Research Article Tropical Legume Crop Rotation and...

Research ArticleTropical Legume Crop Rotation and Nitrogen Fertilizer Effectson Agronomic and Nitrogen Efficiency of Rice

Motior M Rahman Aminul M Islam Sofian M Azirun and Amru N Boyce

Institute of Biological Sciences Faculty of Science University of Malaya 50603 Kuala Lumpur Malaysia

Correspondence should be addressed to Motior M Rahman mmotiorrahmangmailcom

Received 14 January 2014 Revised 29 April 2014 Accepted 29 April 2014 Published 22 May 2014

Academic Editor Antonio Ferrante

Copyright copy 2014 Motior M Rahman et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Bush bean long bean mung bean and winged bean plants were grown with N fertilizer at rates of 0 2 4 and 6 gNmminus2 precedingrice planting Concurrently rice was grown with N fertilizer at rates of 0 4 8 and 12 gNmminus2 No chemical fertilizer was used inthe 2nd year of crop to estimate the nitrogen agronomic efficiency (NAE) nitrogen recovery efficiency (NRE) N uptake and riceyield when legume crops were grown in rotation with rice Rice after winged bean grown with N at the rate of 4 gNmminus2 achievedsignificantly higher NRE NAE and N uptake in both years Rice after winged bean grown without N fertilizer produced 13ndash23higher grain yield than rice after fallow rotation with 8 gNmminus2 The results revealed that rice after winged bean without fertilizerand rice after long bean with N fertilizer at the rate of 4 gNmminus2 can produce rice yield equivalent to that of rice after fallow withN fertilizer at rates of 8 gNmminus2 The NAE NRE and harvest index values for rice after winged bean or other legume crop rotationindicated a positive response for rice production without deteriorating soil fertility

1 Introduction

Rice is the most widely consumed staple food andmost com-mercially important crop formore than 3 billion people in theworldrsquos human population [1] Nitrogen is quantitatively themost essential nutrient for plants [2] and a major constraintand contributing factor for low productivity and widespreadfood insecurity in most rice-based cropping systems in Asia[3 4] The intensive cultivation of cropping practices withhigh yielding rice varieties requires better soil and nutri-ent management [5] Alternatively long-term cropping candegrade soil fertility [6] Soil texture and crop rotation prac-tices can influence rates of N fertilizer application in rice crop[7 8] However imbalanced rates and injudiciousmethods offertilizer application can lead to poor N efficiency N lossesdue to leaching and other chemical and biological processesin soil [9ndash12] resulting in a series of environmental hazardsand economic losesThus it is obvious that poor nitrogen useefficiency (NUE) causes higher production costs and induceslower net returns for rice growers [13] So an efficient N util-ization must be ensured for sustainable crop production for

the benefit of environment and economic reasons [14 15]Optimumuse of N fertilizer is a crucial step to improve NUEwhile a positive relation between soil N supply and crop Ndemand is one of the key factors to appropriate N utilizationby plants [16]

Soil N supply through biological nitrogen fixation (BNF)by associated microbial populations is one of the principalsources of N for rice production However the loss of soil Noccurs continuously through removal of plant or harvestingof grain and chemical processes of the soil [12] In additionthe indigenous soil N supply in wetland ricemay decline withintensive rice cultivation unless it is restored by BNF [17]Considering both environmental and economic perspectivesmaintenance of native soil N resource and improvement of Noutput from plant sources are one of the desirable options toreduce the use of chemical fertilizer in rice cropping system[18] Soil N loss may be minimized by using effective legumecropswhich can supply sufficient BNF input to enhance soilNby improved recycling of N through plant residues [19]Thusthe combined indigenous soil N and N achieved throughlegume in BNF have the potential for N enrichment in soil

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 490841 11 pageshttpdxdoiorg1011552014490841

2 The Scientific World Journal

which will increase NUE of crops and total N output ina lowland rice-based cropping system [20] In addition tofixing atmospheric nitrogen leguminous green manures playa significant role in conserving NO

3

[21 22] It is well recog-nized that the legume plant can add organic N and theirresidues contribute to the improvement of soil texture andmicrobial activity However rice growers believe that the ac-crued N benefits will vary among different legume systems[23]

InMalaysia most of the rice growing areas are well estab-lished with irrigation systems and farmerrsquos practicing doublecropping systems with high yielding varieties of rice crop [5]which mainly depends on inorganic N fertilizer and otherchemical fertilizers The government has spent more than30 billion US$ (RM 92 billion) to import 42 million tonsof mineral fertilizers to sustain crop production in Malaysia[24] Subsequently its policy has focused more towardsagroecological healthier and sustainable food productionpractices through an integrated approach of rice cultivationwith crop rotation using vegetable legume and intercroppingpractices for sweet corn maize and organic farming tominimize the dependence on mineral fertilizers [25ndash27]Inclusion of grain legumes or green manure legume crops inrotation with rice or corn can protect degradation of soil fer-tility [28ndash30] improve soil structure water holding capacity[31] and result in greater productivity and higher incomewhile minimizing production risk and ensuring long-termsustainability as well as ensure a greener environment [3031] Incorporation of crop residues alters the soil environmentthat in turn influences the microbial populationrsquos activity inthe soil and subsequent nutrient cycle [23] and will sustainrice productivity through replenishing soil organic matter[32] The presence of soil organic matter is a key indicator ofsoil quality which provides plant nutrients upon mineraliza-tion and eventually improves soil properties [33]

Legume crop residues contribute to organic N and afterdecomposition by soil microbes throughmineralization addavailable N for the next crop [34] and ameliorate the nutrientstatus of the soil In Malaysia rice growers cultivate two ricecrops per year and sometimes five crops in a two-year periodbut crop rotation practices of rice with tropical grain legumesor green manure legume crops are not often used [27] Thishas brought about soil fertility deterioration which threatensthe ecosystem through intensive application of inorganicchemical fertilizers Thus the appropriate management andefficient utilization of crop residues are important for theproper amendment of soil quality and crop productivity un-der a rice-based cropping system in the tropics [22] Indeedthe use of grain legumes or cover crops has been proven tobe commendable in terms of its positive effects Bush beanlong bean sprouted mung bean seed and winged bean aretraditional vegetables cultivated in marginal land and thereare ample opportunities to adapt these crops in an uplandrice-based crop rotation system Presently growers are con-cerned about the quality and as well sustainable use ratherthan the quantity of food production Attention has beenfocused towards the use of legume crops to improve soilhealth for productivity of rice cropThepractice of using trop-ical legumes such as bush bean long bean winged bean or

mung bean alone or in combination with inorganic N fer-tilizers offers promising scope as an N supplement to ricecrop rotation systems No systematic research has beencarried out on the consequence of N in greenmanure legumeand the productivity of legume crops and their effects on soilN dynamics and contributions to the yield and N uptake ofthe following rice crop in Malaysia The combined effect oflegume residues and indigenous nutrient supplies or fertilizeruptake and losses in rice-based systems is little understoodThe present study was undertaken to assess the addition oflegume residues to plant N uptake NAE and NRE and alsothe amount of fertilizer N essential for optimizing rice yieldwhen legumes are enclosed in the system

2 Materials and Methods

21 Experimental Plan and Management The experimentswere carried out at the greenhouse University of MalayaKuala Lumpur Malaysia during 2010 and 2011 The clayloam soil was collected at depth of 30 cm from rice fieldin Selangor (1∘ 281015840 010158401015840 N 103∘ 451015840 010158401015840 E) Malaysia Nospecific permits were required for the described studies andno specific permissions were required for these activities Inaddition the locations were not protected and the studies didnot involve endangered or protected species The soil usedhad the following chemical properties pH 655 plusmn 020 (1 5wv water) CEC 15 (cmolc kg

minus1 soil) organic C 175 plusmn 048(CHNS analyzer model NA 1500) total N 018 plusmn 004NH4

-N 637 plusmn 125 (mg 100minus1 g soil) exchangeable CaO1710plusmn2115 (mg 100minus1 g soil) exchangeableMgO 108plusmn275(mg 100minus1 g soil) and exchangeable K

2

O 149 plusmn 906 (mg100minus1 g soil) The soils were thoroughly mixed and unwantedinert materials were discarded through sieve (2mm mesh)to produce homogenous soil composites The experimentalpots (height 46 cm times diameter 54 cm = surface area 1m2)were filled with soil up to about 36 cm height (height 36 cm timesdiameter 54 cm = surface area 084m2) of each pot Alldata was converted into 1m2 The seeds of bush bean(Phaseolus vulgaris L) long bean (Vigna unguiculata (L)Verdc) mung bean (Vigna radiata (L) R Wilczek) wingedbean (Psophocarpus tetragonolobus (L) DC) and corn (Zeamays L) were sown in moistened soil to ensure germinationAll legume crops were fertilized with N fertilizer (urea 46N) at rates of 0 2 4 and 6 gNmminus2 while HYV corn andHYV rice fertilized at rates 0 4 8 and 12 gNmminus2 in the firstcycle of the experiment in 2010 Fertilizer was applied in soilprior to the sowing of seeds of bush bean (cv-MKB 1) longbean (cv-MKP 5) mung bean (cv local) winged bean (cvlocal) and corn Corn was used as non-N

2

-fixing referenceplant for estimation of N

2

fixation by N difference method(NDF) In addition 16 fallow pots were assigned to fulfill therequirement of rice after fallow crop rotation Each crop wastested in an individual experiment and each experiment wasconducted under completely randomized design with fourreplications which covered 16 pots for each crop and a totalof 96 pots for all the crop cycles Rice was transplanted asthe 2nd crop after harvesting of first crop cycles of corn andor incorporation of legume residues After completion of the

