t&jüw'iä - WUR · 3_ d. Use Recomm « Project (Phase X) ... Map 8.0.1 66% Reliability of Rainfall...

t&jüw'iä

3/

Mini of Agricultun

National Agricultural

Fertilizer Use Recommendat:

Project (Phase X)

Annex XXX

Description of trie First Priority

Sites in the Various Districts

Volume 8

Nandi District

District No.: 8

Nairobi, June 1987

3_ d. Use Recomm«

Project (Phase X)

Team of Consultants1) ProfessionalStaff fromNAL2)

H. Strobel (ed.)Project Coordinator

Project CoordinationG.HingaDirector NAL

S.W.NandwaCounterpartCoordinator

R. JätzoldR. Rötter

Aaro-ClimatoloaistsJ.W. Onyango

R.F. van de WegE.M.A. Smaling

Soil Scientists / SurveyorsF.N. MuchenaC.K.K. GacheneJ.M. Kibe

P. PietrowiczSoil Chemists

J.N. QureshiP.O.S. Oduor

A.Y. AllanAoronomists

J.O. Owuor

Data ProcessingH. MayrR. DölgerA. Muliro

R. RötterLand Survevors

R.L MilikauD.K. Wamae

B. MwangiS. Wataka

W. BayerAnimal Production

1) German Agency for Technical Cooperation (GTZ) (German AgriculturalTeam (GAT))

2) National Agricultural Laboratories

Fertilizer Use Recommendation

Project C Phase I )

nsL 3-

r. : Methodology and Inventory of Existing Information

An

An

An

n

n

n

e

*=»

X

x x

X X

X X

X X

. x

- 2

- 3

x

: Compilation of results from Former Fertilizer TrialsIn Kenya (2 Volumes)

1 : Inventory of Farming Systems Research in Kenya

'. - 2 : Influence of Fertilizer Application on RuminantProduction

: Maintaining Soil Fertility with Little or No Use ofFertilizers

Detailed Description of the First Priority Sites in theVarious Districts :

1. Kisii 17. Narok2. South Nyanza 18. Samburu3. Kisumu 19. Nyandarua4. Siaya 20. Kiambu5. Busia 21. Muranga6. Bungoma 22. Nyeri7. Kakamega 23. Kirinyaga8. Nandi 24. Embu9. Kericho 25. Meru

10. Trans Nzoia 26. Machakos11. Uasin Gishu 27. Kitui12. West Pokot 28. Lamu13. Keyo Marakwet 29. Kilifi14. Baringo 30. Taita Taveta15. Laikipia 31. Kwale16. Nakuru 32. Nairobi

: Description of Computer Programmes Establishedin Phase I

Scanned from original by ISRIC - World Soil Information, as ICSUWorld Data Centre for Soils. The purpose is to make a safedepository for endangered documents and to make the accruedinformation available for consultation, following Fair UseGuidelines. Every effort is taken to respect Copyright of thematerials within the archives where the identification of theCopyright holder is clear and, where feasible, to contact theoriginators. For questions please contact soil.isricOwurnlindicating the item reference number concerned.

District: Nandi General Aspects 8.0

Annex XXX , Volum<

Distr-lct:

Please note the following numbering mode of Tables and Maps:First NumberSecond NumberThird Number

District NumberTrial Site NumberNumber of Table or Map within Chapter.

- 0 .1 -

Page

Chapter- 8 . O :

General Aspects 0.2

Legend of the Soil Map of Nandi District 0.29

Chapter 8 . X :

Description of the Baraton Trial Site 1.1

3r 8.2:

Description of the Chepkumia Trial Site 2.1


Contents of Chapter 8.0:

.. .. •-• - ; General Aspects

Page

1. Climate and Soils of the District " - ••.".* 0.3

2. Location of Trial Sites and Criteria for their Final Position 0.13

3. Names and Addresses of Government Officers Involved in FURPActivities 0.15

4. Trial Design and Execution Plan 0.16

5. Areas in Nandi District Represented by FURP Trial Sites 0.17

List of Tables

Table 8.0.1 Climate in the Agro-Ecological Zones of Nandi District 0.6

Table 8.0.2 Agro-Ecological Zone and Soil Classification of the

Trial Sites 0.10

Table 8.0.3 Ratings of Criteria Used for Trial Site Selection 0.14

Table 8.0.4 Names and Addresses of Government Officers in the

District ; 0.15< 3 > ' ' • • • • "'•-• -

Table 8.0.5 Major Soil Properties and Climatic Conditions of theAgro-Ecological Units in Nandi District 0.23

