtained. If the amount of available potassiumon soils of both types is similar, the amount of unchangeable potassium in glaciallacustrine soils is four times higher. It is deemed that long term vegetation plants are able

74

to intake the reserve of unchangeable potassium. It reveals possible mineralogicaldifferences between these two types of soils.

Table 6. The influence of potassium fertilizers on the yield of agricultural crops inmoraine and glacial lacustrine soils

Agricultural Fertilization rates kg/ha Moraine Glacial lacustrineplants N P205 KO VGI' p/ps/p VG p/grain yield t/ha

Winter 0 0 0 2,93 4,36wheat 60 60 0 3,94 5,90

60 60 60 4,45 5,8260 60 90 4,39 5,83

LSDO, 0,22 0,25Sugar 0 0 0 22,9 30,7beets 120 90 0 26,2 36,5

120 90 120 33,6 37,4120 90 165 31,1 36,2

LSD0, 1,9 1,9Spring 0 0 0 2,47 3,78barley 60 60 0 2,98 4,24

60 60 60 3,65 5,0260 60 90 3,90 4,80

LSD, 0,14 0,20Perennial 0 0 0 3,29 5,84grasses 60 45 0 4,44 7,38

60 45 60 5,08 7,5660 45 90 5,30 7,83

LSD0, 0,29 0,42

Table 7. Potassium in moraine and glacial lacustrine soils

Sampling Total potassium Unexchangeable Available potassium, mg/kgdepth cm % potassium, mg/kg A-L method Method of

I SkofildMoraine VGI' P/Ps/

0-20 2,16 154 52 9,2V61 19,8 10,8 174

Glacial lacustrine VG ' pj/p//m0-20 2,58 619 94 13,4V % 6,7 8,5 8,7 104

Conclusions1. The lowest amount of total potassium (1,45-2,47%) was in demo-podzolic - I' (haplicarenosols) and gleyic derno-podzolic sandy soils - IPI,' (gleyic arenosols), the highestamount (2,74-4,61%) in sod-gleyic - VG (gleyic combisols) clay loamy and clay soils.2. According to research data during the period of 1985-1993 there were 7,6% soils inLithuania with a very small amount of potassium, 35,4% with small, 33,4% with mediumand 29,8% sufficient. The amount of available potassium in comparison with researchdata ten years ago changed: there was an increase in soils with very small (3,2%) andsmall (5,3%) amount of potassium; a decrease in soils with sufficient (6,2%) and medium(2,3%) amount of potassium.

75

3. When intensifying fertilization by nitrogen and phosphorus, the amount of availablepotassium in the soil decreased, and in order to stabilise the amount of availablepotassium it is necessary to increase the fertilization rates. When in the field crop rotationmanure fertilization was used, the need of mineral potassium fertilizers declined.4. In moraine sandy loam soils the yield of winter wheat, rye, potatoes and perennialgrasses of the first year of use is to a great extent dependent on the amount of availablepotassium (K20), the yield of barley is less dependent. When the amount of availablepotassium in the soil was very low the yield of many agricultural crops was very small;when the amount of available potassium increased to 100-150 mg/kg, the yield increasewas very considerable. Although the increase of potassium (when the amount ofpotassium was over 150 mg/kg in soil) increased the yield, the yield increase wasnegligible, except for the sugar beets.5. In glacial lacustrine silty medium loam soils with a low content of available potassium,potash fertilizers did not increase the yield of winter wheat and sugar beets, because ofthe possibility to assimilate potassium from the other forms; first of all, unexchangeablepotassium, whose reserve in these soils was more considerable than in the moraine sandyloam soils.

References1. Barber S.A. Soil nutrient bioavailability. A mechanistic approach. 1984 by John & Sons, Inc.

-P.199-213; 224-238.2. Black S.A. Soil - Plant relationships / Second edition. John Wiley and Sons, Inc., New York.

1968.-P.431-471.3. Dirvoemio tyrimo medliaga. Valstybinio iemetvarkos instituto fondai. Kaunas, 1971-1985.4. Kuhlman H. and Wehrman J.: (G) Testing different methods of soil analysis for their

applicability for the determination of K fertilizer requirements of loess soils. Z.Plansemahr.Bodenk. 147, 334-348 (1984).

5. Lietuvos dirvo~emio agrochemines savybes ir jq kaita. Monografija. Sudarytojas JonasMa~vila. 1998, -P.107-119.

6. Mengel K., Kirkby E.A. Principles of plant nutrition //International potash institute. -Bern,Switzerland, 1987. -P. 427-452.

7. Potassium availability and uptake. Better Crops. 1987. -P. 12-15.8. B.Shaw J.K., Stivers R.K., and Barber S.A. 1983. Evaluation of differences in potassium

availability in soils of the same exchangeable potassium level. Comm. Soil Sci. Plant Anal.14: 1035-1049.

9. Z.Vai~vila. Judriujq azoto, fosforo ir kalio jtaka remes Okio augalq4 mitybai. Habilitacinisdarbas. Dotnuva-Akademija. 1996. -P.76-97.

10. Van Diest A. Factors Affecting the Availability of Potassium in Soils // Congress onOccasion of the 25t Anniversary of Scientific Board of the International Potash institute.Potash Research - Review and Trends -P.28-33.

11. Boraenn .M. HayHbxe ocHoBbl nlptiMeHnean yno6peHH B 3anauoM perHoHe CCCP.MHHCK, 1981. -200 c.

12. Fop6yaon H.H. MHnepanormn H 41r3H'4ecKa xnMIa noqB. -M.:HayKa, 1978. C.185-208.13. KynaKoBcKa T.H. Mxuepanbnwe yno6peunn H nioopoliHe noqBh HI flnoaoponHe noMn H

ypocafi. -BunbH1oc,1974.-C.82-90.14. [locrmikon A.B., Ilalpax C.A., BHiorpaanoBa P.M. H p. BnAHe coaepxafm nOUBH)K-

HhIX 4DopM docdopa H KaJIHA Ha ypocati cen6,cKoxos3RIcTeHHIX KyJlwTyp no pe3ynhTaTaM

onhrroB arpocnyx66i PCOCP // Hapaerpb WJ1O1OaOpoH/M OCHOBHIX THIOB noqn. -MocKBa,

1988.- C.16-35.

76

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

ABILITY OF SOME NORWEGIAN SOILS TO SUPPLY GRASS WITHPOTASSIUM

Anne Falk OgaardDepartment of Soil and Water Sciences, Agricultural University of Norway,

IntroductionAnalyses of grass crops in Norway show that the mineral composition is often not optimalwith regard to animal health, because of a too high level of K fertilisation andconsequently luxury consumption of K. It was found too high a K/Ca+Mg ratio inapproximately 50% of 125 grass samples from dairy farms in northwestern Norway,evaluated according to risk for grass tetany (1,2). Underestimating of the K supply fromthe soil causes this. Therefore, a project has been started at the Department of Soil andWater Sciences, Agricultural University of Norway aiming at getting more knowledgeabout K dynamics and the ability of different soil types in Norway to supply plants withK. Based on these results, it is an aim to improve computer programs used fordetermining K requirements.

Materials and methods22 field trials in different parts of Norway have been studied. Seventeen of these wereestablished on grass in 1997 or 1998 with a K fertilisation of 0, 60, 120 and 180 kg K/ha.All treatments receive 200 kg N/ha, 30 kg P/ha and 50 kg S/ha. Soil samples are takeneach spring and autumn and analysed for ammonium-acetate-lactate extractable K(K-AL). At start of the experiment the soil samples were also analysed for acid soluble K(extracted with I M HNO3). As some of this extracted K is also soluble in the AL extract,the K-AL value was subtracted from the K-lHNO3 value to give the value of acid solubleK. Yields are determined and plant samples are analysed for K, Ca and Mg. Based onthese analyses the amount of K taken up by the plants from AL-extractable K and non-exchangeable K has been calculated. AL-extractable K is here considered as exchan-geable K, since the amount of AL-extractable K is often close to the amount ofexchangeable K. In this presentation, results from 16 field trials on grass are shown.Some soil characteristics at the start of the experiment are presented in Table 1. Theclassification of the content of K-AL and K-14N0 3 (K-AL not subtracted) used inNorwegian fertiliser planning is given in Table 2.

Table 1. Soil characteristics

Mean Max. Min.Clay (%) 10.2 40 ITot. C (%) 4.1 8.5 1.7pH 6.2 7.5 5.5Acid soluble K (mg K/kg) 770 2650 90K-AL (rag K/kg) 149 323 31

77

Table 2. Classification of the content of K-AL and K-HNO3. All values in mg K per kgdry soil.

Low Medium high High Very highK-AL 0-65 66-155 156-300 >300K-HNO 3 <300 300-795 796-1200 >1200

ResultsFig. I shows that the supply of K from the soil to the grass, both from AL-extractable Kand non-exchangeable K, is considerable even at the highest level of K fertilisation. Thesupply from AL-extractable K was reduced from year to year, whereas the supply fromnon-exchangeable K was lowest the first year. With reduction of the level of easilyreleasable K the supply from non-exchangeable K increased.

kg K/ha rK supply from K-AL

160 160 60

140- 140 *l K supply from non- 140

120 120 exch. K 120--

100 - I. year 2. year -3. yea

80- 80 80 --

60 - 60- 60--

40 - 40 40 -

20 - 20 20

0 . . . 0 .0 .

0 60 120 180 0 60 120 IS0 0 60 120 IS0

K rerilisation (kg K/ha)

Figure 1. Mean values of K supply from K-AL and non-exchangeable K to the grass inthe 1., 2. and 3. experimental year

The K-AL values were considerable reduced the first experimental year for all levels of Kfertilisation. The decrease in the K-AL value the first experimental year was related to theK-AL value at the start of the experiment (R2 =0.68, p<0.001, including all fertiliserlevels). The higher the K-AL level at start the larger was the decrease in the K-AL value.The results indicated that the soil has a certain "equilibrium level" for K-AL that variesbetween different soil types (Fig. 2). Often this "equilibrium level" is higher in a clay soilthan in a sandy soil. The content of AL-extractable K in excess of this "equilibrium level"was easily taken up by the grass. Without K fertilisation the excess of K-AL was taken upduring the first two experimental years, with the major part in the first year. After thismainly small changes in the K-AL level were observed. For K fertilisationrecommendations it is useful to know the level where K-AL stabilises when the soil isdepleted of K. If the K-AL value is far above this "equilibrium level", the soil has a poolof easily available K that ought to be evaluated as a K source for the following crop toavoid luxury consumption of K and unsustainable depletion of K resources.In many of the fields K fertilisation did not increase dry matter yields significantly, evenin the third experimental year. In most cases with reduction of yields without K fertiliser,60 kg K/ha was sufficient to avoid yield reduction. The K content in the grass was,however, significantly increased by K fertilisation. In many of the fields K fertilisationresulted in luxury consumption of K (>2% K in the dry matter). The extent of luxury

78

consumption was related both to the level of K-AL and acid soluble K (Fig. 3). In somefields luxury consumption of K was observed also in the treatment without K fertilisation,despite that a considerable part of the K uptake originated from non-exchangeable K.This shows that a part of non-exchangeable K is easily releasable.

350

300

250

150

50

Sn 1' 7 almn 97 Sirng 98 Autumnn98 SM99 Ajtzm99

Figure 2. Changes in the K-AL level from spring 1997 to autumn 1999 for II differentsoils without K fertilisation

K% Acid K<400 mg/kg Acd K5400nrs

3.5 3.5

3.0 3.0 025 2.5

2.0 2.0 t41.5 •1.5

1,0- 10

0.5 0.50,0 0,0 . .

0 50 o100 150 200 250 300 350 0 50 100 150 200 250 300 350

a) b) K-AL (.S X g)

Figure 3. K% in dry matter yields at K fertilisation of 0 (a, b) and 120 kg K/ha (c, d) andat different levels of K-AL and acid soluble K. Values from the 1. and 2. experimental year

Evaluating the ability of the soil to supply the crop with K on the basis of soil analysesshowed that the yields did not increase with K fertilisation if the K-AL value in springwas above 100 mg K/kg. With K-AL values lower than 100, the value of acid soluble Kwas important whether it was effect of K fertilisation or not. If the acid soluble K valuewas larger than 400 mg K/kg, there were no significant yield effects of K fertilisation the

79

first and second experimental year even at small K-AL values (Fig 4). The third year twoof the fields with acid soluble K between 400 and 1000 mg K/kg showed a tendency ofreduced yields without K fertilisation.

K%3.5 35

10- 30

2.5 25

20 • 20

1.5 1.51.0 Lo

0.5 05

0.0 00

0 50 100 150 200 250 300 350 0 50 10 150 20 250 300 350

e) d) K-AL (.S Mg)

Figure 4: Relationship between K-AL and relative yields without K fertilisation (2*0 kgK/120 kg K +180 kg K) with acid soluble K <400 mg/kg (a) and >400 mg/kg (b). Values

from the 1. and 2. experimental year.

ConclusionsSupply of K from the soil to grass is high in many places in Norway, even at high levelsof K fertilisation. Too high levels of K fertilisation, with consequently luxuryconsumption of K, is therefore commonly. It is recommended to consider K supply fromthe soil in order to exploit this K source more efficiently. Supply from non-exchangeableK is often considerable. Analyses of non-exchangeable K (extracted with e.g. IM HNO3)should therefore be available when planning K fertilisation on mineral soils. The K-ALvalues are very variable. Analyses from previous years are therefore difficult to use fordetermining K requirements.

References1. Kemp A and 't Hart M L 1957 Grass tetani in grazing milking cows. Netherl. Jour. Agric.

Sci. 5, 4-17.2. Synnes 0. M. and lpstad S. 1995. lnnhaldet av mikro- og makronringsstoff i gras, med

utgangspunkt i dei tre nordlegaste Vestlandsfylkafylka. Faginfo.Planteforsk 6, 101-113.

80

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS

FERTILISA TION EFFECT ON SOIL AND CROPS

BALANCE OF PHOSPHORUS IN SOIL AT LONG APPLICATION OFFERTILIZERS AND LIMING

Jinis Vigovskis, Aivars Jermugs

Skriveri Research Center

SummaryEffect of lime and fertilizer applications on field crop yield and total balance ofphosphorus have been determined in a long-term field experiment in Skriveri. It wasestimated that phosphorus balance varies mainly with the rate of phosphorus fertilizersapplied. The leaching loss of phosphorus (0,1- 0,5 kg ha') is a small part of the totalbudgets of these nutrients.

Key words: phosphorus balance, mineral fertilizers, liming, leaching

IntroductionThe application of mineral fertilizers should provide not only economically justified cropsof agricultural cultures, but also to support soil fertility. Last years because of lack ofmeans for purchase of mineral fertilizers, on soddy- podzolic soils quite often are appliedonly nitric fertilizers, and phosphorus fertilizers are used in doses, which do not coverremoval of these elements with a crop.The basic sources of phosphorus for plants are the mobile forms of phosphorus, whichlevel in soddy- podzolic soils is rather low, and phosphoric fertilizers. If the accumulationof stocks of phosphorus of soil stops, the reception of a high-grade crop becomespractically impossible. To find the most rational way of the decision of this question it isimportant to know, as there is a balance of phosphorus at various intensity of applicationof phosphoric fertilizers.The efficiency of application of phosphoric mineral fertilizers under the conditions ofLatvia was investigated by many scientists (2, 4, 5, 6, 7, 9). The majority of theseresearches were carried out on short-term field experiments for definition of influence ofphosphoric fertilizers on a crop of field cultures (2, 4, 5, 6). For drawing up of phosphoricbalance the long field experiences with mineral fertilizers are more significant. Suchresearches are carried out in Latvia (7, 8, 9), Lithuania (1, 3, 10) and other countries (11).

Materials and methodsIn 1981, an experimental drainage system was established at the Latvian ResearchInstitute of Agriculture (at Skriveri, Latvia). The total area (1.6 ha) of the experimentalfield was divided into 16 plots (15x50 m). Each plot was supplied with a seepage tiledrain at a depth of 80-100 cm and an inspection well for drain water sampling andmeasurement of total water amount. The intensity of drain water flow was measured andwater samples were taken daily for 18 years during periods of drainage.Since 1982, long-term field trials were carried out under crop succession with long-termgrass, grain (rye, triticale, spring wheat, barley, oat), potatoes, and rape. The soil wasrecultivated draining soddy- podzolic acid loam, low in plant nutrients. Some relevant soilproperties at the beginning of the experiment were: pH (KCI) 4.7-4.9; sum of

81

exchangeable basic cat ions (method of Kappen- Gilkovich), 12-16 meq kg'; availablephosphorus (DL-method), 10-20 mg P2O5 kg'; exchangeable potassium (DL-method), 40-60 mg K20 kg-l; exchangeable (1 N KCI) calcium, 563-625; exchangeable (1 N KCI)magnesium, 81-115 mg kg-'; and soil organic matter (Tyurin's method), 1.9-2.1 %.According to a 4x4 experimental design, four lime (slate ash with 80 % neutralizingvalue) rates, 0, 3, 6, and 12 t ha -' CaCO 3 and four fertilizer rates, NoPoKo, N45P30K45 ,N 90P60K90, N13sPwK 35 of ammonium nitrate, potassium chloride and superphosphatewere investigated. Slate ash was spread at the beginning of the experiment, and fertilizerswere applied annually in spring.

Results and discussionInfluence of soil liming and doses of mineral fertilizers on the productivity of crop yieldper years 1994- 1998 is characterized in the 1 table.

Table 1.Crop yield in five- year crop rotation (1994 - 1998.)

Fertilizer Yield, t ha"

treatment Triticale Spring rape S rin wheat Potatoes BadeUnlimed soil

NoPOKo 0.77 0.24 1.40 17.4 0.67N45P3oK4s 3.67 1.51 3.57 24.7 2.71NPoKo 3.22 0.88 3.50 35.9 3.75Nj35Pq0Kj35 5.35 1.70 3.88 -34.0 4.06

Limed soilNoPoKo 1.65 0.62 1.60 17.7 0.74N45P3oK45 3.90 1.55 3.69 24.9 2.55N9 PoKo 5.49 1.82 3.64 37.5 3.88N]35PwoK,35 5.52 2.04 4.62 30.5 4.03

Obtained results show that in difference from the previous period of researches, highdoses of mineral fertilizers (N135 PoK135) in last years do not guarantee essential increaseof yield any more and in some cases, as, for example, in case with potatoes, decrease evenobserved of yield is in comparison with dose of mineral fertilizers N90P6oKo.For the period of researches under influence of regular application of doses of mineralfertilizers in soil the contents of easily available phosphorus has changed. Dynamics ofthis process on unlimed and limed soddy- podzolic soil is shown in table 2.

Table 2. Change of the contents of mobile phosphorus mg P205 kg-' in soil at longapplication of fertilizers

Fertilizer treatment 1982 1986 1992 1995Unlimed soil

N0P0Ko 15 15 13 7N4P3oK415 15 13NPK9 o 15 30 31 32N35PK3515 41 54 63

Limed soilNoPoKo 15 15 10 4N4sP3IK45 15 15 15 13NoPoKo 15 33 33 36N_sPoK]3 15 48 80 90

82

As it is visible from results, on allotments of control variant (without fertilizer) there is agradual decrease of stocks of mobile phosphorus, and on limed soil the decrease isexpressed more evidently. On a low background of fertilizers (N45P30K45) the smalldecrease is observed only last years as on unlimed and limed soil. From a dosephosphorus P, in soil gradually, though and it is insignificant, the contents begins togrow, and at Po there is already a constant accumulation of mobile connections ofphosphorus in soil.For the period of researches removal of phosphorus from unlimed soddy- podzolic soil bya crop of field cultures has made on the average from 7.2 kg ha"' ha (control variant) up to33.6 kg ha-' per one year at doses of mineral fertilizers N1.. P90K,. On limed soil the cropof cultures and also removal of phosphorus was higher- on the not fertilized allotments ithas made on the average 9.7 kg ha', and on high doses of fertilizer - 35.9 kg ha'.

Table 3. Average removal and balance of phosphorus from soddy- podzolic soil by a cropat different doses of fertilizer (1994. - 1998.)

Fertilizer treatment Removal P20, kg ha a Balance P20, kg ha-'avera per year average per year

Unlimed soilNoPoKo 7.2 -7.2NOPoKO 23.0 7.0NPKg 25.2 34.8N135PoK,3 33.6 56.4

Limed soilNoPoKo 9.7 -9.7N45P3oK45 24.3 5.7NPK, 33.3 26.7N_3sPoK,35 35.9 54.1

Processes of migration of soluble compounds of phosphorus in soddy- podzolic soilproceed slowly; active fixing them in less soluble form causes that. Therefore washingaway of phosphorus makes of soil by drain water an insignificant part in general balance.On given to low cultivated soil of loss not exceeded 0.1-0.5 kg ha' of phosphorus. Thedoses of phosphoric fertilizers practically did not influence concentration of phosphoricions in water of drain.The account of balance shows, that on low cultivated soddy- podzolic soil all investigateddoses of phosphoric fertilizers are formed by positive balance of phosphorus. Atfertilising limed soil the account part of balance is increased, and indemnificationremoval in comparison with unlimed soil is reduced.

ConclusionsOn allotments of control variant (without fertilizer) there is a gradual decrease of stocksof mobile phosphorus, and on limed soil the decrease is expressed more evidently. On alow background of fertilizers (N45P30K45) the small decrease is observed only last years ason unlimed and limed soil.At Pg, there is a constant accumulation of mobile connections of phosphorus in soil.The leaching losses of phosphorus (0.1-0.5 kg ha-') from soil are a small part of the totalbudgets of these nutrients.

83

The account of balance shows that on low cultivated soddy- podzolic soil all investigateddoses of phosphoric fertilizers is formed by positive balance of phosphorus.

ReferencesI. Ignotas V., Tyla A. Chemical elements in limed soils and in soil water // Baltic Region:

Agriculture in Acid Soils. Collection of articles. Lithuanian Scientific Society, Vilnius-1993.- P. 19- 23.

2. LipenTite l.,tikans J., Kaiocipg V. Impact of lime and fertilizers on nutrient losses throughtile drains fl Integrated land and water management. Challenges and new opportunities.Abstracts (IV Stockholm Water Symposium, 9-13 August 1994) 1994. P.75.

3. Pleseviiene A. Influence of manuring on agrochemical properties in acid and limed soils//Baltic Region: Agriculture in Acid Soils. Collection of articles. Lithuanian ScientificSociety, Vilnius- 1993.- P. 163- 167.

4. Reinfelde L., Timbare R. Normative values of mobile phosphorus and potassium content insoil in Latvia and other European countries H State Scientific Production Enterprise (SSPE)1997. P. 21- 25

5. Rienfelde L. Augsnes agrolimiskas kart~anas materiflu izmantogana / Latvijas PSRVARK zinatn. tehn. inform. un propagandas centrs Riga- 1988.- 47.

6. Ri~ilis G., Ramane H. Ka barojas augi H "Avots" Riga 1989.- 151.7. Stikans J. Efficiency of lime and mineral fertilizers on field crop yielding in acid, little

ameliorated sod- podzol soils // Baltic Region: Agriculture in Acid Soils. Collection ofarticles. Lithuanian Scientific Society, Vilnius- 1993.- P. 177- 181.

8. Stikans J., Ka2ociug V., Lipenite I. Augu barbas vielu izskaloganas melioretas augsnes//Jelgava LLU 1996.- 29.

9. Stikans J., KaociQ V., Lipenite 1. Impact of fertilizers on nutrient losses through tile drainsin Latvia//Proceedings of the Latvian Academy of sciences. 1996.-v. 50.- N 2. P. 85-89

10. Vasiliauskiene V., Birietiene Z., RimAelis J., Rudys 2. Rates and ratios of NPK- fertilizers:effect on soil properties in cultivated pastures on loamy sands// Baltic Region: Agriculture inAcid Soils. Collection of articles. Lithuanian Scientific Society, Vilnius- 1993.- P. 185- 190.

11. A6anea B.2R. Bbunoc 3IeMeHToB nHTaHHS c JpeHaKai<HAbM CTOKOM Hf3 cynecqaHslX U04B//Me. HopaHH H BOAi. xo3ai cTro, MOCKBa- 1992.- 7-8, 10-12.

12. THM6ape P.M!. Banac nTaTeniblx neuiecTr Ha natae // XHMH3au ceJbCKOrOxoa3tcla 1989. N2 21- 3110

84

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

AMOUNT OF PHOSPHORUS IN THE SOILS OF LITHUANIA AND ITS ROLEIN OPTIMIZATION OF AGRICULTURAL CROPS NUTRITION

Zigmas VaiIvila, Kristinas Matuseviius, Jonas Mafvila, Leonas Eitminaviius

Agrochemical Research Centre of the Lithuanian Institute of Agriculture

SummaryHaving summarised the research data on the total and available phosphorus it wasdetermined that the highest content of total phosphorus (0,18-0,26%) was in alluvial, sod-gleyic light loam, sod-gleyc (gleyic combisols) clay loamy and clay soils, also in WestLithuania's demo-podzolic gleyic loamy soils - JP, (gleyic albeluvisols). A little lowercontent (0,009-0,12%) in Central Lithuania's sod-gleyic VG, (gleyic combisols) sandy loarnsand in East Lithuania's demo-podzolic jv (eutric and dystric albeluvisols) sandy oams.In Lithuania soils with a very low content of available phosphorus account for 20,3%,with low content 41,5%, with medium content 22,3%, and with a high content 15,9%.When using intensive nitrogen and potassium fertilization a positive phosphorus balancecould be achieved by applying phosphorus fertilizers at a rate of 45-60 kg/ha. Whenfertilizing by manure on average 15t/ha annually a negligible positive change of P20, wasobserved. The greatest efficacy of fertilizers was obtained in the soils with a very lowcontent of phosphorus (0-50 kg/ha). A considerable yield increase was achieved when theamount of P20 5 was 50-150 mg/kg, a negligible increase when the amount of availableP205 was over 150 mg/kg.Winter wheat was the most sensitive crop to P20 5. The influence on rye was differentthan on wheat and it was different in East and West Lithuania's soils. In West Lithuania'sdemo-podzolic gleyic soils the greatest yield increase was obtained when the amount ofP20 5 was 150-200 mg/kg, in East Lithuania's dero-podzolic soils over 200 mg/kg. Thebest yield of barley was obtained in Central Lithuania's sod-gleyic soils. However themost marked influence of P20 5 on the yield was in West Lithuania's demo-podzolicgleyic soils.The yield of sugar beets and potatoes was lower when the amount of phosphorus was lowin the soil. The largest increase in the yield of sugar beets was obtained when the amountof available P20, was over 200 mg/kg, for potatoes150-200 mg/kg and over 200 mg/kg.

Key words: total and available phosphorus, sandy loam, loam clay, fertilizers, yield.

IntroductionPhosphorus is one of the main nutrients, necessary for all living beings. Although theamount of phosphorus in plants is smaller than nitrogen, potassium and calcium,phosphorus is even more important than calcium and even potassium. Phosphorus iscomparatively stable in the soil. Because of stability and slight solubility phosphorus isusually an indispensable element for plants. Phosphorus takes part in the synthesis ofproteins in plant, accumulation of sugars and formation of grains. When there isdeficiency of phosphorus, the growth of plants is poor, tillering capacity is low, the leavesof plants turn to twine, the stems become violet in tint, the ears of cereals are small, the

85

yield is poor. Phosphorus is necessary for the synthesis of organic compounds and in theprocess of metabolism [1, 5, 10, 13, 14, 15].Plants usually take up phosphorus from the soil and from organic and mineral fertilizers.During the period 1967-2000 a lot of research has been done into the total phosphorusand its change in the soil as well as fertilisation experiments. Some of the research dataare presented in scientific reports, publications, some of them are stored in the funds ofthe Agrochemical Research Centre and State Land Management Institute.

Materials and methodsThe data on the total amount of phosphorus (P20 5) in the soils of Lithuania during theperiod of 1971-1985 were taken from the State Land Management Institute andsummarised at the Agrochemical Research Centre. The soil samples were melted with theanhydrous soda (NaCO3) in platinum vessels.The change of available phosphorus P205 (method A-L) was investigated by multifactorexperiments involving different fertilizer rates in Radvilikis district, Skemiai, in sod-gleyic soil and in the crop rotation (seven-course crop rotation) in iauliai district, Naisiai.Comparison between the research data from 1968-1975 and 1985-1993 was made.The importance of available P20 5 to agricultural plants was determined by elementaryplot testing methods (1585 plots) and the research data (1973-1993) of crop rotation fieldexperiments (24 experiments) were summarised.The following crop rotation was used:

6) grasses of the first year of use7) grasses of the second year of use8) winter crops: rye - in derno-podzolic and demo-podzolic gleyic, wheat - in sod-

gleyic soils9) potatoes - in demo-podzolic and derno-podzolic gleyic soils; sugar beets - sod-

gleyic soil.10) spring barley.

Statistical reliability of research data was evaluated by limit of the least significantdifference (LSD 5 ). Correlation and regression methods were used to estimate thedependence of the yield of agricultural crops and efficacy of fertilizers on available P20 5and fertilizer rates.

Results and discussionSummarised data of the State Land Management Institute showed that the highest contentof phosphorus was in alluvial, sod-gleyic light loam, sod-gley loamy clay and clay soils,also in West Lithuania's derno-podzolic gleyic loamy soils. The amount of totalphosphorus in the 0-20 cm layer was 0,18-0,26%, a little less (0,09-012%) in EastLithuania's demo- podzolic sandy loam soils, also in Central Lithuania's sod-gleyicloamy soils (Table 1).However, the main source for crop nutrition is available phosphorus.According to research data (1985-1993) of Agrochemical Research Centre 20,3% ofLithuanian soils have very small, 41,5% small, 22,3% medium amount and 15,9%sufficient amount of available phosphorus (Table 2).It was determined that the amount of available P205 in soil depended on fertilization,yield of agricultural crops and accumulated nutrients.In the long term experiment (197 1-1998) in Radviligkis district, Skemiai using variousNPK fertilizer rates in sod-gleyic loamy soil the amount of accumulated availablephosphorus in plants varied from 18,5 to 67,2 kg/ha (Table 3).

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Table 1. Amount of total phosphorus in Lithuania's soils (SLMI 1971-1985)

Soil typeSod-podzolic Sod-podzolic Sod- Sod-gelyic Sod- Sod-gley Alluvial

(Jv) and slightly (J1v) podzolic (VG1) gleyic (VG2J) (AK) sand,

sod-podzolic and medium gleyic sandy (VG,) clay light loam sandy loam

Sampling gleyjc (Jp1 v) (J2v) podzoli- (jpV) loan and loan and (p / p) and lightdepth cm sandy zed sandy (p / p;pt) light loam loam loam

(ps; s, / s; loam and light (West (ps ;p / p) (p2 ; m/ (ps ;p / s ;p)ps s,; / sp) loan Lithuania) p,; m)

(ps; p / P; P,)(East

I Lithuania IAmount of total (P20, %

0-10 *Q32 0.11 0.19 009 018 0.20 0.20,10-0,14 0,08-0,12 0,11-0,26 0,08-0,13 0,12-0,26 0.13-0,37 0,17-0,45

11-20 0.11 0.10 0.18 0.09 0.18 8 920,09-0,14 0,08-0,13 0,12-0,22 0,07-0,13 0,12-0,26 0,14-0,30 0,16-0,27

21-30 0.08 0.08 0.13 0.07 0.14 O.l 0.240,03-0,14 0,05-0,13 0,07-0,21 0,04-0,11 0,08-0,20 0,08-0,16 0,21-0,27

31-40 010 0.08 008 0015 0 .180,07-0,16 0,06-0,11 0,07-0,16 0,06-0,10 0,10-0,24 0,08-0,14 0,16-0,21

41-50 "1 QM OJ.O 929 018 0.10 0.150,04-0,17 0,08-0,12 0,07-0,14 0,08-0,12 0,11-0,28 0,08-0,14 0,13-0,17

51-60 0.07 010 0.10 009 0.19 011 0180,04-0,10 0,07-0,13 0,08-0,14 0,08-0,12 0.12-0,29 0,08-0,16 0,16-0,19

61-70 0.07 0.09 0.12 0.10 018 12 0.190,06-0,10 0,08-0,12 0,10-0,16 0,08-0,12 0,11-0,26 0,08-0,14 0,16-0,22

71-80 0.08 0.12 0.13 009 0.18 O.l 0.210,06-0,12 0,09-0,15 0,10-0,19 0,08-0,10 0,12-0,29 0,10-0,16 0,17-0,29

81-90 0.07 013 013 009 0.18 Ol 0.190,06-0,08 0,09-0,15 0,10-0,16 0,08-0,11 0,12-0,26 0,10-0,14 0,16-0,24

91-100 9.07 0,12 .1 O9 8 0.11 0160,05-0,10 0,09-0,14 1010-0,20 1 0,08-0,10 0,12-0,26 0,09-0,14 0,07-0,26

* numerator - average of total phosphorus (P2 0,)

denominator - limits of deviations

A marked increase was found in the treatments where higher rates of phosphorusfertilizers (160-192 kg/ha) and no or lower nitrogen fertilizer rates (0, 38, 76 kg/ha) orpotassium (0, 32, 64) were used. Correlation analysis showed that about 94% change ofavailable P205 (method A-L) depends on the intensity of mineral fertilization. Positivechanges of available phosphorus could be achieved with phosphorus fertilizer rate 45-60 kg/ha. Organic fertilizers have a considerable influence in the crop rotation. It wasproved in iauliai district, Naisiai - in sod-gleyic loamy soil (seven -course crop rotation),where on average 15t/ha of manure was applied annually (60t/ha for sugar beets, 45t/hafor cereals) (Table 4).According to investigations conducted in our Republic and abroad the yield ofagricultural crops depends on the amount of available P20 5 [1, 3, 6, 7, 8, 11, 12].Similar research data about the influence of available phosphorus on yield of agriculturalcrops were obtained by elementary plot testing methods and in the crop rotationexperiments. In these experiments carried out over the period of 1967-1993 it wasdetermined that fertilization by NK fertilizers (without phosphorus fertilizers) and taking

87

into account the change of P205 in soil, the yield increased: for barley - 2,11 to 4,50; rye

- 2,04 to 3,62; sugar beets -23,4 to 38,0; potatoes - 11,2 - 20,7 t/ha (Table 5).

Table 2. Available phosphorus in the soils of Lithuania

Amount of phosphorus in soils (mg/kg)

Area Year of Investigated (% from the investigated area)investigations area, ha very small small average sufficient

(0-50) (51-100) (101-150) (>150)East 1985-1993 1097220 25,9 40,5 18,7 14,9Lithuania 1968-1976 1018300 44,4 34,2 11,5 9,9Middle 1985-1990 1387953 10,8 42,0 28,5 18,7Lithuania 1968-1976 1246804 34,9 44,5 12,9 7,7West 1986-1993 823070 28,8 42,2 16,6 12,4Lithuania 1968-1976 703579 44,9 35,1 9.7 10,3Lithuania 1985-1993 3308243 20,3 41,5 22,3 15,9

1968-1975 2968683 40,6 38,8 11,5 9,3

Table 3. The influence of mineral fertilizers on the change of available phosphorus in sodgleyic sandy loam soil (Radvili.kis distr. Sk~miai)

Fertilizer rate Accumulated Compensation Amount of P20 5 in soilkg/ha phosphorus of mv /kg

(P205) in phosphorus by changeN P205 K20 yield kg/ha fertilizers 1971m. 1998m. over 27 nual

years

0 0 0 18,5 0 57 55 -2 -0,070 0 96 23,6 0 58 50 -8 -0,300 0 192 23,6 0 69 63 -6 +0,220 96 0 30,3 316,8 60 324 +264 +9,780 96 96 33,4 287,4 56 283 +227 +8,410 96 192 37,2 258,1 58 297 +239 +8.850 192 0 36,8 521,7 60 625 +567 +21,000 192 96 37,0 518,9 50 536 +486 +18,000 192 192 36,5 526,0 55 629 +574 +21,26

144 0 96 26,4 0 58 51 -7 -0,26144 0 192 34,4 0 62 53 -9 -0,33144 96 0 46,4 206,8 50 283 +232 +8,59144 96 96 55,8 172,0 56 264 +208 +7,70144 96 192 54,7 175,5 60 243 +183 +6,78144 192 0 49,1 391,0 57 575 +518 +19,18144 192 96 64,0 300,0 60 533 +473 +17,52144 192 192 62,5 307,2 47 520 +473 +17,52228 0 0 32,2 0 58 53 -5 -0,18228 0 96 33,2 0 53 50 -3 -0,11228 0 192 28,6 0 56 53 -3 -0,11228 96 0 46,3 207,3 50 210 +160 +5,93228 96 96 58,3 164,8 53 215 +162 +6,00228 96 192 59,8 160,5 48 214 +166 +6,15228 192 0 55,0 349,0 55 478 +423 +15,67228 192 96 65,5 293,1 66 420 +354 +13,11228 192 192 67,2 285,7 56 484 +428 +15,85

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Table 4. The influence of manure and mineral fertilizers on the change of availablephosphorus in sod-glcyic sandy loam soil ( iauliai district, Naisiai)

Average rates of Average annu Balance of P2O'Accumulated P2O5 in soilfertilizers, kg/ba Intake P205 kg/ha P205 kg/ha kg/ha mg/kg

with with total in in total from *)

N P2O5 K20 manure mineral yield addi- phospho-fertilizers tion rus

yield fertilizers0 0 0 45,0 - 45,0 29,8 - 15,2 1160 86,4 90,6 45,0 86,4 131,4 36,0 - 95,4 216

86,4 86,4 0 45,0 86,4 131,4 44,3 7,1 87,1 79,3 19986,4 0 90,6 45,0 - 45,0 37,2 - 7,8 9186,4 86,4 90,6 45,0 86,4 131,4 49,8 12,6 81,0 73,8 23143,2 86,4 90,6 45,0 86,4 131,4 44,8 7,6 86,6 78,8 196130,0 86,4 90,6 45,0 86,4 131,4 52,5 15,3 78,9 71,1 22986,4 43,2 90,6 45,0 43,2 88,2 46,2 9,0 42,0 34,2 17486,4 130,0 90,6 45,0 130,0 175,0 53,6 16,4 121,4 113,6 32386,4 86,4 45,3 45,0 86,4 131,4 47,2 10,0 84,2 76,4 204864 86,4 136,0 45,0 86,4 131,4 50,0 12,8 81,4 73,6 217* in 1971, at the beginning of the experiment, the amount of P2O in soil was on average 61 mg/kg;coefficient of variation 7,0 %.

Table S. The yield of agricultural crops, fertilized by moderate nitrogen and phosphorusfertilizer rates on the amount of available phosphorus in the soil (1967-1993)

Amount of P20 in soil mg/kg Coefficient of Ratio of Criterion ofSoil <50 51- 101- 151- > regressive equation correlation correlationtype 100 I50 200 200 ya+bx~cx' ratio

Yield t/ha a 1 b cWinter wheat

VG. 2,11 2,93 13,56 14,00 14,50 1,63 10,0193 1-0,30.10" 0,68 10,3

RyeJP1' 2,07 2,96 3,63 3,75 3,55 1,14 0,0215 -0.38.104 0,65 9,8Ji v 2,01 2,45 2,58 3,00 3,70 0,96 0,0209 -0,40.10"4 0,68 10,7

Barley

JP,' 1,91 2,73 3,03 3,19 3,43 1,59 0,0160 -0,3210" 0,52 11,5

VG1 2,60 3,06 3,32 3,54 4,13 2,13 0,0150 -0,43.10" 0,43 9,1J,' 2,15 2,57 2,95 3,26 - 1,33 0,0223 -0,60.10- 0,44 6,3

Sugar beets

VG, 23,4 30,5 32,9 34,0 38,0 25,5 0,0472 -0,56.10" 0,49 6,3

Potatoes without fertilization by manureJPJ 11,7 15,2 16,0 17,1 22,2 1 1,9 0,0327 0,28.10" 0,49 4,4Jlv 10,6 16,5 18,1 24,8 19,2 4,27 0,2007 -0,54-1 -3 0,66 7,9

Potatoes fertilized by manureJP,' 14,5 18,5 1 22,3 25,3 25,7 9,12 0,148 -0,33.10 -' 0,72 7,1J,' 13,2 19,0 21,8 24,5 18,5 1,34 0,356 -I,24.0 . 0,61 5,1

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The lowest yield of agricultural crops and the efficiency of fertilisers were obtained in thesoils with a very low amount of phosphorus (to 50 mg/kg). A considerable increase in theyield occurred when the amount of available P20 5 increased from 50 to 150 mg/kg in thesoil. The winter wheat was the most sensitive for this change. The influence of change onrye was different than that on wheat and it was different in East and in West Lithuaniansoils. In West Lithuanian derno-podzolic gleyic soils the largest increase in yield wasobtained when the amount of P205 was 150-200mg/kg and in East Lithuanian demo-podzolic soils - more than 200 mg/kg. The highest yield of barley was obtained inCentral Lithuania in sod-gleyic soils. However, the most marked influence was revealedin West Lithuania in demo-podzolic gleyic soils. There was determined the correlationratio (il = 0,52) between the yield and the amount of P205 in the soil. An especially largeincrease in yield was obtained when the amount of phosphorus increased from 50 to100 mg/kg.Sugar beets, potatoes yielded more poorly than cereal when the amount of phosphoruswas 50 mg/kg. When the amount of phosphorus was 50-100 mg/kg, the increase in yieldfor sugar beets was 7,1 t/ha or 30,3%, potatoes without manure fertilization 4,7 t/ha,fertilized by manure 4,9 t/ha. The optimal amount of phosphorus in the soil for potatoesfertilized by manure was about 200, without manure fertilization 150-200 mg/kg.A similar influence of P205 for agricultural crops was observed in the elementary plottesting and in the four-course crop rotation ( winter wheat, rye, sugar beets and potatoes,barley, perennial grasses of the first year ) experiments.

Conclusions1. The highest content of total phosphorus (0,18-0,26%) was found in alluvial, sod-gleyic

light loam, sod-gleyic clay loamy and clay soils, also in West Lithuania's demo-podzolic gleyic loamy soils. A little lower content (0,09-0,12%) in Central Lithuania'ssod-gleyic and East Lithuania's derno-podzolic soils.

2. According to the research data collected during the period 1985-1993 by theAgrochemical Research Centre 20,3% soils in Lithuania contain very low, 41,5% low,22,3% medium and 15,9% very low amount of phosphorus in comparison with theresearch data twenty years ago. An especially marked decrease (20,3%) was in thegroup soils with very low amount of phosphorus, an increase in the group of soils withmedium (10,8 %) and high (6,8%) amount of phosphorus.

3. In case of intensive fertilization by nitrogen and potassium in order to obtain a positivebalance of phosphorus it is necessary to use 45-60 kg/ha phosphorus fertilizers.Fertilizing in sod-gleyic soils with manure on average 15 t/ha annually, the change ofavailable P205 in the crop rotation was negligible, but positive.

4. According to numerous research data it was determined that the yield of agriculturalcrops and the efficacy of fertilizers depend on the amount of available P205 in the soil.The lowest yield of agricultural crops and the largest increase in yield was obtained inthe soils with a very low content of phosphorus. The yield considerably increasedthrough phosphorus fertilizers when the amount of P,0 5 was 51-150 mg/kg, the lowestincrease was determined at P205 content over 150 mg/kg.

5. The highest yield of winter wheat, barley and rye was obtained in East Lithuania, forsugar beets, potatoes, fertilized by manure in West Lithuania. When the amount ofphosphorus was over 200 mg/kg and for potatoes without fertilization by manure, alsorye in West Lithuania when the amount of phosphorus was 150-200 mg/kg.

90

References1. Agrochemija. Kaunas, 1999. 142-169 p. Sudarytojas Z.J.Vaigvila.2. Dirvofemio tyrimo medliaga. Valstybinio emttvarkos instituto fondai. -Kaunas, 1971-

1985.3. Gericke S. Ergebnisse von Phosphatdungungsversuchen // Phosphatsaure. -1967.-Bd.27, N

1/2. -S.47-78.4. Lietuvos dirvolermiq agrochemints savybts ir jq kaita. Kaunas, 1998. p.6 4-84. Sudarytojas

J.MaIvila.5. Mengel K., Kirkby E.A. Principles of plant nutrition /International potash institute.-Bem,

Switzerland, 1987.-606 p.6. Petraitiene V. Lauko stjomainos augalq derliaus ir kokybes priklausomumas nuo mineraliniq

traq normuo santykiq bei judriujq maisto medliagq kiekio veltniniame gleji~kame lengvopriemolio dirvolemyje. Habilitacinis darbas. Dotnuva-Akademija. 1997, -115 p.

7. Simmelsgaard S.E., Djurhuus J.The possibilities of precision fertilization with N, P and Kbased on plant and soil parameters//lbido. -P. 179-187.

8. Svedas A. Dirvolemis - traos - derlius. Habilitacinis darbas. -Dotnuva-Akademija, 1993 -88 p.

9. Vaigvila ZJ. Dirvolemio mineralinio azoto, judriujt4 fosforo ir kalio vaidmuo 2emes ,ikioaugalq mityboje. Habilitacinis darbas. Dotnuva-Akademija.

10. ArpoxHMHmi lion pea. 1B.A..roRHa. -MocKaa: BO ArponpoMwnaaT, 1989. - C. 105-347.1I. ,flepcaBrun A.M., flonoBa P.H. 3aBcxMocr ypoias O3HMOtt OCHHUlI OT arpoxMHmeCKHX

cIoIicTB 10MB B OCHOBH61X palioiax ee Bo31Len Bm // ArpoxMmns.- 1984. X23. - C.27-35.12. KacruKnAi IO.H. ArpoxHMH4ecKe acne(Tb peweniiH npo6neMbi 4oc(Iopa B 3eMIeIeJIH

CCCP // ArpoxHMns. -1983. - 210. - C. 16-3 I.13. flerep6yprcKHAt A.B. Arpoxmai H 4nHuionorH IHTaHJI paCTeHHfi. - MOCKa:

Poccenhxo3HWnaT, 197 1. - C. 183-226.14. fpAaHmHnKOa A.M. ArpoxnM~m. H36pan.bue coqlnemH. - M.:Cenbxo3aaaaT, 1963.-

T.LJ.-735 c.15. TomncoH .. M., Tpoy 'D-P. HOqBb H HX nIAoRopoDme. - MoCKBa: Konoc, 1982.-C.287-291,

370-382. / fepeaon c aIPJIHHCXOKO g3bica 3.H.JJKOHIe.

91

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

THE INFLUENCE OF ORGANIC FERTILIZERS ON PHOSPHORIC REGIMEIN THE SODDY - PODZOLIC SANDY LOAM SOIL

Liudmila TripolskajaLithuanian institute of Agriculture, Voke branch

AbstractChanges in soil agrochemical properties and phosphate regime were investigated atregular application of different types of manure and mineral fertilizers over the period1987 - 1998 at the Voke Branch of the Lithuanian Institute of Agriculture. It wasestablished that application of peat manure resulted in a marked increase in humuscontent in the soil, in the reduction of actual soil acidity, and in the increase in thecontent of total and mobile phosphorus. The application of semi - liquid manure had aless marked effect on the accumulation of organic matter and phosphorus, but moreconsiderably increased the content of mobile potassium. A regular application of manureand mineral NPK fertilizers changed the fractional composition of phosphates. Incomparison with the not fertilized soil, the amount of water-soluble phosphates increased1,99 - 4,20 times, and that of mobile phosphates, determined in hot water 22,5 - 54,8times. The amount of organic phosphates in the soil increased only at entering peat andstraw manure, and accounted for 57,1 - 65,1 % of the total phosphorus (in the notfertilized soil- 47,3 %). Application of manure and NPK fertilisers increased the amountof Ca - phosphates and insoluble residue of phosphorus.

Key words: soil, manure, mineral fertilizers, phosphorus, the fractional composition ofphosphates.

IntroductionBrought in the soil phosphorous fertilizers are tranformed depending on the form offertilizers, soil type and its granulometric composition, soil temperature and water regime,time of interaction between soil and fertilizers. Amelioration of soil is accompanied byaccumulation of phosphorus when a positive balance is provided.When mineral phosphorous fertilizers are applied in the soil amount of mobile phosphateand degree of mobility quickly rises /6/. Simultaneously with these processes, theprocesses of fastening of phosphorus in the soil occur (biological sorbtion by micro-organisms, take up of soil minerals by the surface, fixation by oxides and hydrooxides Al,Fe, Ca, Mg etc.). On soddy podzolic sandy oarns the highest contents of mobilephosphorus (according to Kirsanov) was observed at pHKc 5,8 and humidity 60 % fromthe complete moisture retention capacity of the soil, and the maximum mobility ofphosphates (according to Skofild) was established at a more acid reaction ( pHKCe 5,2 ).In many soils more than 50 % of the total content of phosphorus is accumulated in thecomposition of organic compounds. In forest ecosystems, phosphorus of organiccompounds through the process of mineralisation provides more than 80 % of phosphorusneeds of plants /1/. Similar processes also take place in agrocenoses. In contrast tomineral phosphate, the accumulation of organic phosphorus depends not only on the

92

amount of fertilizers, but also on other factors influencing the intensity of mineralisationof phosphatorganic compounds. On the whole, stocks of organic phosphorus in the soilare more stable than those of mineral. In a number of cases, the application of fertilisersdoes not result in an increase of the content of organic phosphorus in the soil /4/. In someworks /2/ also is shown, that at soil amelioration the intensity of mineralisation ofphosphatorganic compounds can increase, therefore the absolute content of organicphosphorus in the soil is reduced.The most significant changes of phosphate regime in the soil occur under the influence ofliming and at regular application of organic fertilisers. The latest research carried out inRussia, /3, 8/has shown, that in limed soils the content of least plant available phosphatesis reduced (almost twice), while the amount of phosphorus, soluble in NaOH is increased.The contents of mobile phosphorus under the influence of liming is increased only on lessbuffering soil. Application of organic fertilizers results in the change of the ratio betweenorganic and mineral phosphorus in the soil. Research conducted in Germany has shownthat in comparison with mineral fertilizers, solid and semi - liquid manure increase theamount of readily available phosphate /9/ more considerably. Similar results werereceived also in Poland /1/.

Materials and methodsResearch subject - sod podzolic sandy loams, regularly manured with different types ofmanure, or manure and mineral fertilizers (FAO classification Hapli-dystric combisol.,CMd-ha).Experiments were set up in 1986 at the Voke Branch of the Lithuanian Institute ofAgriculture. Initial soil agrochemical characteristic was as follows: pHKCt - 4,4-4,5,hydrolytic acidity (according to Cappen) - 34-45 mekv./kg, amount of absorbed bases(according to Kappen- Hilkovits) - 31-47 mekv./kg, content of mobile phosphorus (A-Lmethod) - 161-181 mg./kg, mobile potassium - 189-204 mg./kg, content of humus (accordingto Turin) 1,54 - 1,88 %, total nitrogen (according to Kjeldahl) - 0,098-0,120 %.As fertilizers we used cattle manure: semi - liquid, on straw or on peat, as well as mineralfertilizers - ammonium nitrate, superphosphate and potassium chloride. One rate ofmanure was calculated according to the amount of nitrogen in it and corresponded to300 kg / ha N. Rates of mineral fertilizers were as follows N150P5oK5,0 . The followingintensive crop rotation was used: I.potatoes, 2.annual legume-grass mixture, 3.winter ryefor green material and maize, 4.fodder beets, 5.annual legume-grass mixture, 6.winter ryefor green material and maize.Soil samples for the determination of phosphorus forms and phosphate structure weretaken for 12 years of research. Samples were-selected from the depth of 0-20 cm in fourreplications.Total phosphorus (P total) was determined by oxidation of the soil sample by a mixture ofconcentrated H2SO 4 and HCIO 4. Mobile phosphorus was determined by A - L method.Fractional composition of phosphates was determined according to the method of Changand Jackson (1957), modified by Askinazi, Ginzburg and Lebedeva (1963). Solubility ofphosphates was also determined in hot water.