The Scientific World Journal 3

Table 1 Biomass yield of bush bean long bean mung bean winged bean and corn as affected by nitrogen fertilizer

Nitrogen Biomass yield (gmminus2)(gm2) Bush bean Long bean Mung bean Winged bean Cornlowast

2010 2011 2010 2011 2010 2011 2010 2011 2010 2011 2010 20110 0lowast 0 1482c 1401c 1384c 1368b 1349c 1316c 1798b 1694b 4625d 4495d

2 4lowast 0 1557b 1498b 1459b 1407b 1450b 1417b 1873ab 1847a 5375c 5147c

4 8lowast 0 1655a 1564a 1557a 1492a 1515b 1482b 1906a 1876a 5798b 5603b

6 12lowast 0 1700a 1629a 1619a 1557a 1583a 1577a 1972a 1932a 6352a 6026a

Means followed by the same letters are not significantly different for each treatment mean (119875 lt 005)lowastDenotes N fertilizer rate for corn in 2010

1st cycle of rice crop all legumes and corn were grown inthe same pot as third crop in the 2nd cycle No N fertilizeror other chemical fertilizers were applied in the 2nd yearto estimate the enduring effect of legume residues for thenext crop Concurrently fallow pots were used as rice afterfallow crop rotation cycle Bush bean long bean mung beanwinged bean and corn were planted in early March of 2010and 2011 All legume crops and cornwere harvested at 70 daysafter emergence Rice seedlings (14 d old) were transplantedduring the 2nd week of July for both years In the 1st cyclethe rice crop was fertilized in three stages one third beforetransplanting one third at tillering and one third at panicleprimordial initiation stages respectively Rice was harvestedat the stage of physiological maturity during the second weekof November in both years

Above ground plant parts of all legumes were harvestedand fragmented into small pieces and spread into the potsand incorporated to a depth of about 8ndash10 cm into soil withmulching This was followed by watering and the pot wasleft stagnant for 30 days to prepare for rice transplantingWater was applied every alternate day to keep soil moist untilphysiological maturity of rice plant

22 Determination of Total Dry Matter and Nitrogen Afterharvesting of each crop randomly 200 g fresh plant sampleswere taken and dried to constant weight at 70∘C Dry weightwas measured by digital sensitive balance and convertedinto above ground biomass yield rice grain yield and Ncontent for each crop per unit area Biomass and grain yieldwere determined from each pot Total N concentration wasdetermined by micro-Kjeldahl digestion method [34 35]

23 Estimation of Biological Nitrogen Fixation and NitrogenUse Efficiency (NUE) It is well documented that soil and fer-tilizer are the sources of N for nonfixing crops while sourcesof N for fixing crops (F) are from the soil fertilizer andatmosphere For nonfixing and fixing crops the proportionsof N from all the available sources can be denoted as follows[36]

NdffNF +NdfsNF = 100

NdffF +NdfsF +NdfaF = 100

Ndfa = 100 minus (NdffF +NdfsF)

(1)

where NdffNF denotes N derived from fertilizer for nonfixingcrops NdfsF denotes N derived from soil for nonfixing cropsNdffF denotesNderived from fertilizer for fixing cropsNdfsFdenotes N derived from soil for fixing crops and NdfaFdenotes N derived from atmosphere for fixing crops

The N difference method (NDF) was used to estimate thecontributions of BNF to total N accumulation in the legumes[37] Consider

Ndfa = 100[(Legume N minus Reference N)]

(Legume N) (2)

The followingN-efficiency parameterswere calculated foreach treatment [38ndash40]

N agronomic efficiency (NAE g gminus1) = (grain yield atNx minus grain yield at N0)applied N at Nx and N fertilizerrecovery efficiency (NRE) = (N uptake at Nx minusNuptake atN0)applied at Nx

Datawere analyzed following analysis of variance [41] andtreatment means were compared based on the least signifi-cant difference (LSD) test at the 005 probability level

3 Results and Discussion

31 Biomass Yield and Nitrogen Uptake of Legume CropsLegume crop biomass yield andNuptakewere influenced sig-nificantly with N fertilizer application Winged bean grownwith N fertilizer at rates of 4 8 and 12 gNmminus2 producedgreater biomass (gt185 gmminus2) and N uptake (gt65 gmminus2) forboth years In 2010 the biomass yield of bush bean was 148ndash170 gmminus2 (Table 1) with a parallel N accumulation of 50ndash59 gmminus2 As shown in Table 2 in 2011 the biomass of bushbeanwas 140ndash163 gmminus2 with the comparable N accumulationof 47ndash56 gmminus2 (Table 2) Biomass yield and N uptake ofbush bean long bean and mung bean were slightly lowercompared to winged bean Biomass and N uptake was higherin winged bean compared to the other tested legume crops inboth years All the tested legume crops other than wingedbean recorded consistently identical biomass yield and Nuptake Nitrogen uptake in the different legume species varyaccording to the influence of biomass production and Ncontent in the plant tissues Earlier studies have reportedthat faba bean produced gt10 kg biomass mminus2 which recordedgt35 gNmminus2 [33] Other studies have also reported that N


Table 2 Nitrogen uptake of bush bean long bean mung bean winged bean and corn as affected by nitrogen fertilizer

Nitrogen Nitrogen uptake (gmminus2)(gm2) Bush bean Long bean Mung bean Winged bean Cornlowast

2010 2011 2010 2011 2010 2011 2010 2011 2010 2011 2010 20110 0lowast 0 50c 47c 47d 46c 46c 45d 62b 56b 36d 34d

2 4lowast 0 53b 51b 50c 48c 50b 48c 65ab 63a 43c 40c

4 8lowast 0 57a 53b 54b 51b 52b 51b 67a 66a 48b 45b



Table 3 Nitrogen fixation of bush bean long bean mung bean andwinged bean as affected by nitrogen fertilizer

Nitrogen Nitrogen fixation ()(gm2) Bush bean Long bean Mung bean Winged bean

2010 2011 2010 2011 2010 2011 2010 2011 2010 20110 0 294a 288a 244a 251a 221a 241a 421a 414a

2 0 192b 222b 142b 168b 133b 180b 334b 374a

4 0 165c 161c 119c 125c 92c 118c 294b 318b

6 0 99d 132d 58d 95d 31d 86d 217c 295b

Means followed by the same letters are not significantly different for eachtreatment mean (119875 lt 005)

uptake by cover crops produced 45 to 225 g of N per mminus2[42ndash44] Furthermore total N accumulation produced byVicia fabaL plant residueswere lower (116 to 199 gmminus2) thanthose gained byVicia villosaRoth (164 to 264 gmminus2) [23 44]In this study N uptake by winged bean plant residues wasapparently higher than other crops This was probably due tothe biomass yield of long bean bush bean and mung beanbeing lower than that of winged bean

32 Nitrogen Fixation and Nitrogen Recovery Efficiency ofLegume Crops Nitrogen fixation and NRE of legume cropswere significantly affected by the use of N fertilizer Nitrogenfixation in winged bean was 22ndash42 of the total plant N 10ndash29 in bush bean 6ndash25 in long bean and 3ndash24 in mungbean in 2010 Irrespective of N fertilizer used in 2010 N

2

fixation in winged bean was 30ndash41 13ndash29 in bush bean10ndash25 in long bean and 9ndash24 in mung bean in 2011 asdetermined by the total NDF method (Table 3) The highestN2

fixation was achieved by winged bean (41-42) followedby bush bean (29) long bean (24-25) and mung bean(22ndash24) when all the legume crops were grown without Nfertilizer for both years Earlier studies have shown that N

2

fixation inCajanus cajan (L)Millsp was 44 to 95 [43] whileN2

fixation by Vicia faba and Vicia villosa was 41 and 78of total plant N respectively [44 45]

Winged bean grown with 2 or 4 gNmminus2 obtained appre-ciably higher NRE in 2010 while NREwas remarkably higher(29) when winged bean was grown without N fertilizerin 2011 (Table 4) The superior N

2

fixation and NRE of all

Table 4Nitrogen recovery efficiency of bush bean long beanmungbean and winged bean as affected by nitrogen fertilizer

Nitrogen Nitrogen recovery efficiency ()(gm2) Bush bean Long bean Mung bean Winged bean2010 2010 2011 2010 2011 2010 2011 2010 20110 00c 00c 00c 00c 00c 00d 00d 00d

2 140b 180a 150b 130b 195a 195a 155a 290a

4 163a 153b 170a 155a 165b 160b 145b 205b

6 148b 148b 157b 148a 157b 150c 112c 195c


tested legume crops were directly linked to the lower rateof N fertilizer application Nitrogen recovery efficiency inlong bean was lower in 2011 The lowest NRE was recordedby legume crops treated with the highest rate of N fertilizerused to the preceding rice crop Our findings have shownthat legume residues mixed into rice crop rotation enrich notonly to raise yield but also to nurture and ameliorate soilfertility by virtue of their ability to add ample quantities ofatmospheric N Legumes can make a significant contributionto advance soil fertility and improve soil texture [46ndash48]Biomass yield legume N demand the capacity to fix N

2

andadaptability to specific environments are important attributesfor BNF [49] Nitrogen content in legume above groundbiomass ranged from 45 gNmminus2 to 69 gNmminus2 which wasintegrated into the soil Among the tested legume plantswinged bean supplied substantially higher N over their resi-dues in each season The higher quantities of nitrogen N

2

se-cured in winged bean came from its larger supply of bio-mass production as well as a higher number of nodules