List

Map 8.0.1 66% Reliability of Rainfall in First Rains ' v o,4

Map 8.0.2 66% Reliability of Rainfall in Second Rains 0.5

Map 8.0.3 Agro-Ecological Zones and Trial Sites of the District 0.7

Map 8.0.4 Soils and Trial Sites in Nandi District 0.11

Map 8.0.5 Groupings of Soil Mapping Units Represented by Trial

Sites in Nandi District 0.21

Map 8.0.6 Agro-Ecological Units in Nandi District 0.27

Legend of the Soil Map of Nandi District 0.29

- 0.2 -


1. Climate and Soils of the District

Annual rainfall in the District is both high, averaging 1200 to >2000 mm,and reliable (1000 to 1600 mm reached or surpassed in at least 20 out of 30years). Almost 50% of the District area receives more than 1500 mm peryear. These areas form extended Agro-Ecological Zones for potential teacultivation (LH 1 and UM 1), as shown on Map 8.0.3 - the Nandi Forest abovethe Nandi Escarpment, the South Nandi Forest which is the eastern extensionof the Kakamega Forest (as a zone of high convergence rainfall), the NandiHills (almost completely cleared), and the Northern Tinderet Forest (hereonly the lower part is suitable for tea, as the higher part has a meantemperature of less than 15°C and night frosts occur).

On the border of the present forests, formerly more extensive, teacultivation is being practised. Careful scientific investigation isnecessary to decide which parts of the remaining forests could still beopened for cultivation without endangering the climate-soil environment.The relatively dry area is situated in the north-eastern valley basins ofthe District: Here the annual rainfall average is still high (1200 mm) andthe 66% reliability is not too low which suits maize with at least 400 mmin the first rains and 500 mm in the second rains. There is no real dryspell between the two'seasons.

On the plateau-like main parts of the District, the temperatures are closeto the upper limit of the Upper Midlands (UM), and*to the lower limit ofthe Lower Highlands (LH), thus creating many transitions and localvariations, depending on the prevailing micro-climate. For instance, insome areas of the LH belt, bananas can still be seen whereas this isunusual elsewhere.

Only a small portion, an edge of the Kano Plains, belongs to the LowerMidland Zones (LM) with mean temperatures of at least 21°C, and withadequate rainfall for a Sugar Cane Zone, although the potential is marginaldue to the dry period from December to February and the altitudeapproaching 1500 m (LM 2).

Rainy seasons are not easily distinguished in the District because thereare normally no real dry seasons separating them. The first rains startaround mid-March with a second increase in August' (see Figures 8.1.5 and8.2.5). The 66% probability of rainfall, i.e. amount surpassed in 20 out of30 years, is shown in Map 8.0.1 for the first rains and in Map 8.0.2 forthe second rains. .

A summary of climatic data is compiled in Table 8.0.1, which can be used asa key to the Agro-Ecological Zones Map 8.0.3.

- 0.3 -

3CTE

NANDI

Map 8.0.1

66% RELIABILITY OF RAINFALLIN AGROHUMID PERIOD

OF FIRST RAINS(e. ol Feb.-b. of July)

Amounts in mm, surpassednorm, in 20 out of 30 years

Broken boundaries art uncertain

becau« ol lock ol itlnltD cococd»

o*—

15 80 * s k n l

Nat. Av Lab».. Carman Agf laam. fl. JaalloM

- 0 .4 -

351E

NANDI

0*-

Map 8.0.2

66% RELIABILITY OF RAINFALLIN AGROHUMID PERIOD

OF SECOND RAINS(m. July-m. Feb. or less)

Amounts in mm, surpassednorm, in 20 out of 30 years

Biokwi beundutoi if« uncwldn

b t u i i H ol tack el f«lnl«n i*cof4>

I—IS M « k m

-- • I

Nil «g> I I I» Ooinwn Agi l m H JaaljoM

- 0 . 5 -

Table 8.0.1 rClimate in the Agro-Ecological Zones of Nandi District

Agro-Ecological

Zone

Subzone

univl i

Sheep-Dairy Zone

LU 1 p or two

Tea-Dairy Zone vl i or two

LH 2

Wheat/Maize- vl/l or two

Pyrelliruni Zone

LU 3Wheat/Maize- l/vl or twoflarley Zone

UM 1 por two/threeCoffee-Tea p or twoZone vl i or two

UM 2vl i or two

Coffee Zone

UM .3Margin's! Coffee transitionalZone

UM 4

Sunflower-Maize l/vl or two.