ResultsBefore the beginning of this research (1986) sod podzolic sandy loams were characterizedas very acid soils containing medium content of mobile phosphorus and potassium, andalso organic carbon. Without application of fertilizers, in 12 years of research, the acidity

93

of soil, amount of exchange bases and amount of mobile phosphorus did not changeessentially (Table 1). Content of C,8 and mobile potassium considerably decreased.A regular application of different types of manure together with mineral fertilizersresulted in the reduction of soil acidity from 4,5-4,6 pH (1986) up to 5,1-5,3 pH in 1998.The amount of exchange bases, mobile phosphorus and potassium, accumulation ofhumus considerably increased.The highest accumulation of humus occurred at entering peat manure into the soil. Peatand straw manure also increased the amount of mobile phosphorus in the soil moreconsiderably than semi - liquid manure. And semi - liquid manure had a strongerinfluence on the amount of mobile potassium in the soil.

Table 1. The effect of fertilizacion on the soil agrochemical properties 1986 - 1998 y.

Treatment pHKcL P20 mg/kg KO mg/k Humus %1* 2* 1 2 I 2 I 2

I Without fertilizer 4,4 4,3 181 164 202 62 1,80 1,902 Peat manure (Ne) alter- 4,4 5,1 161 495 191 235 1,88 3,93

nating every seconde yearwith N,,oPsoK 50

3 Straw manure (N,,) alter- 4,5 5,2 176 438 194 440 1,72 2,96nating every seconde yearwith N15oPsoKso

4. Semi-liquid (Na) alter- 4,4 5,1 175 342 189 612 1,74 3,07nating every seconde yearwith N15oP50KI50

5 Semi- liquid manure (No) 4,4 5,3 182 322 204 536 1,82 2,87every year

LSD 0,08 0,12 11 17 12 32 0,11 ,017Note. I - data from 1986 before setting up the test

2 - data from 1998 after the end of the second crop rotacion

Under the influence of fertilizers the amount of total phosphorus in the soil increasedalmost twice. In not manured soil there was 0,062 % of P, in the manured soil with strawor peat manure - 0,112 - 0,113 % of P, in the manured soil with semi - liquid manure itwas a little lower - 0,096 % of P. The fertilizers not only increased the amount of totalphosphorus in the soil, but also increased its availability to plants. The content of mobilephosphorus in the soil increased up to 322 - 495 mg P205 /kg (in the control - 164 mgP2O5 /kg of soil) (Table 2). Differences in the contents of total phosphorus in the soilunder the influence of different types of manure were probably caused by a greatermobility of organic phosphate of semi - liquid manure, which was easily leached indeeper layers of the soil. A high mobility of phosphates of semi - liquid manure is markedin the works of many authors. / 5, 7, 9 /. In our research significant enrichment of soillayer 20 - 40 cm by mobile phosphorus was also observed, however essential differencesbetween solid and semi - liquid manure were not revealed. Besides the increase of theamount of mobile phosphorus, the best availability of phosphorus is indicated by theincrease of the amount of water - soluble phosphorus determined in the solution ofNH 4CI. In comparison with the not fertilized soil, under the influence of fertilizers, the

94

amount of phosphorus determined in NHCI increased by 12,2 - 39,4 mg P205 /kg of soilor from 0,9 % in the not fertilized soil up to 1,2 - 2,0 % from P total in fertilized soil. Butmore considerably increased the amount of phosphorus carried aways by hot water. In thenot fertilized soil an insignificant amount - about 7 mg Pa0 5 /kg of soil is determined, andin the soil applied with manure and NPK - 200-385 mg P0O5 /kg of soil, it made up 7,8-17,5 % of P total.

Table 2. The influence of fertilization on the amount of total and plant available1986 - 1998 year.

exstraction in exstraction inTreatment P total NH 4CI hot water

% % from % frommg/kg P total mg/kg P total

I Without fertilizer 0,062 12,3 0,9 7 0,52 Peat manure (Na) alter- 0,0112 43,2 1,7 200 7,8

nating every second yearwith N15oP50KI50

3 Straw manure (No) alter- 0,0113 51,7 2,0 283 10,9nating every second yearwith Nl 5oPsoK 5o

4. Semi-liquid (Nw) alter- 0,096 32,9 1,5 385 17,5nating every second yearwith N35oP50Ks 0

5 Semi- liquid manure (N,,) 0,090 24,5 1,2 158 7,8every year

Regular application of manure and mineral NPK changed the ratio of organic and mineralphosphorus in the soil. In not fertilized soddy podzolic sandy loams the organicphosphorus made up about 37 % of its total amount (Figure). At fertilizing with peat andstraw manure the amount of organic phosphorus in the soil decreased to 18,8 - 28,1 % ofP total, and the application of semi - liquid manure, on the contrary, increased its contentup to 43,4 - 44,3 % from P total. It is noteworthy that the accumulation of organicphosphorus occurs, basically, at the axpense of phosphorus, soluble by NH4F and NaOHin the first extraction. More available to plants organic phosphates pass in this fraction.Superphosphate brought in together with manure and calcium increase the amount ofphosphates bound with it. In the not fertilizerd soil the content of Ca - phosphates wasestablihed to be 96 mg P20 5 /kg of soil, and in the soil fertilized with manure - 112 - 182mg P2O /kg. However, the share of Ca - phosphate from the total phosphorus in the soilchanged not so essentially.The insoluble residue of P in the soil made up a small part - 0,8 % from P total. Atentering fertilizers its percentage remained rather stable - 0,7 - 0,11 %, and the absoluteamount increased up to 14,5 - 24,7 mg P205 /kg of soil (in the not fertilized soil - 11,0 -mg P205 /kg of soil).

95

ng P205 / kg of soil1900o O]minera phosphate1600 0 organic phosphate1400 "7 -S Ca phosphate1200

100

900

400

200 •

1 2 3 4 5

treatments

Figure. The influence of fertilization on the fractional composition of phosphates

Calculation of the ratio Co: Pots showed that depending on the type of manureenrichment of organic substance by phosphorus as well as dephosphorarion can occur. Inour research in all fertilised treatments significant accumulation of organic carbon andphosphorus occurred. However, at fertilisation with peat and straw manure to phosporusimpoverishment in organic substance occured, A ratio Co,: Porg. increased up to 31,6 -35,4 (on the not fertilized soil 21). And at entering semi - liquid manure, on the contrary,the content of phosphorus increased also the ratio decreased to 18.

DiscussionThe results of our research showed, that regular fertilisation of soddy podzolic sandyloams with manure and mineral fertilizers at positive P balance resulted in substantialgrowth of stocks of total phosphorus in the soil. The role of different types of manure inthe increase of stocks of phosphorus was different. A more significant accumulation ofP,,, occurred at entering in the soil straw and peat manure. Semi-liquid manure had asmaller influence on the accumulation of phosphorus. Probably, it was related to thegreater mobility of organic phosphate in semi-liquid manure.The research also showed that the ratio Pors and Pmi in the soil can considerably changedepending on fertilizers used. Is was established, that at fertilising with straw and peatmanure with NPK the amount of organic phosphorus decreased by 9 - 18 %, and atfertilising with semi-liquid manure it increased by 6 %. The accumulation of organicphosphate occurs basically on the account of more soluble organic phosphate. Thechanges of the amount of Ca - phosphate and of soil acidity at fertilising with manureallow to assume, that a significant part of fertiliser calcium is absorbed by a soilabsorbing complex and insignificant - contacts to phosphate-ions. All investigated typesof manure essentially increased the amount of plant available phosphates, which aredetermined in a solution NH4CI and in hot water. Sharp increase (with 7 up to 200-385mg P 2O5/kg of soil) in phosphorus soluble in hot water presupposes its ability to easiermigration in deeper layers of soil under the influence of atmospheric precipitation. More

96

detailed study of structure of phosphate, taken by hot water is necessary. At fertilisingwith straw and peat manure dephosphorisation of organic soil substances is observed

ReferencesI. Dai, K.H., David, M.B., Vance, G.F., Krzysziwska, A.J., 1996. Characterization of

phosphorus in a sprus-fir Spodosol by phosphorus - 31 nuclear magnetic resonancespectroscopy. Soil Sci. Soc. Am. J., V. 60: 1943-1950.

2. KaypHweB H.C., KapnyxHH A.H., fpnroK B.F. 1983., MirpauHA H TpaucpopMauHRd4ocdopa nxoro HaBo3a B AepHoro-noa3oaHcrol noMBe. ArpoxwMnH, N2 10: 111-118.

3. Ko63apeHro B.H., 1999. M3BeCTKOBaHue H Mo6HnH3aLHR" 4oc4JaToB AepHoro-Ofl30.uHcThIX

oqB paHofl CTCneHH OKyJrlbIYpHHOcTM. ArpoxHMAI, 'o 6: 5-15.4. KonRAHna H.K., 1971. DopMHpOuauHe 4)oc(PaTHom 4lOHlia noLaI HpH cHacTeMaT-eCKOM

JpMeHeHHH yAo6peHHR B CeBOO6 OpOTe H Ha 6ecCMeHnBIX noanax. ArpoxrHi, N : 3-14.5. Koconanona A., 1999. H3yqenIHe npoiteCCOB Tpanc4JopMaaiHH 2orocoepXantHx

coeIHHeHHA B noB-IBe B JIH3MeMpHqeCKHX OllbrIax C OpIMIIqeCKHMH yDO6pelHmlmmH.

JIH3HMeTpHqeCKHC ncchieAoBaHH B a'pOxHmHH, JlBnOBeaCaHHH, MeCirtopalti Harpo3KonormH. - MocKna-HeMHHOBKa, X2 1 : 66-71.

6. Jlana B.B., PhEInx 0.., EOnOBaq A.A., 1998. CoaeplcaHHe 11 nO.IBHcHocTh 4Poc4paToB BlRepHono-noa3onHoHi cynecqaHo nBe F1pH npHMeIeiiHH pa3JlHHq blX (FOpM

4boc4)opoconepwanx yio6peHinI. PoAh aaanTHHOn HHTCHcHIbHKaiIH 3eMneAelA BnOBLImeHHH 3)j4CKTHBHOCTIH arpapHoro npoH3BolcTBa. -)Ko1riO. T. I: 135-138.

7. JlyKHH C., CHMaKOB r., Wii"noua H. IloepH nHThTejlbHbX eLeICTB up1 HHcOJib3OBaHHHopfaH'qecKHX yAo6peHuii. J1H3HMeTpHqeCKHe HccJrejoBaHHR B arpoxHMHH, iOMBOBfeaeHHH,MCnHopauHH x ao3KoormH. - MOCKBa-HeMHMHOBKa: 146-150.

8. IHe6oabcHH H.A., He6oibcmHa 311., 51&oaeua J1.B., 1998. BnHmHie H3BCcTKOBaHA HaHeKOTOpbLi iloKa3aTejiH oc(PaTnoro peIHMa AjepHOBO-OI30IHCTbIX 11OMB. ArpOXHMHR,

N 9: 31-41.9. THuToa B., Bap.aMoBa A1., TpuqbooB A., 1998. HeKoTopbie oco6eHnoCu mrpanHH

$ ocqpaTbiux coetHFeHHK Ha 3a4IocJaqeHHliX noMBax. JlH3HMeTpHMeCKHe HCCBIC1OBaHH !1OqB. - MOCKBa, MrY Mm. JIOMOHOcOBa,: 84-87.

AcknowledgementsThe author is especially grateful to the dr. J.Lubyle for carrying out analyses of phosphates

fraction.

97

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

INFLUENCE OF POTASSIUM AND PHOSPHORUS FERTILIZERS ONBIOLOGICAL NITROGEN FIXATION EFFICIENCY

Natalia Mikhailovskaia, Larisa JurkoBelarussian Research Institute for Soil Science and Agrochemistry

SummaryInfluence of potassium and phosphorus fertilizers on the efficiency of symbiotic andnonsymbiotic nitrogen fixation is discussed. It was found that K and P concentrationstrongly affects N2-fixing microflora survival, propagation and activity in the plant rootzone. There are optimal doses of K and P content providing the formation of profitablesymbiotic and associative relationship plants - introduced Nr-fixing bacteria.

Key words: potassium, phosphorus, biological nitrogen fixation

IntroductionApplication of microorganisms is one of the modem and actual branches of plantgrowing. Use of microbial preparation such as biological fertilizers is both ecologicallyand economically profitable. Symbiotic nitrogen fixing bacteria of the genus Rhizobium isused for inoculation of Leguminous for a long period of time already. Application of freeliving and associative nitrogen fixing bacteria for inoculation of Gramineae started about30 years ago.Biological nitrogen fixation depends on different biological and agrochemical factors:plant genotype, bacterial strain, climatic and weather conditions, soil type, fertility,mineral nutrition level. However biological factors are considered to dominate, soilfertility and mineral nutrition level produce significant effect on the N2 -fixation activityand efficiency. It is known, that content and composition of nutrients in soil stronglyinfluence physiological processes in the plant roots (7). It was found significant role ofpotassium in specific cell enzyme activation (4). These processes are connected withquantity and composition of the root exometabolites, which are used by nitrogen fixingbacteria as energy and nutrient substrates. Influence of potassium and phosphorusfertilizers on the efficiency of symbiotic and nonsymbiotic nitrogen fixation is beingdiscussed.

Materials and methodsField experiment with clover was carried out on sod podzolic loamy soil. Soilagrochemical parameters were as follows: humus 2.1-2.3 %, pH (KCL) 6.0-6.2, P205120-130 mg.kg " , K2O 120-125 mg.kg -'. Plot size is 27 in

2. Clover was grown as puresowing. Local strains of Rhizobium trifolii and Azospirillum brasilense were used forinoculation. Treatment: control without inoculation, inoculation of clover by Azospirillumbrasilense, inoculation of clover by Rhizobium trifolii and dual inoculation by Rhizobiumtrifolii + Azospirillum brasilense. Bacterization treatment were studied under differentdoses of mineral fertilizer application: control, P30KQ- 1, P6oK,2 0 - 2 and N30P60K120 - 3.

98

Treatment gives the possibility to compare the effect both PK- fertilizer and inoculationtechniques have on biological nitrogen fixation activity and efficiency.The pot experiment with barley was carried out on sod podzolic loamy sand soil.Agrochemical parameters of soil are: humus 1.2-1.3 %, pH 5.8-6.0, P20 5 160 mg.kg-',K20 52 mg.kg-'. Barley seed was germinated and inoculated by Azospirillum brasilensestrain (Pen 2000), resistant to antibiotics. 10 plants of barley were grown in one pot withpot capacity of 5.5 kg of soil. Dose of (NH4 )2 SO4 was 15 mg kg'. Exchangeablepotassium content in soil: 0 - 47.5 - 98.2 - 146.8 - 195.5 mg kg -'. Replicates - five.Incidence of Azospirillum brasilense on barley roots was determined by sowing onmodified Dobereiner medium (DAC) with congo red (g/I): KH 2PO.,- 0.4, K2HPO4 - 0.1,MgSO 4 7 H20 - 0.2, NaCI - 0.1, CaCI2 - 0.02, FeC13 . 6 H20 - 0.01, Na2MoO 4.2 H20 -

0.002, malic acid - 2.5, saccharose - 1.0, yeast extract - 1,0, agar -1.5-2.0 (3).For the determination of nodule number on clover roots method of Posypanov (1991)

was used (9). Symbiotic and associative nitrogen fixation activities of clover and barleyroots were evaluated by acetylene reduction method on chromatograph Chrom-4 (10).

Results and discussionClover response to bacteria introduction and soil supply with nutrients elements wasestimated on nodule formation, nitrogen fixation activity of roots, yield and yield responsedue to inoculation. Development of leguminous plants and their productivity depends onthe formation of active plant - nodule bacteria symbiosis. Active nodule number is themost important parameter of plant - bacteria symbiosis function. We have found thatmineral nutrition level strongly affects active nodule quantity. As a result of increase ofpotassium and phosphorus fertilizer doses from 30-60 kg ha' to 60-120 kg ha-' noduleaccount per one clover plant is approximately 1.5 times more at uninoculated treatmentand 1.6 - 1.7 times more at inoculated variants (fig. 1).

nodle number E 3O

Mo., O Azospirillumn

500. UAz +Rh,

400,

200.

100.

0.

1 2 3

Figure 1. Effect of fertilizers and diazotroph inoculation on nodule formation on cloverroots (P30 Kw - 1, PwKi 2o - 2, N3o Po K12o - 3).

Simultaneously the rise of N2-fixing activity of clover roots in 2.0-2.3 times was observedas compared to 30-60 kg ha -' (PK) (fig. 2). Optimal conditions for nodule formation wereat 60-120 (PK) kg ha- .

99

N-fixing actvity0

El AzWpirLill

5 m +Rh,

0-30-60 0-60-120 30-60-120

Figure 2. Effect of fertilizers and inoculation on N2 - fixing activity on clover roots(pm C2H4 g-')

Table I shows the effect of fertilizers and diazotroph inoculation on dry mass yield and Ncontent. Inoculation, in general, provided the increase of clover dry mass, as well asnitrogen content. Symbiosis relationship improvement resulted in the increase of cloveryield. Top clover yield response was also obtained under doses of PK 60-120 (tab. ).

Table 1. Influence of fertilizers and diazotroph inoculation on clover yield (dry mass, c ha')

Treatment Control P30 KI P6oK12o N30 P6, K,2o1 2 1 2 1 2 1 2

Withoutinoculation 31.0 66-8 37.5 75.5 45.8 80.0 50.7 77.8*

Azospiritlum - - 41.6 81.5 53.5 88.6 55.9 88.3*- - 4.1 6.0 7.7 8.6 5.2 10.5*- - 41.4 79.7 51.9 85.8 52.3 83.5*- - 3.9 4.2 6.1 5.8 2.7 5.7**

Azospirillum 44.3 82.5 55.4 90.0 56.4 89.8*+ Rhizobium - 6.8 7.0 9.6 10.0 5.7 12.0**LSD 2.2 4.1

1 - first year, 2- second year* clover yield** yield response due to inoculation

It was found that inoculation of clover by Rhizobium and Azospirillum resulted incomparable effect in process of nodule formation and nitrogen fixation activity in the rootzone of clover. Efficiency of dual inoculation of clover by both Rhizobium andAzospirillum surpassed the effect of separate treatment of clover by Rhizobium orAzospirillum. Similar results were obtained by Galal (5).Efficiency of association of barley roots with introduced bacteria at different potassiumnutrition levels was estimated on incidence of marked Azospirillum brasilense strain (Pen2000), associative nitrogen fixing activity of roots, yield of biomass due to inoculation.Data in figures 3, 4 indicate that there is optimal exchangeable potassium concentration

100

for survival, propagation and activity of associative bacteria on barley roots. Both attillering and earing phases, maximal bacterial population was observed at 100-150 mg kg-K20 content in soil. The increase of potassium dose depressed bacteria population. As it

could been expected A. brasilense population at earing phase was significantly higherthan at tillering phase (8). For biomass a similar trend was observed (fig. 5), the same fornitrogen fixing activity of barley roots (fig. 4).

Incidence ofAbrasilcrtsc

70 Obarng60O

40Y

10/

o 50 100 150 200 250K20. rg/kg

Figure 3. Effect of K content on incidence of nitrogen fixing bacteria A. brasilenseon barley roots s well aig-r)

z. D a"ing

1501

0 50 100 150 200 250

Figure 4. Effect of K content on N2-fixing activity (nmol C21-1,/g/24 h) of barley roots

Potassium concentration plays significant role in specific biochemical processes in the

plant roots. Change of potassium concentration can be accompanied with increase or

reduction of the root metabolites amounts, as well as their chemical composition. It is

known that K contents enhance promotes the excretion of malic acid and its derivativesby root (6). As it was found, malic acid and malates are preferable carbon sources forassociative bacteria of the genus Azospirillum (2,6). That's why potassium concentrationstrongly influences formation of beneficial association between introduced A. brasilenseand barley roots. It is known that effective associative relationships provided the

101

improvement of atmospheric nitrogen use by inoculated plant and the rise of total andprotein N content in agricultural production (1).

50 100 150 200 250

£20, rmg~g

Figure 5. Influence of K content on yield of barley dry mass

ConclusionRegulation of nitrogen fixing microflora propagation and activity in the plant root zone isone of the most important problems in the inoculation experiments. Biologists payprimary attention to the influence of N on biological nitrogen fixation. The effect of Kand P is insufficiently studied at present. Negative results of inoculation experiments mayprobably be connected with insufficient attention to K and P fertilizer effect on N,-fixingmicroflora. So it is known that K and P concentration strongly affects microorganismsurvive, propagation and activity in the root zone. It is evident that there are optimal dosesof K and P provided the formation of profitable relationships between plants and bothspontaneous and introduced N2 -fixing bacteria.

References.I. Bashan Y., Levanony H-. Current status of Azospirillum inoculation technology: Azospirilium

as a challenge for agriculture!!/Can. J. Microbiol. -1990. -36. -P.591-508.2. Boddy R.M., Dobereiner J. Nitrogen fixation associated with grasses and cereals: Recent

progress and perspectives for fujture //Fertilizer Research. -1 995. - 42. -P. 241-250.3. Caceres E.A.R. Improved medium for isolation of Azospirilium sp. // AppI. Environ.

Microbiol. -1982. -V. 44. -4. -P. 990-991.4. Evans H.J., Wildes R.A. Potassium and its role in enzymatic activation // Proc. 8th Colloqu.

Int. Potash Inst. Berne. -1971. -P. 13-19.5. Galal Y.G.M. Dual inoculation with strains of fijaponicum and Abrasilense to improve

growth and biological nitrogen fixation of soybean// Biol. Fertil. Soils. -1997. -24. -P. 317-322.6. Kraffczyk l.,Trolldenier 0. et al. Soluble root exudates of maize: influence of potassium

supply and rhizosphere microorganisns // Soil Biol. Biochem. -1984. -V. 16. - 4. -P. 3 15-321.7. Mishustin E.N., Shylnikova V.K. Biological fixation of atmospheric nitrogen. -1968. -P. 91-

135. (Rus.)8. Okon V., Kapulnik Y. Development and function of Azospirillum-inoculated roots// Plant

and Soil. -1986. -90 -P.3-16.9. Posypanov G.S. Biological fixation of nitrogen. Moscow. -1991. -P. 15-16. (Rus).10. Umarov M.M. Associative nitrogen fixation. Moscow. -1986. -P. 65-71. (Rus.)

102

Regional 1PI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

EFFECT OF VARIOUS PRECEDING CROPS ON THE ACCUMULATIONOF PHOSPHORUS AND POTASSIUM IN A HEAVY LOAM SOIL AND

CEREAL YIELD

Augra Arlauskienk, Stanislava Maikgt~nienJonigkelis Research Station of the Lithuanian Institute of Agriculture

AbstractMultiple-factor field experiments were carried out on North Lithuanian's calcareousheavy loam soil between 1996 - 1999 with a view to estimating legume crops aspreceding crops for winter wheat, and their effect on the accumulation of major nutrientsin the soil when growing cereals in different 2 year rotations. Possibilities ofcompensation of the nutrients removed with the yield of cereals by the residues ofpreceding crops and their green material and farmyard manure were determined. Variousleguminous preceding crops formed the soil differing in nutrient content for winter wheat.The highest content of available phosphorus and potassium was found in the soil afterlucerne, which was 15,2 and 15,0 % higher than that after clover. When growing two-yearcereal rotations after bastard lucerne and red clover the contents of available P205 andK2O declined and after vetch and oats mixture even increased, as compared with theircontents before the establishment of the trial. Green manure had a smaller positive effectthan farmyard manure on the build up of these nutrients in the soil. A high content ofpotassium in perennial grasses and organic fertiliser determined a positive potassiumbalance for cereals grown for two years, while a positive phosphorus balance wasdetermined only by farmyard manure fertilisation.

Key words: preceding crop, green manure, farmyard manure, phosphorus, potassium.

IntroductionHeavy loam soils prevailing in the northern part of the Central Lithuania's Lowland havea high potential fertility. The arable layer of these soils is rich in available potassium,however they contain a low or medium content of phosphorus. Literature sources suggestthat deeper layers of limnoglacial heavy oams' B, horizon contains of a high content oftotal phosphorus - 0,14 - 0,18 % (3). Some authors report that on such soils deep-rootedcrops such as lucerne, which is able to lift nutrients into surface layers and create morefavourable nutrition conditions for other crops, should be grown. There are abundant datain literature about the positive effect of perennial legume crops and green manure on theyield of cereals grown after them (4, 5). However, there are insufficient data on the effectof plant residues and green manure on phosphorus and potassium nutrition of cerealsgrown after them. An opinion prevails that green manure improves soil physicalproperties, promotes microbiological activity, therefore available phosphorus andpotassium become more readily available to plants in the soil, however they do not playthe major role in supplying crops with nutrients (2, 6). Utilisation of soil potential is animportant condition, especially from the ecological point of view, for creating conditionsfor high crop yields (1, 5).

103

Materials and methodsTwo analogous multiple-factor experiments were set up at the Lithuanian Institute ofAgriculture's Jonigkelis Experimental Station in 1996 and 1997; the duration of each was3 years. According to West European countries' soil classification the soil under theexperiments was Calcari - Hypostagnic - Luvisols. The soil agrochemical characteristicsin the 0-30 cm layer was as follows: after clover pHKcI value was 6,3 - 6,5, humus - 2,02 -2,03 %, total nitrogen - 0,128 - 0,138 %, available P205 and K20 - 116 - 124 and 236 - 254mg/kg respectively; after lucerne pHKI was 6,2 - 6,6, humus - 2,07 - 2,20 %, total nitrogen- 0,136 - 0,140 %, available P205 and K20 - 132 and 260 - 277 mg/kg respectively; aftervetch and oats mixture pH KCI was 6,3 - 6,4, humus - 2,03 - 2,13 %, total nitrogen - 0,126 -0,136 %, available P2O5 and K20 - 112 - 121 and 260 - 263 mg/kg of soil.The experiments were conducted in two cereal rotations: winter wheat, spring barley(1st rotation); winter wheat, winter wheat (1]nd rotation). The experimental design ispresented in tables. The contents of available P205 and K20 in the soil was determined bythe A - L method. Phosphorus content in the green material of preceding crops, their

-plant residues and in the grain and straw of winter wheat and harley was determined bythe method of calorimetry, and that of potassium, by flame photometry. Chemicalcomposition of farmyard manure was determined by the following methods: phosphorusby Lorence and potassium by flame photometry.

Results and discussionDiverse agrochemical soil properties were formed after various preceding crops, such asred clover, bastard lucerne and vetch and oats mixture. The highest contents of availablephosphorus (136 mg/kg) and potassium (284 mg/kg) in the soil in the 0 - 20 cm arablelayer was determined after lucerne as preceding crop, these contents were by 15,2 and15,0 % higher than those after clover. Preceding crops and organic fertilisers determineda diverse accumulation of available phosphorus and potassium in the soil after cultivationof different two-year cereal rotations (Table 1). While evaluating only preceding crops itwas established that in the 0 - 20 cm arable layer the highest contents of available P205and K20 were found after harvesting f both rotations' cereals, grown after lucerne andvetch and oats mixture. After harvesting of the second member of the first rotation (springbarley) after vetch and oats mixture the amount of these nutrients found in the soil was by14,6 and 7,0 % higher and after harvesting of the second member of the second rotation(winter wheat) by 16,4 and 6,6 % higher, as compared with the respective data before theestablishment of the trial. After lucerne a decline in these nutrients occurred: availablephosphorus 1,5 and 2,9 % and available potassium 1,4 and 2,1 %. Such variation in thecontents of available phosphorus and potassium in the soil after different preceding cropswas determined by a lower yield of cereals grown for two years and a lower amount ofnutrients removed with it than that after lucerne. After harvesting of cereal rotationsfertilised with farmyard manure the content of available P2O5 increased by 13,0 %, afterthe second rotation - 8,9 %, the content of available potassium increased by 9,7 and7,5 %, as compared with the content before the establishment of the trial. Green manurehad a smaller positive effect on the accumulation of these nutrients. The results ofcorrelation - regression analysis showed that there was no correlation between theamount of available phosphorus in the 0 - 20 cm soil layer after harvesting of cerealrotations and incorporated with organic fertiliser and the amount of available phosphorusaccumulated by preceding crops and its content before the trial. The amount of availablepotassium in the 0 - 20 cm soil layer after cereals grown for two years strongly correlated

104

with the potassium of organic fertiliser applied (r=0,703"" - 0,802'), however a weakerbut significant correlation was established with available potassium accumulated in thesoil by the preceding crops after harvesting of the second rotation (r-0,638*).

Table 1. The influence of preceding crops and organic fertilisation on the content ofavailable phosphorus and potassium in the soil (0 -20 cm) (mg/kg)

Joni.kelis, 1996- 1999 averaged data

Available P 2,O Available K 2 0before after before after

B Fertilisation system the estab- 1st after the estab- Ist afnlind ln

lishment rota- lishment rota- aof the trial tion rotati of the r t o

Preceding crop - cloverThe whole rotation without fertilisers 117 Ill 116 248 251 241(check treatment)1st member without fertilisers, 119 M 118 243 251 246lind - according to Nmln in the soil .Clover aftermath ploughed down to theIst member, lind-according to Nmi, in 119 115 125 247 251 252the soil40 t/ha of farmyard manure plougheddown to the 1st member, lInd- 119 129 128 251 284 282according to Nmin in the soil

Preceding crop - lucerneThe whole rotation without fertilisers 136 130 129 280 276 270Ist member without fertilisers, 135 131 131 284 273 271lind - according to Nmin. in the soilLucerne aftermath ploughed down to theIst member, LInd-according to Nmin in th 137 132 129 282 276 275;oil40 t/ha of farmyard manure plougheddown to the Ist member, lind- 136 144 137 291 296 297according to N in the soil

Preceding crop - vetch and oats mixtureThe whole rotation without fertilisers 116 128 128 257 265 2711st member without fertilisers, 271lind- according to N0 ln in the soil 117 125 137 259 260

Green material of the mixture plougheddown to the 1st member, lInd- 117 133 138 259 277 276according to Nmin in the soil40 t/ha of farmyard manureploughed down to the Ist member, 115 145 138 258 300 281lInd-according to Nmj. in the soil

LSD0, 9,9 17,3 20,0 33,1 50,1 44,6Average after preceding crops (A)

Clover 118 116 122 247 259 255Lucerne 136 134 132 284 280 278Vetch and oats mixture 116 133 135 258 276 275

LSDO5 , act.A: 4,9 8,7 10,0 16,6 25,1 22,4

105

The amount of phosphorus removed with the yield of the first and second cereal rotationsdepended on the amount of phosphorus present in the soil and applied with organicfertiliser, and productivity of cereal rotations and their phosphorus content (Table 2).

Table 2. Amount of phosphorus removed by the plants and its balance in the croprotations kg/ha

Jonigktlis, 1997- 1999 averaged data

Applied Ist rotation lfnd rotationP205 remo- cor- remo- rcor-with ved pensa- ved jensa-

B Fertilisation system organic with balanc ing with alane ing

matter the coeffi- the coeffi-kg/ha id cient 0A yield cient

Preceding crop -cloverThe whole rotation without fertilisers(check treatment) 40,8 74,9 -34,1 54,5 82,7 -41,9 49,3

1st member without fertilisers, 40,8 88,2 -47,4 46,3 102,9 -62,1 39,7lind - according to Nmin in the soilClover aftermath ploughed down tothe 1st member, lind-according to 56,1 99,4 -43,3 56,4 108,4 -52,3 51,8N,,, in the soil40 t/ha of farmyard manureploughed down to the 1st member, 128,4 104,6 23,8 122,8 111,7 16,7 115,0llnd according to Nmi. in the soil

Precedin crop- lucerneThe whole rotation without fertilisers 52,5 100,2 -47,7 52,4 110,8 -58,3 47,41st member without fertilisers, 52,5 109,9 -57,4 47,8 124,1 -71,6 42,3find - according to Nmin in the soil

Lucerne aftermath ploughed down tothe fst member, lind-according to Nmi. 72,6 124,7 -52,1 58,2 135,4 -62,8 53,6in the soil40 t/ha of farmyard manureploughed down to the 1st member, 140,1 127,8 12,3 109,6 138,8 1,3 100,9lind-according to Nmi, in the soil

Precedin crop - vetch and oats mixtureThe whole rotation without fertilisers 14,7 64,8 -50,1 22,7 74,1 -59,4 119,8Ist member without fertilisers, 14,7 76,9 -62,2 19,1 83,3 -68,6 17,6find-according to Nmin. in the soilGreen material of the mixtureploughed down to the Ist member, 30,8 84,1 -53,3 36,6 92,1 -61,3 33,4lInd - according to Nmi. in the soil40 t/ha of farmyard manureploughed down to the fst member, 101,9 91,2 10,7 111,7 95,8 6,1 106,4lInd-according to Nm. in the soil

LSD0, 1 1,01 12,41Average after preceding crops (A)

Clover 66,5 91,8 -25,3 72,5 101,4 -34,9 65,6Lucerne 79,4 115,7 -36,2 68,7 127,3 -47,9 62,4Vetch and oats mixture 40,5 79,3 -38,7 51,1 86,3 -45,8 46,9

LSD05, act.A: 5,50 6,28

106

Correlations were established between phosphorus, accumulated in the yield (y) and thecontent of phosphorus present in the soil before the establishment of the trial (x,) andincorporated with plant residues and organic fertilisers (x2). These correlations areexpressed by the respective linear regression equations:

y-- 119,98+1,78x,, r=0, 799"f, y=79,54+0,33x2 , r=0,668 "'.

While estimating the first (winter wheat, spring barley) and the second (winter wheat,winter wheat) cereal rotations it was determined that the highest content of phosphoruswas removed by the yield of cereals grown after lucerne 115,7 and 127,3 kg/harespectively. After vetch and oats mixture the content of phosphorus accumulated in thecereal yield of the first and second rotations was significantly lower by 13,6 and 14,9 %respectively, than that after clover. In all the backgrounds of preceding crops in bothrotations farmyard manure increased most (17,7 and 11,6 %) accumulation of phosphorusin the cereal yield, as compared with the treatments applied with nitrogen fertiliser. Greenmanure on different backgrounds of preceding crops had a positive effect on phosphorusaccumulation in the yield. In the first rotation (winter wheat, spring barley) green manureincreased the accumulation of phosphorus by 12,0 %, and in the second rotation (winterwheat, winter wheat) 8,3 %, pas compared with the treatment where the second memberof the rotation was applied only with nitrogen fertiliser.The greatest amount of phosphorus was removed by the yield of crops grown afterlucerne, fertilised with farmyard manure and having incorporated their aftermath.Only small amounts of phosphorus were incorporated in the soil with the residues oflegume crops and organic fertiliser. Therefore phosphorus balance of the two-yearrotations (the amount of phosphorus incorporated with plant residues and organicfertilisers, and the amount of phosphorus used for growing of overgound mass of cerealsgrown for two years) except for the treatments applied with farmyard manure, wasnegative. Cereals which gave a higher yield after lucerne as preceding crop removed agreater amount of phosphorus, therefore the highest negative balance of this element wasdetermined here. While after vetch and oats mixture the negativePhosphorus balance was determined by a low phosphorus content in plant residues andgreen manure. The lowest compensation coefficient both in the first and second rotationswas determined in all the fertilisation treatments after vetch and oats mixture 51,1 and46,9 % respectively. While estimating fertilisation treatments the lowest phosphoruscompensation was in the plots fertilised with nitrogen fertiliser 39,3 and 34,8 %respectively. A sufficient amount of phosphorus was incorporated in the soil withfarmyard manure, therefore compensation coefficient here was 114,5 and 107,0 %respectively (in the first and second rotations). In the rotation winter wheat, winter wheat,more phosphorus was removed with the yield; therefore its compensation coefficientshere were smaller than in the rotation winter wheat, spring barley.The amount of potassium accumulated in the yield of the primary and secondary produce of thefirst and second rotations depended on the content of potassium in the incorporated organicmatter, also on preceding crops and soil conditions and on crop productivity (Table3).The correlation between accumulation of potassium in the cereal yield of the first rotation(y) and the amount of potassium present in the soil before the experiment (x,) and thecontent of potassium from ploughed-down plant residues and organic fertiliser (x2), canbe described by the following linear-direct equations:

y= - 146,05+1,12x, r=0,647"'; y= 108,32+0,17x2 , r=0,691".

107

Table 3. Amount of potassium removed by the plants and its balance in the crop rotations kg/haJonikd1is, 1997- 1999 averaged data

Applied Ist rotation lind rotationK20 remo- comn- [remo- comn-

B Fertilisation system with ved balan- pensa- [ ed balan- ensaorganic with ting with tingmatter the ce coeffi- the ce coeffi-kg/ha yield cient o, yield cient %

Preceding crop - cloverThe whole rotation without fertilisers(check treatment) 135,5 119,0 16,5 113,9 129,5 6,0 104,6Ist member without fertilisers, 135,5 134,7 0,8 100,6 145,7 -10,2 93,0find - according to Nmi in the soilClover aftermath ploughed down tothe 1st member, lind-according to 228,4 147,2 81,2 155,2 159,4 69,0 143,3Nmin in the soil40 t/ha of farmyard manureploughed down to the Ist member, 399,0 160,0 239,0 249,4 165,2 233,8 241,5lind-according to Nmin in the soil

Preceding crop - lucerneThe whole rotation without fertilisers 184,2 145,3 38,9 126,8 158,1 26,1 116,5Ist member without fertilisers,fInd- according to Nmin. in the soil 184,2 159,7 24,5 115,3 170,9 13,3 107,8

Lucerne aftermath ploughed down tothe 1st member, lInd-accordingtoNmn 313,0 180,6 132,4 173,3 195,8 117,2 159,9in the soil40 t/ha of farmyard manureploughed down to the Ist member, 447,7 186,3 261,4 240,3 208,7 239,0 214,5lind-according to Nmi. in the soil

Preceding crop - vetch and oats mixtureThe whole rotation without fertilisers 106,0 98,8 7,2 107,4 118,2 -12,2 89,7Ist member without fertilisers, 106,0 112,5 -6,5 94,3 125,0 -19,0 84,8lind-according to Nmi. in the soilGreen material of the mixtureploughed down to the fst member, 224,4 117,8 106,6 190,7 136,0 88,4 165,0lind - according to Nmi. in the soil40 t/ha of farmyard manureploughed down to the lst member, 360,6 131,1 229,5 275,1 136,9 223,7 263,4Ilnd-according to Nmin in the soil

LSD 0o5 13,55 24,17Average after preceding crops (A)

Clover 224,6 140,2 84,4 160,2 150,0 74,7 149,8Lucerne 282,3 168,0 114,3 168,0 183,4 98,9 153,9Vetch and oats mixture 199,2 115,1 84,1 173,3 129,0 70,4 154,4

LSDo5, act.A: 9,06 12,10

The greatest positive and significant effect on the removal of potassium from the soil with theyield had lucerne as preceding crop, while the lowest effect had vetch and oats mixture ascompared with clover. Out of organic fertilisers farmyard manure had the greatest and mostconsistent effect on the increase of potassium content in the first and second rotations 17,3 and

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15,7 % respectively, as compared with the treatments applied with nitrogen fertiliser. Howevergreen manure determined a somewhat lower increase in potassium content in the cereal yield9,5 and 11,2 % respectively, as compared with the plots applied with nitrogen fertiliser.Having calculated potassium balance of rotation cereals grown after different preceding cropsand organic fertilisers it was determined that the amount of potassium accumulated in the cropyield was fully compensated by the plant residues of incorporated lucerne and potassium fromorganic fertilisers. A negative potassium balance was determined in the first rotation after vetchand oats mixture fertilised with nitrogen fertiliser, in the second rotation when cereals had beengrown after unfertilised mixture, and after clover and vetch and oats mixture fertilised withnitrogen fertiliser. When estimating only preceding crops the highest surplus of potassium wasdetermined after lucerne, potassium compensation coefficient here was as follows: in the firstrotation- 168,0 %, in the second rotation - 153,9/o. Having compared organic fertilisers it wasdetermined that farmyard manure had the greatest positive effect on potassium accumulation inthe yield, where its compensation coefficient was on average 252,9 and 236,4 %, while of greenmanure it was on average 171,9 and 155,9 %. On average, after all the preceding crops in theplots fertilised only with nitrogen fertiliser potassium removal from the soil was the leastcovered. The rotation winter wheat, winter wheat removed more potassium with the yield,therefore a lower compensation coefficient was determined here.

ConclusionsVarious leguminous preceding crops formed soil with different nutrient status for winterwheat. The highest content of phosphorus (136 mg/kg) and potassium (284 mg/kg) in thesoil, in the 0 - 20 cm depth of the arable layer was found after lucerne, which wassignificantly higher by 15,2 and 15,0 % respectively than that after clover.1. In the top 0 - 20 cm arable layer, after growing of two-year cereal rotations the

contents of available P20, and K20 declined markedly after bastard lucerne and redclover as preceding crops, while after vetch and oats mixture - even increased, ascompared with their level before the setting up of the experiment. A trend of thesenutrients increase under the effect of green manure was established having harvestedthe second members of the cereal rotation, while under the effect of farmyard manurethe amounts of available P20 5 and K20 in the soil remained significantly higher by10,5 and 10,7 %, as compared with the unfertilised treatment.

2. Determined a positive potassium balance when growing cereals for two years, apositive phosphorus balance was determined only by farmyard manure fertilisation.

3. More phosphorus and potassium was accumulated in the yield of the rotation winterwheat, winter wheat, therefore recovery coefficient of these nutrients due to plant residuesand organic fertilisers was lower than that of the rotation winter wheat, spring barley.

References1. Bauer F. Mutragyazassal kombinalt zoldtragyak es istallotragya hatasanak osszehasonlitasa

vetesforgos tartamklserletben Duna - Tisza kozi lepelhomok // "Novenytermeles".- 1987-36,N2.6. - C.-463 - 479.

2. Le Mare P. H., Pereira J., Goedert W. J. Effects of green manure on isotopically exchaneablephosphate in a dark - red latosol in Brazil//J. Soil Sc. - 1987.-38, N.2.- P. 199 -209.

3. Mavila J. Lietuvos dirvoemiq agrochemines savybes irjq kaita. - Kaunas, 1998. - P. 5 - 190.4. Jo6an K. H. 3en.eHoe yao6penHe.- MOCKBa, 1990.- C. 102- 103.5. Kar r. EnmonorwiecKoe pacTemHeBoncrTo: 03MOKHOCTm 6uonornleCKHX arpodcrceM. -

Mocxia, 1998.- C. 92 - 99.6. MoflceelKo B. P., Eenoyc H. M. ,flticmne 3eieHbix ymo6penxil "a nnoaopoaHe noubi,

ypowafi 0311Mo1 p IH H ero KaqerBo//XHMHl B cx.-996.-2.3. - C. 24 - 25.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

EFFICIENCY OF PHOSPHORUS AND POTASSIUM ON THE ACID ANDLIMED DYTRIC ALBELUVISOLS

Benediktas JankauskasKaltinenai Research Station of Lithuanian Institute of Agriculture

SummaryThe results of two field experiments carried out on acid (pH(Kc 4.2-4.3) sandy loamDystric Albeluvisol showed that the crops sensitive to soil acidity (winter wheat, fodderbeets, spring barley and mixture of clover-timothy) were more productive on limed andfertilised soil. Crops less sensitive to acidity (winter rye, potatoes, oats and mixture oflupine-oats) have the advantage on the acid and non-fertilised soil. The all-nutrientfertiliser application (NPK) increased the yield of crops sensitive to soil acidity on limedsoil by 23.1% and that of crops less sensitive to acidity by 18.0% in comparison to theyield of crops grown in acid soil. The double-strength fertilisers gave less increase inyield than the all-nutrient fertiliser. The efficiency of double-strength fertilisers decreasedin the following decreasing order: NP, NK and PK. The efficiency of phosphorus (P) andpotassium (K) was higher on the limed soil under both crops sensitive and less sensitiveto soil acidity. The efficiency of.phosphorus was higher than that of potassium. The limeamendment increased the efficiency of potassium (K) significantly and efficiency ofphosphorus (P) insignificantly.The results of pot investigations corroborated importance of all-nutrient fertiliser (NPK)examined from results of field experiments. The alone N nutrient increased significantlythe extra yield of cereal crops, but the influence of NK nutrition was by 1.7-3 timeshigher than that of N nutrition. The alone N or P nutrition did not increase efficiency ofpotassium under the cereal crops, when double-strength NP nutrition increased itsignificantly. The efficiency of all-nutrition (NPK) was highest even under theleguminous crops, because biological activity of strongly acid soil was low and it was notchanged essentially by lime amendment during the short period. The lime amendmentincreased the yield and efficiency of nutrients mostly in case of all-nutrient fertilisation.

Key words: Dystric Albeluvisol, lime amendment, phosphorus, potassium, field experi-ment, pot investigation; biodiversity of crops.

IntroductionSoil acidification resulting from acid deposition, microbial processes and root exudationis a natural process. However in the last 150 years, natural acidifying process have beenenchanted by man-made emissions, and agricultural land has received extra acidifyingimputs from ammonium-based fertilisers and the greater utilisation of legumes. Whilstsulphur compounds were the main anthropogenic component of acid rain 20 years ago,nitrogen compounds now dominate /4/. Among analysed athropogenic factors, SO 2emission is the largest source of protons in Poland: it was 52-55% of the total acidificationcontribution, the percentage of nitrogen fertilisation is 30-45% /2/.According to the data of agrochemical soil investigations of 1963-1967, there were 40.7%of conditionally acid soils (pHKc 5.5 or less) in Lithuania: 11.9% of them were very acid

110

(pHKC 4.5 or less), 15.8% were of medium acidity (pHKcg 4.6-5.0) and 13% had a lowacidity (pHim 5.1-5.5). Moreover, about two thirds of conditionally acid soils were inWestern Lithuania. Concerning intensive liming, the area of conditionally acid soils wasreduced. According to the data of 1985-1993, only 18.8% of conditionally acid soils werein the Republic: 1.5% of them were acid, 7% were of medium acidity and 10.2% had alow acidity /8/. Liming of acid soils is a basic means of soil management. Liming by fullrates of CaCO3 according to the hydrolytic acidity of soil was essential for therehabilitation of the strongly acid Dystric Albeluvisols investigated. Soil pH and basesaturation increased whilst hydrolytic acidity and exchangeable aluminium decreased tothe levels favourable for the growth of many agricultural crops. Following liming ofstrongly acid soils the average extra yield over 20 years was 3180 feed units ha-' inLithuania /10/.The chief reason for applying Ca, certainly for arable crops, is not to supply Ca but tomaintain soil pH and optimum nutrient levels. According to results of the long-termliming experiments at Rothamsted and Woburn farms: optimum pH values were 5 forpotatoes and oats, 6.5-7.0 for barley and spring beans /7/. The critical soil pH, valuesbelow which crop growth may be recreated on mineral soils are: 5.9 for red clover, barleyand sugar beet, 6.0 for beans, 5.5 for wheat, while 4.7 for fescues, 4.9 for potatoes, 5.3 foroats and timothy and 5.4 for swedes /12/. Optimum soil pHw.,tr values for the availabilityof the major-nutrition are: 6-8 for nitrogen (N), 6.5-7.5 for phosphorus (P), >6 forpotassium (K) and sulphur (S), 7-8.5 for calcium (Ca) and magnesium (Mg) /3/.The determinant role of nitrogen (N) nutrition in comparison with efficiency ofphosphorus and potassium is evident from investigations in different soil conditions /5, 9,Il/. However there are a lot of vague problems in balanced fertilising of crops withdifferent susceptibility to soil acidity and to available aluminium. Therefore the mainobjective of this paper is to elucidate the efficiency of phosphorus (P) and potassium (K)on the acid and limed Dystric Albeluvisols under the crops of different sensitivity to soilacidity. The results of field experiments were published /5, 6/, therefore in thispresentation they will be only summarised. The main attention will be paid to the resultsof pot investigations.

MethodsThe presented investigations were carried out on sandy loam Dystric Albeluvisol. Theploughing soil layer under the field experiments had the following chemical properties:pHKC1 4.2-4.3, hydrolytic acidity 4.5-5.5 cmol(+)kg ', amount of mobile aluminium,mobile P and mobile K were 50-84, 4.4-6.5 and 49.8-71.4 mg kg" , respectively. The basesaturation was 36.1-40.9%. Two field experiments were carried out at the VezaiciaiBranch of the Lithuanian Institute of Agriculture. The crops sensitive to soil acidity weregrown in the first field experiment, the crops less sensitive to soil acidity were grown inthe second one. Crop rotation of first field experiment contained: I - winter wheat(Triticum aestivum L.) var. 'Mironovskaja 808', 2 - fodder beets (Beta vulgaris L.) var.'Ekendorf', 3 - spring barley (Hordeum vulgare L.) var. 'Dziugiai' as a nurse crop and 4 -mixture of clover-timothy (Trifolium pratense L.-Phelum pratense L.) var. 'Liepsna' and'Gintaras'. These crops are sensitive to soil acidity. Crop rotation of the second fieldexperiment contained: 1- winter rye (Secale cereale L.) var. 'Baltija", 2 - potatoes(Solanum tuberosum L.) var. 'Vilija', 3 - oats (Avena saliva L.) var. 'Skaistunes' andmixture of lupine-oats (Lupinus luteus L.-Aveno saliva L.) var. 'Baltieji' and'Skaistunes'. These crops are less sensitive to soil acidity. The duration of experiments

III

was 8 years (two four-course crop rotations). The scheme of field experiments was: I -fertiliser omitted, 2 - PK, 3 - NK, 4 - NP, 5 - NPK, 6 - lime, 7 - lime + PK, 8 - lime + NK,9 -lime + NP, 10 - lime + NPK.Liming of limed treatments (6-10) was done once at the beginning of the experiments byapplying the full rates of CaCO3 according to hydrolytic acidity (6.75-8.25 t ha'). Thecattle manure (30 Mg ha') and NoP39K1( mineral fertilisers were applied under thefodder beets and potatoes. Only mineral fertilisers were used for grain crops and cropmixtures (N45 P 26K75 and N30P26K100, respectively).The pot experiments were carried out according to more detailed scheme. It contained thefollowing treatment: I - fertiliser omitted (0), 2 - N, 3 - P, 4 - K, 5 - NP, 6 - NK, 7 - PK,8 - NPK on the acid and limed backgrounds.They have were out on the sandy loam Dystric Albeluvisol with the following chemicalproperties: pHKCI 4.2, hydrolytic acidity 4.7 cmol(+)kg -', amount of mobile aluminium,mobile P and mobile K were 7.1, 5.2 and 81.3 mg kg', respectively. The pot ofMicherlich type contained 6.5 kg of dry soil. The dust limestone (33.3 g kg'), containing95.7% of CaCO3, the powdered superphosphate (0.033 g kg-' of P) and potassiumchloride (0.125 g kg' of K) were mixed into the soil before the filling of pots. Theammonium nitrate (0.15 g kg -' of N) was used as a solution in distilled water for wateringof crops after its thinning. The crops were growing three years without change of soil inthe following sequence: spring barley, red clover and spring barley as a crops sensitive tosoil acidity as well as oats, lupine and oats as crops less sensitive to soil acidity. Thefollowing number of plants was left after thinning: 12 of spring barley and oats, 15 of redclover and 8 of lupine. The large biodiversity of crops: crops sensitive (spring barley, redclover) and less sensitive (oats, lupine) to soil acidity as well as cereal grains (springbarley, oats) and leguminous red clover, lupine) represented crops with differentrequirements to the mineral nutrition.