33 Biomass Yield of Rice after Legume Crops Biomass yieldof ricewas strongly influenced by the treatment variables Sig-nificantly greater biomass production was produced by riceafter winged bean with 4 8 and 12 gNmminus2 in both years(Table 5) Biomass yield was lower when rice was rotated withother legume crops than in rice after winged bean rotationbut it was higher than in rice after corn rotation Rice afterfallowwith 8 and 12 gNmminus2 also produced appreciably great-er biomass and it was almost at par with rice after bush bean


Table 5 Biomass yield of rice as affected by N fertilizer and legume residue

N (gmminus2) Biomass yield (gmminus2)Rice after bush bean Rice after long bean Rice after mung bean

2010 2011 2010 2011 2010 2011 2010 20110 0 9860c 9218c 9485c 9287c 9528c 9121c

4 0 10586b 9935b 10694b 10375b 10661b 9869b

8 0 10749ab 10749a 11355ab 10834a 11287a 10717a

12 0 11238a 10840a 11384a 11026a 11319a 10782a

N (gmminus2) Biomass yield (gmminus2)Rice after winged bean Rice after corn Rice after fallow

2010 2011 2010 2011 2010 2011 2010 20110 0 11547b 11075b 9055d 8730d 9414c 9055c

4 0 12622a 12117a 9316c 9055c 10651b 9935b

8 0 12834a 12443a 10261b 9609b 11368a 10423a

12 0 12899a 12541a 10586a 10065a 11270a 10586a

Means followed by the same letters are not significantly different for each treatment mean (119875 lt 005)

Table 6 Nitrogen uptake of rice as affected by N fertilizer and legume residue

N (gmminus2) Nitrogen uptake (gmminus2)Rice after bush bean Rice after long bean Rice after mung bean

2010 2011 2010 2011 2010 2011 2010 20110 0 94d 85c 93c 85c 91c 84c

4 0 104c 95b 104b 95b 102b 94b

8 0 110b 107a 115a 103a 114a 107a

12 0 116a 109a 116a 108a 115a 108a

N (gmminus2) Nitrogen uptake (gmminus2)Rice after winged bean Rice after corn Rice after fallow

2010 2011 2010 2011 2010 2011 2010 20110 0 121b 113b 71d 68d 75c 71d

4 0 134a 125a 76c 72c 85b 79c

8 0 137a 128a 84b 77b 95a 84b

12 0 139a 129a 89a 83a 97a 87a


rice after long bean or mung bean although the level wascomparably lower than rice after winged bean The lowestbiomass yield was produced by rice after corn or rice afterfallow grown without N fertilizer (Table 5) The accumulatedbiomass following rotation with winged bean is possiblyan indication of N contribution from the above and belowground residues of the legume On the contrary a consider-able amount of urea was used and apparently volatile loss ofammonia occurred in rice after fallow rotation with fertilizerA possible reason this was due to the N fertilizer appliedup to panicle initiation stage Earlier studies have suggestedthat an appreciable amount of N can be lost via ammoniavolatilization when urea was applied at sampling stage justbefore top dressing [50] The presence of soil organic matterand decomposed plant residues are the primary determinantsof total plant-available N supply for plant growth which iscontrolled by the balance between N immobilization andmineralization as mediated by soil biota as well as the

contributions from applied organic and inorganic N sourcesand losses from the plant-available N pool [51]

34 Nitrogen Uptake and Nitrogen Efficiency of Rice afterLegume Crops Total N uptake was influenced by N fertilizerapplication in each crop rotation (Table 6) Maximum Nuptakewas observed in rice rotationwithwinged beanwith 48 and 12 gNmminus2 Rice after long bean or bush bean or mungbean with 8 and 12 gNmminus2 obtained appreciably greater Nuptake compared to rice after fallow or corn Rice after fallowor in rotation with corn grown without N fertilizer appli-cation recorded the least N uptake (Table 6) The increasedplant N following rotation with winged bean could probablybe attributed to theN contribution from the addition of largeramounts of above ground plant parts and below ground plantresidues of legume The quality of residues in legume plantsin rotation with rice crops might be the reason for the greater


Table 7 Nitrogen recovery efficiency of rice as affected by N fertilizer and legume residue

N (gmminus2) Nitrogen recovery efficiency ()Rice after bush bean Rice after long bean Rice after mung bean

2010 2011 2010 2011 2010 2011 2010 20110 0 00c 00d 00c 00d 00c 00d

4 0 288a 275a 288a 275a 275a 250b

8 0 295a 238b 294a 238b 288a 288a

12 0 196b 200c 196b 200c 200b 200c

N (gmminus2) Nitrogen recovery efficiency ()Rice after winged bean Rice after corn Rice after fallow

2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00c 00d

4 0 325a 300a 100b 98b 255a 200a

8 0 200b 188b 163a 111a 250a 163b

12 0 150c 133c 150a 124a 183b 133c


N uptake compared to rice after corn and rice after fallowrotation Despite the smaller below ground residues of otherpulses other than cereals and other crops they possess ahigher microbial population in the soil which influences theconcentrations of nutrients released in the rhizosphere for Nuptake by the plants [52]

Among crop rotations rice after winged bean with N atrates of 4 8 or 12 gmminus2 showed the highest N uptake whilstrice after other legumes with N at rates of 4 8 or 12 gmminus2 re-corded intermediate N uptake and rice after corn and riceafter fallow rotation recorded the lowest Soilmicrobial popu-lation increased rapidly when young and relatively succulentgreen manure crop are incorporated into the soil The soilmicroorganisms multiply faster to invade the freshly incor-porated plant residues After decomposition of plant residuesthrough microbial breakdown nutrients remain within theplant tissues and nutrient rich dead microbes which are re-leased and made available to the following crop [51] In ourstudy all legume crops were added into soil at the pod forma-tion stage Apparently this could slightly slow the breakdownof legume residues resulting in poor volatile loss of ammoniaduring rice after winged bean or rice in rotation with otherlegume growing cycles While in rice fallow systems with fer-tilizer a substantial amount of the applied urea are seeminglylost by ammonia volatilization

Nitrogen recovery efficiency (NRE) was influenced sig-nificantly by N fertilizer application in each crop rotation(Table 7)The highest NRE (325) was obtained by rice afterwinged bean with 4 gNmminus2 In this study the observed NREvalues were relatively lower than those reported in previousstudies where N fertilizer was used later in the crop growingperiodTheNREwas significantly higher in 2010 than in 2011possibly due to the fact that the highest grain yield was re-corded in 2010 (Table 7)The higher grain yield of rice in 2010could be due to higher N uptake caused by both legumeresidual effects along with N fertilizer Regardless of fertilizerrice after legumes obtained higher NRE than rice after fallowor corn in both years In India the large variation in NRE

(18mdash1st year and 49mdash2nd year) was observed in rice-wheat systems This difference was directly linked with pooryields in the first year caused by unfavorable weather andhighlights the importance of higher crop growth and yieldto higher NRE [49] Higher NRE values were reported inrotation than in monoculture [40 53] Regardless of Nfertilizer rate the NRE values were 15ndash33 in 2010 and 13ndash30 in 2011 for rice after winged bean (Table 7) The NREvalues were 20ndash29 in 2010 and 20ndash28 in 2011 for riceafter bush bean or long bean or mung bean In our studythe NRE values were lower compared to NRE values (42)obtained in developed countries [50] A possible reason couldbe due to the fact that the present study was carried out undergreenhouse conditions which does not show the full potentialof legume performance while in developed countries studieswere conducted in on-station field conditions

The higher N recoveries in legume rotations could be dueto the enrichment of soil NThe below ground pool of legumeN is an important source of N for subsequent crops [51]When the soil N content rises the amount of sequesteredN contributes to a greater NUE of the cropping system andthe amount of sequestered N achieved from applied N resultsin a higher NRE [51] The average NUE gained by ricefarmers is 31 of applied N based upon on-farm estimationin the major rice production countries of Asia In contrastit is documented that the recovery efficiency of nitrogen forrice normally varies between 50 and 80 in well-managedfield experiments [51] Therefore emphasis has been given toimprove recovery efficiency of nitrogen because the N fer-tilizer is the greatest source of N input and loss from cerealcropping systems

Nitrogen agronomic efficiency (NAE) was affected signif-icantly by N fertilizer application in each crop rotation Riceafter winged bean grown with 4 gNmminus2 recorded the highestNAE (24 g gminus1 to 27 g gminus1) for both years (Table 8) Rice afterlong bean with 4 gNmminus2 also showed a similar trend al-though NAE was lower than rice after winged bean systemsregardless of N fertilizer for both years (Table 8) The NAE


Table 8 Nitrogen agronomic efficiency (g gminus1) of rice as affected by N fertilizer and legume residues

N (gmminus2) Nitrogen agronomic efficiency (g gminus1)Rice after bush bean Rice after long bean Rice after mung bean

2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00d 00c 00d 00d

4 0 130a 125a 212a 171a 148a 129a

8 0 107b 97b 151b 114b 126b 114b

12 0 74c 65c 128c 111b 83c 78c

N (gmminus2) Nitrogen agronomic efficiency (g gminus1)Rice after winged bean Rice after corn Rice after fallow