Zone

LM 1

Lower Midland por two

Sugar Cane Zone

LM2Marginal Sugar l/m —• (m/s)Cane Zone

Altitude

in m

Annual mean

temperature

in °C

Annual av.

rainfall

in mm

66 7 reliability

of rainfall1.'

Isl rains 2nd rains

in mm in mm

Here Forest Reserve

1900-2 400 I8 .0 - I5 .0

1900-2 400 18.0-15.0

1900-2 300 18.0-15.7

I5OO-2OÜO 20.5-17.5

1 500-2 100 650-850 580-800

1 V)0 - l 850 630-820 550-750

1 300-1 800 600-750 500-700

1 280>-1 650 500-680 50U-6U0

1 800-2 100 750-850 650-8001700-2 000 700-780 630-780I5OO-I85O 650-750 550-700

Very small and transitional to 3, sec k<:richo

Very small, sec Kcricho or Uungoma

1600-2 000 19.9-17.5 1 200-1 600 400-600 500-600

Very small, see Kakamcga

1 200-1 500 22.3-20.9 1 200-1580 560-700 500-600

66 % reliability

of growing period

1st rains2) 2nd rains Total3)

in days in days in days

165 or more 190-200 365

155 or more 140-195 295-350

I50ormore 90-135 240-285

140 or more 80-100 220-240

160 or more 190-205 3.6,5160 or more 185-200 345-360150 or more 175-185 325-335

115 or more 115 or less ~23O

170 or more 115-125 285-295

Amounts surpassed normally in 6 out of 10 years, falling during the agrö-humid period which allows growing of most cultivated plants

Mor« if growing cycle of cultivated plants continues into the period of second rains

Agcohumid conditions continue from 1st to 2nd rains in the whole district .

Source: Jaetzold R., and H. Schmidt, ads. (1982): FarmManagement Handbook of Kenya, Volume II/BCentral Kenya, page 24.

- 0.6 -

MAP 8.0.3 AEZS AND TRIAL SITES IN NANDI DISTRICT

35° E

• Site of first priority

8.1 Baraton8.2 Chepkumia

t

AGRO-ECOL ZONES

,30

N

\-~TJTTp'^r

*<£ofli' .". -J'

Forest Reserve :v.*v:p::

Unsuitable sleep slopus ^

(only marked outsidu Nal-

Parks or Foresl Res i

BeM ot A Ë Zones • « • • ^ ^ ^ _

A.E2ones • • , _ _ _ ^ » ^ — m,,,,,,!,,,,,,, ,

Subzoniis

Climatic data for AE2 formulas sec labiés II. 1.2.

II 1.4 and Ö 0.1 or Farm Man Hdb Part II

LFERTILIZER USE RLCOHMKNDATION PROJECT (1987)

0 5

soil boundary, see Map 4

Ministry of AgricultureNational ftyricultura1 LaboratoriesGerman Agricultural Team

10 15 20 25 km

District: Nandi General Aspects 8,0

The Agro-Ecological Zones UM 1 and LH 2 are represented by Trial SitesChepkumia (No.8.2) and Baraton (No.8.1), as shown in Map 8.0.3. Zones LH 1,LH 3, UM 4, LM 1 and LM 2 are covered by Trial Sites.(No. 1.1, 11.1, 11.2,6.2, 2.2, 2.4 a.o.) in Kisii, Uasin Gishu, Bungoma and South NyanzaDistricts. Agro-Ecological Zone UH 1, which extends over 5% of the Districtarea, has mainly very steep slopes and should remain a Forest Reserve.Zones UM 2 and UM 3 (including the transitional areas) cover approximately5% of the District area.

The soils of Nandi District are shown in Map 8.0.4.Nandi District has the advantage of predominantly deep to very deep soilswith high organic matter content (mollic and humic Nitisols and humicAcrisols). • .