Results and DiscussionAccording to results of field experiments the crops sensitive to soil acidity: winter wheat,fodder beets, spring barley, mixture of clover-timothy were more productive on limed andfertilised soil, while crops less sensitive to acidity: winter rye, potatoes, oats, mixture oflupine-oats had the advantage on the acid and non-fertilised soil. The all-nutrient fertiliser(NPK) increased the yield of crops sensitive to soil acidity on limed soil by 23.1% andthat of crops less sensitive by 18.0% in comparison to crops grown on acid soil. Thedouble-strength fertilisers gave less significant increase in yield than the all-nutrientfertiliser. The efficiency of double-strength fertilisers decreased in the followingdescending order: NP, NK and PK. The efficiency of phosphorus (P) and potassium (K)was higher on the limed soil under both crops sensitive and less sensitive to soil acidity(Fig. 1). The efficiency of phosphorus was higher than that of potassium. The limeamendment increased the efficiency of potassium (K) significantly and efficiency ofphosphorus (P) insignificantly.The results of pot investigations with the crops sensitive to soil acidity (Table 1) showthat the yield level of spring barley on the acid non-limed soil was low, and it increasedby 2.8-3 times only under the NP and NPK treatments in comparison with fertiliseromitted treatment. The significant increasing of barley yield due to lime amendment ofsoil was in the treatments with N nutrition as well as only treatments with N nutritionincrease yield of spring barley significantly on the limed soil. The lime amendmentsignificantly increased yield of red clover under all the treatments but the highest

112

increasing was under the PK treatment. The highest yield of red clover was under theNPK treatment on both non - limed and limed soils. The efficiency of NP and NPKtreatments on the yield of spring barley growing after the red clover was much higherthan that on the yield of barley growing before the red clover and the highest yields ofbarley (30.1-62.5 g pot - ) were under the mentioned treatments on both acid and limed soils.

LSDos 170 LSD, = 100

000Exima yield 5

500"40

P K P KNK NP NK

Fertilisation bacgrounds

Figure 1. Efficiency of phosphorus (P) and potassium (K) on the acid (A) and limed (B)Dystric Albeluvisol

S - crops sensitive to soil acidity, LS - crops less sensitive to soil acidity; F u. -feed unit.

Table 1. The efficiency of mineral fertilisers and lime for the crops sensitive to soil acidityPot investigations

Yield in g pot" of dry matter (DM)Treatments spring barley red clover spring barley

acid soil limed soil acid soil limed soil acid soil limed soilF. omitted 4.1 6.1 3.6 6.7 2.4 5.6N 2.5 13.8 5.9 8.9 8.0 9.6P 5.2 6.7 8.9 15.5 7.3 11.7K 3.6 5.8 2.0 6.3 2.7 3.1NP 11.3 15.6 11.8 21.0 31.5 30.1NK 2.6 11.5 7.7 18.8 13.1 8.9PK 5.7 7.4 6.6 24.1 5.0 11.5NPK 12.1 25.7 25.6 31.8 54.8 62.5LSD,, 3.1 1.4 3.6 2.6 5.8 2.3•LSDos 2.2 2.9 4.1

*LSD,, - for both acid and limed soil. F. - fertiliser.

The results of pot investigations with the crops less sensitive to soil acidity (Table 2) weredifferent than those with crops sensitive to soil acidity. The yield of oats growing beforethe lupine increased significantly under all the treatments including N nutrition on bothacid and limed soils, however the highest yield was under the NPK treatments. Thesignificantly positive influence of lime amendment was under N, NP and NK treatments.The efficiency of lime amendment becomes negative under the oats growing after thelupine with NP and NPK treatments. The N, K and NK treatments significantly decreasedthe yield of lupine on the non-limed soil. The lime was able to neutralise the negative

113

influence of N and NK treatments, however it significantly decreased yield of lupineunder fertiliser omitted and PK treatments.

Table 2. The efficiency of mineral fertilisers and lime for the crops less sensitive to soil acidityPot investigations

Yield in g pot- of dry matter (DM)Treatments oats lupine oats

acid soil limed soil acid soil limed soil acid soil limed soilF. omit 7.1 8.7 52.7 44.6 3.7 6.6N 12.4 21.4 22.2 47.8 5.9 7.3P 7.5 8.6 62.5 61.3 6.2 8.0K 5.9 8.5 43.0 48.3 2.5 2.0NP 28.0 38.4 53.6 48.9 30.7 24.4NK 11.2 20.5 10.4 24.6 6.5 9.0PK 7.8 8.9 57.5 50.0 6.7 9.7NPK 38.8 41.7 63.3 62.8 62.7 56.5

LSD0 3.8 6.6 6.2 5.1 3.6 4.6*LSD, 1 5.0 5.2 3.9

*LSDO5 - for both acid and limed soil. F. - fertiliser.

The phosphorus nutrition significantly increased extra yield of barley under the allfertilisation backgrounds: fertiliser omitted, K, N and NK on the limed soil (Fig. 2), howeverthe efficiency of phosphorus on the NK background was as much as 10.3 times higher thanthat on the fertiliser omitted background, 7.5 times higher than that on the K background and3 times higher than that on the N background. The phosphorus significantly increased extrayield of barley only under NK and N fertilisation backgrounds on the acid soil. The limeamendment significantly increased efficiency of P under the NK background andsignificantly decreased it under the N nutrition background. The phosphorus nutrition didnot significantly increase the yield of oats under the fertiliser omitted background on bothacid and limed soils and under K background on the acid soil (Fig. 3). The lime amendmentdecreased the efficiency of P under the NK fertilisation backgrounds significantly andincreased it under the K background. However the efficiency of phosphorus nutrition underthe NK nutrition background was 7.5 times higher on the limed soil and as much as 13.5times higher on the acid soil.

, pu1 , g Pot'l

DM LSD 3.1 DA DM I.SD , 4.45 D

14030 :

30 A20 2. 0 4.

201. . 0 20 z 0.6

o LNK N K 0 A NK N K 0 A

Fertifisation backgrounds Fertilisation backgrounds

Figure 2. Influence of phosphorus on the Figure 3. Influence of phosphorus on theextra yield of spring barley extra yield of oatThe average 2 tests (before and after The average 2 tests (before and afterclover) results: A - acid soil, B - limed soil lupine) results: A - acid soil, B - limied soil

114

The efficiency of potassium nutrition was significant only under NP fertilisationbackground the both acid and limed soils and under both crops spring barley (Fig. 4) andoats (Fig. 5). The lime amendment increased efficiency of potassium nutrient under thespring barley significantly and decreased it under the oats insignificantly.

I'M sDl3.1 3A DMSD4.45 CA25 23.2 10L 25 D20 20

12.1 I 0f -t s 00.4 i

L LNP N P 0 A NP N P 0 A

Fertilisation backgrounds Fertilisation backgrounds

Figure 4. Influence of potassium on the Figure 5. Influence of potassium on theextra yield of spring barley extra yield of oatThe average 2 tests (before and after The average 2 tests (before and after lu-clover) results: A - acid soil, B - limed soil pine) results: A - acid soil, B - limed soil

The phosphorus nutrition increased the extra yield of red clover significantly under allfertilisation backgrounds on the acid and limed soils (Fig. 6). The lime amendmentincreased efficiency of phosphorus under all backgrounds, too. However the highestinfluence of lime amendment was under the K nutrition background. Its increasedefficiency of phosphorus nutrition under the mentioned background by 3.9 times. Thephosphorus increased the extra yield of lupine on the acid soil under the all investigatedfertilisation backgrounds. The highest (52.9 g pot-) extra yield was under the NKfertilisation background and it decreased in the following decreasing order under the: NY,N, K and fertiliser omitted backgrounds. The lime amendment significantly decreasedextra yield of oats under NK and N backgrounds and significantly increased it on thefertiliser omitted background (Fig. 7).

2 pof 0PO

DMDM LSDL = 5.2 0A

12.1 40to4.920

5 .9 4A 531. ,0L

NK N K 0 A NK N K 0 A

Fertilisation backgrounds Fertilisation backgrounds

Figure 6. Influence of phosphorus on Figure 7. Influence of phosphorusthe extra yield of red clover on the extra yield of lupineResults of red clover grown after spring Results of lupine grown after oat:barley: A - acid soil, B - limed soil A - acid soil, B - limed soil

115

The potassium increased the extra yield of red clover significantly under NP, P and Nbackgrounds and the highest increase was under the double-strength NP fertilisationbackground on both acid and limed soils (Fig. 8). However potassium increased the extrayield of lupine only on the NP fertilisation background (Fig. 9). The influence of potassiumwas negative (in many cases significantly) under the N, P and fertiliser omitted backgrounds.The highest negative influence of potassium was under N fertilisation background on thelimed and non-limed soil as well as under the P background on the limed soil.

DM LSDM = 2.9 DA DM LSD. =.2 0 A

-0 -21

L5 -3 L

N P 0 A NP N P 0 A

Fernhisation beckgrounds Fertilisation beckgrounds

Figure 8. Influence of potassium on the extra Figure 9. Influence of potassium on theyield of red clover extra yield of lupineResults of red clover grown after spring Results of lupine grown after oat:barley: A - acid soil, B - limed soil A - acid soil, B - limed soil

The results presented in the Fig. 2-9 demonstrate the importance of all-nutrient fertilisers(NPK). The highest efficiency of the phosphorus (P) and potassium (K) fertilisers was onthe backgrounds of double-strength fertilisers NK and NP respectively, i.e. under the all-nutrient fertilisers (NPK). Including of nitrogen (N) nutrition into the full nutritionstrength was important not only for cereal grains: spring barley and oats, but even for theleguminous: red clover and lupine, because the biological activity of strongly acid soilwas low especially at the first year of investigations. Liming of acid soil improvedgrowing conditions essentially, however the influence of complete mineral nutrition wasmore important.

Conclusions1. According to the results of the field experiments, carried out on the acid (pHcl 4.2-4.3) sandy loam Dystric Albeluvisols:1.1. The crops sensitive to soil acidity: winter wheat fodder beets, spring barley, mixtureof clover-timothy were more productive on the limed and fertilised soil, while lesssensitive to acidity: winter ryes, potatoes, oats, mixture of lupine-oats had the advantageon the acid and non-fertilised soil;1.2. The all-nutrient fertiliser (NPK) increased the yield of crops sensitive to soil acidityon the limed soil by 23.1% and that of crops less sensitive by 18.0% in comparison tocrops grown on the acid soil;1.3 The double-strength fertilisers gave less significant increase in yield than the all-nutrient fertiliser. The efficiency of double-strength fertilisers decreased in the followingdecreasing order: NP, NK and PK.

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1.4. The efficiency of phosphorus (P) and potassium (K) was higher on the limed soilunder both crops sensitive and less sensitive to soil acidity (Fig. 1). The efficiency ofphosphorus was higher than that of potassium. The lime amendment increased theefficiency of potassium (K) significantly and efficiency of phosphorus (P) insignificantly.2. The results of pot investigations corroborated importance of all-nutrient fertiliser (NPK):2.1. The alone N nutrient increased the extra yield of cereal crops significantly, but theinfluence of NK nutrition was by 1.7-3 times higher than that of the alone of N nutrition;2.2. The alone N or P nutrition did not increase efficiency of potassium under the cerealcrops, when NP nutrition increased it significantly.2.3. The efficiency of all-nutrition (NPK) was the highest even under the leguminouscrops, because biological activity of strongly acid soil was low and it was not changedessentially by lime amendment during the short period.3. The lime amendment increased the yield and efficiency of phosphorus and potassiumnutrients mostly in the case of all-nutrient fertilisation.

ReferencesI. Archer J. Crop Nutrition and Fertiliser Use. Ipswich, 1985. - 258 pp.

2. Filipek T. Natural and Anthropogenic Causes and Effects of Soil Acidification// Natural andAthropogenic Causes and Effects of Soil Acidification/ find International ScientificSymposium. Lublin, 1997.- P. 13-17.

3. Foth H. D. Fundamentals of Soil Science. 8' Edition. New York, 1990. -360 pp.4. Goulding K.W.T. and Annis B. Lime, Liming and the Management of Soil acidity/I

Proceedings No 410 of the Fertiliser Society. London, 1998. - 36 pp.5. Jankauskas B. Utilisation of Plant Biological Features for Rational Use of Lime and Fertiliser

on Acid Soil// Natural and Athropogenic Causes and Effects of Soil Acidification. lindInternational Scientific Symposium. Lublin, 1997. - P.531-536.

6. Jankauskas B. Utilisation of Plant Sensitivity to Soil Acidity and its Need for Nutrition atPresent Stage of Agricultural Development// The Present and Future of Crop Science and BeeKeepinging. Kaunas-Akademija, 1998. - P. 174-179. (In Lithuanian with Summary in English).

7. Johnston A. E. and Whinham W. N. Use of Lime on Agricultural Soils/ Proceedings No 189of the Fertiliser Society. Peterborough, 1980. - 32 pp.

8. Mazvila J., Adomaitis T. R., Antanaitis A. et. al. Agrochemical Properties of Lithuania'sSoils and its Change. Kaunas, 1998. - 195 pp. (In Lithuanian with Summary in English).

9. Petraitiene V. The Relationship Between Yield and Quality of Field Crop Rotation Plants andRates, Ratios of Mineral Fertilisers and the Content of Available Nutrition in Soddy-GleyicLight Loamy Soil. Summary of the Research Report Presented for Habilitation. Dotnuva-Akademija, 1997. - 24 pp.

10.Pleseviciene A. and Jankauskas B. Rehabilitation of Acid Soils in Lithuania by Liming andLong Term Manurial Treatment// Soil Quality, Sustainable Agriculture and EnvironmentalSecurity in Central and Eastern Europe. Kluwer, 2000. - P. 285-291.

1 I.Vaisvila Z.-J. Role of Soil Mineral Nitrogen, Available Phosphorus and Potassium on theNutrition of Agricultural Crops. The Work Habilitatus. Dotnuva-Akademija, 1996. - 206 pp.(In Lithuanian with Summary in English).

12.Wild A. Russell's Soil Conditions and Plant Growth. I I" Edition. Harlow, 1988. - 997 pp.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

EFFECT OF N, P AND K FERTILISER COMBINATIONS ON THEPRODUCTIVITY OF THE CROP ROTATION AND SOIL PROPERTIES

Vincas Kup~inskas, Audrius StokusLithuanian Institute of Agriculture's Perloja Experimental Station

AbstractThe present article reports the summarised findings of the field trials carried out at theLithuanian Institute of Agriculture's Perloja Experimental Station carried out over theperiod 1994-1997. On the basis of these findings we estimated the effect of nitrogen,phosphorus and potassium combinations on the productivity of the crop rotation and soilagrochemical properties on light textured soils. The findings of the 91 rotation suggest(trials have been continued since 1961), that the productivity of unfertilised cultivatedcrops compared with the optimal fertilisation remains within the limits of 28,4 % - 62,6 %.Potassium is an indispensable component of mineral fertiliser combinations for growingof lupine-oats mixture. PK fertiliser combination does not suit for winter rye fertilisation.It is necessary to fertilise potatoes and barley with a complete NPK mineral fertilisercombination. Fertilisation with mineral fertilisers only deteriorates soil agrochemicalproperties.

Key words: sandy loam, nitrogen, phosphorus, potassium, crop rotation productivity

IntroductionThe purpose of fertilisation is not only to supply cultivated crops with nutrients and toobtain as high yield as possible but also to systematically increase soil fertility. In order togrow high quality and abundant yield it is vital to investigate the relationship between theyield and soil conditions, mineral fertiliser rates and ratios, to ascertain major conditionsfor the maintenance of the stability of soil fertility and its improvement.The humus layer of the Lithuanian sod podzolic sandy loam and light loam on light andmedium heavy loam soils contains on average 0,09-0,12 % of total phosphorus (P2O5 ),2,01-2,06 % of total potassium (KO) / 51.Experimental evidence of the national and foreign researchers suggest that the yield ofagricultural crops depends on the content of available phosphorus in the soil /2, 8, 9, 10/.Changes in the content of available phosphorus and potassium in the soil depend on thefertilisation intensity /1, 3/, however variation of potassium content at the same rates asphosphorus is lower /7/. Research evidence of the former Czechoslovakia's researcherssuggests that the optimum content of available phosphorus and potassium in the soildepends not only on the ecological conditions of the specific location but also on theinteraction of various elements /6/. T. Kulakovskaja and 1. Bagdevich summarised thedata of 700 experiments and determined that in Byelorussia the efficacy of potassiumfertiliser depends on the soil reaction (pH), content of available potassium and potentialsoil fertility /12/. S. Vudrup reported that the efficacy of potassium fertiliser is mostlydetermined by the soil texture /I1/. The experimental findings obtained by the LIA'sAgrochemical Research Centre suggest that the effect of potassium fertiliser on crop yielddepended on the content of available potassium in the soil; an increase in potassium

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content resulted in a reduction in the yield increase. A negative relationship between yieldincrease and content of available phosphorus was also determined. The highest yieldincreases through phosphorus fertiliser were obtained in the soil very low in availablephosphorus, i.e. to 50 mg/kg of soil /4/. T. Kulakovskaja reports that cereal yieldconsistently increases in line with an increase in available phosphorus to 250 mg/kg /12/.The optimum content of available phosphorus and potassium in the soil is diverse fordifferent crops. If crops are not fertilised with phosphorus and potassium fertilisers thecontent of phosphorus in the soil declines by 15-20 mg/kg, potassium - 25-85 mg/kg after10 years and the soil productivity declines /8/.A current sharp decrease in the number of livestock and production of organic fertiliserhas made evaluation of mineral fertilisers and their various combinations very relevant.The objective of this study is to assess the effect of phosphorus, potassium and theircombinations on the productivity of the crop rotation plants and on soil agrochemicalproperties.

Experimental conditions and methodsWhile summarising the data we used dr. E. Simanauskyt6's findings from the long-termexperiment carried out since 1961, from the ninth rotation (1994-1997).The experiment was carried out by conventional methods on a sod podzolic sandy loamon light loamy soil in the four-field crop rotation where all crops of the rotation weregrown annually: winter rye, potatoes, barley, lupine and oats mixture. The followingexperimental design was used: check treatment, NP, PK, NK, NPK. 4 replications wereemployed. Initial plot size -102-104 in 2, record plot - 30-40 in 2.

Until 1976 cereals were fertilised with 50 kg/ha of nitrogen, phosphorus (P2,) and(K20), potatoes received 70 kg/ha of nitrogen and phosphorus, and 90 kg/ha of potassium.Since 1977 all the crops were fertilised more abundantly. Cereals and oats and lupinemixture were fertilised with 60 kg/ha of nitrogen, phosphorus and potassium, and potatoes- with 90 kg/ha of nitrogen and phosphorus and 120 kg/ha of potassium. During the ninthrotation the crops received the following fertilisation: N - 270, P25O - 270, K20 -

300 kg/ha. The fields were limed in 1978 and 1986 at a rate of 0,5 according to hydrolyticacidity. Crop and soil management practices recommended for light soils were used forthe crop rotation plants. Soil samples were taken in 1993 and 1997 and were analysed atthe Lithuanian Agrochemical Research Centre by the following methods: pHKcI - bypotentiometric, humus - by Turin, hydrolytic acidity - by Kappen, available Al - bySokolov, available P20 5 and K20 - by A-L method.The findings of the ninth rotation (1994-1997) used in this study were obtained from theexperimental fields not fertilised and fertilised with only mineral fertilisers.Meteorological conditions during the experimental period were diverse: in 1994 thevegetative growth season was unfavourable for crops growing, the amount ofprecipitation during this period was 261 mm. (many years' mean of the vegetative growthseason - 430 mm.). The mean daily temperature of this period was +13,8* C (many years'mean - 13,40C). In 1995 the vegetative growth period was by 0,4°C warmer than usual,amount of precipitation was 72,0 % of the many years' rate. In 1996 the air temperaturewas by 0,2°C lower, however the amount of precipitation was only 56,5 % of thenecessary amount. In 1997 the period of plant vegetative period was cooler and wetter;the average daily temperature was by 0,3°C lower, amount of precipitation was by 31,0mm. Higher than usual.

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The data of the yield of all the crop rotation crops and of the crop rotation productivitywere processed by the dispersion analysis.The value of primary and secondary produce was calculated in feed units according toTomme/13/.

Experimental results and discussionMeteorological conditions for the crops of the ninth rotation (1994-1997) growing on sodpodzolic weakly podzolized sandy loam on light loam during the experimental periodwere not favourable. Three out of four experimental years were hot and dry, one year waswet and cool therefore the average annual productivity of the four-course crop rotationwas low during the experimental period (Table 1). This had a n effect on the total annualproductivity of the crop rotation.Lupine and oats mixture grown in the crop rotation after barley demonstrated the leastresponse to nitrogen fertiliser because the largest part of the sward was composed oflegume crops- lupine which is able to accumulate nitrogen. When comparing thetreatment of NP fertiliser combination with the check treatment (without fertilisers), a lowbut significant dry matter yield increase of 0,32 t/ha, or 9,1 % was obtained. Aconsiderably higher dry matter yield of lupine and oats mixture was obtained in thetreatments of PK, NK and NPK fertiliser combinations. When comparing them with thecheck treatment we see that the dry matter yield increase of 0,68, 0,80 and 0,96 t/ha, or19,3 %, 22,8 % and 27,4 % was obtained. Insignificant yield differences were determinedamong the latter fertiliser combinations. In the check treatment which was not fertilised

since 1961 in the ninth rotation the dry matter yield was only 62,6 % as compared withNPK combination which gave the highest dry matter yield of lupine and oats mixture.

Table 1. Effect of N, P and K combinations on the annual crop yield and the productivityof the crop rotation

Perloja, 1993-1997 averaged data

Yield t/halupine-oats winter rye potatoes barley feed units

Treatment mixturedry relat. grain relat. tubers relat. grain relat. amount relat.

matter values values values values values

Checktre e 3,51 - 1,32 - 5,3 - 0,48 - 1816 -treatment

NP 3,83 109,1 2,80 212,1 9,1 171,7 1,00 208,3 2968 163,4PK 4,19 119,3 1,41 106,8 7,7 145,3 1,00 208,3 2431 133,9NK 4,31 122,8 2,77 209,8 7,6 143,4 0,94 195,8 2944 162,1NPK 4,47 127,4 2,86 216,7 12,2 230,2 1,69 352,8 3475 191,4

LSDo5 0,19 - 0,13 - 0,83 - 0,14 - 107*Note: cereals, lupine and oats mixture fertilised with - N 60, P and K 60; potatoes - N9g, Pgo,and K,,0 .

Winter rye showed a sensitive response to nitrogen fertiliser. In all the NP, NK and NPKfertiliser combinations, containing nitrogen fertiliser a markedly higher winter rye grainyield was obtained. When comparing them with the check treatment (without fertilisers)an increase of winter rye grain yield of 1,48, 1,45 and 1,54 t/ha, or 112,1 %, 109,8 % and

120

116,7 % was obtained. Inessential winter rye grain yield differences were determinedamong these fertiliser combinations.PK fertiliser combination was proved to be completely unsuitable for winter rye, the yieldincrease was as low as 0,09 tlha, or 6,8 %. The treatment not fertilised since 1961 in theninth rotation gave 46,2 % of the yield as compared with the NPK treatment, which gavethe highest winter rye grain yield.Potatoes gave the highest yield when fertilised with a complete NPK fertilisercombination. In the ninth rotation comparing this fertiliser combination with the checktreatment a potato tuber yield increase of 6,9 t/ha, or 130,2 % was obtained. A lower by3,1 t/ha, or 25,5 % potato tuber yield was obtained in the treatment of NP combination.PK and NK fertiliser combinations as compared with the check treatment gave asignificant yield increase of 2,4 and 2,3 t/ha respectively, or 45,3 % and 43,4 %, howeverin potato tuber yield these mineral fertiliser combinations markedly (4,5 - 4,4 t/ha) laggedbehind the best NPK fertiliser combination treatment. Potato tuber yield of the checktreatment not fertilised since 1961 made up only 43,4% of the yield of the best (NPK)fertiliser combination treatment.Barley like potatoes produced the heaviest yield in the ninth rotation having fertilisedwith a complete NPK mineral fertiliser combination. As compared with the checktreatment (without fertilisers) 1,21 t/ha, or 252,8 % barley grain yield increase wasobtained. The rest of NP, PK and NK fertiliser combination treatments significantlylagged behind this fertiliser combination. Here as compared with the best NPK treatmenta lower by 0,65-0,69 t/ha, or 44,4 %-40,8 % barley grain yield was obtained. In the checktreatment not fertilised since 1961 in the ninth rotation the yield was only 28,4% of theyield obtained in the most optimum treatment of NPK mineral fertiliser combination.The highest annual amount of feed units 3475 per ha of the ninth rotation in the four-course crop rotation was obtained in the treatment of NPK fertiliser combination. Ascompared with the check treatment (without fertilisers) a yield increase of 1659 FU/hawas obtained. PK mineral fertiliser combination contributed least to the increase of thecrop rotation productivity, an average annual feed unit increase of 615 was obtained hereas compared with the check treatment. In the check plots not fertilised since 1961 anaverage annual feed unit yield per ha was 52,2 % of the feed unit yield obtained in thebest treatment of NPK mineral fertiliser combination.The findings obtained in these experiments confirm the proposition that in the field notfertilised at all for an extended period of time the crop productivity remains from 25 % to45 % of the level which is achieved in the same conditions receiving optimum fertilisation /2/.Effect of N, P and K mineral fertiliser combinations on the soil agrochemical propertiesIn the ninth rotation agrochemical soil indicators changed under the influence of mineralN, P and K fertiliser combinations (Table 2).During the four years of the crop rotation the soil pH had a tendency to acidify. The mostmarked soil acidification process (0,2 units pH) occurred in the treatment of NK mineralfertiliser combination. These processes occurred more weakly in the check treatment(without fertilisers) and in PK treatments. During the four years of the ninth rotation thesoil acidity remained unchanged only in NP and NPK treatments.During the latter four experimental years a very marked reduction occurred in the soilhumus content. The most considerable reduction 0,47 % was determined in the checktreatment of the experiment. The least reduction 0,25 % occurred in NK and 0,29 % inNPK mineral fertiliser experimental treatments. A considerable increase in the soil

121

hydrolytic acidity was found. The greatest increase 27,2 m-eqw/kg was determined in thetreatment of NPK mineral fertiliser combination, while the lowest increase 18,0 m-eqw/kg inPK experimental treatment.During the four experimental years a reduction in the total absorbed bases occurred in allthe experimental treatments, irrespective of mineral fertiliser combinations.While comparing the beginning and end of the ninth rotation very marked changes in theavailable aluminium in the soil are very obvious. In the check treatment an increase inavailable aluminium was as high as 48,7 mg/kg of soil, and 30,6 mg/kg in NKexperimental treatment. The lowest increase 10,0 mg/kg occurred in the treatment of PKmineral fertiliser combination.The soil phosphorus content in the check treatment increased from low to medium level.An increase of 16,0 mg/kg in soil phosphorus content occurred in the treatment of NKmineral fertiliser combination. Increases in soil phosphorus content obtained in theexperimental treatments which did not include phosphorus were illogical and beyondexplanation. The greatest reduction 37,0 mg/kg in soil phosphorus content occurred underthe effect of NP fertiliser combination. A reduction in phosphorus, although small,occurred in the other two experiments not involving phosphorus fertilisers.

Table 2. Effect of N, P and K combinations on the soil agrochemical indicators Perloja,1993-1997

Treatment pHKcI Humus% 'n-eqw/kg soil Available m of soil V %H S Al 1P 2 05 K20

at the beginning of the rotationCheck 4,3 1,34 47,2 35,4 8,0 87 51 42,8treatmentNP 4,4 1,39 47,1 40,8 3,0 147 53 46,4PK 4,4 1,36 44,2 44,3 8,0 152 122 50,0NK 4,2 1,56 49,1 31,9 9,0 83 104 39,4NPK 4,4 1,44 54,2 42,5 9,0 124 93 44,0

at the end of the rotationCheck 4,4 0,87 26,3 16,3 56,7 101 56 38,3treatmentNP 4,4 1,03 26,5 14,6 25,2 110 48 35,5PK 4,5 1,03 26,2 20,3 18,0 128 145 43,7NK 4,4 1,31 28,1 14,2 39,6 99 114 33,6NPK 4,4 1,15 26,3 15,3 32,4 108 102 36,8

differenceCheck 0,1 -0,47 -20,9 -19,1 48,7 14 5 -4,5treatmentNP 0,0 -0,36 -20,6 -26,2 22,2 -37 -5 -10,9PK 0,1 -0,33 -18,0 -24,0 10,0 -24 23 -6,3NK 0,2 -0,25 -21,0 -17,7 30,6 16 10 -5,8NPK 0,0 -0,29 -27,9 -27,2 23,4 -16 9 -7,2

During the four years of the ninth crop rotation the content of potassium declined by5,0 mg/kg of soil only in the treatment of NP fertiliser combination, in the rest of thetreatments a slight increase in soil potassium content occurred.An inconsistent decline in the level of soil base saturation occurred in all the experimental

treatments from 4,5 % in the check treatment to 10,9 % in NP treatments.

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ConclusionsPotassium is an indispensable component of mineral fertiliser combinations for lupine -oats mixture grown on sod podzolic weakly podzolized soils.For winter rye nitrogen is an indispensable mineral fertiliser component. PK mineralfertiliser combination is completely unsuitable for fertilisation.A complete NPK mineral fertiliser composition is necessary for potatoes and barley.In the plots not applied with mineral fertilisers since 1961 (check treatment), as comparedwith the optimum fertilisation treatment, average dry matter yield of lupine -oats mixtureof the four years of the ninth rotation was 62,6 %, 46,2 % of winter rye grain yield,43,4 % of potato yield 28,4 % of grain yield.When fertilising with only mineral fertilisers the soil agrochemical properties deteriorateirrespective of mineral fertiliser combinations.

References1. Benko V., Vnuk L. Odber fesforu ozimnou penicou vo vztanu u zasobe postupneho fosforu

v pode Rostlinna vyroba. 1985.9. -P. 947-9522. Bockman 0., Kaarstad 0., Lie 0. et al. Agriculture and Fertilizers. Oslo. Norway. 1990.

P. 135-139,3. Kerschberger M. BFk-Sollwerte for Makro-Nahrstofiyerhalte and pH-werte auf Ackerland

aes Wichlige Bestandteile der Langfristigen Bodennutrungsprogramme Feldwinchaft, 1984.25. 10. S. 459-461,

4. Lietuvos dirvotemiq agrochemines savybes ir jq kaita / Sudard J. Malvila. Kaunas, 1998.- P. 64-105,

5. Malvila J., Eitminavi6ius L. Pietines Lietuvos dalies dirvo~emiai ir jq savybds /2emdirbyste. Mokslo darbai, Akademija, 1999. - T. 66. -P. 6-26,

6. Niklicek L_ et al. Intaance vlivu pristupneho fosforu a drasliku v pude na vynosy obinin vruznych ekologieckych podminkach H/Rostl. Vyroba. 1984. 30. I. P. 61-70,

7. Petraitiene V. Skirtingq judriojo fosforo ir kalio kiekiq dirvoje bei tratj itaka augalt derliuisdjomainoje// Moksliniq straipsniq rinkinys 'Trqimas'. V., 1991. -P. 38-47,

8. Petraitiene V. Lauko sejomainos augalq derliaus ir kokybes priklausomumas nuo mineraliniqtrt9tq normu, santykiq bei judriujq maisto medliagtt kiekio veleniniame gleji~kame lengvopriemolio dirvo'emyje: Habilitacinis darbas. -Dotnuva-Akademija, 1997. -115 p.

9. Simanauskyte E. ligalaikis mineraliniq traqg naudojimas // emdirbyste. L21 mokslo darbai.- Dotnuva- Akademija, 1996. - T. 56. -P.33-42,

10. Svedas A. Dirvo emis-traos-derlius: Habilitacinis darbas. - Dotnuva-Akademija, 1993. -88 p.

II. Woodruff C. M. Research progress in Missouri and its importance to the fertilizer industry//Farm Chemicals. 1960. -Vol. 123(12). -P.60-62,

12. KynaKoucKa T.H., Boresinq H.M., 5lpotueBn M.H. Meronhi onpeaeiieuin oITHMaJ1bHbXnapamerpoB arpoxHMHqecKHx cBoicrTB, oTpo)KaouHX pa3HyIo cTenein OKyrlbTypeHOCTH Hnpoay THBHoCTH noqB. Teope'rlecKHe OCHoBbi H MerOII onpeiieneHnA OnTHlMaibhXnapaMerpoB cBo CTB nou. -MOCKBa, 1980. -C. 5-15.

13. ToMm3 M. 4. KopMa CCCP. -MocKna, 1964. -448 c.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

SHOOT NUTRIENT INDICES AS INDICATORS OF NITROGEN,PHOSPHORUS AND POTASSIUM DEFICIENCIES IN GRASSLAND

Henning Hogh-Jensenj and Jan K. Schjerring2

'Section for Agroecology and 2Plant Nutrition LaboratoryDepartment of Agricultural Sciences, Royal Veterinary and Agricultural University,

SummaryShoot tissue analysis offers a non-destructive and definitive means of assessing the N, Pand K status of grassland swards. Relative nutrient indices may help to interpretdeficiencies, as they are more independent of crop age that previously used absolute,critical concentrations. Two relative nutrient indices were used to evaluate a fieldexperiment under varying N, P, and K supply and in different plant compositions. Theaim of the study was to evaluate the usability of such indices in interpreting speciesinteractions and to evaluate their usability in fertilizer recommendations.The data indicate that nutrient ratios vary substantially over time, between species andbetween plant communities. The nutrient ratios were thus found to be of value whenevaluating interactions between species as well as responses of species to differentnutrient supply. Also, they may be of value in the estimations of fertilizer recommen-dations in permanent pastures under constant management.

Key words: DRIS, nutrient indices, N:P ratio, N:K ratio, fertilizer recommendations,species interactions

IntroductionThe yield of grassland crops generally varies with soil fertility and climate. In manycases, grasslands are composed of a varying number of species of which some may belegumes. Especially, white clover is a common legume in European grassland due to itscontribution to a high-value fodder (22) and to its contribution to the accumulation oforganic N in the soil (8, 12).Large grassland areas are managed under low-external-input condition. The grasslandspecies consequently face nutrient limitations and especially deficiencies of phosphorus(P) and/or potassium (K) are often reported (e.g. 4; 10; 24). In addition to the generallylow levels, the distribution of P and K within grassland habitats is uneven and dynamic(3; 20) as a consequence of nutrient cycling and low transport rates.Competition and facilitation are forces structuring grassland but knowledge is scarceregarding the influence of P and K availability on the competition and facilitationbetween grass and clover. However, dramatic reductions in clover content of a grass-clover sward due to K deficiencies have been reported (6; 10; 13). This agrees with (25)who found a 39-62% decline in soil exchangeable K contents over three years in mowedgrassland. (19) reported positive effects of increased access of white clover to P and thatadditional K supply interacted strongly.A better understanding of the biotic control of nutrient acquisition and nutrient

- distribution in plant tissue in different plant populations will improve our management of

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low-input grassland. Nutrient ratios have been used to interpret foliar analyses forryegrass (2) and white clover (17).The purpose of the present experiment was to investigate the effect of N, P and K supplyon growth and development of white clover and perennial ryegrass in pure stands and inmixtures and to investigate the usability of nutrient ratios in analysing the interactionbetween species as well as serve as basis for fertilizer recommendations.

Materials and MethodsThe experimental area was located 18 km west of Copenhagen (55'40'N, 12°18'E; 28 mabove MSL; mean annual precipitation 600 mm; growth period of 210 days) in a field thathad been cropped mainly with cereals for the last 30 years without any P or K or organicresidue application. The experimental area was selected because of its cropping history inorder to get an agricultural soil depleted in fertility and the total-N content of the soil wason average low, that is 0.133%, 0.048%, 0.059%, 0.050% and 0.040% at the depths of0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm and 80-100 cm, respectively. Furthermore, theC-to-N ratio was less than 9 in all depths. In the upper 40 cm soil, the NaHCO3-solubleP content of the soil (15) determined spectrophotometrically was 10.8 mg P kg" dry soil,the NH4-acetate extractable content (16) was 70 mg K, 38 mg Mg, 9 mg Na, and 1047 mgCa kg"' dry soil. The soil pH(oo1Mc cI) was 5.1.Establishing the plant communities and experimental treatmentsThe experimental plant communities were established in spring 1997. Seed mixtures wereundersown in a spring barley crop in plots of 20-m2 sizes. The barley crop was harvestedin August and the developing ley received no further treatment before the followingspring except for defoliation late autumn.The mixtures were established by seeding 10 kg seed ha" of white clover (Trifoliumrepens L. cv. Milkanova) in mixture with 20 kg seed ha' of perennial ryegrass (Loliumperenne L. cvs. Tetramax and Borvi). Ryegrass in pure stand was established by seeding25 kg seed ha' and white clover in pure stand by seeding 10 kg seeds ha- .

The experimental treatment of the three crops consisted of application of nitrogen (0,120 kg ha'), phosphorus (0, 20 kg P ha"') and/or potassium (0, 120 kg K ha-') with fourreplicates, applied early spring 1998 and 1999.Biological nitrogen fixationIn the middle of the 20-M 2 macroplots, sub-plots of 2-m2 were labelled with '5N fertiliserearly spring [(NH4)2 SO4 ; 99 atom%; equivalent to 0.22 g N m2 ] in order to determinesymbiotic N2-fixation by the '5N isotope dilution technique (7), using the mixture of theshoot material from the two perennial ryegrass varieties in pure stand as reference.SamplingThe plant materials were analysed for total-N and total-C using the Dumas drycombustion method in a system consisting of an ANCA-SL Elemental Analyser coupledto a 20-20 Tracermass Mass Spectrometer (Europa Scientific Ltd., Creve, UK).The plant material were dry-ashed at 500C for 3 h; solubilized in 3M HCI; dried andsolubilized again in IM HNO3 before filtering. In the solution, P was determinedspectrophotometrically using a molybdophosphate blue method (14) and K was measuredspectrophotometrically with flame emission (21).Calculations and statisticsThe data were analysed using multiple regression analysis of SAS GLM procedures (18).

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Two approaches were applied, which both essentially indicate the deviations of thenutrient ratios from their optimum values. First, two indices (i, ii), on a basis of 100, thatadjust for the N concentration in the herbage were used (5):

Ki = 100 x K% / (1.6 + 0.525 x N%) (i)Pi = 100 x P% / (0.15 + 0.065 x N%) (ii)

The second approach was based on the Diagnosis and Recommendation IntegratedSystem (DRIS) (24) where the nutrient ratios were applied to ryegrass (1) and to whiteclover (17) like in the case of N:

N-index = [ f(N%/P%) + f(N%/K%)] / 2 (iii)

where f(NO/P%)= - n%/p% x 1000 when N%/P% > n%/p%, orN0/!P% CV

f(N0o/p%) = N%/P% 1000 when N%/P% <n%/p% CV

and in which N%/P% is the ratio of the two tissue nutrient concentrations, n%/p% is thecorresponding norm and CV is norm-associated coefficient of variation.

Results and discussionSeasonal dry matter production and N accumulationDuring the two growing seasons the leys yielded according to average under Danishconditions in terms of dry matter (Table 1) and nitrogen (Table 2). Also the accumulationof P and K in the dry matter was as expected (data not shown) and no visible deficienciesof P or K was observed.

Table 1. Dry matter yield (ton ha -') in white clover in pure stand, ryegrass in pure standand grass-clover mixture over the two growing seasons (n=4).

N, P, K - treatment (kg ha -') Pure Clover Clover Mix Grass Mix Pure Grass

lyear 0,0,0 5.6 4.9 2.5 1.60,0, 120 6.1 4.1 2.2 1.80,20,0 6.4 5.0 2.7 1.80,20, 120 6.5 5.1 3.0 1.9120,0,0 5.5 3.7 5.4 5.3120, 0, 120 6.3 2.6 6.4 5.8120, 20, 0 6.5 3.0 6.6 5.2120, 20, 120 6.6 2.2 7.3 5.8

2.year 0,0,0 4.4 2.2 3.2 0.80,0, 120 5.1 4.1 3.4 1.10,20,0 5.3 4.1 4.3 1.30,20, 120 5.7 5.1 3.9 1.0120,0,0 4.2 2.1 6.7 4.9120,0, 120 5.4 3.3 6.2 5.5120,20,0 5.5 3.1 6.5 5.7

1120, 20, 120 5.9 3.1 7.3 5.7

A multiple regression analysis showed that increased access to P and K significantlyincreased the concentration of the nutrient (P=0.0001) in the shoot biomass. Thebiological N2-fixation was, however, not affected (MO.05). An increased supply of N didnot influence the P concentration in the first year (P=0.83) whereas it did in the second

126

production year (P=0.005), which may indicate that the easily accessible P pools tendedto become depleted. An increased supply of N did influence the K concentration,although not significantly (P values from 0.052 and 0.101).

Nutrient indices in shoot materialDue to the influence of N supply on the concentration of P and K in the shoot biomass, itwas expected that nutrient indices would have to relate P and K concentrations to the Ncontent, in accordance with (5) and with the DRIS approach (22).Use of herbage nutrient index for diagnosis and fertilizer recommendationsDue to the coupling of N, P and K demand and uptake of all species, fertilizers are oftenapplied in compounded mixtures of N, P and K. This serve to a large extend as aguarantee for the farmers to avoid yield reductions. However, such an approach haveeconomic and environmental consequences and more precise recommendations aredesired which allow precise fertilizer management on patch or at least on field scale.

Table 2. Nitrogen accumulation, with fixed nitrogen in brackets, in dry matter (kg ha-') inwhite clover in pure stand, ryegrass in pure stand and grass-clover mixture over the twogrowing seasons (n=4).

N, P, K - treatment (kg ha" ) Pure Clover Clover Mix Grass Mix Pure Grass

Lyear 0,0,0 232 (201) 178 (161) 49 180,0, 120 251 (201) 148 (141) 36 240,20,0 280 (225) 189 (179) 46 200,20, 120 271 (223) 191 (181) 58 23

120,0,0 238 (174) 139 (120) 110 81120,0, 120 259 (177) 94 (86) 126 96120,20,0 277 (178) 112 (103) 136 90120, 20, 120 271 (191) 83 (77) 142 102

2.year 0,0,0 163 (142) 65 (58) 52 110,0, 120 200 (170) 131 (121) 62 140,20,0 213 (179) 139 (128) 79 160,20, 120 233 (203) 167 (153) 73 13120,0,0 169 (115) 69 (55) 119 74120,0, 120 211 (167) 108 (87) 114 80120, 20,0 217 (172) 102 (82) 124 82120, 20, 120 232 (190) 98 (81) 135 82

Herbage analyses, even after converting to relative indices, are prone to spatial variabilityas are soil analysis due to the patchy environment of grazed grassland (I1). The results ofherbage nutrient indices are also prone to temporal variability (Fig. 1). Nutrient indicesalso vary between species (Fig. 2A and 2B) and a mean sample can thus not be used frommultiple species communities. Finally, the same species grown under similar conditionsmay experience different growth conditions and thus give different indices as illustratedfor ryegrass growing either in pure stands or in mixtures with white clover (Fig. 3).Consequently, also the relative herbage indices must be used in management with care.

127

130-

I20 N, P,K -0,0,0ogm NlP,K " 0,0,120

1N.PK. 120,0.0

u N.PK. 120,13,120

3100..,- 90 ll ]so

50

40 Junel,8 July?, 98 Aug28,98 0ct20.98 May29,99 Jul7,99 0012,99

Sampling tine

Figure 1: Variation over time in Ki for ryegrass in pure stand (n=4) under different nutrientsupply (N, P, K - kg ha'). Arrows indicate fertilizer application. Means±SE, n=4.

30.

25 Pure ryegrs (0.0,0)

20 M Pur ryagrs (120,0,120) Ar 20. M Pura l..r (0.0,0)

MMPure cbc r (10.0,0)

S .15,

" .25.

Juel,98 JLiy7,99 Aug2898 Oct2098 May2099 Jii7,99 c1299

Sanlting 6.

-.20

re gram (0,0,0). 11111Pur gram (120.20,0)

-. .iW =Pura cour (0,0,0) B= Pura cb°or (120 20,0)

June1,98 Ju,7.98 Aug28,98 0020.98 May29,99 Jul, 99 Ot12.99

Sawling tim.

Figure 2: Variation in K-index (DRIS) (A) and P-index (B) between pure stands of whiteclover and perennial ryegrass (n=4) under different nutrient supply (N, P, K - kg ha l )

during two growing seasons. Arrows indicate fertilizer application. Means±SE, n=4

128

In both approaches of using relative herbage indices (1; 5) the diagnostic norms values ofsuch plant populations must be established on a large number of experiments wherenutrients are applied following a factorial design. The empirical norm values establishedin this manner will be sensitive to changes in the system. Extrapolation to otherenvironments and species will therefore be dubious as already demonstrated by (2).Consequently, management wise it will only have value if the sampling of herbage andthe establishment of the so-called norms is related to a specific fertilizer management due tothe temporal depletion of the resources following the nutrient application (Figs. I and 2 and 3).Soil analyses are valuable but imprecise management tools. Herbage analysis moreclearly reflects the differences between species in assessing the nutrients in the soil.Combining herbage and soil analysis will greatly improve the knowledge of the systemand thus the management options.

glss t. (0,00)l gass (1200120)

10

40 Jun1. 98 July 7. Aug 28,98 Oct20, 95 May29, 90 Jul 79 0¢1 12.99

S.mpUng t5we

Figure 3: Variation in Ki between populations, i.e. perennial ryegrass grown in purestand and in mixture with white clover (n=4) under different nutrient supply(N, P, K - kg ha'). Arrows indicate fertilizer application. Means+SE, n=4

Ranking of deficiencies by DRISThe DRIS approach provides a means of simultaneously identifying imbalances andranking them in order of importance (22). This approach clearly identified N and P as thelimiting nutrients in ryegrass populations and P as the limiting nutrient in white cloverpopulations. Furthermore, white clover in the controls (0,0,0) was also identified as Kdeficient (Table 3). Ryegrass in mixture seems more P deficient and less N deficient thatryegrass in pure stand.However, critically, plant growth can be limited by multiple nutrient deficiencies and yetDRIS indices might be close to or equal to zero. Furthermore, the norm ratios used inDRIS may still vary with crop age and they are resource demanding to establish.In conclusion, these data indicate that nutrient ratios vary substantially over time, betweenspecies and between plant communities. The relative nutrient indices are of value whenevaluating interactions between species. Also, the approach can be of value in theestimations of fertilizer recommendations in permanent pastures under constantmanagement.

129

Table 3: DRIS indices for white clover in pure stand, ryegrass in pure stand and grass-clover mixture averaged over the two growing seasons (n=4) for selected treatments.

N, P, K - treatment (kg ha- ) Pure Clover Clover Mix Gross Mix Pure GrassN 0,0,0 14.5 24.6 -9.1 -13.8

120,20,120 3.1 -1.1 -I1.1 -13.4P 0,0,0 -48.9 -62.9 -65.5 -34.8

120,0,120 -98.2 -85.5 -71.1 -56.6K 0,0,0 -8.2 -8.1 4.7 3.4

120,0,120 11.3 10.4 5.8 5.9

AcknowlegementFinancial support from the Danish Agricultural Research Centre for Organic Farming isgratefully acknowledged

ReferencesI. Bailey JS, Beattie JAM and Kilpatrick DJ (1997a) The diagnosis and recommendation

integrated system (DRIS) for diagnosing the nutrient status of grassland swards: I. Modelestablishment. Plant Soil 197, 125-135.

2. Bailey JS, Cushnahan A and Beattie JAM (1997b) The diagnosis and recommendationintegrated system (DRIS) for diagnosing the nutrient status of grassland swards: 11. Modelcalibration and validation. Plant Soil 197, 137-147.

3. Caldwell MM, Dudley LM and Lilieholm B (1992) Soil solution phosphate, root uptakekinetics and nutrient acquisition: implications for a patchy soil environment. Oecologia 89,305-309.

4. Duru M, Balent G and Langlet A (1994) Mineral nutrition status and botanical compositionof pastures. I. Effects on herbage accumulation. Eur. J. Agron. 3, 43-51.

5. Duru M and Thelier-Huche L (1995) N and P-K status of herbage: use of diagnosis ofgrasslands. In Diagnostic Procedures for Crop N Management (INRA, ed.). Les Collogues,Paris. Vol. 82, pp. 125-138.

6. Evans DR, Thomas T, Williams TA and Davies WE (1986) Effect of fertilizers on the yieldand chemical composition of pure sown white clover and on soil nutrient status. GrassForage Sci. 41, 295-302.

7. Hqgh-Jensen H and Schjoerring 1K (1994) Measurement of biological dinitrogen fixation ingrassland: Comparison of the enriched "N dilution and the "N natural abundance method atdifferent nitrogen application rates and defoliation frequencies. Plant Soil 166, 153-163.

8. Hugh-Jensen H and Schjoerring JK (2000a) Rhizodeposits of nitrogen below-ground inpastures with different grassland species after two years growth. Soil Biol. Biochem.,accepted.

9. Hqgh-Jensen H and Schjoerring JK (2000b) Below-ground nitrogen transfer betweendifferent grassland species: direct quantification by "N leaf feeding compared with indirectdilution of soil "N. Plant Soil, accepted.

10. Iversen K (1943) Forsqg med ajle til bqlgplante-grqsblanding 1937-1940. Tidskrift forPlanteavl 47, 272-286. (In Danish).

11. Jackson RB and Caldwell MM (1993) The scale of nutrient heterogeneity around individualplants and its quantification with geostatistics. Ecol. 74, 612-614.

130

12. Johnston E, McEwen J, Lane PW, Hewitt MV, Poulton PR and Yeoman DP (1994) Effectsof one to six year old ryegrass-clover leys on soil nitrogen and on the subsequent yields andfertilizer nitrogen requirements of the arable sequence winter wheat, potatoes, winter wheat,winter beans (iciafaba) grown on a sandy loam soil. J. Agric. Sci. 122, 73-89.

13. Lowe J (1967) Botanical development and output of a sward seeded with perennial ryegrassand white clover under stated fertiliser treatments. Record of Agricultural Research INorthern Ireland 16, 75-91.

14. Murphy J and Riley JP (1962) A modified single solution method for the determination ofphosphate in natural waters. AnaL Chim. Acta 27, 31-36.

15. Olsen SR, Cole CV, Watanabe FS and Dean LA (1954) Estimation of available phosphorusin soils by extraction with sodium bicarbonate. U.S.D.A. Circular No. 939,19.

16. Page AL, Miller RH and Keeney DR (1982) Methods of Soil Analysis. Part 2. Chemical andMicrobiological Properties., 2 ASA, SSSA, Madison.

17. Rodriguez M and Besga G (1991) White clover DRIS norms for diagnosis of nutrientdeficiencies in pasture. In White Clover Development in Europe. FAO, Rome, pp. 159-1 6 3.

18. SAS Institute Inc. (1993) SAS/STAT® Software: Syntax, Version 6, First Edition. SASInstitute Inc., Cary, NC.

19. Snaydon R W and Baines R W (1981) Factors affecting interactions between white cloverand grasses. In Plant Physiology and Herbage Production (C E Wright, ed.). BritishGrassland Society, Maidenhead, pp. 179-184.

20. Veresoglou D.S. and Fitter A.H. (1984) Spatial and temporal patterns of growth and nutrientuptake of five co-existing grasses. Journal of Ecology 72, 259-272.

21. Walinga L, Lee, JJ van der, Houba VJG, Vark W van & Novozamsky 1 (1995) Plant AnalysisManual. Kluwer Academic Publishers.

22. Walworth J L and Sumner M E (1987) Foliar diagnosis - a review. In Advances of PlantNutrition, Vol. III (ed. Tinker B P). pp. 193-241. Elsevier, New York.

23. Whitehead D C (1995) Grassland Nitrogen, CAB International, Wallingford. 397.24. Wildin JH (1979) The effect of some nutrients on grass-legume interactions. The Journal of

the Australian Institute of Agricultural Science 45, 126-127.25. Younie D and Baars T (1997) Resource use in organic grassland: The central bank and the

art gallery of organic farming. In: Isart J and Llerena J (eds) Resource Use in OrganicFarming, pp. 43-60. Proceedings of the third workshop of European Network for ScientificCoordination in organic farming (ENOF), University of Ancona, Italy, June 1997.