2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00 00d

4 0 269a 236a 147a 163a 212a 138b

8 0 163b 147b 155a 143b 187b 151a

12 0 122c 125c 133b 122b 152c 114c


trends were similar in both 2010 and 2011 Rice after fallowand rice after long bean with 4 gNmminus2 also showed similartrends although NAE credentials of rice after winged beansystems indicate a positive response to rice production with-out deteriorating soil fertility Therefore the nitrogen agro-nomic efficiency and grain yield was significantly increasedby the legume plant residues when supported by organicsources of N The results showed that the increase in theapplication of N caused the decline of agronomic nitrogenefficiency The highest and the lowest agronomical nitrogenuse efficiencies were obtained in the 60 and 180 kgNhaminus1which showed that NAE decreased with the increasing rateof N fertilizer used [54] From this it can be said that thefertilizer response to NRE was poor but grain yield and Nuptake showed significant differences among fertilizer ratesIn this regard NUEwas reduced at higher rates of fertilizer Nrate possibly due to greater losses from soil via volatilizationor leaching losses [53] With respect to fertilizer utilization inrice crop current N fertilizer management strategies must beimproved in upland as well as wetland rice growing areas inMalaysia

35 Grain Yield and Harvest Indices of Rice Rice grain yieldincreased significantly by the amendment of soil with addi-tion of legume residues and N fertilizer application (Table 9)Maximum grain yield (603ndash684 gmminus2) was produced by riceafter winged beanwith 4 8 and 12 gNmminus2 in both years Ricein rotation with corn (293ndash349 gmminus2) and rice after fallow(342ndash371 gmminus2) grown without fertilizer recorded the lowestyield of rice crops Rice after long bean or bush bean ormung bean with 8 and 12 gNmminus2 gave similar yields for bothyears In 2011 a slightly lower yield was obtained but a similartrend was observed in all the crop rotation systems Ricein rotation with corn grown with 8 gNmminus2 and 12 gNmminus2produced comparatively lower yield than other counterpartsIdentical yieldwas observed in rice after fallowwith 8 gNmminus2and 12 gNmminus2 (Table 9) In rice after fallow rotation rice

yield showed a positive response to fertilizer rates evenat 12 gNmminus2 which suggested that higher yields could beproduced with higher rates of N fertilizer application Inboth years legume crop residues incorporation in rice afterwinged bean and rice after long bean crop rotation systemswas effective in producing a satisfactory yield even in 2011when rice after winged bean was grown without N fertilizerIt was observed that rice grain yield decreased about 5ndash33 in the zero-N control among legume crop rotation inthe second year of experiment The rice grain yield provedthat winged bean was more effective than N fertilizer forboth years Similar results were obtained in rice after hairyvetch with 4 or 8 gNmminus2 [44] In 2011 rice grain yield wasslightly lower when grown without N fertilizer in the case ofrice after winged bean rotation but the addition of wingedbean residues contributed noticeably to higher yield levelswhen compared with rice after fallow with 8 or 12 gNmminus2The present findings differed with observations from otherstudies [18] which have reported that rice yield did notincrease or even decrease when rice straw residue was addedwithout fertilizer N The possible reason for this could bedue to the use of rice straw residues under upland conditionswhich were not fully decomposed during the rice growingseasonAdditionally grain yield of rice significantly increasedwhen residues were incorporated into flooded soil [47] Ourresults suggest that legume residues had a positive influenceon both rice yield and N uptake when fertilizer was notused Certainly the influence of legume residues on riceyield depends on the soil nutrient status texture addition oforganic matter amount of residue returned to soil [33] andtiming and levels of fertilizer N used

Addition of legume residues and N fertilizer applicationhad a significant effect on harvest indices (HI) for bothyears (Table 10) In both 2010 and 2011 rice crop rotationwith winged bean grown with 4 8 and 12 gNmminus2 achievedhigher HI compared to the other crop rotation systems Riceafter fallow or corn gown without fertilizer N recorded thelowest HI for both years Rice after bush bean with 8 or


Table 9 Grain yield of rice as affected by N fertilizer and legume residues

N (gmminus2) Yield (gmminus2)Rice after bush bean Rice after long bean Rice after mung bean

2010 2011 2010 2011 2010 2011 2010 2011

0 0 4245c 3583c 4169c 4039c 4072c 3957c

(minus21) (minus33) (minus22) (minus25) (minus24) (minus26)

4 0 4951b 4397b 5016b 4723b 4951b 4492b


8 0 5472a 4723ab 5375a 4951ab 5400a 4887a

(+2) (minus12) (+1) (minus7) (+1) (minus8)

12 0 5537a 5212a 5700a 5375a 5653a 5212a

(+4) (minus2) (+7) (+1) (+6) (minus2)N (gmminus2) Yield (gmminus2)

Rice after winged bean Rice after corn Rice after fallow2010 2011 2010 2011 2010 2011 2010 20110 0 5375b 5081b 3485d 2932d 3713c 3420c

(+1) (minus5) (minus35) (minus45) (minus31) (minus36)4 0 6450a 6026a 4072c 3583c 4886b 4235b

(+21) (+13) (minus24) (minus33) (minus8) (minus21)8 0 6678a 6254a 4723b 4072b 5342

alowast 4723a

(+25) (+17) (minus12) (minus24) (100) (minus12)12 0 6840a 6580a 5081a 4397a 5537a 5049a

(+28) (+23) (minus5) (minus18) (+4) (minus5)Means followed by the same letters are not significantly different for each treatment means (119875 lt 005)lowastParenthesis values denote yield increase (+) or decrease (minus) in percent values are calculated based on rice after fallow with 8 gN mminus2 (100)

Table 10 Harvest indices of rice as affected by N fertilizer and legume residues

N (gmminus2) Harvest indicesRice after bush bean Rice after long bean Rice after mung bean

2010 2011 2010 2011 2010 2011 2010 20110 0 429c 389c 435c 435c 427c 432b

4 0 468b 443b 456b 455b 464b 455b

8 0 509a 439b 457b 457b 476b 456b

12 0 493a 481a 487a 487a 495a 483a

N (gmminus2) Harvest indices ()Rice after winged bean Rice after corn Rice after fallow

2010 2011 2010 2011 2010 2011 2010 20110 0 466b 459b 385c 332c 394d 353c

4 0 511a 497a 437b 396b 414c 377b

8 0 520a 503a 460a 424a 458b 422a

12 0 530a 525a 480a 437a 491a 431a


12 gNmminus2 gave superior HI in 2010 and similarly rice afterlong bean or mung bean with 12 gNmminus2 gave better HIin 2010 Rice after fallow or corn with 12 gNmminus2 showedidentical HI for both years (Table 10) The harvest indiceswere lower in all systems in 2011 except for rice after wingedbean It has been documented that harvest indices increasessignificantly with higher rates of N fertilizer application [55]However on the contrary other studies have reported thatwith increasing N fertilizer the harvest index decreased[56] The lower HI with higher N fertilizer application

suggested that N fertilizer influenced more biological yieldthan economic yield [57] The grain harvest index valueswere 43 at zero N level and 50 at 400mgNkgminus1 across 19upland rice genotypes [16] Nitrogen significantly improvedgrain harvest index nitrogen harvest index and plant heightwhich are positively associated with grain yield [58 59]The higher levels of phosphorus (72 kg haminus1) applicationin rice also recorded higher harvest index [60] Harvestindex is a measure of success in partitioning assimilatedphotosynthate An improvement of harvest index means an


increase in the economic portion of the plant [61] Ourobservations suggest that higher fertilizer N application andtheir residual effect along with N

2

fixation from legume cropsinfluence HI in legume crop rotation systems

4 Conclusions

Thepresent study has shown that both legume residues andNfertilizer affected grain yieldNuptakeNAE andNREwhichwere greater in 2010 than in 2011 Rice rotation by all legumesproduced consistently higher grain yield and NUE than riceafter fallow However the NUE declined with higher levelsof fertilizer N used reflecting poor N utilization by the ricecrop This indicated that though rice rotation with legumecrops plays a significant role in the improvement of grainyield higher levels can be sustained by compatible and propermanagement of residues and N fertilizer The N differencemethod applied in this study exhibited that N produced byall the legumes was readily available and can be used effi-ciently by the rice crop Winged bean was capable of pro-ducing greater amount of biomass and providing high quan-tities of total N in addition to fixing substantial quan-tities of NWithout significant loss of yield level winged beanplant residue incorporation can be an alternative source toN fertilizer for sustainable rice yield However the incor-poration of long bean plant residues requires minimum Nfertilizer (4 gNmminus2) and can be an alternative to the soleuse of N fertilizer while bush bean and mung bean plantresidues along with N fertilizer (8 gNmminus2) can also be analternative toNmanagementmethod to reduceN losses fromN fertilizer applied to rice crop Winged bean plant residuesare able to provide sufficient N to the soil for the rice cropand afford an advantage equivalent to that of 4 to 8 g fer-tilizer Nmminus2 respectively In conclusion amongst the testedlegumes winged bean showed the greatest potential while theother legumes can also be used as a substitute or supplementin place of chemicalinorganic N fertilizers

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

Theauthors thank theUniversity ofMalaya for their generousfinancial support (RG08810SUS) The technical assistanceof the Department of Chemistry personnelrsquos Laboratory forChemical Analysis and to avail their laboratory facilities ishighly appreciated

References

[1] A Makino ldquoPhotosynthesis grain yield and nitrogen utiliza-tion in rice and wheatrdquo Plant Physiology vol 155 no 1 pp 125ndash129 2011

[2] T Mayumi A Tomomi and Y Tomoyuki ldquoAssimilation of am-monium ions and reutilization of nitrogen in rice (Oryza sativaL)rdquo Journal of Experimental Botany vol 58 no 9 pp 2319ndash23272007

[3] S M Haefele S M A Jabbar J D L C Siopongco et al ldquoNi-trogen use efficiency in selected rice (Oryza sativa L) genotypesunder different water regimes and nitrogen levelsrdquo Field CropsResearch vol 107 no 2 pp 137ndash146 2008