1. South-West Nandi •

The area west of the line Tindinyo-Ndurio consists of granitic parent rock.The soils developed here are all Acrisols with a high organic.mattercontent (acid humic topsoil): unit UhG5 is moderately deep to deep, unitUhG2 and UhG4 deep to very deep (Trial Site 8.2) and unit UhG7 very deep toextremely deep.

2. South-East Nandi

The Nandi Hills have shallow soils (units MB3, MB4, MU2, UmU4), but thesoils of the surrounding volcanic footridges and uplands are moderatelydeep to deep (on Basement system gneisses: humic Cambisols and Acrisols,unit UhU4) or deep to very deep (on basic igneous rocks: mollic Nitisols,unit UhBl, cf. Trial Site 1.1. Kisii District: chromo-luvic Phaeozems,units RB5 and FB4., cf. Trial Site 2.4. South Nyanza District: humicNitisols, unit RB2, cf. Trial Site 9.1. Kericho District).Piedmont plains border Kisumu District: map units YU1, YU3, YU4 havePianosols and Vertisols (cf. Trial Site 3.1. Kisumu District), which arepartly saline and/or sodic.

3. North of Tindinyo-Kapsabet-Lessos and South-West of Kapsabet

Soils on intermediate igneous rocks prevail around Lessos. Unit UhI5features shallow to moderately deep Phaeozems, whereas unit UhI3 has verydeep to extremely deep dystro-mollic Nitisols (cf. Trial Site 1.2. KisiiDistrict").Almost the entire northern part of Nandi District lithologically consistsof gneisses rich in biotites and/or hornblendes.Soils are mainly deep to extremely deep. Unit UhNl (Trial Site 8.1) andunit UhFl have humic Nitisols, unit UhN3 humic Acrisols and unit UhN4ferralo-humic Acrisols.Less organic matter occurs in the topsoils of units UmN2 and UhF2 whererhodic Ferralsols and ferralo-chromic Acrisols are prevalent.In the very north of the District, ferralo-chromic Acrisols, developed ongranites, are found. They are covered by Trial Site 11.2. Uasin GishuDistrict.

Part of the Uasin Gishu Plateau extends into Nandi District:, unit LIAI, cf.Trial Site 11.1. Uasin Gishu District.

- 0.9 -


Northwest of Kapsabet and north of Baraton extensive bottomlands and swampsoccur (units BX1 and SAl). These mainly consist of Gleysols with someHistosols.

The basic climatic and soil designations referring to trial sites in theNandi District are summarized in Table 8.0.2.

Table 8.0.2: Agro-Ecological Zone and Soil Classification of Trial Sitesin Nandi District

SiteNo.

8.1

8.2

SiteName

Baraton

Chepkumia

Agro-EcologicalZone

Wheat/Maize-Pyre-thrum Zone (LH 2)

Tea-Coffee Zone(UM 1)

Soil Classification

humic Nitisol

humic Acrisol

- 0.10 -

MAP 8.0.4 SOILS AND TRIAL SITES IN NANDI DISTRICT

35° E

• Site of first Priority

8.1 Baraton

8.2 Chepkumia

QO3Q

KEY

HUN] soil mapping code

— soil boundary

% • towns and major villages

— — tarmac road

^===: other all-weather roads

district boundary

rrrTTT scarp

- river

For LEGEND See APPENDIX

SOURCE

LBDA Reconnaissance Soil Map of theLake Basin Development AuthorityArea, Western Kenya, 1985 (scale1:250,000)

FERTILIZER USE RECOMMENDATION PROJECT (1987) Ministry of AgricultureNational Agricultural LaboratoriesGerman Agricultural Team

10 15 20 25 km


2. Location of Trial Sites and Criteria for their Final Position

In the Nandi District, two first priority sites were selected as shown inMap 8.0.4.

The Baraton Trial Site (8.1) is made up of two blocks on terraced land.Accessibility is very good and the demonstration effect of this site isvery high as it is located directly along the main road. The farmers'fields are quite representative and close to the trial plot. The farmerhappens to be the T.A. in charge of the area around Baraton. The next long-term rainfall recording stations: 08935062, University of East Africa,Baraton and 08935018, Kapsabet District Office are both within 3.5 kmdistance of the trial site.