131

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

THE EFFECT OF PHOSPHORUS AND POTASSIUM FERTILIZATION ON THEYIELD AND GRAIN QUALITY OF WINTER WHEAT

Stephan Gorbanov, Svetla KostadinovaHigher Institute of Agriculture, Plovdiv, Bulgaria

SummaryThe effect of phosphorus and potassium fertilizations on the productivity of commonwinter wheat (Triticum aestivum L.) cv. Bononia at the different levels of nitrogenfertilizing were investigated under the conditions of pot experiments. The study wascarried out on a fluvy slight saline soil with pH (Ho) - 7.3, humus content 3.2 %, Nmin -9.8 ppm, available phosphorus (P20,) - 109 ppm, and available potassium (K20) - 460ppm. It was established that phosphorus and potassium fertilizations were gave a positiveeffect on the nutrient regime of the common winter wheat and on the yield and grainquality. The highest grain yield was obtained at phosphorus fertilizer level 200 mgP20/kg soil. The potassium fertilization increased the yields at nitrogen fertilizer levelsfrom 0 to 400 N mg/kg soil. The changes of potassium nutrient regime by fertilizing didnot change the grain protein concentrations of the wheat. The phosphorus fertilizationincreaced the concentrations of this nutrient in the wheat straw and grain, as well. Itpositively affected the grain calcium concentrations. Potassium fertilization gave a strongpositive effect on the potassium concentrations in the wheat straw and did not influencethe concentration of this nutrient element in the grain.

Key word: winter wheat (Triticum aestivum L.); phosphorus and potassium fertilizations

IntroductionThe common winter wheat in Bulgaria occupies about I million hectares that representsnear 25 % of the total cultivated land of the country (8). The average annual production ofwheat in Bulgaria has been at about 5 million tones grain so far, but in the latest years ithas decreased up to 3 million tones. Many factors affect negatively on the wheatproduction, but the most decisive of them are land property reform and fertilization. Themineral fertilizer application in Bulgaria was sharply decreased and the application ofphosphorus and potassium, especially (3). The potassium balance in Bulgarian agriculturehas always been a negative (3). The phosphorus balance from positive (+90 kg.ha-') hasbecome negative (2). During the periods of intensive phosphorus applications the per centof soils low in available phosphorus reserves was reduced and the per cent of wellsupplied with phosphorus soils was increased. The natural potassium reserves inBulgarian soils are large and the potassium nutrition of plants is satisfactory underconditions of extensive agriculture (7). The needs of potassium fertilizing increase underintensive nitrogen and phosphorus applications. The effect of the phosphorus fertilizingon the productivity and quality of the old Bulgarian cv. Charodeika grown on soils withdifferent available phosphorus was establish by us (7). The effect of potassium on thegrowth and productivity of the new wheat cultivars in Bulgaria was studied on a small scale.

132

The objective of the present study was to established the effect of the increasingpotassium concentrations of the soil at different levels of available nitrogen on the yieldand grain quality of the wheat, and the effect of phosphorus fertilization on the soil low inthese nutrients.

Material and methodsTwo greenhouse pot experiments with increased nitrogen, phosphorus, and potassiumfertilizing levels were conducted. The effect of potassium fertilization and different levelsof nitrogen fertilizing were studied in the first experiment. The aim of the second potexperiment was to establish the effect of increasing levels of phosphorus fertilizing atbackground of applied nitrogen 400 mg N/kg soil. The investigated nitrogen levels were0, 200, 400 and 600 mg N/kg soil and the levels of potassium fertilizing were 0, 200, 400mg K2O/kg soil. The plants were grown in plastic pots (5L volume). Each pot contained5 kg fluvy slight saline soil with pH 012o) - 7.3, humus content 3.2 %, Nmin - 9.8 mgN.kg- , available phosphorus (method of Egner - Riehm) - 109 mg P2,0.kg'I, and availablepotassium (2 N HCL) - 460 mg K2O.kg t'. The different levels of mineral nutrition at twopot experiments were created by applying NH4NO3, Ca(H 2P04).H 20, and K2S04 in theform of water solutions. The Bulgarian high yielding and good quality cv. Bononia wasused in the experiments. The obtained yields of cv. Bononia under breeding trials atdifferent regions of Bulgaria have been up to 8.5 t grain.ha " . Thirty seeds were sown ineach pot at the beginning of December. The wheat plants were reduced to equal numberin each pot (15) at the Zadoks stage 50 (tillering). The removed plants were used foranalyses. The analyses of plant vegetative mass and grain were done after wet combustionusing concentrated H2S04 and H20 2 as a catalyst. The nitrogen and phosphorus contentswere determined by flow-colorimetry using FlAstar 5023 (Tecator). The contents ofpotassium, calcium, and magnesium were determined with AAS (Perkin - Elmer model30 30 B). The grain protein concentrations were calculated by multiplying total nitrogenconcentrations of grain by factor 5.7 (% N total x 5.7). An overall analysis of variance(ANOVA) was performed to evaluate the effect of the experimental treatments on thereferred variables, and Duncan multiple range test (ax = 0.95) was used in order toestablish the difference among the means.

Results and discussionThe obtained results show no significant effect of the levels of phosphorus fertilizing(ranged from 0 to 400 mg P2O.kg' l soil) on the concentrations of plant nitrogen andpotassium at the Zadoks stage 50 (tillering) (Table I). But the phosphorus concentrationwas increased from 0.266 % to 1.353 % P205. The obtained mean values were higherthan the sufficiency range levels for this stage of winter wheat proposed by Bergmann (1).

Table 1. Effect of the phosphorus fertilizing levels on the concentrations of nitrogen,phosphorus, and potassium of wheat plants at tillering

Variants N % P _% K20 %1. N0PoKo 1.88 b 0.334 c 2.39 b2. N4 oPoK 2w 4.67 a 0.266 c 5.13 a3. N4aP 20QK20 4.49 a 1.061 b 5.19 a4. N4WP4oK 2o 4.94 a 1.353 a 5.25 a

133

The potassium fertilization gives a positive effect on the concentrations of plant nitrogen(Fig. 1). The biggest differences were obtained at the higher levels of nitrogen fertilizing.The plants grown at fertilized levels N4,oK 2o and N 0 K0 contained equal nitrogenconcentrations. The fertilised with K4, plants reached the optimal range values of thewinter wheat still at nitrogen level N2 . It proves the favourable role of the potassium onthe nitrogen nutrition of this crop.

%N5.5

54.5 -

43.5 - K2

3 -U K2002.5 - K400

21.5

mg N/kg soil0 200 400 600

Figure 1. Effect of nitrogen and potassium on the nitrogenconcentrations of vegetative mass at tillering

The level of nitrogen nutrition influenced the potassium contents at the vegetative mass ofthe wheat plants at tillering stage (Fig. 2). The plants at nitrogen level 200 mg N/kg soilshowed the highest potassium concentrations at this stage. The higher nitrogen levels (400and 600 mg N/kg soil) reduced the potassium concentrations of the plants, but they weresignificantly higher in comparison with those without nitrogen fertilizing (N,).

% K2O6

-4N

2.5

2 -mg K20/kg soil0 200 400

Figure 2. Effect of nitrogen and potassium on the potassiumconcentrations in the vegetative mass at tillerung

The phosphorus fertilizing favourably affected the grain and straw yields (Fig. 3). The

highest productivity was obtained at fertilized level P20o. The higher phosphorus levels

134

decreased the grain yields, but yields were higher as compared to the phosphorusunfertilized plants (P0 ). These results confirm previously reported by us data relating theeffect of phosphorus with the productivity of cv. Charodeika (4). Under conditions of along-term fertilization experiment, elimination of phosphorus fertilizing for four years ina crop rotation reduced the grain yields of wheat cv. Bononia (6). At the identicalfertilization levels of nitrogen and potassium, the mean grain yields (4 years) were 3700kg.ha-' in the phosphorus-fertilized treatment and 2990 kg.ha" without phosphorusapplications. At the same time, the contents of the available phosphorus diminished from270 mg P205.kg-' to 134 mg P20.kg"' soil, respectively.

g/pot60 -5040 m30 -I Ograin

20 - straw10 W0

1 2 31 - N4 0P20 K2 2 - N4WPwK2W 3 - N4wP4NK2W

Figure 3. Effect of phosphorus on the wheat productivity

The potassium fertilization showed a positive effect on the productivity of wheat grainand straw at all of three levels of nitrogen fertilizing (0, 200, and 400 mg N.kg- soil), butthe strongest expressed differences been at application of 400 mg N.kg' soil (Fig. 4). Atthe moderate nitrogen fertilizing (N 20 ) potassium increased the grain yields with 13 %and 24 %, respectively, in comparison with potassium unfertilized treatment. At fertilisednitrogen background (N4 ), potassium increased the grain yields by 39 % and 46 %,respectively, in comparison with the treatment without potassium fertilization. MacLead(1969) observed similar results for barley (Hordeum vulgare L.) in hydroponics-cultureexperiments. But in the conditions of field fertilization experiment with the same cv.Bononia on the same soil type, this effect of applied potassium was not observed.Reducing of available potassium from 830 mg K20.kg-' to 560 mg K20.kg' soildiminished the grain yield only by 5.7 % in comparison with the treatment withoutpotassium fertilizing. It was due to the considerable natural reserves of soil potassium andto the large root penatration of soil and large absorption of potassium (6).The considerable changes of the concentrations of crude protein in wheat grain dependingon the phosphorus and potassium levels were not observed (Table 2). The establisheddifferences among the treatments were slight and not significant.The phosphorus fertilization had a strong positive effect on the phosphorus concentrationsin grain and straw (Table 3). Only the high phosphorus rates were the positive effect onthe calcium concentrations in the grain. It was due to the larger quantities of calciumapplied with Ca(H 2PO4). H20 and to the synergism between phosphorus and calcium inroot system.

135

gran, - KO straw,g/pot -.- K200 g/pot40 035

30 so

25 24

10

0 ,0 1

0 200 400 600 0 200 400 600

mg N/kg soil mg N/kg soil

Figure 4a. Effect of nitrogen and Figure 4b. Effect of nitrogen andpotassium leves on the grain yields potassium leves on the straw yields

of the wheat of the wheat

Table 2. Effect of the nitrogen, phosphorus, and potassium levels on the grain proteinconcentrations and yields

Potassium fertilized levelsVariants KO K2o K4W

% g/pot % g/pot % g/potNoP 2oo 8.62 0.32 6.63 0.56 7.88 0.59N2WP2W 13.48 2.37 14.31 2.86 12.91 2.83N4WP2W 17.46 4.43 16.19 5.73 15.92 5.94NoP4W 16.02 3.63 17.50 4.43 17.16 6.38

Phosphorus fertilized levelsPo P2o0 P4o

% g /pnot % [g/pot %g/t

_NoK_ 16.19 4.6 14.71 5.73 17.04 569t

Table 3. Effects of the phosphorus fertilizing level on the concentrations of phosphorus,potassium, calcium, and magnesium in the wheat grain and straw

Variants P20 % K20% CaO % . MgO %grain straw grain straw grain

1. N4ooPoK 2oo 0,246 c 0,079 c 0,37 a 2,17 b 0.317 b 0.152 b2. N4WP20 K2 o 0,983 b 0,251 b 0,45 a 2,23 b 0.302 b 0.203 a3. N4 0 P4 0 K20 1,265 4 0,399 a 0,45 q 2,65 a 0.521 a 0.208 a

Potassium fertilization increased the concentrations of this nutrient in the straw and it didnot affect the potassium concentrations in the grains (Table 4). The differences betweenthe concentrations of calcium and magnesium in the wheat grains depending onpotassium applications were not significant.

136

Table 4 Effects of the potassium fertilizing level on the concentrations of phosphorus,potassium, calcium, and magnesium in the wheat grain and straw

P O.% KzO % CaO% MOVariants grain straw grain straw grain

1. NoP2WKo 0,940 ab 0,229 bcd 0,54 a 1,31 e 0.385 abc 0.226 a2. NoP2 oKW 1,040 ab 0,106 gh 0,31 d 1,45 de 0.330 abc 0.179 b3. NoP2oolwK 0,556 c 0,140 fg 0,40 bc 1,69 c 0.380 abc 0.207 ab4. N2ooP2WoKo 1.057 a 0,177 ef 0,44 abc 1,32 e 0.416 ab 0.185 ab5. N2 oP2 oK2W 1,103 a 0,236 abc 0,51 a 1,72 c 0.225 c 0.216 ab6. N2oP2 ,K 4 0,668 bc 0,199 cde 0,31 d 2,32 a 0.367 abc 0.178 b7. N4 WoP2WKo 0,963 ab 0,250 ab 0,45 abc 1,38 e 0.306 bc 0.225 a8. N400P200K 00 0,983 ab 0,251 ab 0,45 a 2,23 ab 0.302 bc 0.203 ab9. N41OP2owK4 1,075 a 0,276 a 0,32 d 2,37 a 0.378 abc 0.200 ab7. N P 2 ,Ko 1,041 ab 0,174 ef 0,41 abc 1,37 e 0.334 abc 0.195 ab8. N6 oPo2 K20 o 0,978 ab 0,190 de 0,34 cd 2,06 b 0.453 ab 0.190 ab9. NrOP2K4oo 0,951 ab 0,203 cde 0,42 abc 2,22 ab 0.503 a 0.192 ab

ConclusionsUnder pot experiments phosphorus and potassium fertilizations proved a positive effecton the nutrient regime of the common winter wheat and on the yield and grain quality.The highest grain yield was obtained at phosphorus fertilizer level 200 mg P2OJkg soil.The potassium fertilization increased the yields at nitrogen fertilizer levels from 0 to 400N mg/kg soil. The changes of the potassium nutrient regime by fertilizing did not changethe grain protein contents in wheat. The phosphorus fertilization increaced theconcentrations of this nutrient in the wheat straw and grain, as well. It had a positiveaffect on the grain calcium concentrations. Potassium fertilization gave a strong positiveeffect on the potassium concentrations in the wheat straw and it did not influence theconcentration of this nutrient element in the grain.

References1. Bergmann, W. Nutritional Disorders of Plants, 1992, Gustav Fischer Verlag, Jena-Stutgard-

New York2. Gorbanov, S.P-, Gorbanova, A.S., Phosphorus fertilization management and balance of

phosphorus in Bulgarian agriculture, Biblioteca Fragmenta Agronomica, Vol. 3, Pulawy,1998, p.1-6

3. Gorbanov, S.P., Manolov, I.G., Kostadinova, S.S., Mineral balances and nitrate policies inBulgaria. The Implementation of Nitrate Policies in Europe, Wissenschafisverlag Vauk KielKG., p. 113-121

4. Gorbanov, S.P., Tomov, T. The effect of phosphorus nutrition on the quality of winter wheatgrain protein, Proceedings of the 9h CIEC World Fertilizer Congress, Budapest, 1984, p.251-253

5. MacLead, L.B., Effects of nitrogen, phosphorus, and potassium and their interactions on theyield and kurnel weight of barley in hydroponics culture, Agronomy Jourmal, Vol.61, 1969,p. 26-29

6. Matev, J., Gorbanov, S.P., Tomov, T. et all, Productivity of crops in four-season croprotation with different fertilization system, Higher Institute of agriculture - Plovdiv,Scientific Works, 1995, Vol. 3, book 1, p 2 11- 2 16

7. Soils in Bulgaria,1960, Zemizgat, Sofia8. Statistical Yearbooks of Bulgaria, 1997.

137

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUMAND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

THE RELATIONSHIP BETWEEN AVAILABLE PHOSPHORUS AND

POTASSIUM CONCENTRATION AND FLAX YIELD AND EFFICACY OFPHOSPHORUS FERTILISER

Alfonsas vedas

Lithuanian Institute of Agriculture

Zofija Jankauskien6,

Lithuanian Institute of Agriculture's Upyte Experimental Station,

AbstractFindings of the experiments carried out between 1996-1998 at the Upyte Experimental

Station on a sod gleyic sandy loam on loam soil suggest that the yield of linseed, strawand long fibre and phosphorus fertiliser efficacy are related with meteorologicalconditions, soil phosphorus and potassium content. The relationship between the yield

and fertiliser efficacy and soil phosphorus and potassium content is expressed byequations. It was determined that the highest yield was obtained in the soil containing

175-212 mg/kg of available P2, and 158-215 K20. Phosphorus fertiliser was effective in

the soil containing less than 150 mg/kg of P2O5 . Phosphorus fertilisation did not have any

marked effect on flax yield quality indicators.

Key words: flax, linseed, straw, correlation regression

IntroductionIt is reported that in flax cultivation and yield formation phosphorus takes the secondplace and potassium - the third /9/. Phosphorus has a positive effect on the developmentof root system, flower formation, increases fibre output, improves its quality and speeds

up maturity /3, 5, 10/. Potassium increases resistance of flax to lodging, reduces disease

incidence on plants, increases linseed yield, improves fibre quality /3, 5, 10/, however notalways /2, 4/. Too high concentration of phosphorus in the soil (over 250 mg/kg) can bedetrimental to plants /12/. In the experiments carried out in Upyte earlier the optimumcontent of available phosphorus for flax was 170-230 mg/kg, and that of availablepotassium - 150-200 mg/kg of soil /1/. Russian researchers have reported that a sufficient

amount of available phosphorus for flax is 100-150 mg/kg (according to Kirsanov), andunder favourable meteorological conditions a quite high yield can be produced even in the

soils poor in phosphorus /8/.Phosphorus and potassium fertiliser should be used according to the status of these

elements in the soil /5, 6, 12,13/. They are most often effective only in the soils poor inthese elements (less than 100 mg/kg) /8/.The objective of this study is to estimate the effect of soil available phosphorus andpotassium on flax yield, its quality indicators and efficacy of phosphorus fertiliser.

Material and methodsThe experiments were carried out at the Upyte Experimental Station's crop rotationbetween 1996-1998 on a sod gleyic sandy loam soil on loam. Arable layer- 30 cm. In the

138

soil samples taken from the amble layer before the establishment of the trial the contentof P20 5 and KO was determined in A-L extraction. Fibre flax 'Baltuiai' was sown afterwinter wheat at a rate of 22 million germinable seed per hectare.Record plot - 20 M2. Replications - 4. Randomised plot design was used.Flax was pulled at early yellow maturity. The stems were macerated by warm method.The strength and flexibility of fibre was determined by a dynamometer and fleximeter.Total and technical length of stems, disease incidence were determined taking 100 plantsper treatment, flexibility and strength of long fibre taking 30 plants per treatment /7/.Yield data were processed by the dispersion analysis method, relationship between theyield and soil agrochemical properties - by the correlation regression method /11/.Meteorological conditions during the experimental years were diverse. The largestamount of precipitation was in 1998 (especially in July), and the least in 1997. Judgingfrom hydrothermal coefficient there was excess of moisture in 1996 in the 3rd ten -dayperiod of May, 2n and 3rd ten-day period of June, 1 ten-day period of July. There was ashortage of moisture in the Is and 2 nd ten -day period of May the 3rd ten-day period ofJuly and the whole August were extremely droughty. In 1997 there was an especiallygreat excess of moisture in the I' ten -day period of May. There was an excess ofmoisture in the 3,d ten-day period of May 2 ten -day period of June, there was ashortage of moisture in the 2nd ten-day period of May, V and 2 ,d ten-day periods of Julyand during the whole months of august. In 1998 there was a shortage of moisture only inthe 2 nd ten-day period of May and 2nd ten-day period of June, there was excess ofmoisture in the I' and 3rd ten -day periods of May, in the 2nd ten -day period of June, inthe I' ten-day period of August and especially in July.

Results and discussionThe soil under experiments was of neutral reaction, and contained quite a high humus andphosphorus content (Table I).

Table 1. Agrochemical indicators of the arable layer of soil

Indicator 1996 1997 1998pH 7,4±0,08 7,6±0,12 7,2±0,12Humus content % 3,8±0,58 3,9±0,82 2,8±0,58Nitrogen content % 0,12±0,026 0,12±0,021 0,13±0,017Available P20 5 mg/kg 220±42,8 142±49,4 183±37,2Available K2 0 mg/kg 164±58,2 118±31,3 185±43,2

Flax yield is reflected by the data provided in Table 2.

Table 2. Seed, stem and long fibre yield (kg/ha)

1996 1997 1998 Average of 3 yearsTreatmentSeed Stem Fibre Seed Stem Fibre Seed Stem Fibre Seed Stem Fibre

Check(untreated) 792 3191 536 789 6987 1595 624 3538 368 735 4572 833P2o 1026 4168 725 757 6748 1337 796 4755 626 860 5224 896LSD,5 269 819 173 150 1030 247 106 1213 233 188 1033 220V% 21 16 24 14 10 12 I1 21 35 17 15 18

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In the unfertilised plots a sufficiently high yield of linseed, stems and fibre was obtainedin all the experimental years. Linseed yield was the most stable. Depending onmeteorological conditions its variation coefficient was as low as 13 %. Variationcoefficient of the stem yield was 46 %, and that of fibre as high as 69 %. Therefore wecan conclude that meteorological conditions have a very great effect on flax yield,especially on stem and fibre yield. Fertilisation does not alleviate the effect ofmeteorological conditions. In a droughty year of 1997 a slightly lower yield was obtainedin the plots treated with phosphorus than in the unfertilised plots, although the content ofavailable phosphorus in the soil was higher than in 1996 or 1998.The flax yield in the plots receiving the same fertilisation depended on the soilagrochemical properties. Linseed yield variation coefficient depending on soil propertiesvaried in different years between the limits of 11-21%, stem yield- 10-21%, and fibreyield- 12-35 %. The least effect of soil agrochemical properties was felt in a droughtyyear of 1997, while the greatest effect -in 1998. They had the greatest effect on fibre output.The relationship between linseed, stem and long fibre yield and available phosphorus andpotassium content in the soil without fertilisation is presented in Figures 1, 2, 3.In 1996 at the variation of available phosphorus content within the limits of 179-253mg/kg, the flax yield is well described by the equations: linseed yield - y1=2092,12-5,54x-0,0022x 2; i1=0,94, stems - y2=15683,00-96,71x+0,1762x2; rI=0,82, long fibre -

y3=3230,63-21,92x+0,0428x 2; 1"=0,54. (Fig 1).

Yield kg/ha

4500400035002000 -- y

2500 -20CO y3

INS) -y 21500

0170 ISO 190 200 210 220 230 240 250 260

Available P2O, mg/kg

Figure 1. The relationship between linseed (yI), stem (Y2), long fibre (y,-) yield andcontent of available phosphorus in the soil when not adding fertilisers, 1996

Yield ksae

8000

- U *oo* -.-- Yl

30002000--

80 90 00 HI0 120 130 140 150 160 170 180 190

Available PO, mg/kg

Figure 2. The relationship between flax (y,), stem (Y2) yield and content of availablephosphorus in the soil when not adding fertilisers, 1997

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In 1997 in the unfertilised plots at the variation of available phosphorus within the limitsof 85-181 mg/kg can be expressed by the following equations: of linseed - y, -434,96+18,64x-0,0647x; Tq=0,997, of stems - Y2 =-4596,00+31,38x-0,0918x2; J=0,73, oflong fibre - Y3 =949,97+8,68x-0,0262x2 ; TI=0,998 (Fig. 2). The highest linseed yield wasobtained at phosphorus content in the soil of 144 mg/kg, stem yield at - 171 mg/kg, longfibre yield at - 166-mg kg of soil.In 1998 flax yield variation with the increase in available phosphorus content from 175 to223 mg/kg, can be described by a parabola and can be expressed by the equations: oflinseed - =-5821,37+64,17x-0,1580x2 ; rI=0,88, of stems - y2=-82506,44+891,09x-2,2804x2; ri=0,89, of long fibre - y3=-9801,05+104,88x-0,2674x2 ; 11-0,66. The highestlinseed yield was obtained at P20 5 content in the soil of 203 mg/kg, straw yield at -195mg/kg, and fibre yield at 196 mg/kg.

Yield kgfra

4000- 0- - U

3000 --- y2

2000 -y3

0

170 [so 190 200 210 220 230Available P2O, mg/kg

Figure 3. The relationship between linseed (y,), stem (y2), long fibre (y3) yield andcontent of available phosphorus in the soil when not adding fertilisers, 1998

The greatest effect of soil available phosphorus was recorded in normal and wet years of1996 and 1998, while the lowest effect in a droughty year of 1997. During all years theeffect of soil phosphorus on flax yield can be attributed to the same regularity: flax yieldvaried in a parabolic pattern with the highest point in the parabola close to 180-200 mg/kgP2 5 . At the content of available phosphorus above 180-200 mg/kg the flax yield declined.The relationship between the effect of available phosphorus concentration in the soil onflax in the plots treated with phosphorus and flax yield was much weaker.Phosphorus fertilisers alleviated the effect of phosphorus concentration in the soil on flaxyield, however it did not distort general regularity. With the change in phosphorusconcentration in fertilised and not fertilised soil flax yield changed in a parabolic pattern.The extreme point of the parabola fluctuated between 175-212 mg/kg P205. Suchconcentration of available phosphorus is considered optimal for flax.Efficacy of phosphorus fertilisers depended on meteorological conditions and soilphosphorus content. A significant yield increase through phosphorus fertilisers wasobtained in 1996 and 1998 (Table 2). In a droughty year of 1997 in the plots treated withphosphorus a slightly lower yield was obtained than in unfertilised plots. Fertiliserefficacy depended on soil properties, however soil phosphorus content played the decisiverole. With the change in phosphorus content relative fertiliser efficacy changed in aparabolic pattern ( Table 3).

141

Table 3. Variation of average relative yield increase through 20 kg/ha of P205phosphorus fertilisers

Increase % atIndicator Regression equation Ti P;O mp/kg in the soil

50 100 150 200Linseed yl=1-0,009992x+0,0000254x 2 0,91 100 45 13 3Straw y]2=1-0,009875x+0,0000232x 2 0,73 100 43 7 -8Long fiber Y'3=1-0,0 1 lx+0,0000298x2 0,67 100 38 4 1Mean y=1-0,Olx+0,000026x 2 0,78 100 46 15 7

Phosphorus fertilisers are most effective in the soil with a low status of availablephosphorus. At its content above 150 mg/kg its efficacy is very weak. Therefore it pays tofertilise flax with phosphorus when the soil contains less than 150 mg/kg of available P2Os.Fertilisation with phosphorus did not have any.tangible effect on flax yield quality.Flax yield is also related to available potassium concentration in the soil. The relationshipbetween the yield in the plots not treated with phosphorus with the content of potassiumin the soil is represented by the data provided in Fig. 4, 5, 6.In 1996 (Fig. 4) with the change of available potassium within the limits of 108-186mg/kg flax yield changed in a parabolic pattern. It can be expressed by the followingequations: of linseed - y,=3652,06+62,95x-0,2112x2 ; rq=0,94, of stems - y,=14467,79+241,04x-0,78006x 2 ; r1=0,89, of long fiber - y3=4601,07+68,06x-0,2139x 2; 71=0,94.Extreme points of the parabola (amounts of available potassium) - 149 mg/kg linseed,154 mg/kg stem and 159 mg/kg long fibre yield.

Yield kg/ha5000

4000 I

3000 -u-y 2

2000 -y3

1000 - "_ _ _ ,

100 110 120 130 140 150 160 170 180 190

Available KO mg/kg

Figure 4. The relationship between linseed (Y1 ), stem (Y2), long fibre (Y3) yield andcontent of available potassium in the soil when not adding fertilisers, 1996

In a droughty year of 1997 (Fig. 5) with the change in potassium content within the limitsof 94-134 mg/kg the yield variations depending on soil potassium status were negligible.They are expressed by the following equations: of linseed - y=2013,16-26,44x+0,1345x2

"q=0,86, of stems - y2=10397,09-58,10x+0,2415x2; r=0,20 and long fibre -y3=3873,92-41,44x+0,1837x 2 ; rl=0,71. Thus fluctuation of soil potassium content in adroughty year of 1997 did not have any more marked effect on flax yield.

142

Yield kg/U

8000

6000 --'__--yl

4000 - y2

.- '-- y3

2000 A A A A ± A A . y

0

90 O0 110 120 130 140Available KO mg/kg

Figure 5. The relationship between linseed (y,), stem (y2), long fibre (y3) yield andcontent of available potassium in the soil when not adding fertilisers, 1997

The content of available potassium in unfertilised plots in 1998 varied within the limits of124-264 mg/kg. Linseed yield expressed by the equation (y,=1571,30-10,44x+0,0261x 2;71=0,85) was positively influenced only by available potassium contents above 200 mg/kg.Stem (equation y2=4454,38-18,90x+0,0665x 2; q=0,74) and long fibre (equationy3=565,95-4,03x+0,0142x2; "q=0,94) yield increased when the content of availablepotassium was from 142 to 264 mg/kg of soil (Fig. 6).

Yield kg/la

5000

4000 = *-

3000 "m _y2

2000 r

'000

0-

120 140 160 ISO 200 220 240 260

Available K20 mg/kg

Figure 6. The relationship between linseed (y,), stem (Y2), long fibre (Y3) yield andcontent of available potassium in the soil when not adding fertilisers, 1998

Summarising the data of the experiments carried out between 1996-1998 it is evident thatwith a change in soil potassium content flax yield changes in a parabolic pattern and canbe expressed by the following equations: of linseed - y,=-232+ 11,74x-0,0273x 2 ; T1=0,89,

of stems y2 =-6132+ 129,2x-0,4096x2; r]=0,68, of long fibre - y3 =-710+15,71x-0,0369x 2; rl=0,87. Extreme points of the parabolas expressed by equations are 215, 158and 213 ng of available K20 per kg of soil. These are the points when with the change insoil potassium status the highest amount of a certain produce is obtained, but fertilisersare no longer effective.

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Conclusions1. Flax yield and phosphorus fertiliser efficacy is determined by meteorologicalconditions.2. With the changes in soil phosphorus content the yield changes occur in a parabolicpattern. The highest yield was recorded at 175-212 mg/kg of P20 5 in the soil.3. Efficacy of phosphorus fertiliser, depending on soil phosphorus content, changed in aparabolic pattern: a yield increase was obtained at a P2O content in the soil below150 glkg.4. With the change in soil potassium content the flax yield changed in a parabolic pattern.Average extreme points of parabolas were: for linseed yield 215, stem yield - 158, longfibre yield - 213 mg K2 O per kg of soil.

ReferencesI. Jankauskiene Z. Dirvoremio agrocheminiq savybiq itaka linq derliui // TrQimo

sistemos ir dirvotemio derlingumas. - Vilnius, 1994.-P. 166-173.2. Robinson B.B., Cook R.L. The effect of soil types and fertilizers on yield and quality of

fiber flax//Journal of American Society of Agronomy.- 193 I.-V.23.-P. 497-5 10.3. T r ocm e S., B on i face R. Influence de [a fertilisaton phosphatee et potassiumque sur la

qualite de divers produits agrcoles // Phosphore et potassium dans les relations sol-plante.Consequences sur Ia fertilisation.-1988.-P. 505-516.

4. Watson C.J., Adams S.N. The effect of fertiliser on yield and herbicide-retting of flax//Rec.agr.Res.Belfast.-1988.-V.36.-P. 21-25.

5. ArpOHOM!mecA Terpa3hI. Boa3eablnaHe n nCpBHHHUM o6pO6OTKa JlbHa-lonrylua noHreHcHBMoI TeXHOJIOruM (non pea. .H. MapTmrona).-MocKBa: : ((PoCcenbxowaHaaT>,1986.-C.16-18.

6. KopeHcKHi H.F., Kopo6aq A.I., FapauonhM M.C. H ap. CnpaBoMIIHK JlbHaola -Muuc:i(YpagxaIk, 1987.-C.65-77.

7. MeTnwe iKe yKaaHtA no npoBeheHMo noneBbI. OnoToB cO iabHoM-ao-1ryHUOM1o-

TopxoK, 1987.-72 C.8. He6oabclx A.H., He6onucHHa 3.fI., rloKpOBCKas r.n. a ap. OnTHMHauA 103

MHF{epu[ILF1lX yao6penuu nogi iea9. fleTpoaa Ji.M. Yao6peuim, ypo)a H KaqecTo ceMnm nonIryfua // JlIeH KHonona,1 9 84 ,

Ho 6.-C.25-26.10. foB6kMeHHe a'ecTana mba-Aonryuaa (pea. Tpyw M.M.)-MocKna:(<Konoc>, 1984.-C.34-44.l1. CHegaKop AX,'. Y. CTaTcr4ecue MeToAbl I n pHMeHeHHH K nocIegOBaHmiM B ceJIbcKoM

Xo3Slc'BC H 6noaornu. Mocicna,-1961, 503 c.12. DoMeHxo J.A., CTpyKOB A.B. HunycrpanbnaI Texiioiors npoH3Roacrma JYhHOC6lpbS. -

JleHaHrpant, 1987.-C.41-47.13. Waqppau C.A., IHHweBCKHi c1.B. Arpo3xonoMHnecKoe o6ocuoBaHHe npHMeHeHRA

KaaiiHHb[x yAo6peHHH B HegepHo3eMHOi 3ce Poccna // Arpoxmns, 1998, Ho 4.-C.5-17.

144

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUMAND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

RYE YIELD IN RELATION TO PK FERTILISATION AND THEIRCONTENT IN THE SOIL

Alfonsas vedas, Daiva Janugauskait&

Lithuanian Institute of Agriculture

AbstractField experiments were carried out in Dotnuva, VeIai~iai and Voke over the period 1994-1998 with the aim of determining the relationship between winter rye yield and soilproperties and fertilisation intensity. The soils under the experiments differed in theirorigin, physical and chemical properties and in productivity.In separate years the maximum winter rye cv.'Rfikai' yield was 4.9-7.8 t/ha in Dotnuva,3.7-5.3 t/ha in V ai~iai and 2.8-3.4 t/ha in Voke. The yield size variations weredependent on the weather during the vegetative growth period, soil agrochemicalproperties, fertilisation level and the use of plant protection means. The relationshipbetween the yield size and soil phosphorus and potassium content and the amount ofnitrogen fertiliser on different PK backgrounds is expressed by regression equations.They showed that in the experiments of the same site where the values of soil propertiesof individual plots vary in a small range, the yield is determined by fertilisation,especially nitrogen, and plant protection level. Effectiveness of nitrogen fertiliser ondifferent P and K backgrounds in different sites changed inconsistently and depended onthe weather, soil properties, preceding crops and management practices.

Key words: winter rye, yield on different phosphorus and potassium backgrounds.

IntroductionWinter rye is one of the most important food cereals and a good concentrated feed.Comprehensive studies on rye cultivation issues have been conducted in Lithuania /3, 4, 7/.Experimental findings /I/ of the studies carried out at the LIA Voke Branch on a sodpodzolic sandy loam and sandy soil suggest that nitrogen fertiliser was the most importantfor winter rye. The effect of phosphorus and potassium fertilisers was much poorerwithout nitrogen fertiliser.The data of the experiments conducted in Lithuania show that I kg of nitrogen appliedtogether with phosphorus and potassium fertilisers increases winter rye yield by 11,2 kg/2/. Experiments conducted earlier on the effect of nitrogen fertiliser and its applicationtime on winter rye involved the varieties of the older generation such as 'Lietuvos 3','Dotnuvos aukgtieji', 'Baltija', 'Beniakonigkieji', 'Kombaininiai' , 'Kustro' /3, 5, 6/.In all the previously done fertilisation experiments fertiliser rates were not closely relatedwith soil properties and yield. Besides, low yields were obtained in all experiments andthe reasons were not ascertained. The reasons for low and inconsistent yield might havebeen unproductive varieties, low fertiliser rates, poor plant protection. Due to this theresults of the formerly conducted experiments are practically inapplicable for intensivevarieties and intensive growing technology.

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It would not be expedient either from ecological or economic point of view to apply to thenew winter rye cv. 'Rflkai' the fertilisation scheme developed on the basis of the findingsof the earlier conducted experiments when fertiliser rates are not linked to the content ofhumus, nitrogen, phosphorus and potassium, and other soil properties and the size of theexpected yield.The objective of our work was to develop the calculation methodology of tetraploid ryefertilisation system which would enable to determine ecologically and economicallyrational nitrogen, phosphorus and potassium fertiliser rates to obtain the yield of adesirable size and quality in a specific field being aware of its soil agrochemicalindicators. We will present here only part of experimental material reflecting the effect ofPK fertilisation and their content in the soil on rye yield.

Experimental conditions and methodsExperiments were carried out in Dotnuva (A. vedas, D. Janugauskaite), Veaidiai (N.Elerinskiene) and Voke (L.Tripolskaja, R. Lisova). The soil in Dotnuva was sod-gleylight loam, in V aiiai - sod podzolic gley moderately podzolized light loam on mediumloam, in Voke - sod podzolic sandy loam on sand with deeper lying gravel.Soil pHKc was determined by potentiometric method, humus content by Turin, totalnitrogen by Kjeldal, available phosphorus and potassium content by A-L methods,mineral nitrogen by the method of calorimetry.Judging from the hydrothermal coefficient of the vegetative growth season in Dotnuva theyear of 1994 was droughty and significantly distinguished itself among the otherexperimental years (HTK - 0.74). The summers of 1995 and 1996 were warm and dry.Such conditions during the grain formation period had a negative effect on graincoarseness. HTK of the vegetative growth season was 1.14 - 1.12. The weatherconditions in Velaidiai in 1995 were not favourable for rye due to an uneven distributionof the amount of precipitation. Droughty weather prevalent in the second half of thesummer in 1996 and 1997 accelerated rye ripening. Weather conditions in Voke duringexperimental years were moderately favourable for rye growing. There were no particulardeviations of temperatures and the amount of precipitation from many years' mean.Phosphorus and potassium fertiliser rate in Dotnuva was calculated to achieve 6 t/ha ofgrain yield. In separate experimental years depending on soil properties 40-66 kg/ha ofphosphorus, 60-125 kg/ha of potassium was applied in Dotnuva. In Velai~iai - 60 kg/haof phosphorus, 140 kg/ha of potassium; in Voke - 50 and 110 kg/ha respectively /8/.In Dotnuva and Ve ai~iai rye was treated with 60, 120 and 180 kg/ha, in Voke - 35, 70and 105 kg/ha of nitrogen, at a single application or in two times after the renewal ofvegetation and after 25-30 days. In Dotnuva one treatment was sprayed with a fungicideat rye booting or heading stage.The crop was harvested at complete ripeness by a combine "Sampo 500" or "Sampo 25".The grain yield data were recalculated into 15% moisture. Experimental findings wereprocessed by the methods of dispersion and correlation - regression analyses /9, 10/.

ResultsAgrochemical characteristics of the experimental soil and the yield.The background of the experimental soil was diverse in different years and differentplaces. Agrochemical data of the experimental soil in Dotnuva show that average amountsof available phosphorus fluctuated within the limits of 121-209, and that of potassiumbetween 115-161 mg/kg, however in separate plots the range of fluctuation was much higher.

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In 1995 in Veaitiai the experiment was set up in a very diverse soil in terms of nutrients.In separate plots the content of available P2O, was from 72 to 320 and that of K20 - 130-346 mg/kg. In 1996 and 1997 the soil was medium rich in phosphorus and potassium.In Vok& the soil was well and moderately well supplied with available phosphorus andpotassium.A very diverse winter rye yield was obtained in the experiments. Its variation dependedon many factors. One of them was diversity of meteorological conditions. Their effectwas especially obvious in 1996. In Dotnuva nitrogen fertiliser was not efficient and theyield was very poor due to the warm and sufficiently wet summer which promoted aheavy occurrence of cereal diseases and lodging of the crop. Owing to the diversity ofmeteorological factors the rye yield in Dotnuva in 1994-1996 in the plots not applied withnitrogen fluctuated within the limits of 1.83-4.24 t/ha (variation coefficient V=39%), inthe N applied plots - 3.30-5.81 t/ha (V=27%). In 1995-1997 in Vekaidiuose - 2.02-2.90(V=1 8%) and 3.50-4.87 (V=16%), in Vok - 1.24-2.26 (V=30%) and 2.68-3.26 (V=7%) t/ha.Therefore it can be concluded that the effect of meteorological conditions on the yieldwas very strong in all the experimental sites, however it did not suppress the other factors.Relationship between the yield and soil phosphorus and potassium contentThe relationship between grain and straw yield and available phosphorus (P205) andpotassium concentration (K20) in the soil can be seen from the equations provided inTable I. Amounts of available phosphorus and potassium in individual experimentsvaried within relatively narrow limits. Variation coefficients most often did not exceed15-20 %. The yield changed very inconsiderably within these limits. Due to this reasoncorrelation coefficients are small and fluctuate close to the limit of probability.Regardless of this a very clear trend was revealed almost in all of the experiments, whichsuggests that in the case of a higher soil phosphorus and potassium content the yield ofgrain and straw increases.Variation of climatic and soil factors also determined efficiency of fertilisation.

Table I. The relationship between grain (y,) and straw (Y2) yield and available P205 (x,)and K20 (x2) concentration in the arable layer

Site Equation r r95% x±SDotnuva y, = 5.72-0.0065x, 0.11 0.17 163±29.7V61aidiai y, = 4.06+0.002x, 0.10 0.20 141±34.7Voke y, = 2.42+0.061x, 0.26 0.20 62±7.8Dotnuva y2=4.93-0.016x, 0.24 0.17 158±31.7Velaidiai y2=4.18+0.0035x, 0.12 0.20 141±34.7Dotnuva y, = 3.9+0.0017x 2 0.12 0.17 143±17.6Velaidiai y, = 2.86+0.0056x, 0.17 0.20 228±39.0Voke y = 1.5+0.006x2 0.33 0.20 180±80.0Dotnuva y2 =3.78+0.0028x 2 0.10 0.17 143±17.6Vt2aidiai y=2.33+0.0094x2 0.19 0.20 228±39.0

Effect of phosphorus and potassium fertilisers on winter wheat yield.The efficacy of phosphorus and potassium fertilisers was investigated on different soilfertilisation backgrounds. The data of PK fertiliser efficacy show that in all of theexperiments a different yield increase was obtained through phosphorus and potassiumfertiliser application and this yield increase depended on the soil agrochemical properties

147

(Table 2). In Dotnuva at 162-180 mg/kg of available P205 in the soil, phosphorus fertiliserdid not have any effect on the yield. Yield differences did not exceed the limits of errorand depended on the variation of soil properties in different treatments of the experiment.In Vhi~iai one kilo of the soil of fertilised plots contained about 116-118 mg, and thatof unfertilised plots - 107-143 mg of available P20. In fertilised plots even withoutfertilisation the yield had to be higher due to higher phosphorus content than inunfertilised plots. It further increased through phosphorus fertilisation. Therefore theyield increase presented in the table is composite. Average yield increase solely throughphosphorus fertiliser amounted to 0.31±0.072 t/ha, and 1 kg of applied P2Os produced4,5 kg of rye grain.The soils in Voke were very diverse. The amount of P205 in fertilised plots was from 70to 371mg/kg, and that in unfertilised plots - 67-405 mg/kg. In 1995 and 1997 at a P20 5

status in the soil of 158 and 371 mg/kg, the yield slightly declined due to phosphorusfertiliser and in 1996 it practically did not increase, although the P205 status in the soilwas as low as 70 mg/kg.The content of available potassium (K20) in the soils of Dotnuva varied within the limitsof 127-161 mg/kg, however efficacy of potassium fertiliser was not related to it. At a K 20status in the soil of 161 mg/kg in 1994 the yield insignificantly decreased due topotassium fertiliser. In 1995 the soil contained practically the same amount of potassium157 mg/kg but the yield increased by as much as 0.36 t/ha, and in 1996 although thecontent of potassium was only 127 mg/kg, the yield declined by 0.28 t/ha.Potassium fertiliser was sufficiently effective in 1995-1997 in Ve ai~iai, although thecontent of available potassium in the experimental soil was fairly high 129-282 mg/kg K20.In Voke a positive effect due to potassium fertiliser was obtained only in 1996, when thesoil contained about 138 mg/kg of K20, however at the same amount of availablepotassium in the soil in 1995 a slightly lower yield was obtained, and in 1997 when the soilpotassium content was about 213 mg/kg the yield did not change due to potassium fertiliser.The complex of phosphorus and potassium fertilisers produced a positive effect in all theplots where yield increase was obtained due to phosphorus and potassium fertiliser.

Table 2. Yield increase through PK fertilisers t/ha

FertilisationSite YearP K PK

Dotnuva 1994 0,12+0,178 -0,07±0,014 0,28±0,1601995 -0,05±0,068 0,36±0,068 0,21±0,0981996 0,02±0,080 -0,28±0,083 -0,01+0,124

Mean 0,03±0,119 0,003±0,062 0,16+0,130Veai~iai 1995 0,46±0,062 0,64±0,052 0,95±0,065

1996 0,14±0,083 0,43±0,078 0,48±0,0601997 0,34±0,069 0,27±0,097 0,48±0,169

Mean 0,31±0,072 0,45±0,078 0,64±0,110

Vok 1995 -0,09±0,028 -0,13±0,073 0,07±0,0551996 0,02±0,063 0,30±0,067 0,47±0,0401997 -0,14±0,074 0±0,046 0.10+0,060

Mean -0,07±0,058 0,06±0,063 0,21±0,052

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Thus the efficacy of phosphorus and potassium fertilisers should be related not only to thereserves of these elements in the soil but also to other soil properties and the general plantnutrition level, determining yield size. Soil physical properties, first of all soil texturalcomposition, determining soil water permeability and a possibility to accumulate andrelease moisture play quite an important role in this process. A rather high rye yield inVoke can be explained by a light soil texture and a peculiar moisture regime, althoughthere were enough nutrients for plants and in some cases there was an excess of them. Insuch soils it is impossible to grow a stable and high rye yield without a radical landreclamation significantly increasing water holding capacity and changing moisture regime.Due to the fluctuation of agrochemical and agrophysical soil properties the yield variednot only in different sites and soils but also in separate plots of the same experiments,which resulted in yield calculation errors not exceeding 10%.The effect of nitrogen fertiliser on winter rye yield on different PK backgrounds.Winter rye yield in almost all the cases was limited by nitrogen nutrition, determined bythe amount of nitrogen fertiliser. Nitrogen fertiliser efficacy is presented without the useof fungicides and retardants.Rye yield changed in a parabolic way through a single application of nitrogen fertiliserrate on different P and K fertiliser backgrounds (Table 3). The correlation was strong, insome cases the correlation coefficient was close to 1.In Dotnuva grain yield increased on the background of phosphorus, potassium and zerowhen increasing nitrogen fertiliser rate to 146-149 kg/ha. Slightly less nitrogen fertiliser116 kg/ha was needed to reach the peak of the parabola on the background of PKfertilisers. This can be explained by the fact that at balanced crop nutrition the highestyield can be achieved by applying slightly lower fertiliser rates.

Table 3. The relationship between rye yield (y t/ha) and the amount of nitrogen fertiliser(x kg/ha) on various P and K background aver in 1994-1997

Site Background Regression equation rI x extrDotnuva 0 y=3,15+0,0209x-0,000070x 2 1,000- 149

P y=3,06+0,0210x-0,000071 x2 0,996 148K y=3,25+0,0199x-0,000068x 2 0,993 146PK y=3,47+0,0229x-0,000099x z 1,000- 116

mean y=3,24+0,0212x-0,000077x2 0,999" 138Vetaitiai 0 y=2,15+0,0240x-0,000078x 0,994 154

P y=2,46+0,0240x-0,000076x 2 1,000- 158K y=2,62+0,0238x-0,000080x 2 0,998" 149

PK y=2,91+0,021 Ix-0,000065x2 0,996 162mean y=2,53+0,0234x-0,000076x 0,998" 154

Voke 0 y=1,86+0,0219x-0,000120x 2 0,996 91

P y= 1,79+0,0218x-0,000116x 2 0,986 94K y=1,79+0,0222x-0,000100x 1,000- I

PK y=2,05+0,0236x-0,00013 Ix2 1,000-" 90mean y=l,88+0,0223x-0,0001 16xz 1,000°" 96

149

In Ve aidiai the yield increased when increasing nitrogen rate to 149-162 kg/ha. Thehighest nitrogen rate was needed on PK background, while the lowest on potassiumbackground. In Voke, on the contrary, it was enough to apply up to 90 kg/ha of nitrogenon PK background, and 11l kg/ha of nitrogen on potassium background.The relationship between nitrogen fertiliser efficacy on different P and K fertilisationbackgrounds and nitrogen fertiliser rate was described by linear equations (Table 4). Thecorrelation was significant in all the cases. Regression equations show that whenincreasing nitrogen rate, efficacy of fertilisers declines irrespective of P and Kfertilisation. Although fertiliser efficacy on different backgrounds in different sites variedinconsistently, it was observed that on zero and P backgrounds it was almost identical. Inthe experiments in Dotnuva nitrogen fertiliser efficacy on potassium background was thelowest. In Ve2aiiiai this reduction was very negligible, while in Voke it was the highest.The greatest amount of grains for 1 kg of fertiliser nitrogen was obtained in V&iaitiai,slightly less in Dotnuva, and the least in Vok&.

Table 4. The relationship between nitrogen fertiliser efficacy (y kg/kg) on variousfertilisation backgrounds and amount of fertiliser (x) aver. 1994-1997

Site Background Regression Grains (kg/ha) produced for Ikg NI equation N 60 N 120

Dotnuva 0 y=20,9-0,070x 16,7 12,5 1,000-

P y=21,0-0,071 x 16,7 12,5 0,996'K y= 19,9-0,068x 15,8 11,7 0,993'

PK y=22,9-0,099x 17,0 11,0 1,000"mean y=21,2-0,077x 16,6 12,0 0,999"

Veaidiai 0 y=24,0-0,078x 19,3 14,6 0,994*P y=24,0-0,076x 19,4 14,9 1,000-K y=23,8-0,080x 19,0 14,2 0,998"

PK y=21,1-0,065x 17,2 13,3 0,996"mean y=23,4-0,076x 18,8 14,3 0,998*

Voke 0 y=21,9-0,120x 14,7 7,6 0,996"P y--21,8-0,116x 14,8 7,9 0,986"K y=22,2-0,100x 16,2 10,2 1,000 "

PK y=23,6-0,131 x 15,7 7,9 1,000""mean y=22,3-0,116x 15,3 8,4 1,000"

Splitting of nitrogen fertiliser rate of 70 or 120 kg/ha into two portions gave verycontradictory results (Table 5). Application of 120 kg/ha nitrogen rate in two timesresulted in many cases in a lower yield than in the case of single application at optimumtime. However in 1996 in Dotnuva in all the plots in 1996 and 1997 in Wiaiiai in theplots not applied with phosphorus and potassium a yield increase was obtained due to thesplit application of nitrogen fertiliser rate. Due to a split application of 70 kg/ha ofnitrogen fertiliser a higher yield was obtained in several plots in 1995 in Voke. However,averaged findings show that split application of nitrogen rate at different time is notexpedient as the yield most often does not increase or sometimes even declines due to this.

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The yield and nitrogen fertiliser efficacy are limited by insufficiently intensive growingtechnology and inadequate use of plant protection means. However even this isdetermined by meteorological conditions. For instance, when fertilising with 120 kg/ha offertiliser nitrogen in Dotnuva in 1995 the yield increased (0,23±0,098 t/ha) throughfungicide application only in the rye plots grown without phosphorus and potassiumwhere the plants were weaker and less resistant to diseases as compared with the onestreated with PK fertilisers. The importance of fungicides increases in wet years,favourable for the occurrence of diseases. Such year was in 1996 when rye grown withoutfungicides lodged and nitrogen fertiliser was not efficient. In the fungicide-treated, andN, 2 applied plots rye produced from 0,98+0,124 to 1,70±0,160 t/ha higher yield than thatin the plots that received the same fertilisation but did not receive any fungicides (Table 6).