[4] S M Haefele K Naklang D Harnpichitvitaya et al ldquoFactorsaffecting rice yield and fertilizer response in rainfed lowlandsof northeast Thailandrdquo Field Crops Research vol 98 no 1 pp39ndash51 2006

[5] N K Ho S Jegatheesan and F K Phang ldquoIncreasing rice pro-ductivity in Malaysia-an independent viewrdquo in Proceedings ofthe National Conference amp Workshop on Food Security KualaLumpur Malaysia December 2008

[6] X R Wei M D Hao M Shao and W J Gale ldquoChanges in soilproperties and the availability of soil micronutrients after 18years of cropping and fertilizationrdquo Soil and Tillage Researchvol 91 pp 120ndash130 2006

[7] J K Ladha and P M Reddy ldquoNitrogen fixation in rice systemsstate of knowledge and future prospectsrdquoPlant and Soil vol 252no 1 pp 151ndash167 2003

[8] S L Zhang Y A Tong D L Liang D Q Lu and E OveldquoNitrate N movement in the soil profile as influenced by rateand timing of nitrogen applicationrdquo Acta Pedologica Sinica vol41 pp 270ndash277 2004 (Chinese)

[9] J Richter andM Roelcke ldquoTheN-cycle as determined by inten-sive agriculturemdashexamples from central Europe and ChinardquoNutrient Cycling in Agroecosystems vol 57 no 1 pp 33ndash462000

[10] G X Xing and Z L Zhu ldquoAn assessment of N loss fromagricultural fields to the environment in Chinardquo NutrientCycling in Agroecosystems vol 57 no 1 pp 67ndash73 2000

[11] J G Zhu Y Han G Liu Y L Zhang and X H Shao ldquoNitrogenin percolation water in paddy fields with a ricewheat rotationrdquoNutrient Cycling in Agroecosystems vol 57 no 1 pp 75ndash822000

[12] C Kirda M R Derici and J S Schepers ldquoYield response andN-fertiliser recovery of rainfed wheat growing in the Mediter-ranean regionrdquo Field Crops Research vol 71 no 2 pp 113ndash1222001

[13] G Wang A Dobermann C Witt Q Sun and R Fu ldquoPerfor-mance of site-specific nutrient management for irrigated rice inSoutheast ChinardquoAgronomy Journal vol 93 no 4 pp 869ndash8782001

[14] W B Stevens R G Hoeft and R L Mulvaney ldquoFate ofnitrogenminus15 in a long-term nitrogen rate study II Nitrogenuptake efficiencyrdquo Agronomy Journal vol 97 no 4 pp 1046ndash1053 2005

[15] S Delin A Nyberg B Linden et al ldquoImpact of crop protectionon nitrogen utilisation and losses in winter wheat productionrdquoEuropean Journal of Agronomy vol 28 no 3 pp 361ndash370 2008

[16] N K Fageria and V C Baligar ldquoEnhancing nitrogen useefficiency in crop plantsrdquoAdvances in Agronomy vol 88 pp 97ndash185 2005

[17] N K Fageria N A Slaton and V C Baligar ldquoNutrient man-agement for improving lowland rice productivity and sustain-abilityrdquo Advances in Agronomy vol 80 pp 64ndash152 2003


[18] N Thuy H Shan S Bijay et al ldquoNitrogen supply in rice-basedcropping systems as affected by crop residue managementrdquo SoilScience Society of America Journal vol 72 no 2 pp 514ndash5232008

[19] E Cazzato V Laudadio AM Stellacci E Ceci andV TufarellildquoInfluence of sulphur application on protein quality fatty acidcomposition and nitrogen fixation of white lupin (Lupinus albusL)rdquo European Food Research and Technology vol 235 no 5 pp963ndash969 2012

[20] D K Kundu and J K Ladha ldquoEfficient management of soil andbiologically fixed N2 in intensively-cultivated rice fieldsrdquo SoilBiology and Biochemistry vol 27 no 4-5 pp 431ndash439 1995

[21] S M Dabney J A Delgado and D W Reeves ldquoUsing wintercover crops to improve soil and water qualityrdquo Communicationsin Soil Science and Plant Analysis vol 32 no 7-8 pp 1221ndash12502001

[22] S Yadvinder S Bijay and J Timsina ldquoCrop residue manage-ment for nutrient cycling and improving soil productivity inrice-based cropping systems in the tropicsrdquo Advances in Agron-omy vol 85 pp 269ndash407 2005

[23] I Rochester and M Peoples ldquoGrowing vetches (Vicia villosaRoth) in irrigated cotton systems inputs of fixed N N fertilisersavings and cotton productivityrdquo Plant and Soil vol 271 no 1-2pp 251ndash264 2005

[24] M S Ali ldquoEvolution of fertilizer use by crops in recent trendsand prospectsrdquo in Proceedings of the International FertilizerIndustry Association p 3 IFA Cross Roads Asia-Pacific KotaKinabalu Malaysia December 2009

[25] A B N M Wan ldquoCountry paper Malaysia impact of landutilization systems on agricultural productivityrdquo in Report ofthe APO Seminar pp 226ndash240 APO Japan 2003 2000 IslamicRepublic of Iran 4ndash9 November 2000

[26] A Faridah ldquoSustainable agriculture system inMalaysiardquo in Pro-ceedings of the Regional Workshop on Integrated Plant NutritionSystem (IPNS rsquo01) Development in Rural Poverty AlleviationUN Conference Complex BangkokThailand September 2001

[27] A R Khairuddin ldquoBiofertilizers in Malaysian agriculture per-ception demand and promotion Country Report of Malaysiardquoin Proceedings of the FNCA Joint Workshop on Mutation Breed-ing and Biofertilizer Beijing China August 2002

[28] D A Derksen K E McGillivary S J Neudorf et alWheat-PeaManagement Study Annual Report Agriculture and Agri-FoodCanada Brandon Research Centre Brandon Canada 2001

[29] A E Russell D A Laird and A P Mallarino ldquoNitrogen ferti-lization and cropping system impacts on soil quality in mid-western mollisolsrdquo Soil Science Society of America Journal vol70 no 1 pp 249ndash255 2006

[30] K Kumar and K M Goh ldquoCrop residues and managementpractices effects on soil quality soil nitrogen dynamics cropyield and nitrogen recoveryrdquo Advances in Agronomy vol 68pp 197ndash319 2000

[31] K M Goh D R Pearson andM J Daly ldquoSoil physical chemi-cal and biological indicators of soil quality in conventional bio-logical and integrated apple orchard management systemsrdquoBiological Agriculture and Horticulture vol 18 pp 269ndash2922001

[32] K Kumar KM GohW R Scott and CM Frampton ldquoEffectsof 15N-labelled crop residues and management practices onsubsequent winter wheat yields nitrogen benefits and recoveryunder field conditionsrdquo Journal of Agricultural Science vol 136no 1 pp 35ndash53 2001

[33] M R Motior T Amano H Inoue Y Matsumoto and TShiraiwa ldquoNitrogen uptake and recovery from N fertilizer andlegume crops in wetland rice measured by 15N and non-isotopetechniquesrdquo Journal of Plant Nutrition vol 34 no 3 pp 402ndash426 2011

[34] G X Chu Q R Shen and J L Cao ldquoNitrogen fixation andN transfer from peanut to rice cultivated in aerobic soil in anintercropping system and its effect on soil N fertilityrdquo Plant andSoil vol 263 no 1-2 pp 17ndash27 2004

[35] J M Bremner ldquoNitrogen-totalrdquo in Methods of Soil AnalysisPart 3 Chemical Methods D L Sparks Ed pp 1085ndash1121 SoilScience Society of America Inc American Society of AgronomyInc Madison Wis USA 1996

[36] IAEA A Manual Use of Isotope and Radiation Methods in Soiland Water Management and Crop Nutrition FAOIAEA Agri-culture and Biotechnology Laboratory Agencyrsquos LaboratoriesSeibersdorf and Soil and water Management and Crop Nutri-tion Section International Atomic Energy Agency ViennaAustria 2001

[37] M B Peoples RM Boddey andD FHerridge ldquoQuantificationof nitrogen fixationrdquo in Nitrogen Fixation at the MillenniumG J Leigh Ed pp 357ndash389 Elsevier Science Amsterdam TheNetherlands 2002

[38] K G Cassman A Dobermann and D T Walters ldquoAgroe-cosystems nitrogen-use efficiency and nitrogen managementrdquoAmbio vol 31 no 2 pp 132ndash140 2002

[39] R J Lopez-Bellido and L Lopez-Bellido ldquoEfficiency of nitrogenin wheat under Mediterranean conditions effect of tillage croprotation and N fertilizationrdquo Field Crops Research vol 71 no 1pp 31ndash46 2001

[40] Z Shi D Li Q Jing et al ldquoEffects of nitrogen applications onsoil nitrogen balance and nitrogen utilization of winter wheat ina rice-wheat rotationrdquo Field Crops Research vol 127 pp 241ndash2472012

[41] SAS ldquoSAS Institute Incorporated Release 91rdquo Cary NC USA2008

[42] J Evans A M McNeil M J Unkovich N A Fettel and D PHeenam ldquoNet nitrogen balances for cool-season grain legumecrops and contributions to wheat nitrogen uptake a reviewrdquoAustralian Journal of Experimental Agriculture vol 41 no 3 pp347ndash359 2001

[43] M B Peoples and D F Herridge ldquoNitrogen fixation by legumesin tropical and subtropical agriculturerdquo Advances in Agronomyvol 44 pp 155ndash223 1990

[44] M M Rahman T Amano and T Shiraiwa ldquoNitrogen use effi-ciency and recovery fromN fertilizer under rice-based croppingsystemsrdquo Australian Journal of Crop Science vol 3 no 6 pp336ndash351 2009