The site near Chepkumia (8.2) is on a rectangular and uniform piece ofland. The farmer is not fully convinced that the project will be profitablefor him. The site has only a moderate demonstration effect as it is notsituated along any road. It is located 2 km ESE of long-term rainfallrecording station: 08934072, Kaimosi Tea Estate.

- 0.13 -


The criteria for the final position of the trial sites are listed in Table8.0.3, which is self-explanatory. Criteria have been rated very good (1),good (2), moderate (3), poor (4) or non-relevant (nr).

Table 8.0.3: Ratings of Criteria Used for Trial Site Selection in NandiDistrict

Criterion Sitenumber

8.1

1

i-H

1

32111

112

431

rH

32

1

rH

8.2

211

11111

232

432

323

?

1. Representativeness of Agro-Ecological Zones2. Representativeness of Soils3. Representativeness of Topography

4. Adequacy of size and shape of the trial plot5. Absence of trees and hedges6. Absence of rocks and boulders7. Absence of termite mounds8. Uniformity of previous land use

9. Accessibility10. Demonstration effect11. Proximity to a long-term rainfall station

12. Availability of storage facilities13. Availability of sturdy fences14. Availability of housing facilities for T.A.s

15. Farmer's willingness to co-operate16. Security - theft17. Security - intruding animals

18. Proximity of on-farm trials19. Representativeness of soils at on-farm trials

- 0.14 -


3. Names and Addresses of Government Officers Involved in FURP Activitiesin Nandi District

The names and addresses of the agricultural staff members in the Districtare listed in Table 8.0.4.

Table 8.0.4: Names and Addresses of Government Officers in the District

OFFICER

DISTRICTD.C.D.A.O.D.C.O.D.E.C.

DIVISIONDiv. Ext.Officer

Loc. Ext.Officer

TechnicalAssistant

SITE

8.18.2

8.1' 8.2

8.18.2

NAME

Cyrus GituaiI.M.J. KibuthuMrs. F.W. Ndungu

P. KichwenP. Kichwen

not metnot met

Ndege KogooKipkemboi Langat

P.O. BOX

60-Kapsabet60-Kapsabet

60-Kapsabet60-Kapsabet

60-Kapsabet

TEL. NO.

4646

4646

Period of site selection in the District: March 1986.

- 0.15 -


4. Trial Design and Execution Plan, Nandi.

(The full details of the methodology for carrying out the fertilizer trialsare given in Chapter IV of the main report).

Selection of Crops. The proposed crop sequences for the three modules inthe Nandi trials are:

Site 8.1 Baraton,Nandi.

RAINY SEASONS1st, Long, March 2nd rains Aug-Oct

51 Standard Maize52 Maize & Beans53 Pot/Cabbages;Forage

Hybrid 625Hybrid 625 + GLP 2Annett/Copenhagen Forage oats

The 1st sequence or module is thus continuous, pure maize, once/year.The 2nd is intercropped maize and beans, also once/year.The 3rd is potatoes or cabbages in the 1st rains, and oats forage in the2nd rains.

Site 8.2 Chepkumia,Kaimosi.

RAINY SEASONS1st, Long, Feb. 2nd, Short, Aug.

51 Standard Maize52 Maize & Beans53 Pot./Cabb.; Beans

Hybrid 625Hybrid 625 + GLP 2B53/Copenhagen

Hybrid 511Hybrid 511+GLP 2GLP 2

The 1st sequence or module is continuous, pure maize, twices/year.The 2nd is intercropped maize and beans, also twice/year.The 3rd is maize/beans in the 1st rains, and potatoes or cabbages in the2nd rains.

Each module contains 2 experiments, namely Experiment 1 and Experiment 2.Experiment 1 is a 4N x 4P factorial, with 2 replications in each module.Experiment 2 i s a 2 x 2 x 2 x 2 factorial, also with 2 replications ineach module, and the factors here are N, P, K and FYM at both sites.

Each module thus consists of 64 plots, and the total for the 3 modules is192 plots.

FYM will be applied only in the first rainy season. The other fertilizerswill be applied in both rainy seasons at Chepkumia, but only in the firstrains at Baraton.

Where maize and beans are intercropped, the fertilizer will go on themaize. The beans will not receive any fertilizer directly, but will"scavenge" from the maize, and from residual fertilizer left in therelevant plots after the first season.