Table 5. Average winter rye yield increase through split application of nitrogen rate ondifferent P and K backgrounds

Yield increase through the application ofSite Yearnot fertilised P K PK

Dotnuva 1944 -0,73±0,120 -0,22±0,141 -0,74±0,088 .0,10±0,129

N6o+ 1995 -0,35±0,098 -0,14±0,088 -0,05±0,097 .0,33±0,146

1996 0,39±0,129 0,40±0,117 -0,02±0,124 0,40±0,160Mean -0,23±0,329 0,01±0,195 -0,27±0,235 -0,01±0,215

Vetaitiai 1995 -0,15±0,180 0,02±0,110 0,02±0,110 -0,18±0,100

No 1996 0,16±0,090 -0,30±0,100 -0,17±0,140 -0,24±0,1101997 0,24±0,170 0,01±0,180 0,05±0,220 .0,09±0,130

Mean 0,08±0,119 -0,09±0,105 -0,03±0,069 -0,17±0,044Voke 1995 0,16±0,065 0,25±0,117 0,39±0,107 -0,16±0,084

N35.35 1996 0,08±0,098 -0,09±0,197 -0,16±0,098 0,26±0,121

1997 0,13±0,125 -0,30±0,147 0,03±0,113 .0,12±0,113Mean 0,12±0,023 -0,04±0,160 0,09±0,161 0±0,134

Table 6. Winter rye yield increase through fungicide application at 120 kg/ha nitrogenfertilisation in Dotnuva

Yield increase of rye fertilised withYearWithout PK P K PK

1995 0,23±0,098 0,06±0,088 0,03±0,097 -0,03±0,146

1996 1,18±0,129 1,59±0,117 0,98±0,124 1,70±0,160

Mean 0,71±0,475 0,82±0,765 0,51±0,475 0,83±0,865

Thus, fertiliser rates giving the highest yield are different in each case and depend on theweather, soil properties, preceding crops, soil and crop management and expected yield.

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ConclusionsOn the basis of the findings of the experiments carried out between 1994-1997 on sodgley light loam (Dotnuva), on sod podzolic gley moderately podzolized light loam onmedium heavy loam (Vlai~iai), on sod podzolic sandy loam on sand with deeper lyinggravel (Voke) with the tetraploid winter rye cv.'Rflkai' the following conclusions weremade:1. The size of winter rye 'RUkai' yield is related to climatic conditions of the vegetativegrowth period, soil agrochemical properties and nutrition level.2. Phosphorus and potassium fertiliser efficacy depends on climatic conditions, soilagrochemical and agrophysical properties and fertiliser rates.3. The yield of the tetraploid rye 'Ruikai' can be adjusted by changing nitrogenfertilisation level. Nitrogen fertiliser efficacy on different P and K backgrounds indifferent sites varied inconsistently and depended on the weather, soil properties,preceding crops and crop and soil management practices.4. Amounts-of phosphorus and potassium fertilisers for the planned yield should becalculated according to parameters of soil properties.

References1. Adomavi ifte J., Meklenburgas A. Mineraliniq NPK tr~q normos javans lengvose dirvose//

Agrotechnika lengvuose dirvofemiuose. LZMTI darbai. 197 1. -T.I S. -P. 55-71.2. Adomaviiit J., Urbelionis J. Augalq mityba ir derliai. 1973. -35 p.3. Bajoriflniend A., Magyla A. Vidutiniq ir prasti prie~scliq kompensavimo galimybes azotu

rugiq - aviiq grandyje// 2emdirbyste. L21 mokslo darbai. 1995. -T.49. -P. 122-132.4. Nedzinskiene T. - L. 2ieminiq rugiq auginimo technologijos supaprastinimo galimybes //

Zemdirbystt. L21 mokslo darbai. 1995. -T. 47. -P. 24 - 3 1.5. Pleseviius K. Mineraliniq trqtq atidavimo laikas svarbiausioms sejornainos kultflroms//

Augalininkyste. L2MTI mokslo darbai. 1965. -T. 10. -P. 6-1I.6. Simanauskyte E. Mineraliniq trqtlq ir menlo derinimo efektyvumas sejomainoje lengvose

dirvosc//LZMTI darbai. 1981. -T. 26. -P. 65-76.7. Siuliauskas A. Papildomo 2ieminiq rugiq trqimo skystomis kompleksinemis tratomis itaka

//emes flkio mokslai. -1995. -Nr.3. -P. 24-27.8. vedas A., Dabkeviius Z., Kadliulis L. ir kt. Klimato ir dirvolemio potencialo panaudojimas

gaminant ger, produkcij4 ir malinant chemini presing4 2emes ukyje// Regiono ekologinistvarumas istoriniame kontekste.- 1998.- P.72-82.

9. Tonkfinas J. Lauko bandymt derliaus duomenq apdorojimas dispersines analizes badu.-196 6 .-4 0 p.

10.CueneKop , AY. CTaTHCrnecKne MeTOaIl B HpHMCfeCHN K HCCJICflOBaln4xM B ceJbCKOM

xo3RAcTre H 6no.norHH. 1961.-504 c.

152

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

EFFECTIVENESS OF PHOSPHORUS AND POTASSIUM ON PASTURESDEPENDING ON THEIR CONTENT IN SOIL

Peteris Berzins, Aija Antonija, Skaidrite BumaneSkriveri Research Centre, Latvian University of Agriculture

SummaryThe influence of NPK fertilizers on pasture productivity in soils with different PKsufficiency level was studied in Skriveri Research Centre. The obtained results wereexpressed as multi-factorial equation of regression. PK fertilization effect was lowerwhen the content of these elements in soil were higher. This gives the possibility forfertilization adjustment based on soil properties.

Key words: perennial grass, fertilization, modeling.

IntroductionMany experiments are carried out in Latvia were fertilization effect on perennial grassesis studied (P. Konrads, 1935; R. Petersone, 1975; A. Antonija, 1970; S. Rulle, 1997; etc.).Authors used mostly traditional experimental schemes. Only few experiments are carriedout with possibility to apply multi-factorial regression for data processing (A. Egle, 1979;Ri. B. Ara(PoHoaa, 1990). For example, such method was used by V. Vasilauskiene (B. A.BacHnaycKeHe, 1987) for processing of pasture experimental results carried out inLithuania. This article includes results about the influence of phosphorus and potassiumfertilizers on pasture depending on PK content in the soil.

Material and MethodsA field experiment was laid out according to Peregudov's twenty-four treatmentsexperimental scheme (B.H. fleperyAoB, 1978). Soil at the site was sod-slightly podzolicwith pHKc 5.7 to 6.2, containing mobile P and K lower than 50 mg kg-' of soil, humuscontent 1.8 to 2 %. Prior to the experiment, soil phosphorus and potassium levels were inthe low range. During several years in soil application, phosphorus and potassiumfertilizers contributed to the establishment of the following backgrounds: soil with highPK sufficiency level (exceeding 200 mg kg' of soil), and soil with high K and low Psufficiency level.In the experiments, the research results of the first three years were used (except for theseeding year) due to fertilization effect that significantly changed P and K status of soil.Pastures were established by seeding mixed grass-legume swards. The yield of freshplant matter was determined by cut these imitating pasture under grazing. Therelationship between fertilizer doses used and the obtained herbage yield were determinedby the following regression equation:y = bo + b1N +b2P + b3K +b4N2 + b5P' + b6K2 + b7NP + bsNK + b9PK,where y - herbage dry matter yield, kg ha ,

b, - yield, obtained without fertilizer use, kg ha ,

b,-9 - coefficients showing influence of NPK fertilization,N, P, K - annual amount of N, P2O and K.O applied with fertilizers, kg ha'.

Fertilization costs were calculated based on fertilizer prices in 2000 when I kg of plant

153

nutrient were sold by Ls 0.15 for N, Ls 0.5 for P2 0 5 and Ls 0.16 for K20. In designationof treatments P and K means their respective oxides - P2O and K20.

Results and DiscussionTable I presents the herbage dry matter yield of pasture obtained in the experiment,which was influenced by the fertilizers applied and PK content in the soil.

Table I. Dry matter yield of pasture herbage, t ha - i

Treatment Designation PK sufficiency level in soillow high P low and K high

NoPoKo 000 2.450 4.320 2.550NoPoK~go 003 3.820 3.660 2.657NoP135Ko 030 2.657 4.053 4.443NoPM35 Ki2 0 033 5.593 6.300 5.797NWoP45K 111 4.680 5.873 5.630NWoP 4SK24o 114 5.420 5.963 5.487NWlPI8oKo 141 5.100 5.653 6.180NoPisoK2o 144 6.297 6.207 5.983N12oP9oKI20 222 6.810 7.490 7.317NJ20PGK3W 225 6.820 7.620 7.430N120P225K]20 252 6.540 6.923 7.497N12oP22sK3w 255 7.347 7.647 7.137NtsoPoKo 300 4.653 6.627 4.747NisoPoKIso 303 5.943 8.610 6.010N18oP13sKo 330 5.623 7.647 7.920NISOP135Kl&o 333 8.817 9.857 9.237N240 P45KQo 411 7.217 9.277 8.057N24oP45K240 414 9.483 11.297 9.447N24oP]BoKo 441 8.543 10.010 9.950N240P 180K 240 444 10.607 11.913 11.727N30PgoK12o 522 7.813 9.530 9.527N30oPgoK 3oo 525 10.607 11.493 10.577N3oPwK]20 552 9.470 10.303 10.020N30WP2 2sK3Wo 555 11.807 12.790 11.793STD 0.497 0.490 0.532RS,, 1.417 1.397 1.517

The research findings indicate, that all the three fertilizers applied had a beneficial effecton pasture productivity; however, most significant herbage yield increase was reachedwith N fertilizer.The soil with high PK sufficiency level provided higher herbage yields in all thetreatments; in soil with low PK sufficiency level these herbage yields showedinsignificant difference compared to yields obtained in soil with low plant nutrient status.In soil with low PK sufficiency level:1. low herbage DM yield below 4 t ha:- was obtained with the input of N, Po-.3s K- ,s;2. medium pasture productivity (4 to 8 t ha' DM) was achieved with the application ofNo-j so P 2 25 KO.3OW;

3. high pasture productivity (above 18 t ha - ' DM) was reached with mineral fertilizerN18-30 P?45-225 K 3o-3o

In soil with high PK sufficiency level:1. low pasture productivity below 4 t ha' DM yield was attained with the application of

154

No Po Kiso;2. medium pasture productivity (4 to 8 t ha- ' DM) was obtaiied with fertilizers N.- 18oP0 225 K0..30 ;3. high DM yields above 8 t ha- ' were reached with mineral fertilizers N8 o-30 o Po- 225 K6 ..3W0.In soil with low P and high K sufficiency level:1. low pasture productivity below 4 t ha- DM yield was reached with No Po Ko-.so;2. medium herbage DM yield from 4 to 8 t ha- ' was produced with N-1980 Po- 225 K0.-300;3. application of mineral fertilizer N,,o3 P45-22 5 K o-3oo resulted in the production of highDM yields above 8 t ha-'.

Table 2. Numerical values of equation coefficientsFertilizer Part of equation PK sufficiency level in soil

component low high P low and K highbo 2486 4053 2550

N b, 14.978 21.673 19.53P b2 14.812 11.413 39.98K b, 15.193 7.741 7.628N2 b4 -0.026 -0.038 -0.039P2 b, -0.079 -0.077 -0.145K2 b6 -0.048 -0.043 -0.037N x P b7 0.039 0.026 0.043N x K b8 0.035 0.049 0.040P x K b9 0.028 0.032 0.013

R2 0.70 0.69 0.70

The calculated numerical values of regression equation indicate (Table 2), that there wasmedium close correlation (r= 0.69-0.70) between pasture productivity and fertilizersapplied. The values of regression coefficients indicate that the efficiency of the appliedfertilizers was lower in soil with high PK sufficiency level; however, N fertilizersignificantly affected pasture productivity. Higher P efficiency was observed in the soilwith high K and low P sufficiency level compared to soil with low PK content.Research results expressed in the form of equations give the possibility to perform differentkind of modeling, i.e. to calculate fertilizer combinations for pasture productivity which werenot included in the experiment. Based on the regression equation we calculated the possiblefertilizer combinations for reaching definite levels of herbage dry matter yields with mostprofitable fertilization costs. The results of some calculations are summarized in Table 3.Table 3. Calculated cheapest amount of fertilizers for obtaining 7 t ha- ' dry matter yield

PK sufficiency Calculated amount of fertilizers, kg ha- ' Fertilization costs,level in soil N P205 K20 Ls hal

Low 235 0 155 59.97High 156 0 35 29.01P low and K high 178 37 64 55.54

Alongside with the calculated amounts of fertilizers, we present the possible fertilizercosts based on fertilizer prices in 2000. The obtained results are to be interpreted in thefollowing way: in case of the establishment of soil background with the calculatedfertilizer rates, the attained DM yield would reach 7 t ha' respectively, and costs for theproduction of this DM yield would be lower compared to other fertilizer combinationwhich would ensure the proper yield level.

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By analogy, it could be assumed that in similar soil and perennial grass swards theobtained final result would be equal. Our calculations indicated that, leaving out ofaccount low P sufficiency level in soil, economic criteria confirm the uselessness of usingP fertilizer for obtaining 7 t ha- 1 DM yield. However, the use of P fertilizer is suitable insoil with high K and low P sufficiency level.Our calculations indicate that applied K fertilizer doses could be significantly lower in soilwith high PK sufficiency level compared to soil with low (plant nutrient) sufficiency level.ConclusionsThe following relationship between fertilizer application and PK sufficiency level in soilwas observed in the experiments.1. Low pasture productivity (below 4 t ha-' dry matter) was obtained when NO, P0 -35 andKo-,, were applied on soil with low PK sufficiency level, No, Po and Kis0 - on soil with highPK sufficiency level, and N0, Po and K,, 8, - on soil with low P and high K sufficiency level.2. Medium pasture productivity (4 - 8 t ha-' dry matter) was obtained when N0 -180, Po- 225and Ko-3oo were applied on soil with low PK sufficiency level, N0,a0, Po-22s and Ko-30o -

on soil with high PK sufficiency level, and Nc-,so, Po- 225 and Ko0o - on soil with low Pand high K sufficiency level.3. High pasture productivity (above 8 t ha - ' dry matter) was obtained when NISo3oo, P45-

225 and K0-o were applied on soil with low PK sufficiency level, N180 300, P S225 and K60 -300 - on soil with high PK sufficiency level, and N180 300, P45 225 and K60 300 - on soil withlow P and high K sufficiency level.ReferencesI. Egle A. (1979). Mineralmaslu efektivitAte kultivet&i plava zema purva ktidras augsna.

Padomju Latvijas lauksaimniecTha, Nr. 10, 18 - 20.2. Konrads P. (1933). Zalaju maslo~ana ar neorganiskajiem un organiskajiem slapekla msliem.

Lauksaimniecibas menegraksts, Nr. 9, 417 - 466.3. Konrads P. (1935). Kalija un fosforskabes maslu ietekme kudrainu augg~u zalajos.

Lauksaimniecibas menegraksts, Nr. 5, 269- 298, Nr. 6, 371 -412.4. Rulle S. (1997). Mineralmslu ietekme uz ganibu zales ra2bu un bainbas elementu bilanci augsna.

Zinfmiskas konferences (1997. gada 13. un 14. februa-) referatu tezes, LLU, Jelgava, 94- 95.5. ATOlraI A. A. (1970). D4erciBHOCTb a3oTHblx yao6peHH B 3aBHcMocTII OT 2103 H CpOKOB

niecenA Ha Ikyab'ypnhIX nacTG~aax flaTBUHICKOi CCP. AaopedbepaT AHcCepTanht HacoHcKane y'eHoAf ereneHM Kainuna ceJlbCKOXO3X.erneunblX Hays, Euraua, 24.

6. Araqonona JI. B. (1990). Ypoxcatiorb riouepnbl Ha Aepnoo - nof3oamfcrbix no4uax npmpa3.MiqHIx yponsix Minepanlbnoro nHTainaa. AnTopeqbepbT ahlccepIauHH Ha coHcKaHHeyWeHOti CTeneuH KaHalAnaTa ceJLCKOXOJ3ArCTBeHHbIX HayK, CKpHBepu, 20.

7. BacHnAycKeie B. A.(1987). HayNHoe o6ocioBaanie MHHepallbHOrO llHTaHfal pa3HbXTpBOCTOC1 B cHcTCMe HHTCHCHBHOrO IClO)lb3OBaHrnI kynTypHbix faCT6LI Ha

MaHeparbHblIX notinax. AnTopedpepaT AnccepTawiw Ha CO84CKaHHeC yMeHot cTeneHii AoiroKpacenbCKOXO39AiCTBeHHhIX HayK, CKpBeps, 46.

8. flerepcone P. D. (1975). BIHAHHe y2o6penrii., o3o6HoBIeHinS TpaBoCTOr H HHvHCHBHOUTlc1oJn,3oana"wI Ha ypo K HOCTh CeHioOcon. ABTope( epaT anccepraun ua COHCKaiHe

yeuorti cTeneni xauAHitaa ceJlbCKOXO39CTBeHHbIX HayK, CKpHBepH, 36.9. flyKe A. T. (1986). OnpeaeleHzie OTHMan1hH46IX HOpM NPK yao6peHn- lpH muoroyKoCuOM

Hcnoalk3onaIHH TpaBocroA. lBIbiweisie ypoxagHOCT. H poUHHoMYhHC HcnoJIb3oiaHne

ceHOKOCOB H nacr6HW. Pira, 3HHarHe,105-12O.10. fleperyaoB B.H., Haanoaa T.H., CoujiiwKoua M.1. MerOnuKa nocTaoKH H MarMaTH coH

o6pa6otiK pe3yiIbTaTOB nonenoo onbira no H3y9eHIU 3aKOHOMepHoceI' - ,ellaBu

MlHepaJbHbrx yao6peHH, nocTaBneHHoM no HenOJHOiI 4SaJrop aHmo. cxeme 1/9(6x6x6).ArpOXHMHSI, 1978, 10, 122-131.

156

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUMAND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

IMPACT OF LIMING AND SOIL REACTION ON CROP'S P AND KACCUMULATION FROM ACID SOIL

Vladislav B. Minin and Anatoly OsipovAgrophysical Research Institute

SummaryThe impact of varying soil reaction on uptake of phosphorus & potassium by spring rapewas studied in the series of pot experiments. The small accumulations of nutrients byrape, as well as crop yield were observed on the acid soil. Simultaneously, theconcentration of these elements in the plant tissue was very different. It may be low orhigh at these conditions. Several levels of soil reaction were formed by the different dosesof lime. Soil reaction and doses of mineral fertilizer affected rape yield and chemicalcomposition dramatically. The high rape yield was correlated with the definite amount ofaccumulated nutrient elements and the appointed ratio between them. So, the optimumratio between elements in the rape tissue are as fallow: K/Ca is 1.3- .3 & P/Ca is 0.16-0.32.For efficient utilizing of phosphorus & potassium fertilizers the definite management ofsoil reaction is needed.

Key words: rape, phosphorus, potassium, soil reaction, lime, crop chemical composition,acidification

IntroductionAcid reaction and process "Acidification" are common for soils that are situated in theareas with humid weather conditions. There are nearly 50 million hectares of agriculturallands with acid soils in Russia. Approximately 60% of European lands have acidificationtendency.Soil reaction effects turnover of phosphorus and potassium in soil - plant system rapidly.It manages processes of precipitation - dissolving, physico - chemical adsorption -dissorption , plant uptake and competition between ions during plant uptake. So, soilreaction influences the chemical composition of crops as well as efficiency ofphosphorus and potassium from mineral fertilisers. For sustainable land use we mustestimate the quantitative relations between soil reaction and chemical elements turnoverin agro-ecosystems and elaborate recommendations for their optimising.The main aim of our investigation was to examine the influence of soil reaction, limingand mineral fertiliser on formation of the mineral chemical composition of rape plants.

Materials and MethodsThe results of four pot experiments carried out in 1996-1999 in the Pushkin Branch of theRussian Agrophysical Institute are presented.

Rape variety and cultivation procedureThe spring rape, variety Belogorsky 2, was used in the experiments. We consider rapeas a model plant to clearly understand the interactions between physico-chemical soilproperties and plant' response for further utilization in the plant-soil system model.

157

Dry seeds were planted in May. The plants were harvested after 10 weeks when theywere at flowering stage. They were watered regularly.

Soil and experimental designAcid sandy-loam sod-podzolic soil (according Russian classification) or DystricCambisols (FAO-Unesco ) was used in this study. It is typical arable soil for territories ofancient Glacier transition. It is characterized by low humus content (2.5 - 3.0%), acidreaction (pH kel - 4.2 - 4.6), low contents of mobile forms (In HCI solution) ofphosphorus and potassium (42 mg P and 83 mg K kg-' dry soil). The soil has not highfixation ability.Soil moist samples were passed through a 5-mm sieve before mixing thoroughly with limeand fertilizer and then were put into plastic pots, that contained 5 kg of soil.Design of experiments includes different levels of soil acidity and nutrition. For thispurpose we used doses of ground limestone that were calculated in accordance to obtainrange of soils with different reaction. Two doses (low and middle) of mineral fertiliser"ecofoska" ( with ratio of NPK - 10:15:15) were applied. Treatments were prepared intriplicate.

Methods of analysisLaboratory experiment included analyses of soil by the following methods:- determination of pH in In KCI suspension (soil : solution = I : 2,5) ;- determination of mobile forms of P and K by 1.0 n HCI (soil:acid=l:5);- determination of heavy metals content by In HCL.All analyses were done according to Russian State Requirements.Data analysis was performed by analysis of variance (ANOVA). The significance ofdifferences in the concentrations and yields were examined with the t-test for normaldistribution.

Results and DiscussionSoil reaction influences crop yields rapidly. Any plant species prefers certain range of soilreaction which is in accordance of its origin. So, because of the nature, rape plants is notvery sensitive to the acid reaction.The acid soil with low concentration of nutrients as well as humus content, that is usualfor the North-West of Russia was used. The wide range of soil reaction (from 4,1 till 6.6pHk, ) was reached in the experiments. Lime as well as mineral fertilizer effected rapeproductivity rapidly. The results from one of the pot experiments is presented n Table 1.It is clear from data that the ecofosca is most efficient on the limed soil.

Table 1. Influence of lime and ecofosca doses on rape yield (g of dry matter/pot)

Dose of Dose of limeecofosca 0 1 2 3

0 1,4 2.8 3.6 4.21 6.0 8.4 8.6 11,22 7.4 10,4 10,8 17,1LSD at p<0.05 1,6

The small accumulations of nutrients by rape, as well as crop yield were observed on the

acid soil. Simultaneously, the concentration of these elements in the plant tissue was very

158

different. It may be low or high at these conditions. The content of the calcium,phosphorus & potassium in the rape tissues, that we have studied in our experiments,varied rapidly (Table 2.) and it depend on soil conditions. Green mass of spring rape maybe used for animal feeding, so its chemical composition must meet the veterinaryrequirements. In this case content of calcium and phosphorus must be close andpotassium content must not be too high. It is possible to use ratio K/Ca & P/Ca for moredetailed analyzing. The optimum ratio between elements in the rape tissue are as fallow:K/Ca is 1.3 - 2.3 & P/Ca is 0.16 - 0.32. As we have calculated the K/Ca as well as P/Caratio depend on the soil reaction. The type of simple relation that that is possible to usefor calculations is as fallows: K/Ca = a - b (pH) - (DE); where DE is the ecofosca doze.

Table 2. Limits of chemical content of rape tissues.

Chemical element Limits of chemical content, %P 0.25 - 0.75K 2.03 - 4.83Ca 0.66 - 2.54

We have calculated the uptake of the chemical elements by plants as well as thecoefficients of their utilization from ecofosca (Table 3). For coefficient calculation wecompared data of phosphorus/ potassium uptake from two variants, that had similar doseof lime, but one with fertilizer, and the other without. These coefficients is not highbecause of the element nature. Moreover, we harvested plant at the early stage, so not fulluptake of elements had occurred. But, we think that the experimental data presented realresults of the plant/soil interactions. One of the results is that the efficientcy of themineral fertilizer and the uptake of phosphorus and potassium are higher at the limed soilwith the reaction close to the neutral. This result may be explained for phosphorus by theso called "liming" phenomena. The soluble ions of aluminum, iron & manganese, thatoccurred at the acid soils, are precipitated together with phosphorus ions. So, phosphorusfrom fertilizer became not available at such conditions. After the liming the metal ionshad been precipitated and phosphorus ions stayed soluble in soil solution and theybecame available for the plants.

Table 3. Influence of lime on the coefficients of utilization of phosphorus and potassiumfrom ecofosca (%)

Dose of Dose of limeecofosca 0 2 3

1 19.4 \2.5 19.6 \ 4.3 17.8 \ 2.8 25.2 \ 5.92 13.1 \2.8 18,8 \ 2.7 14,7 \ 4.5 29.0 \ 3.9Coefficients of utilization : K\P

ConclusionsSoil reaction effected the element composition of the rape significantly.Plants were cultivated on soil with slightly acid reaction contained more calcium andphosphorus than those cultivated on the soil with high acidity. The relations betweenaccumulated elements and soil reaction may be reflected by mathematical equations.The ratio between K : P : Ca is most suitable at the neutral soil reaction.For producing really healthy products for feeding we must forecast their chemicalcomposition. For this reason possible manage soil reaction and soil nutrition.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

COMPARISON OF THE EFFICIENCY OF THE DIFFERENT FORMS OFPOTASSIUM FERTILIZERS

Virgilijus Paltanaviius, Vytautas Liakas, Giedrius Narkevi~ius, Albinas Siuliauskas

Lithuanian University of Agriculture

SummaryIn 1998 - 1999 in biotechnologic laboratory at the Lithuanian University of Agriculturemicro vegetative trials aiming at comparison of the efficiency of different forms ofpotassium fertilizers were carried out. It was determined that for the primary growth (until tillering end) most efficient among other forms of potassium fertilizers proved to bepotassium salt. Potassium sulfate increased barley green and dry matter yields least of all.Total barley green matter yield increase from potassium fertilizers made from 1,4 to 18,5% and dry matter from 4,0 to 22,0% from the yield fertilizing only with NP fertilizers.Different forms of potassium fertilizers had similar efficiency for the barley development(number of leaves) and plant height.

Key words: micro vegetative trial, forms of potassium fertilizers, potassium salt.

IntroductionIn the middle of the XIX th century J.Libig determined the necessity of potassium fornormal plant growth and development [12, 14, 15]. Potassium is the third mineral elementaccording to the need for plant nutrition [1, 14]. Absolute majority of the researchers notethat lack of potassium reduces plant harvest by 5 - 20% and worsens their quality [4, 6, 7,9, 10]. Plants are less resistant to draughts and low temperatures, maturing is slower,reduces resistance towards lodging and fungi diseases [12, 13, 14]. Potassium regulatesand maintains normal metabolism in a plant [11]. It participates in photosynthesis process,stimulates synthesis of sugars and carbohydrates, their movement and accumulation [14].Potassium belongs to the group of the most widespread elements. In the earth - crust itmakes 2,3 %. Plants can absorb it from natural rocks like (KCI, KCI MgCI2 6H2 0, K2SO42CaSO 4 2H20) [14, 15]. However at present the main source of potassium for plants ispotassium fertilizers [1, 2, 3]. At present potassium salt, potassium chloride, potassiumsulfate, potassium nitrate and other forms are mostly widespread in Lithuania.The aim of our research was to compare the efficiency of the mostly widespread fertilizerforms in Lithuania.

MethodsAgrochemic estimation of different forms of potassium fertilizers was carried out bymethod of modified, micro vegetative trials [2, 5]. When carrying out micro vegetativetrials it is not necessary to create conditions identical to natural, but it is indispensable tocreate the same conditions (temperature, humidity, lightening, soil) for all the pots. Soilfor the trials was taken from the arable layer of research field. Land was thoroughlymixed and sifted through 3 mm sieve.Soil pH 6,9, P205 - 114 - 121, and K2O - 102 - 107 mg/kg, humus 2,4 %. Trials werecarried out in plastic pots, filled with 200 g of soil. Each pot contained 50 in advancesprouted barley 'Skarlet' seeds. For the lightening 1000Ilx day lamps were used. After

160

germination barley was grown for 21 days, practically until total absorption of nutritionmatter when sprouts started to turn yellow.Trials were carried out under the following research design:

1. without fertilizers;2. background (amonium nitrate - 58,8 mg. + super phosphate - 100 mg.);3. background + potassium salt - 50 mg.;4. background + potassium chloride - 33 mg.;5. background + potassium sulfate - 38,5 mg.;6. background + potassium magnesium oxide - 80,3 mg.Replications - 4.

The trial was carried out twice: in December 1998 and February 1999. Statistic estimateof the trial data was calculated by method of dispersive analysis.

ResultsTo compare the efficiency of potassium fertilizer forms spring barley was chosen. Barleynot only well meets methodic requirements of micros vegetative trials but well respondsto potassium fertilizers. Besides barley absorbs until the tillering end 40 % of the totalamount of potassium. It allows to obtain objective research results. Our trial results(table and figure) indicate that total yield of the green matter increased from NPKfertilizers by 58,7 - 74,7, and of the dry matter by - 60,4 - 88,2 % as to compared withnot fertilized treatment.

Table. Impact of different potasium fertilizers forms on barley growth, development andgreen matter (tillering period)

Biotechnical laboratory of the Lithuanian University of Agriculture, 1998-1999

Plant Plant Plant Green plant massTreatment number height development

units cm number of gleaves

1 2 3 4 5 6First trial (1998)

I.Without fertilizers 35 17,6 3-4 3A4 61,82.NP (background) 35 21,4 4-5 53 1003.Background+potassium salt 35 24,0 5-6 6,66 1184.Background+potassium chloride 35 24,9 5-6 6,01 1075.Background+potassium sulfate 35 24,2 5-6 5,71 1016.Background+potassium 35 24,6 5-6 6,08 108magnesium oxide

LSD0 1,761 _ 0,285Second trial (1999)

l.Without fertilizers 45 18,9 3-4 4431 73,62.NP (background) 45 21,6 4-5 6,02 1003.Background + potassium salt mg 45 25,7 5-6 7 14 1194.Background + potassium chloride 45 25,9 5-6 T709 1185.Background + potassium sulfate 45 25,2 5-6 6 83 1136.Background + potassium 45 25,8 5-6 7,09 118magnesium oxide

LSD05 1,910 0,356

161

Table continued1 2 3 4 5 6

An average for two trialsI.Without fertilizers 40 18,3 3-4 3,95 67,82.NP (background) 40 21,5 4-5 5,83 1003.Background + potassium salt 40 24,8 5-6 6,90 1184.Background + potassium chloride 40 25,4 5-6 6,55 1125.Background + potassium sulfate 40 24,7 5-6 6,27 1086.Background + potassium 40 25,2 5-6 6,58 113magnesium oxide

LSD 0, 1,835 0,320

Though both trials were carried out according to identical methods, the research resultsdiffered a little. Total yield increase from fertilizers was higher in the first trial, whereaspotassium fertilizers were more efficient in the second trial. In the first trial potassium saltaccording to the increase of green matter yield had essential advantage against otherforms of potassium fertilizers were within the limit of errors. According to dry matteryields in both trials advantage of potassium salt against other potassium fertilizers formswas noted. Potassium magnesium oxide was more efficient than potassium sulfate andpotassium chloride.

200

'" -- 167 -- "

140 -

1 2 0 1 5 4 : 1 6 0

20

1 2 3 4 5 6

Treatm ents

Treatments:7. without fertilizers;8. background (amonium nitrate - 58,8 mg. + super phosphate - 100 mg.);9. background + potassium salt- 50 mg.;10. background + potassium chloride - 33 mg.;11. background + potassium sulfate - 38,5 mg.;12. background + potassium magnesium oxide - 80,3 mg.

Figure. Comparison of the impact of different potassium fertilizer forms on barley dry matter

In both trials in control treatment barley formed 3 - 4 leaves whereas when fertilized withnitrogen phosphorus potassium fertilizers 5 - 6 leaves. In treatments with different formsof potassium fertilizers essential differences concerning plant development, number of

162

leaves on a plant height were not noted. Potassium fertilizers stimulate formation ofleaves as well as plant growth.

Conclusions.1. Potassium salt had essential advantage against potassium chloride, potassium sulfateand potassium magnesium oxide, increasing yields of barley green and dry matter in thefirst growth periods.2. Potassium magnesium sulfate had tendency to more increase barley green and drymatter yields in the first growth periods than potassium sulfate and potassium chloride.3.All forms of potassium fertilizers had essential impart on barley height and number ofleaves, though essential differences among fertilizer form under research were not noted.

ReferencesI. Fertilizers, An Introduction// EFMA (European Fertilizer Manufacturers Association), 1999.2. Paleckiend R. Skystos tra$os ig kalio ir amonio fosfat: fizikints chemines savyb~s ir

gavimas. Daktaro disertacijos santrauka. -Kaunas: Technologija. 20 00 .-2 3p.3. Sviklas A. M. Specialiqjt skystujq tr$q gainybos teorija, technologija ir efektyvumas.

Kaunas, 1993. -278p.4. Siuliauskas A. Zemes fikio kultflr trqimo kalio tr omis efektyvumasll 2emes fikio

informacija Nr. 8/76/ Lietuvos TSR Iemes fikio ministerija. Centrinis Mokslints ir technintsinformacijos biuras. -Vilnius, 1974. -P.6-7.

5. The Fertilizers (Sampling and Analysis) Regulations// Agriculture. Statutory Instruments.London, 1991, No. 973.

6. Zakarauskaite D., Siuliauskas A. Mineraliniq trq~q itaka lieminiq kviediq ir vasariniq mie~iqderliui nevienodai fosforo ir kalio turintiose dirvose// Grodq ir paarq gamybos didinimas:Lietuvos Z0A mokslo darbai. -Vilnius, 1983. XXIX. -1(93). -P. 62-73.

7. Seqioc n.7. 344e1TnHBOCn. MxnepanibHb[x yao6peHlfl H Xo3hltTBax JIrHTOBCKOi CCP//HTorH pa6oTbi rocytapcreHHOl arpoxHiMwtmecKOif cayx6l a CCCP: Haym. Tp. -M., 1971. -C. 21-26.

8. Borjnennq .M., JIana B.B. Yao6penHe 3epnoaix KynbTyp a BenopycH// XHMIm a ceiBCKiOMxo3eACTae. -1998. X2 4. -C. 9-10.

9. flanvrina'uoc B., IOpunauriiC 10., WlonaycKac A. 344(PCen1Tnhlaoc'rh UpHMCeiettKaJIl[HInX ynio6peHaal non 3epHOnbde Ky~RbTypbl B 3anaaanlo 3011C JIHTOBCKOil CCP/IHIt'eHC(iPHKaUaiA CeCJbCKOXO3RtCTBeHHOrO IEpoH3BoacTaa: Hayq. Tp. JIHT. CXA / Mnn. CXCCCP. -Bnlhnioc. -1977. XXIII. -2(66). -C. 3-17.

10. locnexoB .A. HeKoTopble HTOFH aaiuoapaoro noneBoro onbira THMHpa3eacco IaxtaIeMlH 3a 60 nT//H3a. THMHpA3eB. c.-x. aKaa. -1972. -Bin. 2. -C.28-47.

11. llanoa C.H., MenKoepoea A.A., JIlana B.B. H ap. PeCHM OHTaHHaS AMHMeHN aoroM,4Poc( opoM H KanHcM yzo6peHnni [pe paH61X cnoco6ax HX BHeceKR// ArpOXHMHR. -1980. -X2 11. -C. 81-88.

12. Kyx /LY. CHcreMbLi yno6peHHs Ran noay1menHA MaKCHMaiSthiX ypoxcaeB / flepeaoit c anril.H.B.raaerAHa; non pea. 3.M.LWxonae. -M.: Konoc, 1975. -416c.

13. HenpaHoa A.B., Barpnuaeua B.H. Flpo6neMa KaJI Ha KaulrajoakI3 noqoax// XHMISI BceJbcKoM xo3aAcTee. -1997. -X2 4. -C. 40-4 1.

14. IMeJIKHH B.Y. foqnaelsii KaIIHg H KaHIH6ahe yao6peHaa. -MocKBa. -Konoc. -1966. -C.36-47

15. I0pauairflmc 10.10. 06ecneHeuocm [1041B nOnnnHWHblM KanneM H a)4)ieKrnaHocThIpHMeeHmm xaniHnulx yao6peanfl B 3anaRnoi 3OHe JlwrcCKolt CCP: AaTopeq.aHC... Kana. c.-x. nayK. -Kaynac, 1974.-56c.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

GRAIN YIELD RESPONSE OF SPRING BARLEY TO SEED PLACEDPHOSPHORUS AND NITROGEN IN NORWAY

Annbjorg Overli, Bernt Hoe] and Bjorn Molteberg

The Norwegian Crop Research Institute, Apelsvoll Research Centre,

IntroductionFor spring-sown cereals in Norway the fertilizer is usually band placed about 5 cm belowthe seed and between alternate seed rows. The mobility of phosphorus (P) in soil is low,especially when soil temperature is low, which is often the case at the time of sowing inNorway. The purpose of this study was to establish whether the placement of a smallamount of P and nitrogen (N) in the immediate vicinity of the seed at sowing time wouldenhance the early growth of spring barley, and in turn increase the grain yield at harvest.

MethodsThe trials were mainly located in the southeastern part of Norway, in 1999, on soilswhose P status was judged to be adequate on the basis of ammonium lactate (AL)extraction ((gner et. al 1960).Experiment ISpring barley was grown in II annual field trials. The experimental plan was a split-plotdesign with different amounts of band placed P fertilizer on main plots, and small amountsof various combinations of seed-placed P and N on subplots. Other nutrients were applieduniformly to all plots, in amounts sufficient to prevent deficiencies. In addition to smallamounts of N on some subplots, all plots received 100 kgN ha-' as row fertilizer.Experiment 2Spring barley was grown in 11 annual field trials. The experimental plan was a split-plotdesign with surface applied or band placed compound fertilizer on main plots (100 kgN ha-). There were three subplot treatments: no fertilizer, seed-placement (10kg P ha - '+5 kg N ha-'). and broadcast (10 kg P ha- ' +5 kg N ha'). The fertilizer source used onsubplots was monoammonium phosphate.

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ResultsExperiment IA small amount of seed-placed P+N gave significant increases of grain yield. However,seed-placed P or N alone gave no significant yield increase compared to the treatmentwithout seed-placed fertilizer.

Grain yield, Ia ha' O no fertilizer

6000-5000- E EMAP, 2,5 kg N + 5 kg P

D0 MAP, 5kgN+ 10kgP4000-

3000 OMAP, 10kgN+20kgP

2000 -calcium nitrare. 5 kg N

1000- 0 ammonium nitrate, 5 kg N

0 E3 triple superphosphate, 10 kg P

Figure 1. Average grain yield at subplot treatments (different combinations of seed-placed P and N (kg P and N ha"')) Norway 1999. MAP=monoammonium phosphate.

Experiment 2On the whole, seed placement of a small amount of P+N gave significant grain yieldincreases compared to the treatment with no seed-placed P+N. The same small amount ofP+N broadcast on the surface gave no grain yield increase. The observed yield increaseswere thus mainly a result of more favourable placement of the fertilizer, in relation to theplant roots.

Grain yield, kg ha'

6000

5500

4500

broadcast 0 -0 04 1 20 20' 30'ed-placrd kSl 0 '4 1 '0

band placed 0 20 20 20

Figure 2. Grain yield with different placement and amounts of phosphorus fertilizer,spring barley, Norway 1999.

ConclusionPromising results were obtained in spring barley with seed placed P+N in small amountsin addition to traditional band placed fertilizer. Phosphorus is a limited resource, and ifthis method is able to improve P-efficiency, it will be of great importance. This studycontinues and will also include experiments in other cereal species, onions and potatoes.Referencestgner, H., Riehm, H. & Domingo, W. R. 1960. Untersuchungen fiber die chemische Boden-Analyse als Grundlage flir die Beurteilung des Nahrstoffzustandes der Boden. Kungl.LantbrukshOgskolans Annaler, 26, 199-215.

165

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS

FERTILISA TION EFFECT ON SOIL AND CROPS

COMPARISON OF TIHE EFFICIENCY OF DIFFERENT FORM OFPHOSPHORUS FERTILIZERS

Virgilijus Paltanaviius, Arnoldas tepelk, Vytautas Liakas, Albinas giuliauskas

Lithuanian University of Agriculture

SummaryIn 1998 - 1999 in bio technologic laboratory at the Lithuanian University of Agriculturein the chamber of artificial climate micro vegetative trials were carried out. Theefficiency of different forms of phosphorus fertilizers most widely applied in Lithuaniawas compared in the trials. The data received indicated that all researched forms ofphosphorus fertilizers - amophosus, diamophosus, superphosphate and doublesuperphosphate increased the yield of green and dry matter significantly. The highestyields of barley biomass were obtained when fertilized with superphosphate thoughdifferences among the treatments fertilized with diferent forms of phosphorus fertilizerswere within the limit of errors. Barley plants under the impact of phosphorus fertilizerswere 15 - 17% taller and had I - 2 leaves more than fertilized only with nitrogen andpotassium fertilizers.

Key words: barley, micro vegetative trials, forms of phosphorus fertilizers,

superphosphate.

IntroductionThe role of phosphorus in live organism is significant. There is no life without it. It is theessential element in the nucleus of cells, it is found in vitamins, ferments, albumencombination [6, 7, 9]. Phosphorus participates directly in energetics of alive cells, inprocesses of respiration and fermentation [7,9]. According to its importance formingharvests of plants it is in the second place after nitrogen [12]. Phosphorus stimulates thematurity of plants, under its influence spring barley matures by 5 - 7 days earlier thanwithout it [6, 8]. Phosphorus is important for the botanic composition of in long term -grass - plots [10]. Under its influence the resistance of plants to negative growth factorsincreases, root systems grow stronger, increases the amount of sugar in sugar beets orcontent of starch in potato tubers, the quality of cereal and leguminuous crops gets better[1,2,5,6,9].To fertilize plants various phosphorus acids are applied to produce phosphorus fertilizersmetaphosphorus (HPO3 ), pirophosphorus (H 4P207) and orthophosphorus (H3PO4) acidsare mainly used [3, 4, 1I, 12]. At present in Lithuania the following forms of phosphorusfertilizers are most widely applied: amophosus, diamophosus, superphosphate and doublesuperphosphate. Other forms of phosphorus fertilizers are applied less.We aimed at comparing the efficiency of the most widely applied forms of phosphorusfertilizers.

MethodsThe comparison of the efficiency of different forms of phosphorus fertilizers was carriedout by the method of micro vegetative trials. The methodics of the trials allows to make

166

conclusions concerning the ability of plants to absorb phosphorus from different forms offertilizers [1, 3]. Barley 'Skarlet' was chosen for the trials. Its root system is not strongand barley does not have any specific requirements for mineral nutrition. Before the endof the tillering period barley absorbs about 30% of the total amount of the phosphorus,accumulated until the full maturity [8, 9]. Thus the results obtained well represent theresponse of the plants to fertilizers [3, 9].Taking into account the forms of phosphorus fertilizers used in Lithuania lately thefollowing experimental design was chosen:

I. Without fertilizers.2. Background (amonium nitrate - 58,8 mg + potassium chloride - 33,3 mg).3. Background + diamophosus - 41,7 mg.4. Background + superphosphate - 100 mg + amonium nitrate - 22 mg.5. Background + amophosus - 38,5 mg.6. Background + superphosphate - 100 mg + amonium nitrate - 12,4 mg.7. Background + double superphosphate -43,5 mg.8. Background+ superphosphate - 100 mg.

Replications - 4.Plants were grown in plastic pots, filled with 200 g of soil. Each pot contained 50 seedwhich were sprouted in advance. Distilled water was used for watering. Lightening -1000 Ix day lamp light. The place of the pots was changed every three days, to have thesame lightening conditions for the plants.Barley after germination was grown 21 days practically until the complete absorbtion ofnutritious matter, when the leaves of the plant turn yellow.For the micro vegetative trails soil was taken from the field research plot. Field soil is wassod glacious ligh loam - pH 6.9, P205 - 114 - 122, K20 - 102 - 107 mg/kg, humus - 2.4%.Plant height, number of leaves, yields of green and dry matter were observed andmeasured in trials.The statistic probability was calculated by the method of disperse analysis.

ResultsThe efficiency of the forms of phosphorus fertilizers in micro vegetative trials wasestimated according to biometric measurements (pIant height and number of leaves) andaccording to parameters of green and dry matter barley yields.Data in scientific literature states that phosphorus is most significant for the plant in thefirst periods of there growth. In the variants with phosphorus fertilizers barley grow anddeveloped more rapidly. In the period of three weeks after germination they formed 5 - 6leaves and started bashing process. In the meantime in the control (without fertilizers)barley had 3 -4 and fertilized with nitrogen potassium fertilizers -4 -5 leaves (table 1).All forms of phosphorus fertilizers significantly increased the inner plant height it tocompare with fertilized with nitrogen potassium fertilizers. Comparing the influence ofdifferent forms of phosphorus fertilizers on barley biometric parameters it is seen thatthere is no advantage of one against the others. Estimating the efficiency of forms ofphosphorus fertilizers according to their impact on barley biomass yields it is seen that inthe first trial the advantage of superphosphate against other forms of phosphorusfertilizers can be easily determined. In the second trial all the forms of phosphorusfertilizers under research had similar efficiency with tendency towards superphosfateadvantage.

167

Table 1. Impact of different forms of phosphorus fertilizers on barley growthdevelopment and green matter (bushing period) yields

Biotechnic laboratory at Lithuanian University of agriculture, 1998-1999

Plant Plant Plant develop- Green plant

Research variants number height ment, number mass

units cm of leaves units g I %

First trial (1998)1. Without fertilizers 35 17,6 3-4 3,48 68,92. NP (background) 35 20,2 4-5 5,05 1003. Background + diamophosus 35 22,7 5-6 5,88 1164. Superphosphate + amonium nitrate 35 23,5 5-6 6,07 1205. Background + amophosus 35 23,2 5-6 5,91 1176. Superphosphate + amonio salietra 35 23,4 5-6 6,02 1197. Background + double superphosphate 35 23,0 5-6 5,98 1188. Background + superphosphate 35 23,0 5-6 6,17 122

LSD0, 1,82 1 0,366 7,61

Second trial (1999)1. Without fertilizers . 45 18,9 3-4 4,43 71,92. NP (background) 45 19,9 4,5 6,16 1003.Background + diamophosus 45 22,0 5-6 6,64 1084. Superphosphate + amonium nitrate 45 23,9 5-6 6,96 1135. Background + amophosus 22,7 5-6 6,77 1106. Superphosphate + amonio salietra 45 23,4 5-6 6,88 1127. Background + double superphosphate 45 23,7 5-6 6,91 1128. Background + superphosphate 45 23,6 5-6 6,90 112

LSD 5 2,11 0,306 5,39An average for two trials

1. Without fertilizers 40 18,3 3-4 3,96 712. NP (background) 40 20,1 3-4 5,61 1003. Background + diamophosus 40 22,4 5-6 6,26 1124. Superphosphate + amonium nitrate 40 23,7 5-6 6,52 1165. Background + amophosus 40 23,0 5-6 6,34 1136. Superphosphate + amonio salietra 40 23,4 5-6 6,45 1157. Background + double superphosphate 40 23,4 5-6 6,45 1158. Background + superphosphate 40 23,6 5-6 6,54 117

LSD05 1,96 0,336 6,50

Table 2 represents barley dry matter yields in different variants. It is seen thatsuperphosphate was the most efficient phosphorus fertilizer. Besides the barley harvestsin the second trial were higher and differences among different trials more clear. In thistrial not only superphosphate but also double superphosphate had advantage againstamophosus and diamophosus.

168

Table 2. Comparison of the impact of different form of phosphorus fertilizers on barleydry matter

Biotechnic laboratory at Lithuanian University of agriculture, 1998-1999

Variants First trial Second trial At an average for two trials1998 1999 9 %

I. Without fertilizers 0,360 0,440 0,400 1002. NP (background) 0,513 0,607 0,560 1403. Background + diamophosus 0,595 0,685 0,601 1504. Superphosphate + amonium nitrate 0,647 0,730 0,689 1725. Background + amophosus 0,593 0,683 0,638 1606. Superphosphate + amonio salietra 0,627 0,693 0,660 1657. Background + double superphosphate 0,575 0,690 0,633 1588. Background + superphosphate 0,606 0,711 0,658 164

LSD, 0,04 0,06 0,05

Conclusions1. All forms of phosphorus fertilizers researched in the trial stimulated barley growth inthe first periods of their growth. In the period of bushing barley in the variants fertilizedwith phosphorus fertilizers formed at an average by one leave more and were by 2.1-3.8 cmtaller than fertilized only with nitrogen potassium fertilizers, however essential diferenceamong forms of phosphorus fertilizers was not fixed.2. Superphosphate had essential advantage against other forms of phosphorus fertilizersincreasing barley biomass yields in the first periods of their growth. Double superphosphatehad tendency to more increase barley harvests than amophosus or diamophosus.

References1. Bollons H.M., Barraclough P.B. Inorganic orthophosphate for diagnosing the phosphorus

status of wheat plants// Journal Plant Nutrition. -1997. -20. Nr. 6. -P.641-655.2. Gardiner D.T., Christensen N.W. A sample model for phosphorus uptake kinetics of wheat

seeding//Journal Plant nutrition. 1997. -20. Nr. 2-3. -P.271-277.3. Paleckient R. Skystos traltos ig kalio ir amonio fosfatq: fizikines chemines savybes ir

gavimas. Daktaro disertacijos santrauka. -Kaunas: Technologija. 20 00 .-2 3p.4. Sviklas A. M. Specialiuj4 skystujq trot gamybos teorija, technologija ir efektyvumas.

Kaunas, 1993. -278p.5. The Fertilizers (Sampling and Analysis) Regulations// Agriculture. Statutory Instruments.

London, 1991, Nr. 973. -P115-123.6. ArpoxHMMa. Floa pen. SroxiHa B. A. MocKna, 1989. -C.254-299.7. BaH-Be3ep. Ooc( op H em coCJHH HHA. MocKBa. 1962. --C.57-788. Hnauou C.H., Menlo3epona A.A., Jlana B.B. H lp. PewHM nlITamHA mMeHA a3OTOM,

$)OC4pOpOM H Kaniem yao6pennfi npH pa3HFAX cnoco6ax ix BHecena // ArpoxMa. -1980.-N 11. -C. 81-88.

9. KyK ,.Y. CncTeMbh yno6penHa naA nonyIeFiHRA MaKCHMalbbiX ypoxaeB / fepenao c aran.H.B.Faaennf; non pea. 3.H.lhoFuie. -M.: Konoc, 1975. -416c.

10. JleoHoB O.H. 34mICrniiHOM HOBSIX 4IopM a30rHhIX, 4oc(DpHblx H ICnuHHHbx yalo6peHHV1 HaMHOro OHHx Tpaaax: A4rYopedpelTx ac. Ha moHcK. yN. cren. n-pa c-x Ha1c -NMIHcr, 1992.-2.24-35.

I1. CB1irl.ac A. HccnenonaH e 4T1H3HKO-XHMHHeCKHX CnOHCcrB Bono-conenix pacrnoponnoaH4bocDaTa Kap6amina c uenlho nonyqeuHs KoMoinexcbix yAo6peuwfl. (lAHcepraunKanA. XHM. HayK.). -Kaynae, 1977. -C.89-113.

12. TexHonoMna d)ocopHblx H KoMnneCKHblX yaoipeaiii. Flon pea. 3BCHH'4Ka C. )I. HEpoacKoro A. A. MOCKBa, 1987.-C.47-63.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS*

FERTILISATION EFFECT ON SOIL AND CROPS

INFLUENCE OF PHOSPHORUS NUTRITION ON FRUIT CROPS QUALITY

Ramdane DrisDepartment of plant production University of Helsinki

AbstractDuring the harvest period of 1992-1995 leaf, fruit and soil samples were collected in 14apple orchards located in the southern part of Finland, including the Aland Islands. Thework consisted of evaluating the phosphorus nutrition in commercial apple orchards. In theexperimental material we had 12 cultivars as follows Maikki, Transparente Blanche, RedMelba, Atlas, Red Atlas, Jaspi, Lobo, Ranger, Aroma, .kerr, Samo and Raike. Weanalysed the concentartion of phosphorus in leaves, fruits and soil. In the results phosphorusranged 1.3-3.5 and 0.4-1.2 g/kg of dry weight in leaves and fruit, respectively. Thediminished phophorus concentration is related to limited root growth during the period whenphosphorus is taken up to the fruit. In early June, phosphorus uptake often decreases sharplyregardless of soil management treatments, with the exception of irrigated sod, where rootlength increases and is maintained throughout the fruiting season.