[45] E Cazzato V Tufarelli E Ceci AM Stellacci andV LaudadioldquoQuality yield and nitrogen fixation of faba bean seeds asaffected by sulphur fertilizationrdquo Acta Agriculturae Scandinav-ica B Soil Plant Science vol 62 no 8 pp 732ndash738 2012

[46] P Sullivan ldquoOverview of cover crops and greenmanures funda-mentals of sustainable agriculturerdquo ATTRA-National Sustain-able Agriculture Information Service Fayetteville Ark USA2003 httpwwwattrancatorgattra-pubPDFcovercroppdf

[47] B Singh Y H Shan S E Johnson-Beebout Y-S Yadvinder-Singh and R J Buresh ldquoCrop residue management for lowlandrice-based cropping systems in Asiardquo Advances in Agronomyvol 98 pp 117ndash199 2008


[48] K H Diekmann S K de Datta and J C G Ottow ldquoNitrogenuptake and recovery from urea and green manure in lowlandrice measured by 15N and non-isotope techniquesrdquo Plant andSoil vol 148 no 1 pp 91ndash99 1993

[49] E L Balota A Colozzi-Filho D S Andrade and R P DickldquoMicrobial biomass in soils under different tillage and croprotation systemsrdquo Biology and Fertility of Soils vol 38 no 1 pp15ndash20 2003

[50] W R Raun and G V Johnson ldquoImproving nitrogen use effi-ciency for cereal productionrdquo Agronomy Journal vol 91 no 3pp 357ndash363 1999

[51] F Wichern E Eberhardt J Mayer R G Joergensen and TMuller ldquoNitrogen rhizodeposition in agricultural crops meth-ods estimates and future prospectsrdquo Soil Biology and Biochem-istry vol 40 no 1 pp 30ndash48 2008

[52] D Dawe A Dobermann J K Ladha et al ldquoDo organic amend-ments improve yield trends and profitability in intensive ricesystemsrdquo Field Crops Research vol 83 no 2 pp 191ndash213 2003

[53] D RHuggins andW L Pan ldquoKey indicators for assessing nitro-gen use efficiency in cereal-based agroecosystemsrdquo Journal ofCrop Production vol 8 no 1-2 pp 157ndash185 2003

[54] J S Shahzad ZM Roghayyeh Y Asgar KMajid and G RozaldquoStudy of agronomical nitrogen use efficiency of durum wheataffected by nitrogen fertilizer and plant densityrdquoWorld AppliedSciences vol 11 no 6 pp 674ndash681 2010

[55] K M Panahyan and S S H Jamaati ldquoResponse of phenologyand dry matter remobilization of durum wheat to nitrogen andplant densityrdquoWorld Applied Sciences Journal vol 10 no 3 pp304ndash310 2010

[56] A Hamidi and A M Dabagh ldquoStudy of grain yield and itscomponents biomass and harvest index of two hybrid of cornunder plant densities and nitrogen fertilizer levelsrdquo IranianJournal of Agricultural Sciences vol 10 no 1 pp 39ndash35 1995

[57] N H Hazeri A Tobeh A Gholipouri H Mostafaei and S SH Jamaati ldquoThe effect of nitrogen and phosphorous rates onfertilizer use efficiency in lentilrdquoWorld Applied Sciences Journalvol 9 no 9 pp 1043ndash1046 2010

[58] N K Fageria ldquoYield physiology of ricerdquo Journal of PlantNutrition vol 30 no 6 pp 843ndash879 2007

[59] N K Fageria A Moreira and A M Coelho ldquoYield and yieldcomponents of upland rice as influenced by nitrogen sourcesrdquoJournal of Plant Nutrition vol 34 no 3 pp 361ndash370 2011

[60] M M Alam M H Ali A K M Ruhul Amin and M Has-anuzzaman ldquoYield attributes yield and harvest index of threeirrigated rice varieties under different level of phosphousrdquoAdvances in Biological Research vol 3 no 3-4 pp 132ndash139 2009

[61] X Li W Yan H Agrama et al ldquoUnraveling the complex traitof harvest index with association mapping in rice (Oryza sativaL)rdquo PLoS ONE vol 7 no 1 Article ID e29350 2012

Submit your manuscripts athttpwwwhindawicom

Nutrition and Metabolism

Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Food ScienceInternational Journal of

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Evolutionary BiologyInternational Journal of



which will increase NUE of crops and total N output ina lowland rice-based cropping system [20] In addition tofixing atmospheric nitrogen leguminous green manures playa significant role in conserving NO

3

[21 22] It is well recog-nized that the legume plant can add organic N and theirresidues contribute to the improvement of soil texture andmicrobial activity However rice growers believe that the ac-crued N benefits will vary among different legume systems[23]

InMalaysia most of the rice growing areas are well estab-lished with irrigation systems and farmerrsquos practicing doublecropping systems with high yielding varieties of rice crop [5]which mainly depends on inorganic N fertilizer and otherchemical fertilizers The government has spent more than30 billion US$ (RM 92 billion) to import 42 million tonsof mineral fertilizers to sustain crop production in Malaysia[24] Subsequently its policy has focused more towardsagroecological healthier and sustainable food productionpractices through an integrated approach of rice cultivationwith crop rotation using vegetable legume and intercroppingpractices for sweet corn maize and organic farming tominimize the dependence on mineral fertilizers [25ndash27]Inclusion of grain legumes or green manure legume crops inrotation with rice or corn can protect degradation of soil fer-tility [28ndash30] improve soil structure water holding capacity[31] and result in greater productivity and higher incomewhile minimizing production risk and ensuring long-termsustainability as well as ensure a greener environment [3031] Incorporation of crop residues alters the soil environmentthat in turn influences the microbial populationrsquos activity inthe soil and subsequent nutrient cycle [23] and will sustainrice productivity through replenishing soil organic matter[32] The presence of soil organic matter is a key indicator ofsoil quality which provides plant nutrients upon mineraliza-tion and eventually improves soil properties [33]

Legume crop residues contribute to organic N and afterdecomposition by soil microbes throughmineralization addavailable N for the next crop [34] and ameliorate the nutrientstatus of the soil In Malaysia rice growers cultivate two ricecrops per year and sometimes five crops in a two-year periodbut crop rotation practices of rice with tropical grain legumesor green manure legume crops are not often used [27] Thishas brought about soil fertility deterioration which threatensthe ecosystem through intensive application of inorganicchemical fertilizers Thus the appropriate management andefficient utilization of crop residues are important for theproper amendment of soil quality and crop productivity un-der a rice-based cropping system in the tropics [22] Indeedthe use of grain legumes or cover crops has been proven tobe commendable in terms of its positive effects Bush beanlong bean sprouted mung bean seed and winged bean aretraditional vegetables cultivated in marginal land and thereare ample opportunities to adapt these crops in an uplandrice-based crop rotation system Presently growers are con-cerned about the quality and as well sustainable use ratherthan the quantity of food production Attention has beenfocused towards the use of legume crops to improve soilhealth for productivity of rice cropThepractice of using trop-ical legumes such as bush bean long bean winged bean or

mung bean alone or in combination with inorganic N fer-tilizers offers promising scope as an N supplement to ricecrop rotation systems No systematic research has beencarried out on the consequence of N in greenmanure legumeand the productivity of legume crops and their effects on soilN dynamics and contributions to the yield and N uptake ofthe following rice crop in Malaysia The combined effect oflegume residues and indigenous nutrient supplies or fertilizeruptake and losses in rice-based systems is little understoodThe present study was undertaken to assess the addition oflegume residues to plant N uptake NAE and NRE and alsothe amount of fertilizer N essential for optimizing rice yieldwhen legumes are enclosed in the system

2 Materials and Methods

21 Experimental Plan and Management The experimentswere carried out at the greenhouse University of MalayaKuala Lumpur Malaysia during 2010 and 2011 The clayloam soil was collected at depth of 30 cm from rice fieldin Selangor (1∘ 281015840 010158401015840 N 103∘ 451015840 010158401015840 E) Malaysia Nospecific permits were required for the described studies andno specific permissions were required for these activities Inaddition the locations were not protected and the studies didnot involve endangered or protected species The soil usedhad the following chemical properties pH 655 plusmn 020 (1 5wv water) CEC 15 (cmolc kg

minus1 soil) organic C 175 plusmn 048(CHNS analyzer model NA 1500) total N 018 plusmn 004NH4

-N 637 plusmn 125 (mg 100minus1 g soil) exchangeable CaO1710plusmn2115 (mg 100minus1 g soil) exchangeableMgO 108plusmn275(mg 100minus1 g soil) and exchangeable K

2

O 149 plusmn 906 (mg100minus1 g soil) The soils were thoroughly mixed and unwantedinert materials were discarded through sieve (2mm mesh)to produce homogenous soil composites The experimentalpots (height 46 cm times diameter 54 cm = surface area 1m2)were filled with soil up to about 36 cm height (height 36 cm timesdiameter 54 cm = surface area 084m2) of each pot Alldata was converted into 1m2 The seeds of bush bean(Phaseolus vulgaris L) long bean (Vigna unguiculata (L)Verdc) mung bean (Vigna radiata (L) R Wilczek) wingedbean (Psophocarpus tetragonolobus (L) DC) and corn (Zeamays L) were sown in moistened soil to ensure germinationAll legume crops were fertilized with N fertilizer (urea 46N) at rates of 0 2 4 and 6 gNmminus2 while HYV corn andHYV rice fertilized at rates 0 4 8 and 12 gNmminus2 in the firstcycle of the experiment in 2010 Fertilizer was applied in soilprior to the sowing of seeds of bush bean (cv-MKB 1) longbean (cv-MKP 5) mung bean (cv local) winged bean (cvlocal) and corn Corn was used as non-N