- 0.16 -


5. Areas in Nandi District Represented by FURP Trial Sites

The aim of FURP Phase I is to select trial sites which, as far as possible,are representative of the agriculturally high and medium potential areas ofKenya. This consideration constituted the backbone for making decisions asto where to establish these FURP trial sites.

Two representativeness maps are drawn-per district. One refers to the soilsonly (Map 8.0.5: Groupings of Soil Map Units), and in the second one (Map8.0.6) Agro-Ecological Units (AEUs) are shown in which, according to theinformation available, the soils and the climate can be consideredhomogeneous.

Map 8.0.5 shows the representativeness of FURP trial sites for NandiDistrict only as far as soils are concerned. Since FURP can only covermajor physiographic units (mainly uplands, plateaus and plains), minorunits such as mountains, hills, swamps and bottomlands indicated in theSoil Map (Map 8.0.4) and described in the accompanying Legend (cf. Appen-dix: M-, H-, S- and B-units), are beyond consideration when it comes torepresentativeness.

The explanation for Map 8.0.5 shows 19 generalized "Groupings of Soil MapUnits". These groupings have the same or similar soil properties and, assuch, they represent a specific soil environment, typified by one of theFURP trial sites.

The codes in the explanation to Map 8.0.5 refer to a specific trial site(8.1, 8.2, etc.) and to a specific degree of representativeness of soils(A, B+, B-). The combination of both forms a "Soil RepresentativenessCode". Unit 8.1.A, for instance, covers an area which is highly represented(A) by the trial site Baraton (8.1). Unit 6.1.B+ covers an area which ismoderately represented (B) by the Trial Site Kamakoiwa, Bungoma District(6.1), although information on soil properties reveals slightly betterconditions in the represented area in Nandi District than at Kamakoiwaitself (B+).

The explanation to Map 8.0.5 also lists those units of the Soil Map (Map8.0.4) which are considered in the various groupings. This is to excludethe smaller physiographic units, such as HGC and BX1, which, for carto-graphic reasons, partly occur as inclusions of units coded A, B+ or B-,instead of unit C, to which they actually belong.

A breakdown of soil properties referring to the Groupings of Soil Map Unitsis given as part of Table 8.0.5.

The soils of the Nandi District are well represented by the FURP trialsites. This is testified by Map 8.0.5 which shows a high percentage of A-cover (highly representative).

The trial sites of Nandi District itself are representative of large partsof the District. Baraton (Grouping 8.1.A) represents the humic Nitisols inthe central biotite gneisses area; Chepkumia (Grouping 8.2.A) representsthe south-eastern humic Acrisols on granites.

- 0.17 -


Sites in Bungoma and Uasin Gishu District are highly representative oflarge parts of the northern Nandi District: Groupings 6.1.A, 11.1.A,11.2.A. They represent non-humic Ferralsols and Acrisols.

In the area around Nandi Hills, Volcanic Footridges with humic Nitisols arehighly represented by Trial Site 9.1, Kericho District (9.1.A), and thepiedmont plains in the south are represented by Trial Site 3.1, KisumuDistrict (3.1.A).

Trial Site 7.4, near Tindinyo, is put in brackets, as it has not yet beenidentified. It is, however, necessary to represent large parts of CentralKakamega District by a trial site on very deep nito-rhodic Ferralsols. Aslong as the site is not operational, the area should be considered as C(not represented by a trial site).

Nandi District is also moderately represented (B-cover) by its own trialsites. For the Baraton trial site, Grouping 8.1.B+ refers to soil map unitUhFl, which is on richer gneisses, and Grouping 8.1.B- refers to soil mapunits UhN3 and UhN4, which are poorer and shallower Acrisols.

For the Chepkumia trial site, Grouping 8.2.B+ holds for soil map unit UhG7,which has deeper soils, and Grouping 8.2.B- represents soil map unit UhG5,which has shallower soils with a thinner acid humic topsoil.

In the northern parts of the District, Grouping 6.1.B+ represents nito-rhodic Ferralsols and ferralo-orthic Acrisols, developed on rich gneisses.A large Grouping adjacent to Nandi Hills is 12.1.B-, referring to soil mapunit UhU4. The soils have a thinner, acidic, humic topsoil than the soilsat Trial Site 12.1, West Pokot District.