Key words: apples, nutrition, quality, translocation, leaf, sampling

IntroductionPhosphorus is like nitrogen and sulphur irreplacable raw materials for the plant's proteinsynthesis. It has some quite special functions as ingredient in the nucleic acids which are animportant part of the germ plasm as well as in the ATP, which can be considered the plant'smeans of payment for all energy demanding processes. Phosphorus is natural in certainminerals but the raw material quarried for manufacturing phosphoric fertilisers is mainlyphosphorite of organic origin.Phosphorus is the most immobile of the major plant nutrients and in soil it can be renderedunavailable to plants. Plants take up their phosphorus mainly as orthophosphate, the uptakebeing increased with increasing root surface area as well as with improved radial geometryof root system. Mass flow can play a part in the transport of phosphate towards plant roots.Root infection by endotrophic mycorrhizal fungi can stimulate growth by increasing the rateof phosphate uptake. Many soils in their native stage do not contain sufficient availablephosphorus. Soluble forms of phosphorus react rapidly with soil to form slightly solubleinorganic compounds which are available to plant. In acid and slightly acid soils phosphateis absorbed by sesquioxides and clay minerals. In calcareous soils more insoluble calciumphosphates are formed (1, 7, 9, 10). The aim of this work is to investigate the role ofphosphorus in fruit trees nutrition.

Material and methodsAt harvest time of 1992-1995 leaf, fruit and soil samples were collected in 12 appleorchards located in the southern part of Finland, including the Aland Islands. Experimentswere conducted according to a completely randomized block design with four blocks. Inevery plot, there were four healthy and homogenously bearing trees. The experimentalcultivars were Transparente Blanche, Melba, Red Melba, Atlas, Jaspi, Lobo, Ranger, and

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Aroma originated from Canada, Aker6 from Sweden and Samo (Melba x Huvitus) andRaike (Duchess x Lobo) from Finland. The apple cultivars Melba and Aker6 were grownin the mainland and Transparente Blanche, Samo, Raike, Red Atlas, Aroma and Lobo inthe Aland Islands. 'Transparente Blanche', 'Red Atlas', Ranger, Jaspi and 'Aroma' weregrown in the same orchard. The cultivars were grafted on A2 rootstocks. The trees wereplanted from 10 to more than 20 years ago.The orchard managements were doneaccording to the integrated production recommendations. Light pruning of the trees wasdone during early spring. Fertilization was based on soil fertility analysis and NPKfertilizers were broadcasted in spring on tree rows. The amount of nitrogen given wasabout 40 kg/ha. Most orchards were irrigated time to time during the growing season. Soilsamples were taken during September at the-depths of 0-20 and 20-50 cm per orchard.Soil samples to be analyzed were a mixture of 20 subsamples, taken randomly in theorchard by a steel auger. The samples were air-dried at room temperature and groundedto pass through 2 mm sieve. The particle-size distribution of the inorganic matter of thesoil was determined by a pipette method.Soil phosphorus was extracted with acid ammonium acetate (Vuorinen and Makitie,1955). Phosphorus in the ash extracts was determined by the ammonium vanadate method(Jackson, 1958). Leaves sampling, during the different physiological stages of fruitdevelopment, apple leaves from branches bearing (BF) and non-bearing fruit (BNF) fromthe experimental fields were sampled two times in 1994 (1 4.8. - 16.8.; II 25.8. - 21.9.)and 1995 (I11 18.7. - 27.7.; IV 24.8. - 6.9.), respectively. Leaves were collected between10 and 14 PM, according to the method used in the Agronomic Research Station of SaintGiuliano (SRA Corse, France) (13). Leaves were taken following the equatorial pattern ofthe tree (North - South - East - West) from the outside middle canopy of the tree (avoidingthe top and the bottom), at the height of 1.5 m. A total of 40 leaves per tree and 160leaves per plot were collected. Leaf samples were dried at 70 C for 24 h and thenpulverised. In our work we took the mean value of leaves picked from both branches. Atharvest a randomised set often apples per replicate was taken for chemical analysis.To avoid the phosphorus fixation to the extent possible the soil must be limed to a pHbetween 6.3 and 7.3. All pH-values mentioned are related to pH measured in distilled water.If potatoes, oats, barley or ray are dominating the crop rotation a pH closer to 6.0 must bedesirable, while a pH closer to 7.0 is convenient for alfalfa, clover, oilrape and most fieldvegetables. The pH-value is not always the best indicator for the need of liming. In Swedenthis is above all the case on very humus-rich soils. More generally it can be said that liminghas to take place where the plants take marked amounts of aluminium from the soil. Also thealuminium-content in the Spurway extract is a good indicator, probably better thanmeasuring only pH. By expensive crops like carrots, onion, lettuce, Chinese cabbage etc. theSpurway extract should not contain above 4 mg Al per litre soil. By Al-levels above 10 mgper litre soil liming isjustified independent of which cultures are dominating.For fruit phosphorus analysis, stems and seed vessels with seeds of six apples per replicatewere removed with an apple borer and the apples cut with a slicing machine (Hopart VS9A). During 1993 and 1994, slices were frozen at -20°C, then freeze dried for 12 - 16 h andvacuum packed in laminate bags. In 1995, freeze-drying machine (Edwards EF 10/10) wasunavailable and the samples were dried at 60 - 650C for 48 - 96 h. The percentage of drymatter matter in fruit flesh was determined by weighing apple slices before and after drying.For analysing phosphorus, leaf and fruit samples were pulverised and concentration ofdry matter determined by drying pulverized samples (2 g) at 105 C for 1.5 h. Leaf

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samples were ashed at 475 C and ash was dissolved in 0.5 M HCI. Phosphorus in the ashextracts was determined by the ammonium vanadate method (Jackson, 1958).

Results and discussionsThe average need of phosphorus for apple trees is 50 - 60 kg/ha. In clay soils, the need ofphosphorus is 30 kg/ha more than is lost by the crop in order to keep the phosphorus contentof the soil in the same level. The total content of inorganic phosphorus in soil is in the rangeof 0.02 to 0.15%. With normal fertilization it is difficult to affect the amount of soil solublephosphorus fraction. If the amount of phosphorus in soil is 3000 kg/ha, a change of 10 kg/hain phosphorus fertilization will affect the soil phosphorus content only by 0.33%. In anexperiment, after 15 years of heavy phosphorus fertilizing (60 kg/ha) the soluble fraction ofphosphorus was twice as high as without phosphorus fertilization (8, 11, 12). In ourexperiment, at harvest time of 1992-1995 leaf, fruit and soil samples were collected in 12apple orchards located in the southern part of Finland, including the Aland Islands. In thematerial which consisted of 12 cultivars, phosphorus ranged 1.3-3.5 and 0.4-1.2 g/kg of dryweight in leaves and fruit, respectively. In part of leaf samples phosphorus content wasbelow the recommendation limits, 2-3 g/kg . The average of soil phosphorus in the depth of0-50 cm ranging between 9 and 98 mg/l, was rather high in some samples as compared withthe recommendation. There seemed to be a slight correlation between phosphorus in fruitand soil. There was no clear relationship between leaf and fruit phosphorus. An example ofphosphorus concentration in apple leaves and fruit at harvest 1993-1995 in an individualorchard. Soil phosphorus content was "about 23 mg/I in this orchard situated in the AlandIslands. The mean content of phosphorus per fresh weight at harvest in several applecultivars was below 100 mg/kg which is not enought to satisfy the maintenance of storagequality. For acceptable apple quality a minimum phosphorus level of 120 mg/kg of freshweight in fruit is required. The response to added phosphorus may be modified by factorslike soil management, water supply and inherent availability in the soil. It is established thata correct balance of concentrations of phosphorus in the fruit is important in ensuring asinorganic phosphate, esterified to a carbon chain, or is attached to another phosphorus by anenergy-rich pyrophosphate bond involved the energy transfer mechanism including thegeneration of ATP and the formation of sugar and alchohol esters.In normal mineral soil phosphorus has very low solubility and because of that also littlediffusion into the soil-water. The normal phosphorus content in the soil-water in a soil notrecently fertilised normally is between 0.03 ppm and 0.12 ppm. Based on a medium-level of0.06 ppm P and a water-uptake of 300 litres per square-meter. This should only add 0.18 kgP per ha to the culture. This means that the roots partly will have to find precipitatedphosphorus, partly to dissolve this by lowering the pH. The hydrogen ions excreted asexchange ions by uptake of potassium, magnesium, calcium and other positive ions areresponsible for this local pH-lowering. By increasing phosphorus deficiency the rootswill also excrete increasing amounts of organic acids, especially citric acid. By strongP-deficiency a pH-lowering down to three units below the original pH has been verified.This means that the uptake of phosphorus is always energy-demnading, the more the lowerthe phosphorus supply is. The P-uptake is thus very much dependent on a good root-breathing and of a good root-temperature. The importance of the soil-temperature for the P-uptake is nearly compared to the temperature influence on the molybdenum uptake. Just likenitrogen some phosphorus is annually released via decomposition of the humus-content inthe soil. Approximately 10 kg P is released together with 50 kg N. If, in the long run thehumus-content shall not be impoverished the same amount must be given as plant-parts as

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well as manure. This release of phosphorus is just like the release of nitrogen on its peak inthe beginning of August. Also the supply of tricalciumphosphate should increase as theopposite will cause a more phosphorus-fixing soil. All Scandinavian cultured land but forgreenhouses seems to be more or less phosphorus fixing. This means that if phosphorus issupplied only via the soil a bigger amount must be added per culture than what the culturetotally takes from the soil. This might mean that a good crop is only possible on a soil withlow phosphorus condition - 5 times phosphorus than need is added.Phosphorus also functions as a structural element in the macromolecules of DNA and RNAand serves as the bridging molecule in phospholipid biomembranes. Inorganic phosphate inthe cytoplasm has a function by influencing the activity of various enzymes suchphosphofructokinase. After pollination there is an increase in phosphorus transport towardsthe young developing seeds. During seed germination phytin phosphorus is mobilized andconverted into other phosphate forms needed in the metabolism of young plants. There arelarge differences in nutrient inflow rates into the roots, values ranging from 0.1-0.2 pmol cm-'s-'for apple to 1.3-2.8 pmol cm's'" for cherry (2, 3, 8, 9, 12).The fruit itself apparently absorbs sufficient quantities of phosphorus from the xylem sap sothat sap concentration of phosphorus is greatly lowered. There is higher quantities ofphosphorus in the xylem sap of defruited trees than fruiting trees. At the same time the leafconcentration of phosphorus was not different from normal level (0.23-0.24% DW). Theuptake of phosphorus into apple fruit follows the weight increase of the fruit, and uptakecontinues until harvest. The steady uptake of calcium may be furthered by increasing theavailability of phosphate early in the growing season by fertilizing with water-solublephosphate fertilizers. It is cautioned, however, that too much phosphate may risk theprecipitation of calcium phosphate at the root surface and results in a deficiency of calcium.Phosphate fertilization does not always increase leaf and fruit phosphorus. Nitrogenfertilization, especially addition of nitrate may decrease phosphorus uptake. Ammoniumnitrogen can increase phosphorus uptake, but the detrimental effects of ammonium oncalcium nutrition outweighs possible benefits (11, 12, 13, 15).In Nordic countries since long the dominating P-fertiliser has been super-phosphate P9, amaterial where the main part of the gypsum is still left behind in the fertiliser. This makesP9 a combined fertiliser with 8.8 % P + 12 % S. From 1990 Triple-super-phosphate - P20 -is also available. In this product nearly all gypsum is removed, why the amount ofphosphorus has increased to 20 % while the S-content is below I %. By using P20 ormixtures based on P20, S-supply in another form might be motivated. This is also relevantfor lighter soils if P9 has been added in the autumn.

ConclusionTrees suffering from phosphorus deficiency are retarded in growth and the shoot/root drymatter ratio is usually low. Apple trees show a reduced growth rates of new shoots, andfrequently the development and the opening of buds is unsatisfactory. The symptoms ofphosphorus deficiency appear in the older leaves which are often of a darkish green colour.The leaves of deficient fruit trees are frequently tinged with brownish colour and fallprematurely. In phosphorus deficiency, especially the level of inorganic phosphorus in stemand leaves and the phytin phosphorus of fruit are decreased. In apple trees, phosphorusdeficiency results in an impairment in fruit setting and development of fruits and seeds andoften only small fruits of poor quality with delayed maturity are produced. Phosphorusdeficiency may contribute to greater deterioration of apples during storage and exacerbatescalcium deficiency, since these elements interact intimately in the cell (4, 5, 11). The

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increase in cell size of low-phosphorus fruit is a consequence of a decreased phospholipidlevel in the cell membranes. Low phosphorus content in the apple tissue is related to internaland low-temperature breakdown. Low-temperature breakdown often develops in apple fruitgrown in clean-cultivated orchards. Total-herbicide clean cultivation reduces the averagephosphorus concentration of apples. The diminished phophorus concentration is related tolimited root growth during the period when phosphorus is taken up to the fruit. In early June,phosphorus uptake often decreases sharply regardless of soil management treatments, withthe exception of irrigated sod, where root length increases and is maintained throughout thefruiting season.

AcknowledgementsThe authors are greatful to the Ministry of Agriculture and Forestry of Finland, theGovernment of the Aland Islands, Fruit Growers Association of the Aland Islands, Alandsh6gskola (Aland University College) and Kemira Agro Ltd Horti for financial support.

ReferencesI. Dris, R. 1997. Effect of NPK fertilization on clementine. Acta Horticulturae 448:375-381.2. 2. Dris, R. 1998a. Variation in the storage life of 'Lobo', 'Aroma', 'Red Atlas' and 'Raike'

apples during three years. Acta Horticulturae 485:133-137.3. Dris, R. 1998b. Postharvest quality of apples grown in the Aland Islands. Acta Horticulturae

466:35- 40.4. 4. Dris, R. and R. Niskanen, 1997a. Ppstharvest performance of apples grown in the Aland

Islands 993-1995 with reference to preharvest calcium treatments. Department of PlantProduction, Horticulture Section, University of Helsinki, Helsinki, 99 p.

5. Dris, R. and R. Niskanen, 1997b. Effect of calcium on the storage quality of apples grown inFinland.Acta Horticulturae 448:323-327.

6. Dris, R. and R. Niskanen, 1998a. Quality changes of'Lobo' apples during cold storage. ActaHorticulturac 485:125-13 1.

7. Dris, R. and R. Niskanen, 1998b. Nutritional status of commercial apple orchards in theAland Islands. Acta Agriculturae Scandinavica, Section B, Soil and Plant Science 48:100-106.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

THE INFLUENCE OF FERTILISATION ON DIFFERENT BACKGROUNDS OFSOIL TILLAGE ON AMOUNT AND CONCENTRATION OF PHOSPHORUS IN

GRAIN PRODUCTION

Dalia Feizien6Lithuanian Institute of Agriculture

SummaryThree field experiments were set up on different landscape positions at the Kaltin~naiResearch Station of the Lithuanian Institute of Agriculture during 1995-1998. Croprotation of these experiments was as follows: w. wheat, s. barley and oats. It was revealedthat 1) by increasing the grain yield of a crop, the amount of P taken by a crop alsoincreased, while the P concentration in the grain had a tendency to decrease; 2) P mobilitywas influenced by soil moisture content, which in turn, was affected by climaticconditions and by soil tillage system chosen. 3) grain yield and its quality was affected bylandscape position due to differences of soil moisture content and nutrient distribution inthe soil at the separate locations of hilly relief

Key words: cereals, phosphorus, soil tillage.

IntroductionConventional soil tillage on a hilly relief comprises autumn soil ploughing. According toresearch data found in literature soil ploughing is the main reason for both soil water andsoil tillage erosion manifestation on hilly landscape. The data obtained at the KaltinenaiResearch Station revealed that autumn soil ploughing might be successfully replaced byother methods of soil tillage [4]. One of the antierosion measures is suitable soilfertilisation. Only on limed soil and fertilised by the right rates the crops produce the bestyield and reduce water erosion extension [7]. According to the data obtained in theResearch Station mentioned the rates of fertilisers should be differentiated according tothe landscape position by reducing the rates of them on foot of the slope and on aninterhill lowland [5, 6].Lower mobility of phosphorus often results in accumulation of this nutrient near the soilsurface when fertiliser is broadcast in reduced tillage systems. Research data collected inUSA showed comparable levels of phosphorus uptake between no-tillage and conven-tional tillage systems [1, 3].The research data collected in our Republic up to now did not let us give the right answerabout the complex action of soil tillage and application of mineral fertilisers carried out inthe same field experiment.

Material and methodsThree field experiments were set up (one on top of a hill, one on slope and one on foot ofthe slope) at the Kaltinenai Research Station in 1995. Soil - sody-podzolic (AquicGlossoboralf). Soil texture - sandy loam overlying sandy loam on top of a hill and on theslope of a hill, while soil texture on foot of the slope was loam overlying loam accordingto the USDA soil classification system. The degree of erodebility - slight. Slopeinclination -60. Slope aspect - western. Nutrient status of arable soil layer was, on

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average, as fallows: pH 5.9, mobile phosphorus 72 mg/kg, mobile potassium 219 mg/kg,amount of humus 1.97% on top of a hill. On slope and foot of the slope: 5.3, 46 mg/kg,

187 mg/kg, 2,32% and 5.5, 53 mg/kg, 150mg/kg and 4,08%, respectively. The soil waslimed (5.0 tfha of lime) in 1995.The field experiments were set up according to the research design presented below:

Factor A - soil tillage systemsTreatment Crop rotation Primary tillage Presowing tillage

I w. cereals deep ploughing (20-22 cm) cultivation + harrowings. cereals deep ploughing (20-22 cm) cultivation + harrowing

I1 w. cereals shallow ploughing (14-16 cm) cultivation + harrowings. cereals Roundup + chiselling (20-22 cm) cultivation + harrowing

Ill w. cereals shallow ploughing (14-16 cm) harrowing with a rotary knifeharrow

s. cereals Roundup harrowing with a rotary knifeharrow

IV w. cereals shallow ploughing (14-16 cm) harrowing with a rotary knifeharrow

s. cereals 0 Roundup + harrowing with a

I rotary knife harrowFactor B - fertilisation systems

I Not fertilised.2 The rates of NPK fertilisers according to nutrient status in the soil and the yield

planned (moderate rates).3 The rates of NPK fertilisers according to nutrient status in the soil and the yield

planned by 25% higher than in the treatment 2 (high rates).

In the first treatment of the factor B no fertilisers have been used. In the second and in thethird treatment the rates of mineral fertilisers have been calculated according to their amountpresent in the soil. P and K fertilisers were broadcast on the soil surface before presowingtillage. Nitrogen fertilisers for winter cereals were broadspread in the spring just after reno-vation of the crop vegetation, while N-fertilisers for spring cereals were broadspread andslightly incorporated into the soil surface by presowing tillage equipment prior to cropdrilling. Fertilisers used: ammonium nitrate, granular superphosphate and potassium chloride.Three-course crop rotation was executed: w. wheat, s. barley and oats.The winter of 1995-1996 was cooler and drier than usual. The spring was late. Vegetationperiod was drier than usual. In 1997 the months of June-July were dry and warm. Theamount of precipitation during these months reached only 53.3% of the amount describedas a long-term one. 1998 was unusually wet. The amount of precipitation during the June-August period was by 55.6% greater than that for a long-term one.

Results and discussionA number of factors influence the amount of phosphorus in the grain, i.e. soil moisturecontent, depth of soil tillage, nutrient status of the soil and amount of mineral fertilisersapplied and, finally, the amount of the grain yield planned. Soil tillage systems had a greatinfluence on the distribution of nutrients in the arable soil layer. This has direct impact onaction of fertilisers and, subsequently, different effect on grain production. The plantanalyses carried out in this research let us reveal phosphorus uptake in different soiltillage systems (Fig.).

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. ..-- i i-i i

... . .

isi

Figure. Grain yield, P amount in grain yield and P concentration in grain production atdifferent lanscape positions.

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Winter wheat.On top of the hill, the concentration of total P in the grain production was, on average,0.81% or by 0.04% greater than on the slope, and by 0.06% greater than that on foot ofthe slope. Vegetation period for this cereal growing was drier than usual. Under theseclimatic conditions the mobility of P was lower in the treatments with shallow tillage.This led to lower concentration of P in the grain. In the treatments with shallow tillage(treatment 11I, factor A) the concentration of P in the grain was lower, on average, by0.02-0.04% on top of a hill, by 0.01-0.07% on the slope and by 0.01-0.02% on foot of theslope as compared with the deep tillage treatments. It should be noted that by increasingthe yield of the crop, the P uptake by the crop increased as well, while P concentration inthe main production had a tendency to reduce. This tendency was mentioned at alllandscape positions and in all soil tillage systems.According to the findings found in the literature the action of P fertilisers is greaterpronounced on soils poor in P. Moreover, N-fertilisers, especially NIt can increase the Puptake [2, 3]. Our results of the investigation confirmed that only in the treatments withdeep soil tillage carried out on slightly eroded top and slope of a hill (treatment 1, factorA). Data showed that by applying high rates of NPK fertilisers the amount of P in themain production and P concentration in the grain increased on top of a hill and on slopeby 0.14% and by 0.10%, respectively as compared with that of the moderate rates offertilisers.Spring barley.On top of a hill, the concentration of total P in the grain production was, on average,0.76% or by 0.01% lower than on the slope, and by 0.06% lower than that on foot of theslope.During the emergence-tillering stage of the crop the soil water content was sufficient forthe crop development. P mobility in all soil tillage systems and at all landscape positionswas well pronounced. In the treatment III and IV of the factor A P mobility was higherthan in the treatments of the intensive soil tillage (treatment I and II, factor A). Datarevealed that P concentration in the grain on top of a hill was greater by 0.03% in thetreatments of the extensive soil tillage as compared with that of intensive ones.Common conformity was revealed concerning changes of total P concentration in grainproduction in the background of deep ploughing followed by a cultivation to 10-12 cmdepth (treatment 1, factor A) at all landscape positions. When the moderate rates of NPKfertilisers were applied the total P concentration in grain production reduced by 0.01-0.04% as compared with that of not fertilised treatment. When the high rate of fertiliserswas applied the P concentration remained at the same level (foot of the slope), orincreased by 0.01% (top of a hill) and by 0.06% (slope) as compared with the grain of s.barley fertilised with the moderate rate of fertilisers. It is worth to point out that theamount of P in the grain production depended directly on the yielding capacity of thecrop, i.e. by increasing the yield, the P uptake increased also.When deep ploughing was replaced by deep soil chiselling (treatment I1, factor A) theP concentration in the grain production altered in another way. On top of a hill, byapplying moderate or high rates of fertilisers the grain yield and P uptake increasedregularly, but P concentration in the main production was stable and amounted to 0.73%.On slope of a hill, by applying high rates of NPK fertilisers the grain yield had a tendencyto reduce, while P concentration and P uptake uniformly increased. This may beexplained by more suitable soil moisture conditions, which in turn, secured an optimal

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mobility of nutrients. In addition, in this soil tillage system, either moderate or high ratesof NPK fertilisers produced the heaviest grain yield as compared with other soil tillagesystems comprising the same fertilisation level. On foot of the slope, by applyingmoderate rates of NPK fertilisers the grain yield and P uptake increased, but Pconcentration reduced by 0.04% as compared with that of the not fertilised s. barley.When high rates were used the grain yield, P uptake and P concentration increased (by0.19% than that of moderately fertilised barley).When herbicide Roundup was sprayed in the autumn followed by presowing harrowingwith a rotary knife harrow (treatment III, factor A) by applying moderate rates offertilisers on top of a hill and on slope of a hill the P concentration either remained at thesame level (on slope) or increased (on top of a hill +0.05%). On foot of the slope, theconcentration of P decrease by 0.04% as compared with that of not fertilised barley. Highrates of fertilisers on top and slope of a hill reduced P concentration, while on foot of theslope it slightly increased. Grain yield by applying higher rates of fertilisers increased aswell.When herbicide Roundup was sprayed in the spring followed by presowing harrowingwith a rotary knife harrow (treatment IV, factor A) the changes in P concentration weredifferent on separate landscape positions. On top of a hill, by applying high rates of NPKfertilisers the P concentration reduced consequently. On slope of a hill, the Pconcentration was similar either in not fertilised or in moderately fertilised treatments, butwhen high rate of fertilisers was applied this index increased by 0.04%. P concentrationreduced even by 0.16% when the high rate of fertilisers was applied on foot of the slope.Oats.P concentration in grain production was very similar at all landscape positions andamounted to 0.40%.Vegetation period was unusually wet and cool. Due to heavy and frequent rains the croplodged at early stage of its development (beginning of heading). Grain ripened slowly andsome kernels have germinated being in the panicle. This had a negative effect on yieldformation.On the background of deep ploughing, P concentration in the grain by applying moderaterates of NPK fertilisers remained at the same level (on top of a hill) or reduced by 0.02-0.04% (on slope and foot of the slope) as compared with that of not fertilised crop. Whenhigh fertiliser rates were used this index slightly decreased on slope of a hill, while on topand on foot of the slope it increased, on average, by 0.02%. It is possible that Pconcentration reduction was affected by soil water erosion manifestation due to rainysummer. In spite of P migration in the soil is low, the great amount of precipitationinfluenced both water erosion occurrence and loss of fertilisers applied.On top of a hill, on the background of soil chiselling (treatment II, factor A), Pconcentration in the grain production increased simultaneously by increasing the rates offertilisers applied. On foot of the slope, this index reduced by 0.03%. It should be pointedout that soil tillage system comprising chiselling has reduced significantly water erosionextension as compared with the deep soil ploughing.P concentration in grain production was, on average, by 0.01-0.04% lower in theextensive soil tillage systems (treatment III and IV, factor A) at all landscape positions ascompared with that of the intensive ones. Crop yielding was low due to lodging.

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Conclusions1) By increasing the grain yield of a crop, the amount of P taken by a crop also increased,while the P concentration in the grain had a tendency to decrease;2) P mobility was influenced by soil moisture content, which in turn, was affected byclimatic conditions and by soil tillage system chosen.3) grain yield and its quality was affected by landscape position due to differences of soilmoisture content and nutrient distribution in the soil at the separate locations of a hillyrelief

References1. A systems aproach to conservation tillage / Edited by Frank M. D'Itri. Lewis publishers, Inc.

1985, P. 90-95,2. Barber S. A. Soil nutrient bioavailability //2nd ed. John Wiley & Sons, Inc. 1995, P. 79-80.3. Black C. A. Soil fertility evaluation and control. Lewis publishers, 1993, P. 155-170.4. Feiza V. Pagrindinio &mmes dirbimo bfdq ir intensyvumo tyrimai kalvoto reljefo Vakarn

Lietuvos dirvose // Daktaro disertacijos referatas. Dotnuva, 1993. 40p.5. Feizien6 D. Mineralinitj trgq§ normqt efektyvurnas mie2iams kalvoto reljefo Zemaitijos

dirvose / LZI MSR, Nr. 75 / Trqimas. Dotnuva-'Akademija, 1994. - P. 150-164.6. Feiziene D. Mineraliniq troqt norm'4 efektyvumas 2ieminiams kvietians kalvoto reljefo

Zemaitijos dirvose // L21 MSR, Nr. 75// Troimas. Dotnuva-Akademija, 1994. - P. 73-87.7. Jankauskas B. Dirvofemio erozija. - V., 1996. -P. 135-136.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUMAND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

NUTRIENT CHANGES IN CROP PRODUCTION AND SOIL WITHAPPLICATION OF DIFFERENT CROPPING SYSTEMS

Ona BundinieniDtiktas Research Station of the Lithuanian Institute of Agriculture

SummaryThe experiment was conducted on the soddy podzolic slightly podzolized, minimum andmedium eroded sandy loam soil.Three cropping systems were investigated in the field crop rotation: I - biological -organic, 2 - integrated and 3 - intensive (winter wheat, maize, barley + underseeding,clover I year) and two: I- biological - oragnic and 2- intensive in the ley growing rotaion* The preceeding crop in both rotations was oat - vetch mixture for green forage. Theinfluence of those cropping systems on the crop producitivity, soil fertility and nutrientbalance were studied.Data of the first rotation show, that the ley yield was the highest obtained in experiment( without mineral fertilizers it amounted 57.5 and with mineral fertilizers 68.2 GJha"

). Inboth treatments the content of humus increased in the soil while available phosphorus andpotassium have increased only in the treatment with mineral fertilizers. The NPK balancewas positive. In the field crop rotation the most appropriate was the integrated croppingsystem.

Key words: cropping systems, field crop rotation, Icy, nutrient balance.

IntroductionThe attempts to increase plant productivity in many cases are not economically efficient,however the risk of environment pollution is increasing. Data obfained in EstonianAgricultural University have shown, that the medium rates of mineral fertilizers (40-60 kgha " NPK) and 60 tha" of manure in the integrated cropping system allow to yield4669 fodder units per ha. This was only by 702 fodder units lower, than in the intensivesystem, however 1 kg NPK in the integrated system resulted 18.2, and in intensive one -only 13.9 fodder units / 9/. Similar results were obtained in Lithuania / 3, 5 /. In the caseof total or partial rejection of chemical measures, while applying intensive croppingsystem, the organic fertilizers cannot supply the nutrients to plants in needed quantities,because then the availability of nutrients is lower as compared with mineral fertilizers/2, 10, Il/. While manure and mineral fertilzers are applied, the plant production qualityis improving, soil nutrient quantity is increasing and microbiological processes becomemore active /13, 14/. In Voke, on sod podzolic sandy loamy soil, the acidity wasincreasing and available potassium was decreasing while fertilizers were not used.Changes of humus and phosphorus were not essential due to the crop rotation with 50%of legumes + grass mixtures / 7 /. However the acidity / might be changeable because ofthe sun acitivity /Nebolsin A.N. /15/. On heavy soil with the application of 80 t/hamanure, yield increased by 35%, with application of 40 tha" manure + NPK minearl

.181

fertilizers - by 54% and with mineral NPK fertilizers - by 55.5% /1/. However none of thementioned fertilization systems not ensured a positive N and K balance /4, 5, 7/.With higher nutrient accumulation in plant production, nutrient content in soil decreased.Balance calculations prove, that soil fertility does not decrease, if I ha receives withmineral fertilizers 120 kg N, 40 kg P2O and 120 kg K20 annually. The coefficient ofcompensation of phosphorus and potassium should be 200 - 300 and 150%correspondingly /6, 7, 12/.So, the main measure of nutrient regulation is the application of mineral fertilizers. Oneof the purposes of this experiment, conducted in the Dflkgtas research station on soddypodzolic slightly podzolized minimum and medium eroded soil in 1993 - 1997, was todetermine the changes of nutrients, among them, potassium, in soil and their balancewhile keeping different cropping systems.

Research conditions and methodsThe experiment was set up in the southern (2043/ - 7039' 0 and northern (5045/ - 8010')slopes of hills in the upper, medium and lower parts of the hills. The plots were arrangedrandomly along the latitude lines. The soil was sod podzolic slightly podzolized,minimum and medium eroded sandy loam overlying the morainic loam. Soil was limed byI rate of lime according to the soil hydrolitic acidity in 1991. Soil pH of topsoil after theliming was 5,6 ( by potentiometric method), available P205 - 244, K20 -188 mgkg' (A-Lmethod), humus content - 1.7% ( method by Tiurin ), total nitrogen - 0.17% (by Kjeldalmethod).Three cropping systems were investigated in the field crop rotation: 1- biological-organic, 2- integrated and 3 - intensive (winter wheat, maize, barley + underseeding,clover I year ) and two (1- biological - organic and 2- intensive ) in the Icy growingrotation the preceeding crop in both rotations was oat - vetch mixture for green forage,fertilized with 60 kgha "' NPK.The manure in field crop rotation (treatments 1 -3) was incorporated after winter wheatharvesting and in ley growing rotation before the sowing of preceeding crop. Rates of themineral fertilizers in the treatment 2 of field crop rotation were calculated according tothe nutrient content in soil and level of planned yield. The pesticides in this treatmentwere used depending on the abundance of weeds, plant diseases and pests. The rates ofmineral fertilizers were increased by 20% in the treatment 3, winter wheat and barley atthe stage of tillering were additionally treated with nitrogen fertilizer.With manure application during rotation in total - 343 N, 252 P205 and 513 kgha' K20were incorporated in soil. In the treatment 2, annually 44 kg N, 35 P205 and 45 kgha -'K20 were added in the form of mineral fertilizers, in the treatment 3 - 50, 56 and65 kgha-' correspondingly. The ley was treated by 60 kg/ha NPK annually.When calculating balance, the nutrients in seeds deposit, soil biological nitrogen (15kgha 1 ) and nutrients in plant residues were added annually to the nutrient incomes. Theoutcome included plant nutrient uptake and nutrient losses with runoff soil surface, soilleaching and N gaseous losses ( 30% from mineral fertilizers, 15% from manure). It wasassumed that in loamy soil plants are receiving 40% N and K20 and 15% P20 5 frommineral fertilizers and 25, 80 and 50 % from of manure /17/.Soil sampling was done before the experiment establishment and annually after theharvest, plant sampling - during the harvest. Samples were analysed at the AgrochemicalResearch Centre of LIA and in Duk~tas research station according to the methodsapproved in Lithuania.

182

Yield data were calculated using methods of dispersion and correlation - regressionanalyses.

Results and discussionWhen applying chemical measures, field crop rotation yield energy mass increased by20,8- 23,8 GJha-' or 1.8 -2.0 times, however there were not found the reliable differencesbetween the integrated and intensive systems (Table I ).The plants used 0.11 - 0.19 kgha-'NPK for production of I GJ of supplemental energy mass or I kg NPK has resultated5,2- 9,1 GJ. In the Icy growing rotation the energy mass of biological - organic croppingsystem was by 2,2 higher, than in the same treatment of the field crop rotation and by 7,0-10,0 Gfha- higher than in the integrated and intensive treatments of the field croprotation. When the Icy was fertilized, the energy mass has increased by 10,7 GJha" or by18.6%, means, that 1 kg of NPK has resulted 14,8 GJ. The energy mass of fertilized Icywas by 17,7-50,7 GJha -' or by 35 -43.6% higher than the obtained in the integrated andintensive treatments of the field crop rotation.

Table 1. Producitivity of crops and nutrient balance of different cropping systemsDak.tas, 1993- 1997

t Active nutrient balance+- kgha' andTreatment MetabolizableI

(cropping system) energy Gjha-' compensation %I nitrogen phosphorus potassium

Field crop rotation ( FCR )Biological- organic 26,7 -

-20,1 -0,6 -14,1Integrated 47,5 3, 386,38,3 83,8 60,9

-23,4 +30,0 -24,3Intensive 50,5 -________

33,1 188,0 31,5LSD,5 4,2

Ley growing rotation ( LGR )+44,2 (-) +8,9 (-) +11,5 (-)

138,4 (-) 130,9 (-) 129,4 (-)Intensive 68,2 +53,8 (9,6) +18,5 (9,6) +33,1 (21,6)

137,6 (134,3) 286,9 (309,6) 152,3 (189,2)LSDo, 9,9LSDo 4,1

Note: in the brackets - in the grasses growing rotation

The energy mass depended on the fertilizers rate ( r= 0.57 , ros= 0.51). It also dependedon nutrient content in the soil and nutrient nitrogen amount incorporated with fertilizers(in the first year of application when growing winter wheat and Icy I y, R=0.81, in thesecond year after application, when growing maize and ley II y R=0.97, in the third yearafter application, when growing barley and Icy III y, R=0,91 and in the fourth year afterapplication, when growing clover and Icy IV y. R=0.88, while R05

= 0.63)The plant uptake of the biological - organic cropping system in the field crop rotation was53,8 kgha-' N, 7,7 kgha-' P and 51,2 kgha' K and it made up 49% N and for 96% P and K

183

at all outputs. In the same treatment in the ley growing rotation the plant uptake washigher(169.4; 14.8 and 81,6 kgha' and 80.5; 100 and 98% consequently). While fertilizing inboth rotations, plant uptake has increased, however its part in the nutrient balance did notchange so far. In the field crop rotation on the average 80% of nitrogen, over 90% ofphosphorus and about 85% potassium were received from fertilizers of all nutrient 142.5;97.4 and 184.6 kgha" consequently. In the ley growing rotation those figures were such:40,85 and 60% of all nutrient incomes : 329,8; 134.5 and 275,3 kgha'.The plant uptake depended on the nutrient content in soil and that of the fertilizers ( in thefirst year R,= 0.93, R,=.66 and RK=0.7 2 , in the second year - 0,98; 0.96 and 0,98, in thethird year - 0,55; 0,63 and 0,86 in the fourth year - 0,76; 0,51 and 0,77 consequentlywhile Ro5= 0.63).Though quite a big amount of nitrogen was incorporated into the soil, active balance inthe field crop rotation was negative with intensivity 33,1 - 38,3%. In the ley growingrotation even without mineral fertilizers, N balance was positive. Probably the ley, whichconsisted of 50% of lucerne, used the biological nitrogen in soil or nitrogen from the plantresidues.Phosphorus amount was not sufficient enough for crops in some cropping systems and didnot compensate the plant uptake as it should be reaching 200-300% / 12 /. None of thestudied cropping systems ensured positive potassium balance. Even in the Icy growingrotation it was positive, but without mineral fertilizers did not compensate soil potassiumcontent to 150% / 7. 16/.Soil acidity decreased after the liming and it remained on the same level during thecourse of the rotation (Table 2).

Table 2. Changes in the soil nutrients in different cropping systemsDflk~tas 1990- 1997

Agrochemical indices

Treatments available(cropping system) pHKc1 humus % total ni-

trogen % P205 K 20trogen_ _ %mgkg "' soil

field crop rotationBefore liming (1990y) 4,7 1,50 0,14 234 180

5,4 1,64 0,14 221 234Biological-organic 5,9 1,60 0,14 176 232

5,4 1,39 0,15 208 248Integrated 5,9 1,42 0,18 216 251

Intensive 5,4 1,46 0,15 223 2155,6 1,54 0,23 272 228

Icy zrowing rotationBefore liming (1990 y) 4,2 1,94 0,14 292 110

- 5,4 1,88 0,14 275 115Biological-organic 5,6 2,02 0,21 240 102Intensive 5,5 1,88 0,14 240 166

5,6 2,03 0,22 264 169Note :in the nominator- at the beginning, in the denominator - at the end of thel-st rotation

184

Soil humus and total nitrogen content in both rotations increased in the treatment withmineral fertilizers. Humus content decreased after the ploughing of old grassland due tothe more intensive mineralization. In both treatments of the Icy rotation, the content ofhumus and total nitrogen increased as well as concentration of humic acids in theintensive treatment.The soil was sufficiently supplied with available phosphorus and potassium, however inboth rotations their quantity decreased in the biological - organic treatments. Phosphorusmineral fertilizers increased the available amount of P205 in soil but the balance inintegrated cropping system was not positive.The amount of available K20 in soil increased a little while keeping both rotations andfertilizing crops. Potassium is a mobile element and it might leach to the deeper layers ortransform into less available forms. It might also be biologically fixed /16/. The field croprotation plants probably could not reach potassium from deeper soil layers, which waseasy for Icy with lucerne in the sward.

ConclusionsSummarising the data of the 1-st rotation it might be concluded:I. The producitivity of field crop rotation in the integrated cropping system was 47.5GJha'. With more intensive fertilization the yield increase was not reliable. The Icy inbiological - organic system produced 57.5 GJha' of energy mass while, in the intensivesystem - 68.9 GJha" consequently.2. The balances of nitrogen and potassium were negative in all systems of the field croprotation. A more intensive fertization has resulted in a positive phosphorus balance. In theIcy growing rotation the NPK balances were positive.3. Manure rate once a rotation was not sufficient for humus, phosphorus and potassiumincrement in soil, but it stopped soil acidity. Soil nutrient amount has increased after theapplication of mineral fertilizers: humus content increased by 0.03 - 0.08 percentageunits, available P20 5 by 8 - 49 mg/kg, available K20 by 3- 13 mgkg- ' in the field croprotation. In the Icy growing rotation the humus content increased by 0.14 - 0.15percentage units in both treatments. In the intensive system with leys the content ofavailable P205 increased by 24, available K20 by 3 mgkg' consequently.So, in the minimum and medium eroded poor in humus, but sufficiently provided withphosphorus and potassium soils growing of ley is rational because the yields are quitehigh and the soil is not depleted. Growing field crops in the integrated cropping system ismore appropriate.

ReferencesI. Bagdoniene V., Arlauskient E.A., lepetien A. Melo ir mineralinitq tr~q efektyvumas

stjomainoje// Zemdirbystt. L2I mokslo darbai.- Dotnuva-Akademija.- 1998. -T.63.-P. 70-782. Fagerberg B., Salomon E., Jonsson S. Comparisons between conventional and ecological

farming systems at Ojebyn / Swedish Journal of Agricultural Research - 1996.- Vol. 26(Nr.4).- P. 171-179

3. Gavenauskas A. Organines, tausojantios ir intensyviosios femdirbystes sistemq palygina-masis ivertinimas II Daktaro disertacijos santrauka.- Kaunas- Akademija.- 1998.- P. 27

4. Greimas G., Janugien6 V. Sdjomainq naumas ir dirvoiemio derlingumas jvairiai jas trqSiant//Zemdirbystes mokslo darbai ir ateitis.- Dotnuva- Akademija.- 1996. -P. 103-107

5. Gulys S. Organines- biologines ir intensyviosios ermdirbystts itaka augalq derliui ir maistomedliag balansui Vakart Lietuvos dirvo emiuose //Biomedicinos mokslq srities agrono-mijos krypties V doktorant4 konferencijos pranegimai.- Dotnuva-Akademija.- 1998.- P.25-28

185

6. Ma2vila J. (sudarytojas / Lietuvos dirvotemiq agrochemines savybes ir jq kaita.-Kaunas.-1998.- 195 P.

7. Tripolskaja L., Greimas G. Del jvairiq trqgimo sistem poveikio susiformavusio dirvoiemioarmens agrocheminit savybiq poky~iai / 2emdirbystd. L21 mokslo darbai. - Dotnuva-Akademija.- 1998.-T. 63.-P. 55-68

8. Vaigvila Z., Ma2vila J., Rylikiene ir kiti. Mineraliniq trqq itaka .emes 0kio augalq derliui,jo kokybei, maisto mediagq balansui ir ekologinei bfklei vidutinio sunkumolimnoglacialiniame priemolio dirvofemyje // 2emdirbyste. L2I mokslo darbai.- Dotnuva-Akademija.-1997.-T. 60.-P. 24-37

9. Vipper H., Poder 1. About the effect of agrotechnology on the yield of crops on level of soilmanagement systems //Problems of field crop husbandry and soil managament in Balticstates -Tartu.- 1995.-P. 137-143

10. ,lepaanir JI.M. flpHMeHeHne yIo6peHnH B HHTeHCHBHOHt 3eMae JCIHH //ConpeMeHHoepa3BHTHe HayH HJX Maek f.H. rIpAmumnwiona. AH CCCP Bcecoo3. o6uxecroflo'{BOBCeIB.-M.-199I.-C. 15-20

1I. KaHT r. BHorHxqecioe paCTeHHeBoICTBO: B03MO)KHOCTH 6HO.norwlqeCKHx arpocHcTeM.-M.,-1998-207 C.

12. KAp6aaue X.A. O6ecneqeuocTb noi $0oc)opoM H HpHMeHeIIHe 4)oC4)OpHbIX yAo6peHiR B3aoHcKoA CCP //HoabIIIleHHe rpoyKTHBHOCTH ceJlbCKOXO3rjCTBeHHbIX KybTyp.- TapTy.-1983.- C. 17-18

13. Jlana B.B., HBaxuetKo HAl. ,JHMaHTOaa E.M. H3MeHeH nnORO1O1HH ICpHOBO-nOfl3OJlHCrbIX noHB 1pH ciCHcTeMaTHwecxoM OpMMeHeHHH ygto6peHrl //HoqBoBeACHHC.-2 000 .No 3. C. 340-345

14. MnHeen B.F.,FOMOHOBa H.O., 3eHOBa F.M. R gp. I43MeHeuHe CBOrICTB ACpHOBO-nolanaHCTOi nOHBbI H ee MHKpO6ouieHo3a npH HHTCHCHBHOM aHTpO1O1CHHOM BO3IeCTBHH

// Ho'BoaeneHne.- 1999. -N24. C. 455-46015. He6ojibCHH A.H., He6onhCHa 3.11. H3MCHeH e HeKoTopLIX CBOtCTB HOMBCHHOfO

nOrJIOuajojUoero KOMhneKca aepHoBo-Hoa3OnHcToI JIerKOCyrHHHCTOii FIOMBLI noixBJIKMHHCM H3BeCTKOBaHt // ArpoxHif.- 1997.-N10.-C. 5-12

16. FIHCRKHH Bq. Ho'renHHztl KajMAf KarniHhie yzio6penniA.-M.,-1966.- 334 c.17. SrolHH S.A. /penaKTop/ ArpOXHMH.-M., 1982.- 573 c.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUMAND PHOSPHORUS

FERTILISATION EFFECT ON SOIL AND CROPS

THE INTERRELATION OF THE AMOUNT OF POTASSIUM DETERMINEDBY DIFFERENT METHODS IN GLACIAL LACUSTRINE SOILS OF

LITHUANIA

Antanas Antanaitis, Jonas Mafvila, Jadvyga Lubyt , Zigmas Vai~vilaAgrochemical Research Centre of the Lithuanian Institute of Agriculture

SummaryThe content of potassium was analysed in different solvents: CH 3CH(OH)COOH +CH 3COOH +CH 3COONH, pH 3,7 (A-L method), 2% NaHCO 3 + 0,76%(NH4 2 S04, 0,01M CaCI2, 0,03% MgSO4 , CHCOON- 4 + trilon B (pH 4,65); 2 N HCI in 10 fertilizationtreatments in Sakiai district, Kriflkai in glacial lacustrine silty medium loam soils. Theresults are provided and discussed in the present paper.Itwas determined that the amount of available potassium first of all depends on thesolution used in extraction, concentration of the solution and pH.The most similar amount of potassium to the A-L method in these soils was obtainedusing the solutions: 2% NaHCO3 + 0,76% (NH4)2SO4 (78-111% in comparison with theA-L method) and CHCOONH4+trilon B, pH 4,65 (51-102%).Using the 0,01 M CaCI2 solution for extraction of potassium the amount of potassium wasonly 12-23% in comparison with the amount of potassium analysed by the A-L method;twice larger amount than using 0,01 M CaCI2 was obtained using 0,03% MgSO4 solution.There was a reliable correlation between the amount of potassium determined using 2%NaHCO 3 + 0,76% (NH4)SO,, 0,01 M CaCI2, 0,03% MgSO 4, CH 3COON 4 + trilon B(pH 4,65) solutions and the A-L method.Using the extraction of potassium by 2N HCI solution the exchangeable and also non-exchangeable potassium was dissolved and this was the reason for obtaining the largestamount of potassium. This method was not good enough to show the dependence ofincrease in potassium on spread fertilizers and there was no reliable correlation with theA-L method. The most considerable dependence of potassium was on the origin of soil.A distinct difference of the amount of non-exchangeable potassium was obtained inglacial lacustrine silty (591-710 mg/kg in treatment without potassium fertilizers) and inmoraine sandy loam (269-367 mg/kg in treatment in Skemiai) soils.The correlation between the yield of winter wheat and the amount of available potassiumwas not reliable in glacial lacustrine silty medium loam soils with a low and mediumamount of potassium analysed by the A-L method. However, the correlation between theyield of potatoes and the amount of available potassium was reliable. That is why for thedetermination of potassium fertilizer rates for crops in glacial lacustrine silty origin soilsit is necessary to analyse not only available potassium, but also in soils with differentgranulometric texture to check up the amount of non-exchangeable potassium.

Key words: soils; extraction; available, exchangeable and non-exchangeable potassium.

IntroductionFertilization should be very rational because of decrease in price for agriculturalproduction, growing expense for fertilizers and energy resources, more severe ecological

187

requirements. Fertilizing soils it is necessary to take into account the agrochemicalproperties of soils and a need of particular plants for nutrients. Therefore the relationshipbetween soil agrochemical properties and the yield should be close.According to research data (during the period of 1971-1995) the yield of agriculturalcrops and the efficacy of fertilizers depend on the amount of available K20 (A-L method)in moraine light loam sandy soils. Especially a large increase in yield was obtained in thesoils with a very low content of potassium (0-50 mg/kg), a little less - in soils with a lowcontent of potassium (5 1-100 mg/kg).According to the experimental findings in glacial lacustrine silty loamy soils the efficacyof potassium fertilizers for crops was weak in the soils with a low content of potassium.The investigation in Krifkai (during the period of 1990-1995) revealed that the yield ofwheat did not increase, and the increase in yield of perennial grasses and sugar beets wasnot reliable. Similar results were obtained in akiai, where the silty soils with a lowcontent of potassium prevail; comparatively good yield of agricultural crops was obtainedwithout the use of potassium fertilizers.It means, that the A-L method was not sufficiently suitable for this type of soil or therewas a need for different scale of evaluation. The objective of the present paper was todiscuss these questions.

The conditions of investigation and methodsPotassium in soils is divided into water soluble, exchangeable, reserve and fixed, non-exchangeable, including fixed potassium in. insoluble silicate and organic compoundsaccording to P.Amold [1], B.FIIenwKH [14], C.E3ap6ep [8]. However, the same authorsindicate the change of different potassium forms in soils or different amount in soilsdiffering in genesis. Some authors refer to the dependence of agricultural crops on theamount of available K20 in soil [3, 9, 11, 12]. Other authors note the possibility of someagricultural crops to uptake potassium from different forms, though [4, 8]. That is why theefficacy of potassium fertilizers was different even if amount of potassium was the same.We have chosen the solvent for potassium extraction from these types of soils taking intoaccount the forms in which potassium can exist.We analysed potassium soluble in water, in weak solution of salts - 0,01 M calciumchloride (5), 0,03% magnesium sulphate (6), ammonium acetate and trilon B pH 4.65, inweak alkaline solution (pH 8,0) of 2% ammonium carbonate and 0,76% ammoniumsulphate (7), in buffer of ammonium acetate - lactic (A-L) (3) and in 2 N HCI solution(10). Potassium in these solvents was determined by flame fotometer.The amount of potassium was determined by different methods in glacial lacustrine sod-gleyic (gleyic combisols) silty medium loam soil with clay in deeper layer in Sakiaidistrict, Kriflkai. In 1990 we set up a testing field with 13 fertilization treatments, in 1998it was a little modified by changing the fertilization rates for the same crops.The amount of potassium was determined by different methods in 1998 and 1999, inlayers: 0-20; 20-40; 40-60; 60-90cm. The data presented in this article were obtainedfrom the investigations in the 0-20 cm layer. In 1998 winter wheat cv. Zenta, in 1999potatoes cv. Venta were grown.Trying to ascertain if the time of taking samples depends on the amount of potassium theexperiment was done, the samples were taken from the 10 treatments, the threereplications: in spring before fertilization (before nitrogen fertilization for winter wheat),in summer when the growing was intensive and after harvesting.

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The research data were calculated by the method of disperse analysis, the correlationbetween the A-L method and other methods was obtained, also between the amounts ofpotassium determined by various methods and yield.In addition, the standard deviation coefficient of variation was determined; the amount ofpotassium was determined by different methods.