2

-fixing referenceplant for estimation of N

2

fixation by N difference method(NDF) In addition 16 fallow pots were assigned to fulfill therequirement of rice after fallow crop rotation Each crop wastested in an individual experiment and each experiment wasconducted under completely randomized design with fourreplications which covered 16 pots for each crop and a totalof 96 pots for all the crop cycles Rice was transplanted asthe 2nd crop after harvesting of first crop cycles of corn andor incorporation of legume residues After completion of the
















(1)




(Legume N) (2)
















2010 2011 2010 2011 2010 2011 2010 2011 2010 20110 0 294a 288a 244a 251a 221a 241a 421a 414a

2 0 192b 222b 142b 168b 133b 180b 334b 374a

4 0 165c 161c 119c 125c 92c 118c 294b 318b

6 0 99d 132d 58d 95d 31d 86d 217c 295b




2



2




2




2 140b 180a 150b 130b 195a 195a 155a 290a

4 163a 153b 170a 155a 165b 160b 145b 205b

6 148b 148b 157b 148a 157b 150c 112c 195c



2


2






2010 2011 2010 2011 2010 2011 2010 20110 0 9860c 9218c 9485c 9287c 9528c 9121c

4 0 10586b 9935b 10694b 10375b 10661b 9869b

8 0 10749ab 10749a 11355ab 10834a 11287a 10717a

12 0 11238a 10840a 11384a 11026a 11319a 10782a


2010 2011 2010 2011 2010 2011 2010 20110 0 11547b 11075b 9055d 8730d 9414c 9055c

4 0 12622a 12117a 9316c 9055c 10651b 9935b

8 0 12834a 12443a 10261b 9609b 11368a 10423a

12 0 12899a 12541a 10586a 10065a 11270a 10586a




2010 2011 2010 2011 2010 2011 2010 20110 0 94d 85c 93c 85c 91c 84c

4 0 104c 95b 104b 95b 102b 94b

8 0 110b 107a 115a 103a 114a 107a

12 0 116a 109a 116a 108a 115a 108a


2010 2011 2010 2011 2010 2011 2010 20110 0 121b 113b 71d 68d 75c 71d

4 0 134a 125a 76c 72c 85b 79c

8 0 137a 128a 84b 77b 95a 84b

12 0 139a 129a 89a 83a 97a 87a








2010 2011 2010 2011 2010 2011 2010 20110 0 00c 00d 00c 00d 00c 00d

4 0 288a 275a 288a 275a 275a 250b

8 0 295a 238b 294a 238b 288a 288a

12 0 196b 200c 196b 200c 200b 200c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00c 00d

4 0 325a 300a 100b 98b 255a 200a

8 0 200b 188b 163a 111a 250a 163b

12 0 150c 133c 150a 124a 183b 133c











2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00d 00c 00d 00d

4 0 130a 125a 212a 171a 148a 129a

8 0 107b 97b 151b 114b 126b 114b

12 0 74c 65c 128c 111b 83c 78c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00 00d

4 0 269a 236a 147a 163a 212a 138b

8 0 163b 147b 155a 143b 187b 151a

12 0 122c 125c 133b 122b 152c 114c









2010 2011 2010 2011 2010 2011 2010 2011

0 0 4245c 3583c 4169c 4039c 4072c 3957c


4 0 4951b 4397b 5016b 4723b 4951b 4492b


8 0 5472a 4723ab 5375a 4951ab 5400a 4887a


12 0 5537a 5212a 5700a 5375a 5653a 5212a





alowast 4723a





2010 2011 2010 2011 2010 2011 2010 20110 0 429c 389c 435c 435c 427c 432b

4 0 468b 443b 456b 455b 464b 455b

8 0 509a 439b 457b 457b 476b 456b

12 0 493a 481a 487a 487a 495a 483a


2010 2011 2010 2011 2010 2011 2010 20110 0 466b 459b 385c 332c 394d 353c

4 0 511a 497a 437b 396b 414c 377b

8 0 520a 503a 460a 424a 458b 422a

12 0 530a 525a 480a 437a 491a 431a






2


4 Conclusions




Acknowledgments


References


































































Journal of




Agronomy





Microbiology




Volume 2014







































(1)




(Legume N) (2)
















2010 2011 2010 2011 2010 2011 2010 2011 2010 20110 0 294a 288a 244a 251a 221a 241a 421a 414a

2 0 192b 222b 142b 168b 133b 180b 334b 374a

4 0 165c 161c 119c 125c 92c 118c 294b 318b

6 0 99d 132d 58d 95d 31d 86d 217c 295b




2



2




2




2 140b 180a 150b 130b 195a 195a 155a 290a

4 163a 153b 170a 155a 165b 160b 145b 205b

6 148b 148b 157b 148a 157b 150c 112c 195c



2


2






2010 2011 2010 2011 2010 2011 2010 20110 0 9860c 9218c 9485c 9287c 9528c 9121c

4 0 10586b 9935b 10694b 10375b 10661b 9869b

8 0 10749ab 10749a 11355ab 10834a 11287a 10717a

12 0 11238a 10840a 11384a 11026a 11319a 10782a


2010 2011 2010 2011 2010 2011 2010 20110 0 11547b 11075b 9055d 8730d 9414c 9055c

4 0 12622a 12117a 9316c 9055c 10651b 9935b

8 0 12834a 12443a 10261b 9609b 11368a 10423a

12 0 12899a 12541a 10586a 10065a 11270a 10586a




2010 2011 2010 2011 2010 2011 2010 20110 0 94d 85c 93c 85c 91c 84c

4 0 104c 95b 104b 95b 102b 94b

8 0 110b 107a 115a 103a 114a 107a

12 0 116a 109a 116a 108a 115a 108a


2010 2011 2010 2011 2010 2011 2010 20110 0 121b 113b 71d 68d 75c 71d

4 0 134a 125a 76c 72c 85b 79c

8 0 137a 128a 84b 77b 95a 84b

12 0 139a 129a 89a 83a 97a 87a








2010 2011 2010 2011 2010 2011 2010 20110 0 00c 00d 00c 00d 00c 00d

4 0 288a 275a 288a 275a 275a 250b

8 0 295a 238b 294a 238b 288a 288a

12 0 196b 200c 196b 200c 200b 200c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00c 00d

4 0 325a 300a 100b 98b 255a 200a

8 0 200b 188b 163a 111a 250a 163b

12 0 150c 133c 150a 124a 183b 133c











2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00d 00c 00d 00d

4 0 130a 125a 212a 171a 148a 129a

8 0 107b 97b 151b 114b 126b 114b

12 0 74c 65c 128c 111b 83c 78c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00 00d

4 0 269a 236a 147a 163a 212a 138b

8 0 163b 147b 155a 143b 187b 151a

12 0 122c 125c 133b 122b 152c 114c









2010 2011 2010 2011 2010 2011 2010 2011

0 0 4245c 3583c 4169c 4039c 4072c 3957c


4 0 4951b 4397b 5016b 4723b 4951b 4492b


8 0 5472a 4723ab 5375a 4951ab 5400a 4887a


12 0 5537a 5212a 5700a 5375a 5653a 5212a





alowast 4723a





2010 2011 2010 2011 2010 2011 2010 20110 0 429c 389c 435c 435c 427c 432b

4 0 468b 443b 456b 455b 464b 455b

8 0 509a 439b 457b 457b 476b 456b

12 0 493a 481a 487a 487a 495a 483a


2010 2011 2010 2011 2010 2011 2010 20110 0 466b 459b 385c 332c 394d 353c

4 0 511a 497a 437b 396b 414c 377b

8 0 520a 503a 460a 424a 458b 422a

12 0 530a 525a 480a 437a 491a 431a






2


4 Conclusions




Acknowledgments


References


































































Journal of




Agronomy





Microbiology




Volume 2014


































2010 2011 2010 2011 2010 2011 2010 2011 2010 20110 0 294a 288a 244a 251a 221a 241a 421a 414a

2 0 192b 222b 142b 168b 133b 180b 334b 374a

4 0 165c 161c 119c 125c 92c 118c 294b 318b

6 0 99d 132d 58d 95d 31d 86d 217c 295b




2



2




2




2 140b 180a 150b 130b 195a 195a 155a 290a

4 163a 153b 170a 155a 165b 160b 145b 205b

6 148b 148b 157b 148a 157b 150c 112c 195c



2


2






2010 2011 2010 2011 2010 2011 2010 20110 0 9860c 9218c 9485c 9287c 9528c 9121c

4 0 10586b 9935b 10694b 10375b 10661b 9869b

8 0 10749ab 10749a 11355ab 10834a 11287a 10717a

12 0 11238a 10840a 11384a 11026a 11319a 10782a


2010 2011 2010 2011 2010 2011 2010 20110 0 11547b 11075b 9055d 8730d 9414c 9055c

4 0 12622a 12117a 9316c 9055c 10651b 9935b

8 0 12834a 12443a 10261b 9609b 11368a 10423a

12 0 12899a 12541a 10586a 10065a 11270a 10586a




2010 2011 2010 2011 2010 2011 2010 20110 0 94d 85c 93c 85c 91c 84c

4 0 104c 95b 104b 95b 102b 94b

8 0 110b 107a 115a 103a 114a 107a

12 0 116a 109a 116a 108a 115a 108a


2010 2011 2010 2011 2010 2011 2010 20110 0 121b 113b 71d 68d 75c 71d

4 0 134a 125a 76c 72c 85b 79c

8 0 137a 128a 84b 77b 95a 84b

12 0 139a 129a 89a 83a 97a 87a








2010 2011 2010 2011 2010 2011 2010 20110 0 00c 00d 00c 00d 00c 00d

4 0 288a 275a 288a 275a 275a 250b

8 0 295a 238b 294a 238b 288a 288a

12 0 196b 200c 196b 200c 200b 200c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00c 00d