Results and discussionThe amount of available potassium determined by the A-L method in glacial lacustrinesilty medium loam soil with clay in deeper layer, fertilized by various NPK rates variedfrom 81,7 to 143,0 mg/kg for winter wheat (in 1998), for potatoes - 99,7 - 142,7 mg/kg(in 1999); the samples were taken three times during the vegetative growth period; thedata are presented in Table I and Table 2.

Table 1. The amount of available potassium determined by different methods mg/kg inglacial lacustrine medium loamy soil (Trial of winter wheat)

Sakiai district, Krifkai, 1998Extracting solution

Fertilizer CHCOONH 4+ 2% 2N HCIrates CH3COOH+excage CH3COONH4Fertilizer C 3CO)O NaHCO+ 0,01M 0,03% 0x76%able + exch +0,02 tril BCC(OH) 076% CaCl, MgSO 4 non-exch angeable pH 4,65

pH 3,7 (NH41S04 angeable angeable

AprilN1PoKo 112±10 90±12 13,8±1,3 32,8±5,2 794±72 682±93 80±13NoPsoKwo 120±11 94±6 15,2±1,0 35,7±0,6 876±32 756±42 87±2NwPoKtw 131±6 117±29 19,9±2,7 46,8±7,5 864±58 733±76NWPtuKo 113±6 90±9 13,4±1,6 33,8±6,2 812±34 699±45 85±4NnoP"Ktw 143±24 112±24 20,9±8,3 53,0±22,2 827±52 684±67 100±18N, 20PtsKo 127±12 102±13 18,2±5,8 43,8±16,2 728±77 601±100 88±4N120P1wK1, 143±29 112±21 19,7±6,7 46,7±16,8 848±63 705±83 101±17

June

NoPoKo 82±8 91±32 11,4±1,2 24,0±3,6 753±65 671±84 85±14NPoK, 82±4 81±7 12,8±1,0 27,0±1,3 798±24 716±32 91±10NwPtuK% 87±9 78±16 15,4±2,0 29,8±3,7 779±35 692±45 95±9NwaPsoKimo 82±8 82±13 12,4±0,6 25,7±1,8 797±26 715±34 88±12N,2oPwKtu 94±11 88±7 16,9±5,4 34,0±9,3 832±77 738±101 102±10N12oPisK0 90±11 84±10 16,5±5,1 32,7±8,9 782±9 692±11 100±6NjzoPjwKte 88±6 86±7 14,3±3,1 29,0±6,9 871±44 783±58 100±11

August

NoPwKo 99±7 86±11 14,0±2,4 35,8±7,9 714±27 615:35 88±12NoPoKw 105±2 93±10 13,1±2,3 38,8±9,0 816±51 711±66 92±6NwPwKjao 103±10 98±10 14,5±1,7 47,0±7,1 818±56 715±73 101±8NoPlwKw 102±14 88±12 13,2±4,2 42,0±11,3 814±57 712±74 87±15N2oPgoKiso 116±17 102±11 16,9±5,6 50,3±11,7 820±54 704±71 105±10

N320PteK% 116±11 94±6 15,2±3,4 44,7±11,5 728±38 612±50 89±16

N,2oP.oKso 121±33 105±14 17,1±4,2 45,7±1 1,I 843±26 722±34 109±15

189

Table 2. The amount of available potassium determined by different methods mg/kg inglacial lacustrine medium loamy soil (Trial of potatoes, akiai district, Kriaikai, 1999)

Extracting solution

Fertilizer CH3COONH 4+ 2% 2N HCIras CHOH+ N,01M 0,03% exchange CHCOONH4

COOH 0,76% CaCI, MgSO 4 n-bl pHn,65rlnonexh xc pH 4,65PH 3,7 (NH 4)2SO 4 angeable angeable

May

NPwKo 103±11 105±6 23,0±3,9 44,2±6,8 745±68 642±39 100±12NwPwKw 107±8 107±10 24,9t3,7 49,0±6,9 841±84 734±38 100±0NwPKlw 117±16 125±10 25,2±5,8 55,3±3,3 757±86 640±34 112±10NoPsaKwo 108±5 111±10 24,0±2,1 47,7±8,8 739±82 631±38 101±7Nj2oPwKj" 121±5 124±8 28,6±5,2 56,5±11,5 762±47 641±39 114±5Nj2oPjaoK% 120±16 124±13 28,5±8,3 59,8±20,7 746±92 626±65 111±10N12oPaaiso__ 111±6 120±6 25,7±0i,5 49,8±4,0 828±90 717±20 111±6

JuneNoPwKo 110±9 98±8 17,1±3,7 46,3±12,1 749±100 639±69 96±13N PKw 122±4 109±3 20,2±1,8 48,7±3,1 832±75 710±57 107±3NwP,&oKw 123±10 112±12 23,3±4,0 57,3±3,1 821±93 698±34 111±6N'oPoKm 117±5 106±9 20,1±2,3 46,7±2,1 838±78 721±9 102±5NI[oPgoKiw 143±19 134±25 27,8±6,9 72,0±23,1 958±68 815±86 124±12NtoPgaoKw 120±9 124±39 24"2±6,6 63,7±17,8 872±68 752±66 115±15NjtzPisoKiso 123±22 123±33 23,7±6,1 62,0L14,7 925±94 802±52 113±12

SeptemberNmPwKo 100±12 111±6 17,8±2,5 36,5±2,5 811±65 711±54 99±11Nw °oK 109±10 118±7 20,7±2,0 41,8±5,4 891±42 782±39 104±4NPwKtw 115+13 128±7 23,5±3,9 55,7±6,8 812±107 697±41 112±11NqPaoKw 109±8 112±5 18,4±2,6 38,0±6,2 803±63 694±31 102±9N[2oPgoo 118±8 131±12 24,5±5,0 54,5±12,8 866±112 748±50 111±8Nt2GPtgoK% 131±14 124±13 24,4±4,9 36,5±5,7 812±42 681±54 121±25NlzP1soKso 124±14 130±12 23,2±2,7 40,8±19,2 864±91 740±43 114±4

The highest content of available potassium was obtained in the treatment where higherfertilization rates were used. In April of 1998 the samples from the treatment of wintercrops (without potassium fertilization last autumn) were taken; the amount of availablepotassium was 112,3 mg/kg (the method A-L); in treatments N12oP9 o;18oK8 o - 143 mg/kg.However, the amount of available potassium in samples taken in June was 61-73% incomparison with the samples taken in spring. The reduction in available potassium wasobtained not only by the A-L method, but also using A -2% NaHCO3 + 0,76 (NH4)SO 4, B- 0,01 M CaCI, C - 0,03% MgSO 4 methods; the difference was negligible analysing bymethod E - CH 3COONH , + trilon B, pH 4,65. It is deemed that the reduction in theamount of potassium occurred because of uptake of available potassium by winter cropsbut also, as it is referred [8,14] that in dry period of the year and in summer when soilhumidity is changing, the larger amount of potassium is fixed to unavailable forms. Afterwinter crops yield, when soil humidity increased, the amount of available K20 increasedagain according to research data (potassium was analysed by A-L, A, B, C methods),although did not reach the same level as in spring.

190

The most noticeable dependence on the amount of potassium in soil was the solutionsused for extraction, its concentration and pH. Using extraction of potassium by 2%NaHCO3 + 0,76% (NH,)2 SO4 solution the amount of potassium was similar to theamount of potassium obtained by the A-L method (78-111%) and there was a tendency toshow the intensity of potassium fertilizers. If the rich fertilization (especially with ratesexceeding the need of plants) was used, this method did not reveal completely the amountof potassium applied with potassium fertilizers. Using the ammonium acetate with trilon(pH 4,64) extraction the amount of available potassium in comparison with the A-Lmethod was 51-102%, but in this case, the increase in the amount of potassium because ofthe use of the highest potassium fertilization rates was revealed even weaker.However, analysing the glacial lacustrine soil by this method during the vegetative period,the dependence on changing soil humidity in summer was not so considerable. A loweramount of available potassium was obtained using weaker solvents for extraction ofpotassium. Using the 0,01 M CaCI2 solution for extraction of potassium the amount ofpotassium was only 12-23% in comparison with the amount of potassium analysed by theA-L method; twice larger amount was obtained using 0,03% MgSO4 solution. The largestamount of potassium was obtained using the 2N HCI solution for extraction of potassium.Exchangeable and non-exchangeable potassium was dissolved in this method. Ininvestigated glacial lacustrine silty medium loam soils (during the period of 1998 and1999) in samples taken three times during vegetative period the amount of non-exchangeable potassium was 547-815 mg/kg and in the treatment without potassiumfertilization 591-710 mg/kg. This method is not good enough for the illustration ofdependence of increase in potassium on spread fertilizers, the most considerabledependence was on origin of soil.Distinct different amount of non-exchangeable potassium was obtained in glacial lacustrinesilty and moraine sandy loam soils, the amount of available potassium in these soils wassimilar, though. The amount of non-exchangeable potassium in silty soil of Kriakai,

akiai district (treatment without potassium fertilization) was 591-710 mg/kg, in morainesandy loam soils in Sk~miai, Radvili§kio district (the same treatment) - 269-367 mg/kg).According to research data presented in Table 3, the correlation with the A-L method wasnot reliable when the extraction of potassium in glacial lacustrine silty soils with variousfertilization rates from 2N HCI solution was done.This proved the above - mentioned idea that it presents slightly the dependence ofincreased amount of potassium on mineral fertilizers. But the correlation between theamount of potassium analysed by other methods (A,B,C,E) and A-L was reliable (Table 4).According to research data (1998 and 1999) the correlation between the winter wheatyield and the amount of potassium analysed by different methods was not reliable, whilefor potatoes this correlation was reliable, except the extraction of potassium by 2 N HCIsolution and the case of non-exchangeable potassium.It means that the soil evaluation table worked out according to the amount of availablepotassium (A-L method) for winter wheat was not suitable; because some crops, forexample, winter wheat and in previous test sugar beets uptake not only availablepotassium, but also uptake the potassium from the non exchangeable forms. When theamount of potassium in soil was the same as in mentioned treatment, the potassiumfertilizers increased the yield of potatoes.That is why it is necessary to determine not only available potassium (method A-L or A,B and E), but also non-exchangeable potassium in glacial lacustrine silty soils of differentgranulometric composition.

191

Table 3. The interrelation of potassium amount determined by different methods with A-

L. (y-amount of potassium A-L method, x- other methods) in treatments from Nwo Po Ko

det. de .

Extracting solution Equation r(T) coef F(t) Equation r(1) coe. FI)

Winter wheat

April 1998 August 19982%NaHCO 3+0,76%

(NH4) 2SO4 y-24,7+x 0,89. 79 18,8 y=15,6+0,98x 0,80* 64 8,8

0,01 M CaCI2 y= 59,6+3,9x 094- 89 406 y=41,3+4,53x 0,86* 74 14,4

0,03 % MgSO 4 y761,7+l.56x 0,94* 88 38,7 y5 9 ,5+1,1 3x 0,65 43 3,7

2 NHCI __-__32,8+0,779x- 0,13 1,6 0,2 y=2358,7-6,8x+0,0052x2 0,35 12 0,50,5 N CH-lCOONH 4 + 8,2 N trilonB,-14,65 =-18,7+1,61x 0,98* 95 85,4 =611,5-10,97x+0,059x2 0,70 49 1,4,N ion chanebl 6 0,+,1xNon-exchangeable y=-160,1+1,12x- 0,37 13 0,5 y=-194,5+1,1lx-0,001x2 0,12 1,5 0,2

Potatoes

May 1999 September 19992%NaHCO3+0,76% 09-1350,5+23,4x-(NH 4)2SO 4 y24,7+0,75x 0,94- 88 38,40,093x2 0,4 x -

0,01 MCaCI2 y=36,8+2,94x 0,90* 81 21,6 ,47,5+3,1x 0,84* 71 12,4

0,03 % MgSO 4 y-50,1+1,21x 0,96- 92 593 -=111,1+0,093x 0,07 0,5 0,03

2N NHCI Y=-551,1+l, 7 7 x- 4-8230,8

0,0012x 2 0,81 66 2,0 0,0075x2 + 1 2 7 x 0,48 23 0,8

0,5 N CH3COONH 4 +19

202 N trilon B,pH4,65 y6,3+0,99x 0,90* 81 21,4 y=22,9+1,26x 0,96 93 65,8

Non -exchangeable y=-413,6+1,64x- 2

potassium 0,0013x2 0,81 66 1,9 =1085,7-2,6x+0,0017x 0,26 6,8 0,4

Table 4. The interrelation of potassium amount determined by different methods withyield (y-yield, x- the amount of potassium) in treatments from N,0 P90 Ko.

det. det.

Extracting solution Equation r(l) coef. F(t) Equation r(r) coef. F(t)

1 2 3 4 5 6 7 8 9Winter wheat

April 1998 August 1998

A-L 9 ,00x 0,82 67 2,0 y=24,5-0,38x+0,002x2 0,74 55 1,60,001x2 ,8

2%NaHC0 3+0,76% y-10,2+0,292x-(NH 4)2SO 4 0,001x 2 0,51 26 0,8 y=29,9-0,547x-0,003x2 0,77 59 1,7

0,01 IMCaCI 2 y=6,04 -0,17x+0,006x 0,43 18 0,7 y-17,6-1,78x+0,06x' 0,87 76 2,5

0,03 % MgSO, y-7,2-0,125x+0,0016x2 0,52 28 0,9 y=12,2-0,35x+0,0043x

2 0,48 23 0,8

2 N NHCI y-6,62+0,034x- y-17,2-0,038x+ 0,18 30'00002x

2 0,00003x2 3 0,3

0,5 N CHICOONH4 + y--18,4-0,32x+ y1l,4-0,295x+0,02NtrilonB,pH4,65 0,0018x 2 0,91 83 2,2 0,0016x2 0,70 50 1,4

Non-exchangeable =-2 ,4+0, 03 x- 05 13 0 25,02xy035 1 0 5 2,3 +, 2 073 54 1,5

potassium 0,0000,0002x0,73

192

Table 4 continued2 3 4 5 6 7 8 9

PotatoesMay 1999 September 1999

A-L =-I 115,5+19,60x-0,084x' 0,93- 87 3,7 r-437,4+7,57x-0,03x' 0,98* 95 6,4

2%NaHCO,+0,76% y=- 1014,6+(NH4),SO 4 17,47x-0,073x 2 0,94' 88 3,9 r-209,9+3,22x-0,01 2 0,91" 83 3,10,0 1 M CaCz y=-6897+ y-0,+06x

52,97x-0,971x 2 0,94* 89 4, -107,3+0,67x- 0,91 82 3,0__________________0,204x2 09' ,

0,03% MgSO4 y=-393,7+ -,1026+539x-15,43x-0,140x 2 0,91' 84 32 0-0 5 x - 0,58 34 1,0

2 N HCI y-464,2+1,26x- y-3927,6+9,32x-0,0008x2 0,86 75 2,4 0.0055x2 0,65 43 1,2

0,5 N CH'COONH4+ -, 802,7+14,55x-0,02 N trilon B,pH4,65 =-65,8+0,86x 0,86- 75 14,7 0,063x2 0,96- 92 4,7Non-exchangeable =-398,9+1,28x- 0276,7+0,82x-potassium 000922 0,86 74 2,40,2*correlation reliable at 95% probability level

According to the research data, when the amount of potassium is over 500-600 mg/kg,some crops, for example, winter wheat are available to uptake potassium from non -exchangeable form. Due to this reason, a specific evaluation scale should be elaboratedfor the mentioned plants in these soils.

Conclusions1. The content of available potassium in glacial lacustrine silty medium loam soil

depends on the solution used in extraction, concentration of the solution and pH.2. The most similar amount of available potassium to the A-L method in silty loamy soils

was obtained using solution of 2% NaHCO 3 + 0,76% (NH4)2S0 4 (78-111% incomparison with the A-L method) and ammonium acetate with trilon B (51-102%).

3. Using the 0,01 M CaCI 2 solution for extraction of potassium the amount of potassiumwas only 12-23% in comparison with the amount of potassium analysed by the A-Lmethod; twice larger amount than using 0,01 M CaCI2 was obtained using 0,03%MgSO 4 solution.

4. There was a reliable correlation between the amount of potassium determined using2% NaHCO 3 + 0,76% (NH4)SO4 , 0,01 M CaCI 2, 0,03% MgSO,, CH 3COONH4 +trilon B (pH 4,65) solutions and the A-L method.

5. The highest content of potassium was obtained using the extraction of potassium by2NHCI solution, because the exchangeable and non-exchangeable potassium wasdissolved. This method was not good enough to show the dependence of increase inpotassium on spread fertilizers and there was no reliable correlation with the A-Lmethod. The most considerable dependence of potassium was on the origin of soil.

6. A marked difference of non-exchangeable potassium was obtained in limnoglacialsilty (591-710 mg/kg in the treatment without potassium fertilizers) and in morainesandy loam soils (269-367 mg/kg in the treatment in Skemiai, 1998).

7. The correlation between the yield of winter wheat and the content of availablepotassium was not reliable in glacial lacustrine soils with a low and medium content ofpotassium analysed by the A-L method.

193

8. For the determination of potassium fertilizer rates for crops in glacial lacustrine siltyorigin soils it is necessary to analyse not only available potassium, but also in soilswith different granulometric texture to measure the content of non-exchangeablepotassium part of which can be uptaken by crops such as winter wheat and sugarbeets.

References1. Arnold P.W. Papers read to the Fertiliser Society in London, Proceedings, No 72. 1962.2. Kuhlman H. and Wehrman J.: (G) Testing different methods of soil analysis for their

applicability for the determination of K fertilizer requirements of loess soils. Z.Plansemahr.Bodenk. 147, 334-348 (1984).

3. Lietuvos dirvolemit4 agrochemines savybds ir jq kaita. Monografija. Sudarytojas JonasMa2vila. 1998, -P.107-119.

4. B.Shaw J.K., Stivers R.K., and Barber S.A. 1983. Evaluation of differences in potassiumavailability in soils of the same exexchangeable potassium level. Comm. Soil Sci. PlantAnal. 14 P. 1035-1049.

5. Salomon E. Extraction of soil potassium with 0,01 M calcium chloride compared of officialSwedish methods. Communications in Soil Science and Plant Analysis, 1998, Vol. 29, Iss.19-20, P. 2841-2854.

6. ArpoxnMw4ecKe MeTOaEI nccneaoaHHi nOMB. Vi3a. ,,HayKa", MOCKBa 1965, 436 c.7. Methods of Soil and Plant analysis. Agricultural Research centre department of soil science.

Finland, Jokioinen 1986, P. 1-45.8. Bap6ep C.A. bionorHmecKaa nociynHocrh nHTaTemlHbIx Bemecr B B noMBe. MocKBa, BO

,,ArponpoMn3aar", 1988, 376 c.9. Borneawi H.M. Haytnhie OCHOBBI npHMCHeHHm yzIo6peKHuf B 3anajmoM pernone CCCP.

MHHcK, 1981. -200 c.10. Ba-euHn 1.T. MeToabi onpeaeneHHM Ka HAS B noMBe // ArpoxHMHwecKHe MeTOhI

HccJleAoBaaHH noqn. M., ,,HayKa", 1975 c.191-218.11. KylaocKan T.H. Mlnepanbale yao6peHHx H nnofopoAHe nOMBbI // flnofopo)nIe 0oqB H

ypocarf. -BHalhmoc, 1974.-C.82-90.12. FIocTKoB A.B., Wapau C.A., BMiorpaaoua P.14. H Tp. BnnAHHe cogepwanHi

nOIBHCHLIX 4opM 4 oc(Dopa H Ka1AH Ha ypoiafl cenbcKoxo3XiicTneHHbIx KyRLTyp nope3yabraraM onbroB arpocnyfc6hi PC$CP / flapauerpti noaopoHA ocHoRHbix THnOBnoMB. -MocKaa, 1988.- C.16-35.

13. [oai. OnpeaenHHe nogrB HhxX 4opM 4Doc4opa R KHJIHX HO Meonly 3rHepa-PHMa-)TOMHuro (A- A ) FOCT 26208-84.

14. FIMeJIKHH B.Y. fIoHneaHnl I Kaa H KaJimHiHle yjto6peulM. - MocKua 1966. - 13g.:

,,Konoc", 336

194

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS

FERTILISATION EFFECT ON SOIL AND CROPS

EFFECT OF FERTILISATION SYSTEMS ON THE BALANCE OF NUTRIENTSAND SOIL AGROCHEMICAL PROPERTIES

Irena Krigtaponyt6Jonigklis, experimental station of the lithuanian institute of agriculture

AbstractIn 1960 an agrochemist K. Pleseviius established a long term fixed experiment at theJoigkelis Experimental Station with the aim of developing scientific fundamentals offertilisation systems on North Lithuania's heavy textured soils.During three rotations of seven -course crop rotation (1960 - 1981) it was ascertainedthat it is most efficient to apply organic fertiliser on such soils at a time to the wholerotation - sugar beets. Phosphorus and potassium fertilisers can be applied every 2 - 3years. When fertilising with N338P357K4 28 the amount of available phosphorus in the soilremained stable; addition of 40 t/ha of farmyard manure resulted in an increase inphosphorus content by 20 mg/kg soil. Available potassium content through NPK andfarmyard manure fertilisation increased by 30 mg/kg.In 1982 after reconstruction of the trial the fourth rotation was started. It was determinedin the fourth and fifth rotations (1983 - 1994) that if growth regulators and chemical plantprotection means are used, organic fertiliser can be applied either to winter wheat or tosugar beets. The highest crop rotation productivity was obtained having replaced organicfertilisers by the equivalent mineral fertiliser amount and having applied on averageNgP 1 K1 23 kg/ha per year. When fertilising with N 435P 345 K465 mineral and organicfertilisers the content of available phosphorus in the soil increased by 34 - 52 mg/kg, andthat of available potassium declined by 12 - 17 mg/kg. Application of various fertilisationsystems resulted in the reduction of humus content in the soil.

Key words: crop rotation, fertilisers, soil, phosphorus, potassium, balance, accumulation,fertilising system.

IntroductionThe crop rotation productivity depends not only on the amount of organic and mineralfertiliser but also on their combination. An optimum fertilising system secures a high croprotation productivity and maintains stable soil fertility (7, 8). The action of phosphorus inthe form of mineral fertiliser is most efficient in the crop rotation with a low phosphorusstatus in the soil. Experimental evidence suggests that in a five-course crop rotationapplication of optimum fertiliser rate N84P72K84 to the crops with a low phosphorus statusin the soil (50 - 100 mg/kg) the content of phosphorus in the soil increased by 31 mg/kg,in the soil with medium content of phosphorus (101 - 150 mg/kg) it did not change, andin the soil with a high content of phosphorus (151 - 200 mg/kg) - declined insignifi-cantly. Such fertiliser rates maintain a stable 150 - 200 mg/kg potassium content onheavy loam (2, 3). An optimum content of K20 in the soil was established to be 130-160 mg/kg in Germany, 170 - 200 mg/kg of soil in Lithuania (4, 6). A combination ofmineral fertiliser and farmyard manure enables to supply plants with nutrients for more

195

than one vegetative growth season. Such fertilisation system secures good plant nutritionwith mineral nutrients at the beginning of the vegetative growth season, while manureserves as reserve of nutrients for later growth and development stages of plants. Havingsummarised 40 years' experimental data in Byelorussia it was concluded that phosphorusand potassium present in mineral fertilisers and farmyard manure are equivalent in thenutrition of most crops. (10). As on heavy soils due to slow mineralisation plants utiliseonly part of phosphorus and potassium incorporated into the soil with organic fertiliser inthe year of fertilisation, application of their higher rates would provide nutrients to thecrops grown after. Having applied higher PK fertiliser rates for 2 - 3 years in one time theyield of the crop rotation crops on moderately heavy and heavy textured soils is obtainedthe same and often even higher than in the case when fertilisers are applied every year(5, 8). Nutrient balance must be calculated so that nutrients distributed in the crop rotationcould not only secure normal crop nutrition during the vegetative growth period but alsowould not reduce soil fertility (9). Since variation of nutrients in the soil depends not onlyon the fertilisation system but also on crop structure, soil tillage, potential productivity ofcrops and other factors. Findings of the experiments conducted at the Lithuanian Instituteof Agriculture show that plants utilise only about 5 - 10 % of P2O5 from the soil annually,of K20 - 14 % and utilise 10 - 25 % and 60 - 70 % respectively from applied fertilisers.To achieve a positive balance phosphorus content removed with the yield must becompensated by 300 % and that of potassium by- 150 % (1). A six-course crop rotationexperiment whose all fields were spread in time and space was carried out with a view tocomparing to which crop sugar beets or their preceding crop- winter wheat it is better toapply manure. Experimental objectives also involved calculation of the amounts ofnutrients removed with the yield of the crop rotation crops and nutrient balance anddetermination of variation of agrochemical soil properties.

Material and methodsIn 1960 experiments were started at the Lithuanian Institute of Agriculture's Joni~ktlisExperimental Station with the aim of comparing fertilisation systems on a sod gley heavyloam soil. At the start of the first rotation experiments were done in the soil with a verylow phosphorus status and high potassium status, whose agrochemical characteristics wasas follows: pHKcl - 6,5 - 6,9 (potentiometric method), humus - 2,03 - 2,50 % (Turinmethod), and available phosphorus and potassium 41 - 48 and 162 - 184 mg/kg of soil(A - L method). The experiment was conducted in a seven-course crop rotation. Onaverage N48PSK 63 of mineral fertilisers were applied during the three rotations. Aftercompletion of three rotations the trial was reconstructed and the fourth six-course rotationwas started. The soil agrochemical characteristics was as follows: PHKCI - 6,3 - 6,4;(potentiometric method) humus - 2,06 - 2,29 % (Turin method), available phosphorusand potassium 64 - 124 and 194 - 253 mg/kg of soil respectively (A - L method). Thefollowing crops were grown in this crop rotation every year winter wheat, sugar beets,barley, barley undersown with perennial grasses, perennial grasses of the first and secondyear of use. In this article we presented average NPK fertiliser rates of the last tworotations. Individual treatments of winter wheat and sugar beets were treated with 40 t/haof solid manure. Mineral fertiliser rates for winter wheat - NQP6QKo (treatments 2 - 4)and N12sP20 K3 61 (treatment 5), for sugar beets- N15 PlsoKso (treatments 2 - 4) andN188P15oKso (treatment 5), for barley - N60 (treatments 2 - 4) and N,8 (treatment 5), forbarley undersown with perennial grasses - N60P45K9G (treatment 2 - 5), for perennialgrasses of the first year of use- P60K90 (treatment 2 - 5), for perennial grasses of the

196

second year of use- N9,P6OK9o (treatment 2 - 4) and N13tP,,K o kg/ha (treatment 5).During the latter rotations treatments 2 - 4 received N435P345K465 mineral fertilisers,treatment 5 - N587P486K736, or on average N73PssK 7s kg/ha annually (treatments 2 - 4), andin treatment five besides the main fertilisation, N93P 1K.23 kg/ha which corresponds to40t/ha of manure was additionally applied.

Results and discussionFertilisation systems had a great effect on the productivity of the crop rotation crops.After three rotations it was revealed that on heavy textured soils it is most efficient toapply organic fertilisers in one time for the whole rotation - sugar beets, phosphorus andpotassium fertilisers should be applied every 2 - 3 years. Annual application of N48P51K63as fertiliser and manure increased the amount of available phosphorus in the soil by 20mg/kg, and that of potassium by - 30 mg/kg.After the completion of three rotations the soil had a different content of phosphorus.Fertilisation with mineral NPK fertilisers resulted in low phosphorus status in the soil (92mg/kg), while fertilisation with manure and mineral fertilisers resulted in mediumphosphorus status in the soil (113 - 124 mg/kg). After the reconstruction average croprotation yield increased by 73,7 % when crops were applied with mineral fertilisers(N,,P 58K78) during the Iv-th and V-th rotations in the sixth -course crop rotation on thesoil with a low phosphorus and high potassium status (Table 1). In the soil with a mediumphosphorus status where the crops were treated with organic and mineral fertilisers theaverage annual yield of the crop rotation crops increased 7,5 % as compared with themineral fertilisation system. When organic fertilisers were replaced by the equivalentamount of mineral fertilisers and N 8P8,1K,23 was applied per year, the yield on the soilwith a medium phosphorus status was 12,0 % higher than in the case of lower NPKfertiliser rates application.

Table 1. The effect of fertilisation systems on the crop rotation plantsJoni~kelis, 1983 - 1994 m.

Spring First SecondSprig yer o yea ofAverage

Winter Sugar Spring barley year of year of feedTreatment wheat beet barley under- use pe- use pe- units perrennial rennial

i/ha t/ha t/ha sown yeart/ha grasses grasses per ha/ha t_/ha t/ha

1. Without fertilisers 3,8 20,1 2,1 2,1 5,1 2,0 44042. N435P345K46 5,4 36,8 4,1 3,8 5,4 5,6 76483. 40t/ha of manure towinter wheat N435P345K 6 + 6,1 39,1 4,3 4,1 5,7 5,5 8244means of plant protection4. 40 t/ha of manure tosugar beet + nure 5,4 39,7 4,5 4,2 5,7 5,7 8188sugar beet + N4351P345K465

5. N43 PJ4K4, + NPKequivalent to 40 t/ha ofmanure: to winter wheat + 6,1 39,1 4,4 4,2 5,7 5,8 8562means of plant protection

LSD, 0,16 0,93 0,11 0,18 0,22 0,30 98

197

The size of the crop rotation crops' yield and the amount of individual elements had thegreatest effect on the accumulation of nutrients in the yield. In the six-course croprotation the highest sugar beet leaf and root yield was obtained and the highest content ofnutrients was accumulated when sugar beets were fertilised with organic mineralfertilisers: N - 232,6 kg/ha, P20 - 66,7 kg/ha, K2 0 - 379,1 kg/ha. When fertilising withNj50 P5soKj50 fertilisers sugar beet yield accumulated 60,2 kg/ha of phosphorus, K20 -350,7 kg/ha, and having replaced manure by the equivalent NPK fertiliser rate, i.e.fertilising with N1,g Pj 50K150 the sugar beet yield accumulated 70,6 kg/ha of phosphorus,K20 - 386,9 kg/ha. When fertilising winter wheat with N90P60K 0 fertilisers, grain andstraw yield accumulated 44,8 kg/ha of phosphorus and K20 - 83,2 kg/ha. When fertilisingwheat with organic and mineral fertilisers the yield accumulated 48,1 kg/ha of phosphorusand K20 - 95,2 kg/ha. When farmyard manure had been replaced by the equivalentamount of NPK, the yield accumulated 51,6 kg/ha of phosphorus and 105,7 kg/ha of K20.When barley was grown after sugar beet and was applied with nitrogen fertiliser, the yieldaccumulated 77,4 - 88,6 kg/ha of N, 32,7 - 37,5 kg/ha of P 20, and 65,1 - 76,3 kg/ha ofK20. To produce 3,8 - 4,2 t/ha of barley grain (together with straw) grown withunderseeding 31,0 - 35,1 kg/ha of available P20 5 and 72,7 - 79,2 kg/ha of K20 was used.Perennial grasses accumulated 33 - 35 kg/ha of phosphorus and 129 -153 kg/ha of KOin the dry matter yield of5,4 - 5,8 t/ha.During the fourth and fifth rotations the amount of phosphorus in the mineral andmineral-organic fertilisation systems applied with fertilisers was much higher than itsamount accumulated in the yield, therefore a positive balance of phosphorus was obtainedin all the fertilisation cases (Table 2). In the untreated control plots the plants utilisedfrom the soil 128,6 kg/ha of phosphorus during twelve years. When fertilising withN73P58K78 mineral fertilisers the feed unit yield was obtained by 73,7 % higher, howeverphosphorus fertiliser compensated 147,1 % of phosphorus accumulated in plants.

Table 2. Effect of fertilisation systems on the balance of phosphorus in the crop rotationand its variation in the soil

Joni~kelis, 1983 - 1994

Applied Amount oftoehrAccu-

Treatment mula- Batn- Com- phosphorus in +with tion in ce kg/ha pen- the soil m 1994ers yield sation % 1982 m 1994 msers

1. Without fertilisers - 128,6 -128,6 64 63 -12. NPK 345 234,5 +110,5 147,1 92 126 +343.40 t/ha of manure towinter wheat NPK + means 486 257,5 +228,5 188,7 113 149 +36of plant protection4. 40 tha of manure to 499 253,1 +245,9 197,2 124 176 +52sugar beet +NPK5. NPK equivalent to 40 t/haof manure: to winter wheat 486 266,8 +219,2 182,2 124 174 +50+ means of plant protection

198

Having fertilised with organic - mineral fertilisers or having replaced farmyard manureby the equivalent amount of mineral fertilisers, the surplus of phosphorus reached 219,2 -245,9 kg/ha. The compensation coefficient was 182,2 - 197,2 %. When compensatingphosphorus utilised by plants by phosphoric fertilisers by 147,1 - 197,2 %, its amount inthe soil increased by 34 - 52 mg/kg during twelve years. In the six-course crop rotationutilisation of phosphorus fertilisers was to a great extent determined by the size of thecrop yield and soil properties, especially soil texture, amount of nutrients and phosphorusfertiliser rate. Depending on its amount in the soil, utilisation of phosphorus fertiliser inthe crop rotation was from 24,9 to 30 7 %.When employing different fertilisation systems, potassium (K20) balance was negativei.e. plants utilised 180,2 - 367,5 kg/ha from soil reserves (Table 3).

Table 3. Effect of fertilisation systems on the balance of potassium in the crop rotationand its variation in the soil

Jonigktlis, 1983 - 1994

Applied Accu- Amount oftogether mula- Balance Comp9n-

Treatment with tion in kg/ha % siu inth 1982a ~soil mnfertilisers yield 1982 19941. Without fertilisers - 450,3 -450,3 196 172 -242. NPK 465 832,5 -367,5 56 206 194 -123. 40t/ha of manure towinter wheat NPK + 736 916,2 -180,2 80 237 220 -17means of plant protection4. 40 tha of manure to 725 920,0 -195,0 79 249 249 -sugar beet + NPK5. NPK + NPKequivalentto 40 t/ha of manure: towte0 ha mans- tof 736 947,7 -211,7 78 244 253 +9winter wheat + means of

plant protection

Unfertilised crops of the 6 course crop rotation accumulated 450,3 kg/ha of potassium(K20) in the yield, while fertilised with P345K465 crops produced a higher yield, whichaccumulated a higher content of K20 by 382,2 kg/ha than in the control and potassiumfertilisers compensated plant accumulated potassium only by 56 %. When fertilising withorganic-mineral fertilisers or replacing farmyard manure by mineral fertilisers the yieldwas by 85,9 - 94,4 % higher than in the control, and potassium fertilisers compensated78 - 80 % of potassium utilised by plants. When fertilising 465 kg/ha of K20 per rotation(or 78 kg/ha per year) its content in the soil was not maintained stable and it declined by12 mg/kg. Having replaced farmyard manure by NPK fertilisers and applying with them123 kg/ha of K20 per year the content of potassium in the soil increased by 9 mg/kg.When in the six-course crop rotation the amount of available potassium in the soil was172 - 253 mg/kg, the percent of potassium fertiliser utilisation was high 63,3 - 82,2 %.A high utilisation rate of potassium was determined by potassium fertiliser rates, intensityof nitrogen and phosphorus fertilisation, size of agricultural crops yield, potassiumcontent plants, soil texture and reaction.

199

Agrochemical soil properties changed under the effect of fertilisation. During twelveyears the soil acidified by 0,4 - 0,5 pH in all the fertilised plots (Table 4).

Table 4. Changes in the agrochemical propertiesJonigkelis, 1983 - 1994

pHK Humus %

Treatment 1982 change over 1982 change over12 years 1982 12 years

1. Without fertilisers 6,4 -0,5 2,06 -0,12

2. NPK 6,3 -0,4 2,14 -0,22

3. 40t/ha of manure to winter wheat 6,3 -0,4 2,15 -0,09NPK + means of plant protection4.40 t/ha of manure to sugar beet 6,3 -0,5 2,26 -0,12+NPK

5. NPK + NPK equivalent to 40 t/haof manure: to winter wheat + means 6,3 -0,5 2,29 -0,33of plant protection

Humus content declined: when fertilising with a high amount of N98P1K) 23 fertilisers(Treatment 5) by 0,33, with optimal amount of N73Ps8K78 (Treatment 2) by 0,22, whenfertilising with farmyard manure and NPK fertilisers by 0,09 - 0,12 percentage units.

Conclusions1. On a heavy loam soil low in phosphorus (92,0 mg/kg) and high in potassium (196,0mg/kg) having treated the crop rotation plants with N73P58K78 fertiliser rate the yieldincreased by 73,7 %. On the soil moderate in phosphorus (113 - 124 mg/kg) havingfertilised the crop rotation plants with organic-mineral fertilisers the average crop rotationyield increased by 7,5 %, and having replaced farmyard manure by the equivalent amountofNPK fertilisers (N98P81K 23) by 12,0 %.2. Without fertilisation in the soil low in phosphorus producing a lower yield the contentof phosphorus declined by 1 mg/kg and that of potassium by 24,4 mg/kg.3. In the mineral fertilisation system having treated the plants with N73P58K78 fertiliserrate the content of phosphorus in the soil low in phosphorus increased by 34 mg/kg during12 years, while that of potassium declined by 12 mg/kg. In the organic-mineral fertilisationsystem or having replaced farmyard manure by the equivalent amount of NPK fertilisers thecontent of phosphorus in the soil moderate in phosphorus increased by 36 - 52 mg/kg, andthat of potassium remained the same or declined by 17 mg/kg.4. When fertilising crops in the crop rotation only with NPK mineral fertilisers the content ofhumus declined by 10,3 %, and having replaced farmyard manure by the equivalent amountof NPK fertilisers by 14,4 %, in the organic- mineral fertilisation system by 4,2 - 5,3 %.5. Assessment of the productivity of the crop rotation plants, indicators of nutrient balance,findings of the soil agrochemical tests suggests that organic-mineral fertilisation system issuperior.

200

References2. Adomavidifitd J., MaAauskas V., Vasiliauskiene V. ir kt. Augalq derliaus ir jo kokybts

priklausomumas nuo mineraliniq NPK trSq~ normq//2emdirbyst6 L±1 mokslo darbai. -Dotnuva-Akademijna. 1995. -T44.-P. 112-122.

3. Bagdoniene V. Arlauskien6 E. A. Sejomainos augalq derliaus ir dirvofemio biologinioaktyvumo priklausomumas nuo judriojo fosforo kiekio dirvofemyje ir trqimo//2emdirbyste.LZI mokslo darbai. Akademija-1999. -T65. -P. 48 - 62.

4. Bagdoniend V. Judriujq fosforo ir kalio kiekiq ir traq itaka sejomainoje auginamq augalqderliui//2emdirbyste L2I mokslo darai.-Dotnuva - Akademija, 1995.-T. 47.-P.80 - 88.

5. Kerschberger M., Richter D. Ergebnisse eines 12 jharogen P - steigerungsversuches auf einerLobstvarzede im Bezirk Halle//Acch. Ackerund Pflanzenbau and Bodene. -1988. -T.32. No6. -S. 369 - 377.

6. Plesevitius K., Krigtaponyte I, Bagdonien6 V. Sunkiq dirvq tr~gimo sistemq palyginimas /Agronomija L±I mokslo darbai. V. Mokslas 1987. -P. 75 - 91.

7. Vaitvila Z. J. Dirvolemio mineralinio azoto judriujt fosforo ir kalio vaidmuo 2em s 0kioaugalq mityboje: Habilitacinis darbas. -Dotnuva - Akademija, 1996. -206 p.

8. Fopfiiea A. m., ropeKo H. M. 0 fplHunnax nhlanmlpoBaHmm CHCTeMbi yRo6peHHR BceBoo6opoTe//floqM., arpoxHM. H 3xon. npo6. 4popmHp. BbiCOKOJEpOflyKcr. arpoieno3oB: Bcec.KoFUi. Te3. Aorn. -IlywHHo, 1988. C-195 - 197.

9. rpe6eHt B. B. BAHSKHe paJJIHMIHX CHICIVM ylo6peVHHS Ha npoJy0-rHBHOCTCCJlbCKOXO39I1CTBeHHX Kyflb1ryp H nJloopoDHe nOqB // Hay9HO - npa-rHiqeCKH.? Olrr Bar)pOIpoMTWJIeHHoM npOP3BOaCrBe.-MHmcK, 1990. -63 c.

1O. liauioBa T. H. lporHo3HpoBanHe J44CeHBHOCTH yAIO6pCHHi C HCI[oJ1l3oBaHHeMMaTemaTmt ecKHX Moieneg. M. 1989. C. -94 - 125.

11. KyiiaOBCKas T. H. IloBeHiO - arpoxHMHecKoe OCHOBbI, nonyqCHH BblICOKMIX ypowcaeB. -MHHCC. 1978. -C. 127- 130.

201

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

SOIL POTASSIUM AND PHOSPHORUS IN DIFFERENT CROP ROTATION BYINFLUENCE OF FERTILISATION SYSTEM

Livija ZarinaPriekuli Plant Breeding Station, Latvia

SummaryLong-term crop rotation experiment has been conducted in Priekuli (Latvia) since 1958.The experiment includs II different crop rotations and five different fertilizationsystems. Measurements of soil nutrient content and crop yield were performed every year.During 40-year's period, the influence of crop rotation and fertilization system on soilfertility properties was fixed. In unfertilized background content of potassium byinfluence of crop rotation changed at 61; in farmyard manure- 106; in NPK- 99; infarmyard manure + NPK- 147; 2 NPK- 214 mgkg -' of soil. Amount of phosphoruschanged at 34; 51; 73; 53 and 214 mgkg' respectively. The optimal fertilisation systemfor provision of soil fertility is farmyard manure plus mineral fertilizers.

Key words: soil, potassium, phosphorus, crop rotation, and fertilization systems

IntroductionSoil is one of the fundamental natural resources on which life on earth depends. Its mainquality is fertility, which with chemical propeties also is characterised. Content of readilyavailable potassium and phosphorus in the soil are leading elements.The economic and environmental sustainability of farming is dependent on the efficientuse of potassium and phosphorus. Therefore there are many-sided correspondent investi-gations world-wide established (Fortune, 1999. Mashauskiene & Mashauskas, 1994,Mikkelsen, 1998). Nevertheless most exact results long-term investigations reflected.Long-term field experiments are essential to our understanding of, and opportunity to testthe sustainability of agricultural systems (Johnston, 1995).The problem of rational use of fertiliser has been intensively studied in many countries(Ekeberg&Riley, 1995). This information can give an indication of the sustainability andagronomic efficiency of the fertilization system concerning potassium and phosphoruscontent in the soil in different crop rotations.

Material and methodsSiteThe experiment is located in Priekuli ((57'19'N, 25'20'E) on a soddy podzolic light loamwith the following characteristics in the year of establishing (1958): organic mattercontent 2.1 %, soil pHHcI 5.8 to 6.1, P20 5 80-100mg kg'" , and K20 100-120 mg kg'. Theinitial characteristics of the soil of crop rotations 10 and II in 1980 were pH 5,8- 6,0,organic matter content 1,9 %, P2, 135 mg/kg and K20 150 mg/kg.The normal mean temperature varies from -6.2 0C in January to 16.7 0C in July. The meanannual rainfall is 691 mm.

202

TreatmentsThe experiment included nine different rotations (1-9). In 1980 two additional rotationswere added (10-11). The clover in rotations 2 -5 was red-clover, which was established asan undersown crop in barley. The clover in rotation 8 was white clover. Five differentfertilisation treatments were compared with the crop rotations as sub-plots within eachfertiliser treatment. Crop rotations 1-6 were only included in the fertiliser treatmentN132Pl8oK 270.The disposition of variants is presented in the figure. The trial plots were 5900 m' . In1959, 22 tha' of springlime was given. Measurements of soil nutrient content and cropyield were performed every year. Plant-available P and K were determined by themethod of Egner et al (1)., where the soil was extracted with an ammonium lactatesolution.

67 89123451213141512131415112314151213141512131415112131415

St. manure St. manureNlslK 0 20 tha' NIaP.K 2, N.PJC13 20 tha'+ Straw+13P 70N PsK, s N PoKs

10

11

Figure. the position of fields of long-term experiments at Priekuli

Fertilization systems1. Unfertilized2. Farmyard manure, 20tha'3. N66PgK[354. Farmyard manure, 20 tha' plus N6 P9oKs55. N130PI, 0K270

Crop rotations1. Barley- potato- barley or oat2. Barley-clover-rye- potato3. Barley- clover- barley- rye- barley- potato4. Barley- clover- potato5. Barley-clover- clover- rye- barley- potato6. Black fallow- rye7. Barley- rye- oat- rye8. Rye- rye- rye- rye- clover- clover- clover- clover9. Black fallow- rye- barley- rye

10. Potato- barley (established in 1980)11. Potato (monoculture, established in 1980)

203

Results and discussionsAfter 40-year period the soil fertility properties changed essentially (Table 1, 2). Thelevel of soil potassium and phosphorus content increased across the fertilization systemsaccording to the increasing rate of application. The overall average of P20, and K 20

concentration was classified as low in 1958 (80-100 mgkg' K, 100-120 mgkg- P of drysoil). This level was kept for 10 years, however with tendency to increasing (Zarina,2000). Overall major increasing of both, P20, and K 2 0 , in background with the rate 2NPK was observed. However, in the crop rotation No.1 the content of potassium andphosphorus was similar also in fertilizer background farmyard manure + NPK. In theother crop rotations the indices were slightly lower.The results of this trial confirm earlier experience that crop rotation is one of the mostimportant components of soil management. This fact confirms the results of other authors(Loes, & Qgaard, 1997.)

Table 1. The influence of crop rotation and fertilization systems on K20 content of soil,(mgkg-', 1999)

Crop Fertilization system -

rotation 0 Farmyard NPK Fetiiato 2 NPKmanure manure + NPK

1. 79 212 245 375 3682. 62 109 146 228 3023. 18 143 212 294 407

4. 51 106 202 268 367

5. 49 121 188 358 390

6. - - - - 240

7. - - - 1 342

8. 355

9. - - - 398

10. 89 225 239 329 319

11. 107 255 289 198 244

Table 2. The influence of crop rotation and fertilization systems on P20 content of soil(mgkg-', 1999)

ro n Fertilization systemroinFryr Farmyard

roatonFamyrd NPK 72 NPmanure manure + NPK

1. 46 121 300 426 4262. 17 70 227 373 4283. 18 70 256 398 4404. 12 106 263 397 4675. 17 105 251 395 4156. - - - 237

7. - 447

8. - 378

9. - - - 382

10. 158 274 383 474 428

I. 233 164 209 179 251

204

ConclusionsCrop rotation is one of the most important components of soil management. In Latviaconditions of sufficient amount of P20, and K20 are assured in fertilizer background ofNPgOK 30 A superior rate of PK fertilizer is not expedient.The optimal fertilisation system for provision of soil fertility is farmyard manure plusmineral fertilizers.

ReferencesI. Ekeberg, E., Riley, H. (1995). The long-term fertilizer trials at Moystad, S.E.Norway. In:

SP report No 29, Research Centre Foulum, 83-105.2. Fortune, S. et al. (1999). Optimising phosphorus and potassium management for crop

rotations in UK organic farming systems. In: Jorgen E.Olesen et al, Designing and testingcrop rotations for organic farming. DIAS, 267-275.

3. Johnston, A.E. (1995). The significance of long-term experiments to agriculturalresearch. In: SP report No 29, 19 -23.

4. Loes, A-K. and Qgaard, A.F.(1997). Changes in the nutrient content of agricultural soilon conversion to organic farming in relation to farm-level nutrient balances and soilcontents of clay and' organic matter. Acta AgricScan.,Sect.B, Soil and PlantSci.47,pp.201-214.

5. Mashauskiene,A.& Mashauskas, V.(1994). The effect of phosphorus and potassiumperiodical application on the crop rotation productivity and soil fertility. In: Reports ofthe scientific conference, fertilizer applications systems and soilfertility. Vilnius.pp.291 -292.

6. Mikkelsen,G.,(1998). Mixed farming, consequence for soil fertility. In: APMinderhaudhoeve -reeks nr.2.Wageningen. pp. 150.

7. ZarinaL.(2000). Influence of black fallow on soil properties. In: Proceedings inAgronomy No2,2000.77-79. In Latvian.

205

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

PROSPECTS OF BALANCED POTASSIUM AND PHOSPHORUSFERTILISATION IN LITHUANIA

Sigitas Lazauskas, Vytas MagauskasLithuanian Institute of Agriculture, Dotnuva-Akademija, 5051, Kedainiai, Lithuania

SummaryIn Lithuania fertilisers are essential for achieving good yields of agricultural crops,because the natural soil fertility is low. Substantial increase in the use of mineralfertilisers started only in the sixties. Application of phosphorus during the period 1956-1990 increased from 7 to 41 kg/ha, potassium from 5 to 76 kg/ha. In the first years oftransition to market economy the use of fertilisers dropped down to 11 kg/ha of P2O5 and13 kg/ha K20 in 1995. Later some recovery in fertiliser use became evident. However,balance of potassium remains negative and phosphorus shows the very slight surplus.Content of phosphorus and potassium in most of the multi-nutrient fertilisers is relativelylow, and the ratio with nitrogen is too wide for prevailing Lithuanian soils and crops. Theprogramme for calculation of balanced fertilisation rates prepared by the Department ofAgrochemistry of LIA is available to farmers

Key words: potassium and phosphorus, fertiliser, soil, yield, field crops

IntroductionIn recent years there have been deep changes in agriculture in Lithuania. There are 68000new private farms, 2000 agricultural partnerships and 314000 small household plots.Agricultural producers face dramatic shifts in markets, old patterns of technologies aregiving way to new ones, and environmental issues are becoming more important foragricultural policy. This development much depends on research and input industrieswhich are the main driving forces (2). During the last decade reduced markets foragricultural production, lower income of farmers have led to lower inputs in agriculture inLithuania. Application of fertilisers, especially phosphorus and potassium, was reducedand in general became lower than optimum needed to meet the requirements ofagricultural crops and to maintain the soil fertility status. Large variation among farmswith regard to management of fertilisers exists not only because of economic reasons, butalso due to diverse education of farmers, their future plans, etc.Fertiliser management must be adjusted on the basis of the most recent research findingsin order to meet the new requirements: better return on investments in fertiliser and at thesame time lower ecological impact. Thorough knowledge of the way in which fertilisersinteract with the environment is important (4). Balanced fertilisation in a broader sense isstill a task for researchers and policy makers in Lithuania.

Material and methodsThis paper reports on the most important aspects of P and K fertilisation management inLithuania. Yield and fertiliser consumption data are collected from official statistics. Dataon the fertiliser efficiency are based on the results of field trials conducted over the period

206

1964-1998 at the Lithuanian Institute of Agriculture. Variance analyses, F and t criteriawere used to estimate significance levels.

Results and discussionAn increase in crop yield has been one of the most desirable features of Lithuania overthe last century. Trends of the yield were much higher over the period 1950-1993, thanthat over 1881-1939. Increase in yield at the end of the 19 th and first half of the 20 thcentury was mostly achieved by changing farming system. In the second half of the 20 thcentury yield increase was mostly related to the improved growing techniques:fertilisation, new varieties, plant protection. Grain yield increased from 0.52 t/ha in 1956to 2.86 t/ha in 1986-1988. This relatively stabile development of agriculture wasinterrupted in 1989-1990 when the Land Reform and Transition to the Market Economystarted. Grain yield in 1992-1995 declined to 1.76-2.10 t/ha. Only in 1996-1997recovering of yields of the main crops becomes evident (Fig. 1).

Yield t/ha 0 Winter wheat4 33 Spring barley

3 .6 3

35

S 2.93

2 74 2 .2.85

2 ~ 13A2,22--24 24 2 .37 2.39

2.22

1 .76.6 4

0.53

1996.90 1991.94 1995 1996 1997 199 1999

Figurel. Yield of winter wheat and spring barley in Lithuania in 1986-1999

In Lithuania fertilisers are essential for achieving high yields of agricultural crops,because the natural soil fertility is low. Until 1939 the use of mineral fertilisers was verylow. Substantial increase in the use of mineral fertilisers started only in the sixties. From1956 till 1990 the application of mineral fertilisers increased from 14 (of N, P2O, K20)to almost 200 kg per hectare of arable land. Application of phosphorus fertilisers duringthe same period increased from 7 to 41 kg/ha, potassium - from 5 to 76 kg/ha. A declinein fertiliser use was in the first years of transition period. Use of fertilisers dropped to 30kg/ha of nitrogen, I Ikg/ha of P20, and 13 kg/ha K20 in 1995 (Fig. 2). Later somerecovery in fertiliser use became evident.

207

NPK kg/ha ofagriculture land

N P K

250 - N

P 20 5

0K 20

200 19

1515

104LO0 8199

7 72 60

50

20

10-

986-90 1991-94 195 4 996 599 199

Figure 2. Fertiliser nutrient use in Lithuania during the period 1986-1998

Phosphorus fertilisers have been used in Lithuania since the second half of the 19th

century. The production of phosphorus fertilisers in Lithuania was started in 1868,however, on a large scale only in 1963. Powder and granular superphosphates werealmost solely used until 1969. During the period 1970-1990 superphosphates accountedfor 38-20% and ammonium phosphate for 32.9-53.7 % of the total phosphorus used inagriculture. Nitrophoska can be mentioned as another widely used phosphorus containingfertiliser during that period.Potassium fertilisers before sixties were used in very low amounts mostly as kainit orsilvinit. Later the use of potassium started rapidly to increase with large imports of potassiumchloride. Importance of kainit and silvinit is recovering in relation to organic agriculture.Privatisation of fertiliser industries encouraged investments in new technologies for moreefficient, economically viable and environmentally safer production. Fast liberalisation ofthe fertiliser market resulted in a wider choice, and a wide range of new multi-nutrient.fertilisers have become available to a Lithuanian farmer. Today 10 companies, including3 Lithuanian factories, supply 45 different multi-nutrient fertilisers (containing more thanone of the primary nutrients nitrogen, phosphorus and potassium) for the local market.From them 37 containing P and K in different ratios. In addition 5 straight potash and 2straight phosphorus fertilisers are available on the market.Recently in Lithuania a new development of liquid fertiliser production has been started.Liquid fertilisers offer a farmer the advantage of reduced manual handling and theopportunity to apply fertilisers and some plant protection products in one application.Experimental liquid multi-nutrient fertilisers containing 14% nitrogen and 10% potassiumis the second year under testing at the Lithuanian Institute of Agriculture. 2 year fieldexperiments showed positive effect of this fertiliser on yield and quality (protein content,sedimentation) of winter wheat.

208

Content of phosphorus and potassium in most of the multi-nutrient fertilisers is relativelylow, ranging from 8 to 44%, and the ratio with nitrogen is too wide for prevailingLithuanian soils and crops. There are some constrains from fertiliser productiontechnology side, however, through production and more intelligent marketing some shiftto optimum can be made. This problem can also be partly solved with adequatemanagement of fertilisers on a farm. Experiments at the Lithuanian Institute ofAgriculture were conducted with ammonium phosphate fertiliser with the ratio of N:P farfrom optimum (containing 12% N and 50% P205 ). Long term experiments showed apossibility of application of ammonium phosphate once in four years with the amount ofP2O calculated for 4 crops of the rotation and with additional application of nitrogen inthe second, third and fourth year (Table 1). The same was partly true for potassium.

Table 1. Effect of distribution of phosphorus fertilizer on crop yield in a 4 crop rotationDotnuva, 1971-1994 m.

Average yield of cr6ps t/ha (annual average)Treatment potatoes barley Perennial grasses winter Average

(dry matter) wheat (100 feed units/ha)Without fertilizer 20.2 3:12 _, 3.91 4.24 51.9N34.60P60 K60 annually 24.6 3.82 4.18r 4.96 " 60.9N34.6oK6o annually, 24.6 3.86 4.08 5.18 61.7P240 every 4 years _ "

LSD, 2.1 0.40 0.36 0.46 3.0

Application techniques is an important factor in increasing fertiliser efficiency. Duringthe recent years farmers have purchased a number of combined drills for fertiliserplacement. Placement of NPK 18:9:9 (Kemira) N o9oP 3.,sK3o 5 in experiments at theLithuanian Institute of Agriculture in 1996-1998 with spring barley increased yield by0.25-0.31 t/ha on neutral and 0.27-0.49 t/ha on acid loamy soil (Figure 3).

[0 ncvral soil, LSDOS0,28 t/ha

yield tla [s acid soil, LSD05=0,31 5/ha

5.12 5.26 -

-- .09 '563

2

Without Broadcast Placement Broadcast Placementfertiliser NwP 301 30 N"P 45K45

Figure 3. Influence of fertiliser placement on the yield of spring barley, LIA, 1996-1998

209

On the basis of the data of the field experiments carried out at the Lithuanian Institute ofAgriculture, Institute's Agrochemical Research Centre, branches and experimentalstations basic, minimum and maximum fertiliser rates for different crops were specified,the correction coefficients for fertiliser rates were established for various soils andnormatives for fertiliser efficiency have been determined taking into account the yieldquality. Recently these rates has been revised with respect to the latest research findings.Basic rates were adjusted mainly in order to make fertilisation environmentally safe andeconomically sound. Maximum rates - in order to meet obligations for HELCOM and tocomply with the EU directives. Maximum rates are supposed to become an importantsupplement to the "Codes for Good Agricultural Practice in Lithuania", which was issuedin 2000.A first computer programme for making fertiliser plans was elaborated in Lithuania inearly eighties with joint efforts of several institutions. An individual fertiliser plan wascalculated for all Lithuanian collective and state farms each year (4). The programme forcalculation of balanced fertilisation rates prepared by the Department of LIA is availableto farmers. Several attempts to create a computer database for field experiments havebeen made, but only the database for experiments with fertilisers (containing data startingin 1966) is used on a wider scale. This database functions successfully at theAgrochemical Research Centre of LIA (1).Animal production is traditionally highly important for Lithuania and major part ofagricultural crop production is used as fodder. Farmyard manure produced on farms is avery important source of potassium and phosphorus, however, its content and availabilitydepends on many factors, such as type of animal, manure collection and storage method,time and type of application in the field. New fertiliser normatives for manure is underdevelopment in Lithuania with respect to these factors.It was a political target of HELCOM, in whose work Lithuania participates, to reduce thenutrient discharge into water by 50%. Recommendation of HELCOM from 6 February1992 stresses the importance of calculation of nutrient balances in order to evaluate theimpact of fertilisation on the environment. Calculations of potassium and phosphorusbalance in Lithuania based on revised normatives and official statistics were made for theyears 1996, 1997 and 1998. A slight surplus of phosphorus 4.8-8.7 kg/ha was found whenthe amounts of nutrients accumulated in the yield was compared to those applied withmineral and organic fertilisers. With regard to rather low coefficient of uptake ofphosphorus by plants, 150-200% difference between applied and removed phosphors canbe rated as normal. Potassium balance is negative because of reduced application oforganic and mineral fertilisers (Table 2). Removal of potassium by plants was only 75%covered by fertilisation. Negative balance of potassium can lead to depletion of soilreserves of this nutrient, reduction of yield quality, poorer resistance to lodging anddiseases.

210

Table 2. Phosphorus and potassium balances in Lithuanian agriculture

N, P20, K2O kg/ha of agricultural land RatioYear Input Output Balance Input/Total With fertilisers (with yield output %

mineral organic of crops)

Phosphorus1996 21,8 14,7 7,1 17,0 ±-4,8 1281997 26,3 19,5 6,8 18,0 +8,3 1461998 26,6 20,0 6,6 17,9 +8,7 149

1996-1998 24,9 18,1 6,8 17,6 +7,3 141Potassium

1996 30,6 16,3 14,3 46,6 -16,0 661997 41,5 22,5 13,6 48,9 -7,4 851998 37,2 24,0 13,2 50,2 -13,0 74

1996-1998 36,4 20,9 13,7 48,6 -12,1 1 75

ConclusionUse of potassium fertilisers in Lithuania declined from 76kg/ha in 1990 to 13 kg/ha in1995 and phosphorus from 41 to I kg/ha respectively. Later some recovery in fertiliseruse became evident. However, potassium balance remains negative and phosphorusshows a very slight surplus.Content of phosphorus and potassium in most of the multi-nutrient fertilisers is relativelylow, and the ratio with nitrogen is too wide for prevailing Lithuanian soils and crops. Aprogramme for calculation of balanced fertiliser rates prepared by the Department ofAgrochemistry of LIA is available to farmers

References1. Buivydaite V., Vaisvila Z. Database of experiments of fertilisation of Lithuania. Proceedings

of the Fourth Regional Conference on Mechanization of Field Experiments(IAMFE/BATLIC'95), Kaunas/Dotnuva, Lithuania, August 8-10, 1995, pp. 146-150.

2. Giselquist D., Gill S., Toma L. et al. Agricultural input industries in EU accession Countries.Regional and international trade policy. World Bank technical paper No.434, 1999, pp. 6 1-9 0.

3. Matusevicius K., Vasiliauskiene V., Masauskas V. Agrocheminiu tyrimu centrui 30 metu.Zemes ukio mokslai. Vilnius, 1996, Nr. 2, 3-12.

4. The Fertiliser industry of the European Union. The issues of today, the outlook fortomorrow. 1997. EFMA/DGIII.P.48.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

AGROCHEMICAL ASPECTS OF THE DYNAMICS OF PHOSPHORUS INSOILS OF KALININGRAD OBLAST

Panasin V.I., Slobozhaninova V.D., Novikova S.I.

Kaliningrad, GCAS

Positive influence of entering of phosphorous-bound fertilizers and phosphoriting onincrease of mobile phosphorous in soddy-podzolic soils by was determined. Thespecifications of the consumption of phosphoric fertilizers for shear of the contents ofmobile phosphorous in soils are designed. The acid-alkaline reaction of soil solutionrenders significant influence to transformation of the forms soil phosphorous. Dynamicseries of a level of application of phosphoric fertilizers and contents of mobilephosphorous in soils of the Kaliningrad oblast for the last 33 years are adduced. The closecorrelation between these ingredients is established.Soddy-podzolic soils of various texture are the most extended on the territory of Kaliningradoblast. There are particular features in distribution and properties of parent materials of theregion. Soil-forming rocks were shaped under influence of activity of a glacier bothconsequent processes of fluid wash and redeposition of glacial formations. Local native bornsedimentary strata with considerable diversity of a lithologic structure basically have servedas a material for accruing a strata of quaggy surface detrital deposits, caused considerablediversity of soil-forming materials on chemical composition and distribution.Parent materials of area can be divided into five genetic groups: glacial, fluviaglacial,ancient-alluvial and alluvial-lake depositions, and also buried peat. Their difference ongenesis and granulometric texture stipulates a difference in total chemical composition,specially in the contents of basic elements of a nutrition. However dominating parentmaterials are poor by reserves of phosphorous or availability for a nutrition of plants is low.According to results of the first tour of examination (1965-1969.), specific gravity of soilswith low contents of mobile phosphorous (less than 100 mg/kg soil) vas 78.5 %. Only10,6 % of squares of agricultural grounds were highly provided with P205. The averageweighed contents of mobile phosphorous constituted on 81 mg/kg on plough-lands, 65 onhay-makings and 68 mg/kg of soil on pastures (on Kirsanov method). For expired 35years of mobile phosphorous in soils of area have increased considerable and nowconstitute 128 mg/kg of soil, thus it is necessary to deem two periods:- 1965-1993 y. - intensive application of different means of a chemization, when thecontents of mobile phosphorous has increased with 74 up to 131 mg/kg of soil;- 1994-2000 y. - fall-of entering in soil of all kinds of fertilizers and as inquest decreasingof its reserves with 131 up to 128 mg/kg of soil.The improving of a phosphate regime of soils is connected to increase of mean annualapplication of phosphate fertilizers and also phosphoriting.Our research display connection of reserves of mobile phosphorous with differentagrochemical properties of soils. In particular, contents of mobile phosphorous is ininverse relationship granulometric texture. It a little differs from the data of other writers[3; 10], that is explained by greater cultivating of mild soils (Table 1).

212

Table 1. Contents of mobile phosphorous in soddy-podzolic soils of different texture,mg/kg of soil

Soil n P0 2 x+SxSandy 1771 214±4.8Sand loamy 11445 166±1.1Light loamy 41789 148+0.5Medium loamy 17964 143±0.7Heavy loamy 769 117±2.9Loamy 334 110±5.2

The note: hereinafter n - quantity of models; x - mean value; Sx - average deviation.

The greatest decreasing of the contents of mobile phosphorous s marked when transitionfrom sand to sand loamy soils - 48 mg/kg of soil. When physical clay increase I%,quantity of mobile phosphorous decreases on average by 2.1 mg/kg of soil.Some of the contributors [3; 6] consider, that the availability to plants of phosphorous ofsoil and fertilizers s augmented with increase of humus-enriching of soils. We establishminor reduction of reserves of mobile phosphorous with increase of the contents ofhumus, that is connected to regional features, high percolative water regime and intensivewashing away of calcium from a soil absorptive complex.Acidity of soil solution renders the greatest influence to the contents of the mobile formsof phosphorous in soil [4; 8].Our research gives evidence, that reserves of mobile phosphates are augmented inaccordance with neutralizing soddy-podzolic soils of the Kaliningrad oblast, thus 0.1 cstipulates increase of the contents P2O5 on 4 mg/kg. (Table 2).

Table 2. Influence pHKc, on the contents of mobile phosphorous, mg/kg

pHKCI n P202 (x+Sx)Up to 4.5 2342 89+4.6-5.0 5109 108±1.35.1-5.5 10748 126±0.95.6-6.0 17696 142+0.7More than 6.0 38184 170+0.5

The study of influence pHKclon a background of different texture on a modification of thecontents of mobile phosphorous in soddy-podzolic soils of the Kaliningrad oblast hasrevealed its maximum reserve (233 mg/kg of soil) in neutral sand soils, minimum (48) - invary acid clay ( Table 3).

Table 3. The contents of mobile phosphorous in soddy-podzolic soils of different texturedepending on pHKCh mg/kg of soil

Soils Classification of soils on pHK.,up to 4.5 4.6-5.0 5.1-5.5 5.6-6.0 6.0

Sandy 123±11.7 155±14.1 174±7.8 193±6.6 233±8.5Sand loamy 107±4.4 123±3.3 140±2.3 161±2.2 189±1.7Light loamy 88±2.0 108±1.8 124±1.1 142±1.0 168±0.7Medium loamy 73±3.2 89±2.3 114±1.7 129±1.2 161±0.9Heavy loamy 70±20.4 72±9.7 97±9.9 100±5.0 134±3.7Loamy 48±12.6 40±12.5 80±8.7 93±11.9 133±7.0

213

Content of mobile phosphorous is on the average reduced with increase of physical clay nsoils on 1% in group of vary acid soils on 1.5, medium acid - 1.7, acescent - 1.9, in closeto neutral and neutral - 2.0 mg/kg of soil. However the strongest connection of texturewith the content of mobile phosphorous is established on vary acid soils, where itsreserves in sand soils exceed by 2.6 times the content in clay soils.In sand soils a modification pHKcj on 0.1 put conditions to the greatest increase of thecontents of mobile phosphorous, on the average on 5.5 mg/kg, least - 3.2 on heavy loam.Numerous research [1; 2] testifies convincingly that the systematic entering of phosphoricfertilizers promotes increase of reserves of mobile phosphorous in soil. Thus the intensityof its accruing depends on properties of soil, case doses of phosphoric fertilizers andduration of their application.On figure are exhibited dynamics of application of phosphoric fertilizers and contents ofmobile phosphorous in the soils of the Kaliningrad oblast for the last 33 years.

Mean contents, mg/kg Phosphat fertilizers,of soil kglhectare of the crop

140130 50

120 7 1 1 - 9 7 40

100 -30

90 -2080 -[ I-1070-60 -4 --- :-1-L---- 0

1966- 1971- 1976- 1981. 1986- 1991- 1996 1997 1998 Yw

1970 1975 1980 1985 1990 1995

1-1lMean contents of phosphorous, mg/kg of soilME Application of phosphoric fertilizers, kg/heclaie of soil

Figure. Correlation of application of phosphorous-bound fertilizers and contents ofmobile phosphorous in soddy-podzolic soils of the Kaliningrad oblast.

On the basis of the data integrating fixed experiments we assume, that decreasing of soilsacidity promotes availability to plants of phosphorous of soil and fertilizers, the effectfrom application of phosphoric fertilizers reduces (Table 4).

Table 4. Efficiency of phosphoric fertilizers depending on acidity of soddy-podzolic soils, %

Quantity of pHKC6 Addition of ield at entering, P kg/hectareexperiences 60 902P 12 150

N60 K6044.5..5.0 19.4 24.3 37.7 47.2

1 6.0.. .7.0 10.2 18.7 32.5 no dataNqoKqo

5 4.0.. .4.7 15.8 23.9 33.9 41.68 5.4...5.5 16.7 32.8 39.2 53.94 5.7.. .6.0 16.3 20.6 25.5 34.8

214

Higher yield is obtained on a background NK 60 on medium-acid soils. Maximumincreases of k crop are obtained on acescent soils at further increase of a nitrogen-potassium background (N90K90).At the same time our research indicates increase of availability to plants of phosphorousof soil and fertilizers when reserves in soddy-podzolic soils increase (Table 5).

Table 5. Efficiency of phosphoric fertilizers on a background N, 60K depending on thecontents of mobile phosphorous in soddy-podzolic soils, %

P205 mg/kg n Addition of yield at entering P, kectareP20__mgkg _30 60 - 90 120 15024-100 5 10.3 13.1 16.9 17.8109-145 2 14.1 18.4166-176 1 14.0 19.3 29.0 40.7> 25.0 2 20.2 22.6 24.2

The positive operation of increasing doses phosphorous-bound fertilizers on a phosphateregime of soils is well-known. Entering of phosphorous at a dose of 30 kg per hectare isaccompanied by very sluggish rates of accruing of mobile phosphates. Entering ofphosphorous at higher doss 90 and 180 kg per hectare allows to increase considerably thecontents of mobile phosphorous in soil in a shorter period [1; 2; 9].Entering of 360 kg per hectare ground phosphate in the sum for circle of crop rotationincreased the contents of mobile phosphorous in medium loamy soddy-podzolic soil on38 mg/kg of soil, in heavy loam, at a dose 270 - on 24...30, and at a dose 540 - on 63...87[1;9].According to our data, phosphoriting changes a phosphate status of soils essentially at alllevels of acidity (tab. 6). The entering of ground phosphate in vary acid and acescent soilswith low contents of phosphorous promotes increase of the contents of mobile phosphatesaccordingly on 90...158 and 70...206 mg/kg of soil; on close to neutral, well provided byP205 on 62... 140; on neutral with high contents - on 70... 121. Thus the most noticeablemodification of the contents of phosphorous available for plants happens on soils with alow level of cultivation.The obtained long-term data on share of the contents of mobile phosphorous fromentering off the ground phosphate are the reliable specification and good criterionpermitting to forecast a modification of a phosphate mode of soils and to evaluate qualityof such relevant agrochemical measure, as phosphoriting (Table 7).According to the data of a number of the writers the liming results to mobilisation ofphosphates of soil, and the positive operation of lime oscillates in time and depends on adose of chemical meliorant. Writers explain this appearance by decrease of activity ofiron and aluminium on-and-a-half oxides and considerable reduction of binding by it of aphosphoric acid of introduced fertilizers, that creates favourable conditions for masteringby plants of phosphates from soil [2; 7; 9].Our research determined a little bit diverse regularity of conduct of mobile phosphorousat liming. In particular, entering of chemical meliorants almost everywhere promotes adecrease of contents of mobile forms of phosphorous in arable layer of soddy-podzolicsoils of Kaliningrad oblast. It is possible to explain by regional features of properties ofsoils: specificity of humus status, predominance of humin in fractional composition ofhumus and capacity of soils to transfer a part of soil phosphorous introduced withfertilizers, in organomineral complexes (Table 8).

215

Table 6. Influence of ground phosphate on the contents of mobile phosphorous in soddy-podzolic soils, mg/kg of soil

Treatment After enterin Mean1987 1988 1989 1990 for4 ears

_H 4 .5. P20 mg/kg of soil

Background 17 16 18 16 17Background +1.0 ton 109 124 13 97 108Background+ 1.5 ton 156 164 151 145 154Background + 2.0 ton 182 198 164 158 176

pH 4.7, P205 - 15...20 mg/kg of soilBackground 20 23 21 20 21Background +1.0 ton 85 96 87 74 86Background + 1.5 ton 195 196 184 178 188Background + 2.0 ton 208 198 223 216 221

pH 5.8, P20 5 - 136... 150 mg/kg of soilBackground 140 139 126 115 130Background +1.0 ton 210 221 212 206 212Background + 1.5 ton 255 258 244 238 249Background + 2.0 ton 285 293 272 262 278

pH 6.4, P205 - 186... 195 mg/kg of soil _

Background 172 171 170 165 170Background +1.0 ton 280 282 239 224 256Background+ 1.5 ton 325 325 243 235 291Background+ 2.0 ton 368 368 252 247 316

Table 7. Modification of the contents of mobile phosphorous in soddy-podzolic soils ofthe Kaliningrad area from I ton of ground phosphate, mg/kg of soil

Name POup to_25 26-50 51-100 101-150

n 329 822 1196 321Before application 20 39 73 123After application 99 147 157 209Shere P20, of I ton ground phosphate, +, +54 +61 +58 +61

Table 8. Influence on liming to the contents of mobile phosphorous, mg/kg of soil

(n=4200)

Before liming After liming Chan-

Groups Mean Classification of soils on pHXcI mean ges,ofpH P2 05 up to 4.6-5.0 5.1-5.5 5.6-6.0 more P 205 +,-

4.5 than 6.0Up to 4.5 108 84 104 99 102 124 103 -54.6-5.0 122 118 109 114 121 116 -65.1-5.5 149 - - I 132 136 130 -195.6-6.0 161 137 143 141 -20More than 6.0 184 - 163 163 -21

216

Sharply decreased level of application of phosphoric and organic fertilizers, the cessationof work on phosphoriting of soils for the last years has caused overflow of an offset ofphosphorous from arable soils above its addition. So, in 1991-1995. The receipt ofphosphorous in soil with mineral fertilizers has decreased by 60 %, with organic - by 43,7(as contrasted to 1986-1990 y.), that has resulted in negative balance: the deficit ofphosphorous has constituted 5.5 kg per hectare of an area under crop.Agrochemical properties of Kaliningrad soils render an essential influence on accruing ofphosphates in soddy-podzolic soils.Increasing of contents of mobile phosphorous under application of ground phosphate inbadly cultivating soils is marked.Changes of soil solution pH and of contents of mobile phosphorous influence positivelythe intensity of consumption of phosphorous by cultivating crops and efficacy ofphosphate fertilizers.

References1. KacHuKHi IO.H4. 4 xp. ,le~iaB1e H nocJeaeHcrBme Bo3pacTatowHx 1ao3 *cc(bopHblx

yno6peIri B ceBoo6opore Ha JnerKocyrnrmHlco.i nepHnoBo-noa3oncroC novAe. B.KH.:Pe3ybTaTli Hccne21oBaHHri B J1RlHTeljhbIX OnblTaX c ynio6peHHAMH no 3OHaM cTpaHbl. M.:B4YA. 1980. Bbm. 9. C. 4-36.

2. KHpnHHKOB H.A. H up. Ports 4ocqpopa H M3BecTH B npouecce oKynhTypmBaIul aepnoBo-nom30,jHabIx noqB H nonlyqeHHH BbICOKHX ypo~xaen ce~nbcKoxo3aicTnenHlb1X KyALhTyp. B.Ku.: Pe3ynbTaThi HccnejoBaH.m B AIHTCJUHhIX OnJbiTax c yno6peuHMmn no 3ouaMcrpaHM,.M.: BIIYA. 1979. 8. C.46-58.

3. KyjiaKocm T.H. louBeHHo-arpoxMHwecKHe OCuOBBI noym H a BBICOKHX ypoiaeB.MHHcK: Ypaaxaia. 1979. 272 c.

4. KynaKoBcKas T.H. OIITHMH3aaHm arpoxHMmqecKoIi cUcreMbi no4eHHoro nHTauHHSpacreuHAl. M.: Arponpomn3alar. 1990. 216 c.

5. He6onbcHu A.. l aBecrKoauHe - cpejjCrBO opeHHoro y4MyLeHHM KHCJIhIX n0MB. J.:JIel3iaT. 1979. 133 c.

6. lerep6yprcKmrl A.B. COCd2Op B nOMBC H dOC)aTHOe nHTaHe pac-reHHi. flyumno. 1980. 31 c.7. CRo6uaKoaa O.B., CyATaHo P.A., JIHTBHHOBa E.C. CocToHnHe H ncPCCKTHBb

HcuOJqb3OBanHRa 4 oc4 opHTHOM MyKHH/ArpoxHMHR. 1978. No 10. C.23-28.8. COKOIOBa A.B. ArpoxMmni oc(bopa. M.: HayKa. 1950. 150 c.9. YTOMKHI B.r. Teopsn H npaKTHKa 3q4xex'rHBHoro bocbopHpoBaHHA KHclALIx noq

HeqepnoaeMHo. 30MLI POCOiCKO. OeepatrIH. ABropedy. A11cc. li-pa c.-x. Hay. M. 1995.102 c.

10. qIHpHKoB $.B. ArpoxHM KaJ1Hs H 4oc~opa. M.: CenbxorH. 1956. 272 c.

217

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISA TION EFFECT ON SOIL AND CROPS

LONG TERM EFFECTS OF POTASSIUM AND PHOSPHORUS SURPLUS INPASTURE ECOSYSTEM

Jonas Gutauskas', Alvyra Slepetiene''Lithuanian Institute of Agriculture (LIA), Department of Grassland Husbandry,2Lithuanian Institute of Agriculture (LIA), Analytical Laboratory,

AbstractIn a 40 year-old experiment, located on a LIA's Valinava experimental dairy farm theeffects of different fertilising level of PK on pasture were investigated. The aim of thefield trial was to determine the effect of the inorganic PK fertiliser application on longterm pasture, explain variation in PK surplus and PK use efficiency on conventional dairyfarm, interaction between animals, soil and plant production and to determine the totalbudget of soil PK and changes in humus content. Intensive grazing on the background ofthe inorganic PK fertiliser application had a significant effect on K accumulation in thesoil and migration in deep 30-50 cm horizon. The P accumulates in the topsoil 0-20 cm.Long term pasture utilization for grazing had an essential effect on reducing humuscontent in the soil and higher concentration of mobile humic acids. It was found that Presponse was similar for different levels of K fertilization.

Key words: pasture, grazing, fertilization, soil, potassium, phosphorus, humus, mobilehumic acids.

IntroductionHigh concentration of cattle and stocking rate have a strong effect on the farmingenvironment, surface and ground water and this is becoming a complicated environmentalproblem (Halberg et al., 1995; Thomas, 1995; Steinfeld et al., 1996). Phosphorus ismainly lost by surface runoff, and runoff losses from no-till fields contain relatively moreof the soluble forms of P because organic matter and organic P accumulate in the uppersoil layer (Gaynor, Findlay, 1995). K is less mobile and less prone to leaching than NO,-,but more so than phosphate (Laegreid, 1999). The main source for plant nutrition isavailable potassium. In the soils of Lithuania the content of available potassium is higherthan available phosphorus (Mazvila, 1998). The availability of soil potassium (K) to cropsdepends on the mineralogical composition and its relationship with existing K dynamics.Fertilizing strategy and crop species could also have an influence (Salomon, 1999). Inpasture ecosystem the organic matter and livestock excreta accumulate in the topsoil andtake part in the processes of mineralization and humification there (Buciene et all, 1997).A positive effect of perennial grasses on the concentration of PK, humus and humus acidshas been established (Magyla et all, 1997; Slepetiene, 1998).The objective of this experiment was to evaluate the residual effects of different Kfertilization application on DM yield, botanical composition and its concentration in thetopsoil and subsoil. The purpose of this paper is to explain the variation in PK surplus,humus and mobile humic acids accumulation in the soil and discuss the use efficiency on

218

long term pasture ecosystem in a conventional dairy farm. It is a new area from theviewpoint of farm ecology.

Materials and MethodsThe experiment was carried out between 1961...2000 on the cultivated pastureestablished in 1957 on the Valinava experimental dairy farm. From 1961 the experimentwas carried out following the below given theoretical design:

1. Control. P0K02. P60Ko3. PK 304. P60K605. P60Kgo

The soil under experiments was sody gleyic, podzolized light loam, with a pHKCI value-6.6...7.1; humus content-2.3...3.2%; K,0-100... 120 and P205-50...70 mg kg' l at thebeginning of field experiment (Zimkus, 1982). The botanical composition of the pastureswards was the following: grasses- 67.2...73.1% on a DM basis, white clover -22.2.. .29.2%, forbs -3.6.. .4.7%. The experimental plots were grazed 3 or 4 times duringthe season with a heard of dairy cows. The following methods were used for thedetermination of: mobile P20 5 and K20-A-L method; total potassium-flame photometric,total phosphorus-calorimetric method; total N-Kjeldhal method; humus content-Tiurinmethod; mobile humic acids (fraction HA-I) -Ponomariova-Plotnikova modified Tiurinmethod (Ponomariova el all, 1980).The experiment is being continued.

Results and DiscussionIn the 4 0h year of pasture use the grass phytocenosis with a rich from an biodiversitypoint of view botanical composition formed. In PK fertilized treatments grasses accountedfor 52.0.. .62.3% of DM yield, white clover -12.9.. .23.5%, forbs -20.0 ... 32.2%.The intensive grazing on the pasture over the last 40 years had a positive impact on theimprovement of all agrochemical properties of the soil. The inorganic PK fertiliserapplication resulted in an essential PK accumulation in the soil (Table 1; Table 2). Butthe concentration of P and K in the pasture soil horizons had different nature. The Paccumulates in the topsoil (0... 10 cm and 10.. .20 cm) when the highest concentrationand surplus of K is observed in the subsoil (30.. .50 cm). Considerable reduction ofavailable phosphorus was found in the treatment without application of phosphoricfertilisers in the topsoil. The amount of available phosphorus in this treatment in thetopsoil was 36.. .56 mg kg" .Effect of grazing and application of mineral PK fertilizers on pH level of soil wasnegligible and remained almost the same during 40 years.Intensive grazing on the background of the inorganic PK fertiliser application had asignificant effect on N and humus accumulation in the soil (Table 3; Table 4). Long termpasture utilisation insures that organic matter moves into the topsoil and takes part in theprocesses of mineralization and humification there (Arlauskas, Slepetiene, 1997;Slepetiene, 1998). Therefore humus and humic acids tended to accumulate in the 0-10 cmand 10-20 cm layers. In the case of PK fertilizer application the large amount of pastureplant residues and roots and prevalent humification processes resulted in the followingaccumulation of humus: 0-10 cm layer 5.68...6.15%, 10-20 cm layer 2.84...3.33%, 20-

219

30 cm layer 1.58...2.13%, 30-50 cm layer 0.614...0.738%. The concentration of mobilehumic acids shows a close correlation with the humus content in the soil (Figure).

Table 1. Amount of total potassium in different layers of soil in the 40 year - old pasture

Layer of soil (cm)

Treatment 0-10 10-20 20-30 30-50

K % of soil

Control PoKo 0,477 0,479 0,550 0,715

P60 KO 0,514 0,479 0,526 0,816

P60 K3o 0,533 0,516 0,591 0,748

P60 I 0,532 0,538 0,570 0,749

P60 K" 0,566 0,509 0,528 0,744

LSDos 0,0648 0,0891 0,1514 0,2174

Table 2. Amount of total phosphorus in different layers of soil in the 40 year - old pasture

Layer of soil (cm)

Treatment 0-10 10-20 20-30 30-50

P % of soil

Control Po1K( 0,044 0,036 0,028 0,029

P6o Ko 0,076 0,041 0,028 0,026

P,0 Ko 0,078 0,046 0,029 0,026

P6 K60 0,076 0,046 0,034 0,031

P60 Kgo 0,074 0,044 0,033 0,030

LSDos 0,0119 0,0053 0,0056 0,0102

Table 3. Amount of nitrogen in different layers of soil in the 40 year - old pasture

Layer of soil (cm)

Treatment 0-10 10-20 20-30 30-50

N %of soil

Control POKo 0,282 0,157 0,063 0,061

P60 KO 0,327 0,168 0,055 0,068

P6o K3o 0,332 0,181 0,074 0,078

P60 K" 0,338 0,181 0,083 0,097

P60 K" 0,332 0,190 0,093 0,062

LSDo, 0,044 0,0212 0,0312 0,0239

220

Table 4. Humus content in different layers of soil in the 40 year - old pasture

Layer of soil (cm)Treatment 0-10 10-20 20-30 30-50

Humus % of soilControl P0K0 4,97 2,66 1,68 0,602PlO KO 5,68 2,84 1,58 0,614P60 K" 5,91 3,06 1,76 0,706P" K" 5,98 3,17 1,99 0,675P, Ko 6,15 3,33 2,13 0,738

LSoD0 0,466 0,342 0,469 0,230

C mgkg" 3500 - Layer3000 -- 0 30-50cm2500

2000 a 20-30cm

1500

1000 0 10-20cm

500

0 0 0-10cm

P0 P60 P60 P60 P60KO KO K30 K60 K90

Figure. Amount of mobile humic acids in -10, 10-20, 20-30 and 30-50 cm soil layers.Valinava experimental farm, 2000.

ConclusionsLong term pasture utilization had a positive impact on the improvement of allagrochemical properties of the soil. The application of the inorganic PK fertiliser had astrong and stable effect on the processes of PK accumulation in the soil. The Paccumulates in the topsoil (0...20) cm when the highest concentration and surplus of K isobserved in the subsoil (30.. .50) cm. Grazing on the background of the PK fertiliserapplication had significant effects on N and humus accumulation in the soil. The humusand mobile humic acids tended to accumulate in the topsoil (0... 10 cm and 10.. .20 cm).The residual effect of K surplus increased the risk of unbalanced mineral content inforage. Therefore, in our research a special attention was paid to the influence of grazing,especially the uneven distribution of returned nutrients. Research should also beperformed in order to establish relationships between agricultural activities and negativeenvironmental effects.

221

ReferencesI. Arlauskas M., Slepetiene A. Effects of conventional and minimum soil tillage systems,

diverse fertilization and various crop rotations on the humus composition of loamy soils//Therole of humic substances in the ecosystems and environmental protection. Proc. of the 8t

Meeting of the Int. Humic Substances Society, Wroclaw, Poland, September 9-14, 1996. -Wroclaw, 1997. - P.513-516.

2. Buiene A., Gutauskas J., Kadiiulis L. Dirvolemio organines dalies mineralizacija ir azotoi~plovimas iS suartos ilgametes ganyklos//Lietuvos klimato ir dirvolemio potencialoracionalaus naudojimo perspektyxos. Mokslin~s konf pranegimai. Vilnius, 1997m. vasario20d. - Dotnuva-Akademija, 1997. - P.86-92.

3. Gaynor J.D., Findlay W.I. Soil and phosphorus loss from conservation and conventionaltillage in corn production//Journal of Environmental Quality.- 1995.- Vol.24.-P.734-741.

4. Halberg N., Kristensen S.E., Kristensen S.I. Nitrogen turnover on organic and conventionalmixed farms//Journal of Agricultural and Environmental Ethics.- 1995, 8(l).-P.30-5 1.

5. Laegreid M., Bockman 0. C., Kaarstad 0. Agriculture, Fertilizers and the Environment. -CABI Publishing, 1999. -294p.

6. Lietuvos dirvo2emiq agrocheminds savybs irjq kaita (sud.J. Malvila).-Kaunas,1998.-195p.7. Magyla A., Sateikiene D., Slepetien6 A. Augaliniq liekanq kiekis, jql sudetis ir dirvofemio

humusas ivairios specializacijos stjomainose//Ll1 mokslo darbai. - Dotnuva, 1997.- P. 56-75.

8. Ponomariova V.V., Plotnikova T.A. Humus and Soil Formation.- Leningrad, Nauka, 1980.-220p. (in Russian).

9. Slepetien6 A. Ilgalaikiq kulttiriniq ganyklq itaka humifikacijos procesuidirvo2emyje//Augalininkystes dabartis ir ateitis. Moksliniq straipsni4 rinkinys. - Kaunas-Akademija, 1998.- P.592-598.

10. Salomon E. Effect of previous potassium fertilisation on yield and content of potassium,magnesium and calcium in ryegrass and white clover// NJF XXI Congress Rapport. NordiskJordbrugsforskning Nr.2. - 1999.-Vol.8 .-P. 148.

I1. Steinfejd H. et all. Livestock - environment interaction. Issues and options.- WREN media,Suffolk, UK, 1996.- 56p.

12. Thomas C., Bax LA.. Environmental pressures on dairy farming in the UK//Applied researchfor sustainable dairy farming.- Lelystad, 1995, P.81-84.

13. Zimkus Z. Kalio tra~q jvairi4 dozi4 efektyvumas kultarineje ganykloje//L2I Moksliniqstraipsniq rinkinys.- Vilnius, 1982. - Nr. 43.-P.51-55.

14. Zimkus Z. Ilgalaikis kalio normtl tyrimas ganykloje//L2I Mokslo darbai. 2emdirbyste. -Dotnuva-Akademija, 1995. - T. 46. P. 39-42.

222

Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

INFLUENCE OF MULTI-NUTRIENT FERTILIZERS ON THE YIELD ANDQUALITY OF SPRING BARLEY AND RAPE

Virgilijus Paltanavi ius

Lithuanian University of Agriculture

AbstractField experiments were carried out in 1996-1998 at the Experimental Station of theLithuanian University of Agriculture on sod-gleyic light loam soil. The yield of springbarley was increased by 1.53-1.56 t/ha on average with the application of NPK fertilisers.However, the most efficient fertilisation of spring barley from the viewpoint of economywas with multi-nutrient fertiliser NPK 17:17:17. The highest yield increase in spring rapewas found with the application of multi-nutrient fertiliser PUJ5:15 before sowing plusammonium nitrate at seedling stage.

Key words: multi-nutrient fertilisers, spring barley, oilseed rape, yield, quality

IntroductionMore than one nutrient, most often three: nitrogen, phosphorus and potassium must beapplied for good crop performance. Separate application of these nutrients increases costsof application, risk of soil compaction and finally reduces the efficiency of fertilisation(1, 3, 4). With new forms of fertilisers it is possible to achieve higher efficiency offertilisation management and finally higher efficiency of fertilisers in a broad sense.(2, 5, 6, 7). Nowadays various multi-nutrient fertilisers are imported to Lithuania bydifferent companies. Recently the Lithuanian company ARVI started production of multi-nutrient fertilisers.The aim of this work was to evaluate the efficiency of these new multi-nutrient fertilisersin field experiments with spring barley and rape.

MethodsField experiments with spring rape and spring barley were carried out in 1996-1998 at theExperimental Station of the Lithuanian University of Agriculture on sod-gleyic light loamsoil, with the following characteristics: pHKcj- 6.7-7.2, humus - 2.2-2.3%, available P,0 5- 110-140 mg/kg and K2 O- 125-132 mg/kg.The spring barley variety Roland was applied with 60 kg/ha and the spring rape varietyStar with 90 kg/ha of N, P 20, and K20. Multi-nutrient fertilisers with different ratio ofN:P:K (17:17:17, 10:10:10 from ARVI and 16:16:16 imported from Belarus azophoska)and P:K (15:15 from ARVI) were applied before sowing. Granular superphosphate (SSP)and potassium chloride (KCI-MOP) were applied before sowing and ammonium nitrate(AN) at the beginning of tillering in barley and seedling stage in rape.Analyse of variance was performed and F and t criteria were used to evaluate thesignificance levels and to calculate the least significant difference (LSD).

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ResultsIn the experiments with spring barley the efficiency of fertilisers was high in all 3 years(1996, 1997, 1998) of investigations (Table 1). The yield of spring barley was increasedby on average 1.53-1.56 t/ha with application of fertilisers. Very close results wereobtained with the application of the same rate of NPK with multi-nutrient and withstraight fertilisers. The only exception was NPK 10:10:10 fertiliser, the application ofwhich resulted in 0.37 t/ha lower yield than that of NPK 17:17:17.However, the price of 1 kg of nutrients in azophoska was 2.50 Lt in comparison with 1.45Lt in multi-nutrient fertiliser NPK 17:17:17 of local production. Therefore in order toproduce I t/ha of extra grain yield 294 Lt was needed with azophoska and 167 Lt withfertiliser NPK 17:17:17. So the more efficient fertilisation of spring barley from theviewpoint of economy was with multi-nutrient fertiliser NPK 17:17:17.

Table I. Influence of multi-nutrient fertilisers on the grain yield of spring barley

LUA, 1996-1998

1996 1997 1998 AverageTreatment Increaset/ha % t/ha % t/ha % t/ha %

I tfha

Without fertiliser 2.6 100 3.07 100 3.66 100 3.10 100 -

NPK 17:17:17 3.6 141 4.37 142 6.00 163 4.66 150 1.56NPK 10:10:10 3.7 143 4.29 140 5.84 160 4.29 138 1.19PK 15:15 +AN 3.6 139 4.35 142 5.98 163 4.63 149 1.53SSP+ KCI 3.5 138 4.23 138 6.19 169 4.65 150 1.55(MOP) + ANNPK 16:16:16" 3.6 139 4.34 141 5.96 163 4.63 149 1.53

LSD0, 0.27 0.29 0.49*- azophoska

The main characteristics of barley grain are shown in Table 2. Protein content in grainincreased by 0.66-1.07% with the application of fertilisers. The highest protein content inspring barley grain 10.05% occurred with the application of multi-nutrient fertiliser .PP-15:15 before sowing plus ammonium nitrate at the beginning of tillering. It is worthmentioning that the effect on yield in this treatment was lower.

Table 2. Influence of multi-nutrient fertilisers on spring barley grain characteristicsLUA, 1996-1998

Treatment % in dry matter Content of (g/kg) Feed

starch protein fats fibre P K Ca Mg unitsWithout fertiliser 61.64 8.98 3.59 6.21 2.54 5.67 0,62 1.16 1.41NPK 17:17:17 60.87 9.64 3.54 5.92 2.78 5.52 0.64 1.19 1.41NPK 10:10:10 60.87 9.64 3.54 5.92 2.78 5.52 0.64 1.19 1.41

PK 15:15 +AN 62.15 10.05 3.47 5.92 2.70 5.69 0.64 1.18 1.42

SSP-+ KCI (MOP)+AN 62.10 9.82 3.42 6.13 2.71 5.7 0.68 1.17 1.41NPK 16:16:16" 62.02 9.24 3.51 6.19 2.57 5.99 0.61 1.26 1.40-azophoska

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In the experiments with spring oilseed rape the efficiency of fertilisers was also high in all3 years (1996,1997,1998) of investigations (Table 3) and the yield was increased by onaverage 35.3-39.8%. The highest yield increase 0.77 t/ha in spring rape occurred with theapplication of multi-nutrient fertiliser F1L5:15 before sowing plus ammonium nitrate atseedling stage. Somewhat lower yield was obtained with the application of otherinvestigated multi-nutrient and straight fertilisers.

Table 3. Influence of multi-nutrient fertilisers on the seed yield of spring rapeLUA, 1996-1998

1996 1997 1998 AverageTreatment - Increaset/ha % tlha % t/ha % t/ha % Inra

t/ha

Without fertiliser 2.04 100 1.67 100 1.72 100 1.81 100 -

NPK 17:17:17 2.60 127.4 2.59 155.1 2.15 125.5 2.45 135 0.64NPK 10:10:10 2.58 126.3 2.73 163.5 2.24 130.3 2.52 139 0-71PK 15:15+ AN 2.66 130.2 2.78 166.5 2.30 133.8 2.58 142 0.77SSP + KCI (MOP) + AN 2.64 129.0 2.71 162.3 2.25 130.8 2.53 140 0.72NPK 16:16:16' 2.60 127.4 2.64 158.0 2.13 124.2 2.45 135 0.64

LSDo, 0.216 0.326 0.118*- azophoska

Application of fertilisers increased fat content in seed - an important characteristic ofoilseed rape (Table 4). The highest fats content 41.58% was obtained with the applicationof multi-nutrient fertiliser NPK 10: 10: 10.

Table 4. Influence of multi-nutrient fertilisers on characteristics of spring oilseed rapeLUA, 1996-1998

Dry Fats Erucic Glucosi- Pro- Fibre Ash Contentof(g/kg)Treatment matter acid nolates teins

% % % % % % % P K Ca MgWithoutWtt 87.76 40.34 0.0 19.19 19.13 5.98 4.40 7.59 14.24 8.60 2.30fertiliser8

NPK 17:17:17 83.12 41.52 0.0 20.79 19.30 6.04 4.48 7.89 14.41 8.56 2.34

NPK 10:10:10 87.18 41.58 0.0 20.21 19.96 5.74 4.41 7.93 14.46 8.95 2.36

PK 15:15 +AN 86.92 41.22 0.0 19.74 20.47 5.60 4.39 7.68 14.84 9.19 2.41SSP + KCI(MP 87.10 41.30 0.0 19.39 20.56 5.56 4.29 7.67 14.75 9.00 2.48(MOP) + AN

NPK 16:16:16* 87.20 41.33 0.0 19.87 20.18 5.62 4.35 7.51 14.50 9.25 2.37LSD,,

*azophoska

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Conclusions1. The yield of spring barley was increased by 1.53-1.56 t/ha on average with theapplication of NPK fertilisers. However, the most efficient fertilisation of spring barleyfrom the viewpoint of economy was with multi-nutrient fertiliser NPK 17:17:17.2. The highest protein content in spring barley grain 10.05% occurred with theapplication of multi-nutrient fertiliser t4,Pl 5:15 before sowing plus ammonium nitrate atthe beginning of tillering.3. The highest yield increase in spring rape was found with the application of multi-

nutrient fertiliser ",PIU-5:15 before sowing plus ammonium nitrate at seedling stage.4. The highest content of fats (41.58 %) in the seeds of oilseed rape was found with the

application of multi-nutrient fertiliser NPK 10:10:10.

References1. Baginskas B., 2emaitis A., Narkeviius J. ir kt. Agrochemija.-V.: Mokslas, 1984.-P. 27-282. Ma~vila J., Vai~vila Z., Radionas V. ir kt. Ilgalaikio trqimo mineralin~mis trzomis

[taka derliui, dirvoiemio agrochemin~ms savybems, maisto mediiagq igsiplovimui //Antropogeniniq veiksniq itaka dirvoemio derlingumui.-V., 1992.-P. 52-56.

3. Onaitis A. Tr9gimas.-V., 1989.-P. 6-10.4. vedas A. Dirvolemis - trqAos - derlius. / Habilitacinis darbas.-Dotnuva - Akademija,

1993.- 88 p.5. ABAIOHH H.C. ArpoxnMnM. 14s - Ho MOCKOaCKoro yHHBepcHTeTa, 1982io- 343 c.6. BorAenunq H.M. HayqHbie OCHOBbi npMeHeHHm yAo6peHHM B 3ananHoM perHoHe

CCCPio- MrnicK, 1981.- 200 c.7. KyYIaKOBCKaA T.H. MHHepanbHule yno6peHHa H nrJo1foponbje Ho4BhI. H fLoglopoble

HOqbLI H ypoxa.- BnmnbIoc, 1974.-C. 5-15.

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Regional IPI/LIA Workshop, Lithuania, 2000POTASSIUM AND PHOSPHORUS:

FERTILISATION EFFECT ON SOIL AND CROPS

CHOPPED CLOVER MULCH IN ORGANIC VEGETABLE PRODUCTIONCONTAINS LARGE AMOUNTS OF EASILY AVAILABLE P AND K

Anne-Kristin Loes', Hugh Riley2, Sissel Hansen] and Steinar Dragland2.1 Norwegian Centre for Ecological Agriculture

2) Norwegian Crop Research Institute of, Apelsvoll Research Centre

IntroductionOrganic vegetable growers often have reduced access to farmyard manure, and greenmulch may be used as a combined method of nutrient supply and weed control. With theamounts of mulch commonly applied, much more phosphorus (P) and potassium (K) isapplied than will be removed in yields. If this surplus of nutrients can be stored in the soil,the green mulch method may be a way of enriching the soil with nutrients that are easilyavailable to plants. On farm level, crop rotations must be designed to integrate fields ofmulch growing and vegetable production.

MethodsAt the research centre Kise, field trials were performed in red beet (Beta vulgaris L.) andDutch white cabbage (Brassica oleracea L.) in 1998 and 1999. Chopped red clover(Trifoliumn pratensis L.) was used as mulch material, two applications of each 3 cmthickness (after settling) during each season. Yields and plant uptakes of N, P and K wererecorded, and the soil was sampled at various times to investigate the availability of thenutrients remaining in the soil. The soil samples were analysed for available P and K byextraction with AL-solution (0.1 M ammonium lactate and 0.4 M acetic acid, pH 3.75),and for acid-soluble K by IM nitric acid, to assess soil K reserves.

ResultsMulch application increased the yield levels of both crops, but the effects were morepronounced in cabbage than in red beet. On average, cabbage hearts yield was 49 tonnesha" without application, 60 tonnes with one and 68 with two applications. For red beet,the corresponding yield levels were 32, 39 and 41 tonnes ha". Considerably morenutrients were applied than were removed in saleable products. For P, the surplus ofnutrients was on average 39 kg ha -' in cabbage and 51 in red beet. For K, the surplus was230 kg" in cabbage and 364 in red beet. These amounts are large compared to the amountof P and K removed by the yields (saleable parts), which was on average for P 23 kg ha-in cabbage and 12 in red beet. For K, it was 159 kg ha-'in cabbage and 126 in red beet. Ifyields of crop residues above soil are included, the surplus was reduced for P to 23 kg ha"in cabbage and 47 in red beet, and for K 100 kg ha' in cabbage and 180 in red beet. Thisis a considerable amount of plant nutrients.

227

A substantial portion of the P and K that was not accounted for in plant products wasfound to be available in the topsoil (0-25 cm) in late autumn. P-AL levels increased from25 to 29 mg P kg-' in cabbage, and from 27 to 35 in red beet (p<0.05). K-AL levelsincreased from 65 to 113 mg K kg' in cabbage, and from 71 to 128 in red beet (p<0.01).Values of acid-soluble K minus K-AL increased from 221 to 276 mg K kg-' incabbage(p<0.01), and from 232 to 301 in red beet. No indications of increase in P or Kconcentrations were found in the subsoil (25-60 cm), which shows that the nutrients arestored in the topsoil and not leached down the soil profile. For K, the increase in K-ALand acid-soluble concentrations is larger than the surplus of K. For P, not all surpluscould be recovered as P-AL. The remaining amount has probably increased the content oforganic P in soil. As this value is large and highly variable as compared to P-AL,differences in organic P would have been difficult to measure in this experiment.The area required to produce the required amount of mulch was approximately 2.5 timesthe size of the vegetable land by the first application, and 1.5 times the size by the second.The method of green mulch may be a way of distributing P and K between fertiliser-producing and -receiving fields in an organic vegetable production system with access tomore land than is necessary for the growth of vegetables.

Publication

This material is being prepared for scientific publication.

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POTASSIUM AND PHOSPHORUS:FERTILISATION EFFECT ON SOIL AND CROPS

Proceedings of the Regional IPI WorkshopOctober 23-24, 2000LITHUANIA

SL.1610. 2000 10 16. 16,5 cal. pub .1.Copies 200. Order NoPublished by the Lithuanian Institute of AgricultureAkademija, Kedainiai distr., LT-505 I, Lithuania

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