4 0 325a 300a 100b 98b 255a 200a

8 0 200b 188b 163a 111a 250a 163b

12 0 150c 133c 150a 124a 183b 133c











2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00d 00c 00d 00d

4 0 130a 125a 212a 171a 148a 129a

8 0 107b 97b 151b 114b 126b 114b

12 0 74c 65c 128c 111b 83c 78c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00 00d

4 0 269a 236a 147a 163a 212a 138b

8 0 163b 147b 155a 143b 187b 151a

12 0 122c 125c 133b 122b 152c 114c









2010 2011 2010 2011 2010 2011 2010 2011

0 0 4245c 3583c 4169c 4039c 4072c 3957c


4 0 4951b 4397b 5016b 4723b 4951b 4492b


8 0 5472a 4723ab 5375a 4951ab 5400a 4887a


12 0 5537a 5212a 5700a 5375a 5653a 5212a





alowast 4723a





2010 2011 2010 2011 2010 2011 2010 20110 0 429c 389c 435c 435c 427c 432b

4 0 468b 443b 456b 455b 464b 455b

8 0 509a 439b 457b 457b 476b 456b

12 0 493a 481a 487a 487a 495a 483a


2010 2011 2010 2011 2010 2011 2010 20110 0 466b 459b 385c 332c 394d 353c

4 0 511a 497a 437b 396b 414c 377b

8 0 520a 503a 460a 424a 458b 422a

12 0 530a 525a 480a 437a 491a 431a






2


4 Conclusions




Acknowledgments


References


































































Journal of




Agronomy





Microbiology




Volume 2014



























2010 2011 2010 2011 2010 2011 2010 20110 0 9860c 9218c 9485c 9287c 9528c 9121c

4 0 10586b 9935b 10694b 10375b 10661b 9869b

8 0 10749ab 10749a 11355ab 10834a 11287a 10717a

12 0 11238a 10840a 11384a 11026a 11319a 10782a


2010 2011 2010 2011 2010 2011 2010 20110 0 11547b 11075b 9055d 8730d 9414c 9055c

4 0 12622a 12117a 9316c 9055c 10651b 9935b

8 0 12834a 12443a 10261b 9609b 11368a 10423a

12 0 12899a 12541a 10586a 10065a 11270a 10586a




2010 2011 2010 2011 2010 2011 2010 20110 0 94d 85c 93c 85c 91c 84c

4 0 104c 95b 104b 95b 102b 94b

8 0 110b 107a 115a 103a 114a 107a

12 0 116a 109a 116a 108a 115a 108a


2010 2011 2010 2011 2010 2011 2010 20110 0 121b 113b 71d 68d 75c 71d

4 0 134a 125a 76c 72c 85b 79c

8 0 137a 128a 84b 77b 95a 84b

12 0 139a 129a 89a 83a 97a 87a








2010 2011 2010 2011 2010 2011 2010 20110 0 00c 00d 00c 00d 00c 00d

4 0 288a 275a 288a 275a 275a 250b

8 0 295a 238b 294a 238b 288a 288a

12 0 196b 200c 196b 200c 200b 200c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00c 00d

4 0 325a 300a 100b 98b 255a 200a

8 0 200b 188b 163a 111a 250a 163b

12 0 150c 133c 150a 124a 183b 133c











2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00d 00c 00d 00d

4 0 130a 125a 212a 171a 148a 129a

8 0 107b 97b 151b 114b 126b 114b

12 0 74c 65c 128c 111b 83c 78c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00 00d

4 0 269a 236a 147a 163a 212a 138b

8 0 163b 147b 155a 143b 187b 151a

12 0 122c 125c 133b 122b 152c 114c









2010 2011 2010 2011 2010 2011 2010 2011

0 0 4245c 3583c 4169c 4039c 4072c 3957c


4 0 4951b 4397b 5016b 4723b 4951b 4492b


8 0 5472a 4723ab 5375a 4951ab 5400a 4887a


12 0 5537a 5212a 5700a 5375a 5653a 5212a





alowast 4723a





2010 2011 2010 2011 2010 2011 2010 20110 0 429c 389c 435c 435c 427c 432b

4 0 468b 443b 456b 455b 464b 455b

8 0 509a 439b 457b 457b 476b 456b

12 0 493a 481a 487a 487a 495a 483a


2010 2011 2010 2011 2010 2011 2010 20110 0 466b 459b 385c 332c 394d 353c

4 0 511a 497a 437b 396b 414c 377b

8 0 520a 503a 460a 424a 458b 422a

12 0 530a 525a 480a 437a 491a 431a






2


4 Conclusions




Acknowledgments


References


































































Journal of




Agronomy





Microbiology




Volume 2014



























2010 2011 2010 2011 2010 2011 2010 20110 0 00c 00d 00c 00d 00c 00d

4 0 288a 275a 288a 275a 275a 250b

8 0 295a 238b 294a 238b 288a 288a

12 0 196b 200c 196b 200c 200b 200c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00c 00d

4 0 325a 300a 100b 98b 255a 200a

8 0 200b 188b 163a 111a 250a 163b

12 0 150c 133c 150a 124a 183b 133c











2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00d 00c 00d 00d

4 0 130a 125a 212a 171a 148a 129a

8 0 107b 97b 151b 114b 126b 114b

12 0 74c 65c 128c 111b 83c 78c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00 00d

4 0 269a 236a 147a 163a 212a 138b

8 0 163b 147b 155a 143b 187b 151a

12 0 122c 125c 133b 122b 152c 114c









2010 2011 2010 2011 2010 2011 2010 2011

0 0 4245c 3583c 4169c 4039c 4072c 3957c


4 0 4951b 4397b 5016b 4723b 4951b 4492b


8 0 5472a 4723ab 5375a 4951ab 5400a 4887a


12 0 5537a 5212a 5700a 5375a 5653a 5212a





alowast 4723a





2010 2011 2010 2011 2010 2011 2010 20110 0 429c 389c 435c 435c 427c 432b

4 0 468b 443b 456b 455b 464b 455b

8 0 509a 439b 457b 457b 476b 456b

12 0 493a 481a 487a 487a 495a 483a


2010 2011 2010 2011 2010 2011 2010 20110 0 466b 459b 385c 332c 394d 353c

4 0 511a 497a 437b 396b 414c 377b

8 0 520a 503a 460a 424a 458b 422a

12 0 530a 525a 480a 437a 491a 431a






2


4 Conclusions




Acknowledgments


References


































































Journal of




Agronomy





Microbiology




Volume 2014



























2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00d 00c 00d 00d

4 0 130a 125a 212a 171a 148a 129a

8 0 107b 97b 151b 114b 126b 114b

12 0 74c 65c 128c 111b 83c 78c


2010 2011 2010 2011 2010 2011 2010 20110 0 00d 00d 00c 00c 00 00d

4 0 269a 236a 147a 163a 212a 138b

8 0 163b 147b 155a 143b 187b 151a

12 0 122c 125c 133b 122b 152c 114c









2010 2011 2010 2011 2010 2011 2010 2011

0 0 4245c 3583c 4169c 4039c 4072c 3957c


4 0 4951b 4397b 5016b 4723b 4951b 4492b


8 0 5472a 4723ab 5375a 4951ab 5400a 4887a


12 0 5537a 5212a 5700a 5375a 5653a 5212a





alowast 4723a





2010 2011 2010 2011 2010 2011 2010 20110 0 429c 389c 435c 435c 427c 432b

4 0 468b 443b 456b 455b 464b 455b

8 0 509a 439b 457b 457b 476b 456b

12 0 493a 481a 487a 487a 495a 483a


2010 2011 2010 2011 2010 2011 2010 20110 0 466b 459b 385c 332c 394d 353c

4 0 511a 497a 437b 396b 414c 377b

8 0 520a 503a 460a 424a 458b 422a

12 0 530a 525a 480a 437a 491a 431a






2


4 Conclusions




Acknowledgments


References


































































Journal of




Agronomy





Microbiology




Volume 2014



























2010 2011 2010 2011 2010 2011 2010 2011

0 0 4245c 3583c 4169c 4039c 4072c 3957c


4 0 4951b 4397b 5016b 4723b 4951b 4492b


8 0 5472a 4723ab 5375a 4951ab 5400a 4887a


12 0 5537a 5212a 5700a 5375a 5653a 5212a





alowast 4723a





2010 2011 2010 2011 2010 2011 2010 20110 0 429c 389c 435c 435c 427c 432b

4 0 468b 443b 456b 455b 464b 455b

8 0 509a 439b 457b 457b 476b 456b

12 0 493a 481a 487a 487a 495a 483a


2010 2011 2010 2011 2010 2011 2010 20110 0 466b 459b 385c 332c 394d 353c

4 0 511a 497a 437b 396b 414c 377b

8 0 520a 503a 460a 424a 458b 422a

12 0 530a 525a 480a 437a 491a 431a






2


4 Conclusions




Acknowledgments


References


































































Journal of




Agronomy





Microbiology




Volume 2014


























2


4 Conclusions




Acknowledgments


References


































































Journal of




Agronomy





Microbiology




Volume 2014








































































Journal of




Agronomy





Microbiology




Volume 2014
























Research Article Tropical Legume Crop Rotation and...

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