Groupings which show a combination of codes occur where different soils aregiven in one Soil Map unit: so-called associations or complexes. In Map8.0.5, Grouping ll.l.A/C is an example, representing soil association LIAI,which has rhodic Ferralsols and ferralic Cambisols (A), but alsohydromorphic soils: gleyic Cambisols and mollic Gleysols (C).

Areas which are not represented by any one trial site with respect to soilsare coded C. This involves the shallow soils of Nandi Hills and somescattered hills, swamps and bottomlands in other parts of the District.

The second representativeness map, Map 8.0.6, shows the integratedrepresentativeness of FURP trial sites involving both soils and climate.The map units are named "Agro-Ecological Units", and they represent aspecific soil-climate environment, typified by FURP trial sites.All combinations of the different soil-climate environments occurring inNandi District are shown in the Agro-Ecological Unit Map (Map 8.0.6) andare explained in Table 8.0.5. The codes for the Agro-Ecological Unitsconsist of three parts: site, soil representativeness and climaticrepresentativeness. Site and soil representativeness are taken from Map8.0.5. In addition, Map 8.0.6 and Table 8.0.5 indicate the codes whichrefer to the representativeness of the climatic environment (smallletters).

- 0.18 -


Several degrees of representativeness are given according to the prevailingtemperature regime and the rainfall in the agro-humid period of the longrains.

All areas in Map 8.0.6 which are marked with code "a" (highlyrepresentative) are within the same temperature belt and receive the sameamount of rainfall (+/- 10%) in the agro-humid period of the long rains asthe trial site to which the code refers.

The map units marked with code "b" (e.g.: b++, b+- ,b+*) are only modera-tely represented by trial sites. In the AEU 8.1.A.b++, for instance, thesoils are highly represented by the Baraton Trial Site (8.1.A), but theclimate (b++) indicates that this Agro-Ecological Unit belongs to the nextwarmer temperature belt and receives 10-20% more rainfall than the BaratonTrial Site.

Areas which are not represented by any one trial site, i.e. soils and/orclimate not represented by any site, are coded 0.

The criteria set for the sub-division of the various degrees of repre-sentativeness with respect to soils and climate are further elaborated uponin Chapter IV.2 of the main report.

- 0.19 -

£ X P L A N A

I

o

oI

Degree of representativeness

A highly representative

B+ moderately representative(soils of map unit are slightly morefavourable than soils at the trial site)

B- moderately representative(soils of map unit are slightly lessfavourable than soils at the trial site)

C non-representative

Trial sites

1.1 Otamba - Kisii District1.2 Kiamokama - Kisii District2.4 Oyugis-Ober - South Nyanza District3.1 Paponditi - Kisumu District

6.1 Kamakoiwa - Bungoma District6.2 Tongaren - Bungoma District(7.4) 2>between Butere and Kaimosi - Kakamega District

...I soil map units

8.8.9.1111.212.1

Baraton - Nandi DistrictChepkumia - Nandi DistrictSosiot - Kericho DistrictEldoret Moi TC - Uasin Gishu DistrictTurbo - Uasin Gishu DistrictKapenguria - West Pokot District

Soil RepresentativenessCode (Map 8.0.5) n>

1.1.B-1.2.B-2.4.A3.1.A

>

6.1.A6.1.B+6.2.A(7.4).A8.1.A8.1.B+8.1.B-8.2.A8.2.B+8.2.B-9.1.A11.1.A/C11.2.A12.1.B-

C 3 >

Soil Map UnitsIncluded (Map 8.0.4)

UhB1, UhV2UhI3RB5, FB4YU1, YU4,YUC

UmN2LI3, UhF2, UmF2UmR1UhD1UhN1UhF1UhN3, UhN4UhG2, UhG4UhG7UhG5RB2LIAIUhG1, UmG2, UmG3UhU4

others

Legend see Appendix

1) Digits show trial site number; letters indicate degree of representativeness.For cartographic reasons, Soil Representativeness Code C is not indicated for the many scattered hills, bottomlands, and floodplains. These areas should be considered inclusions of units with Representativeness Codes A, B , and B .

2) This site is still to be identified. See Subsection 8.0.5 for explanation.3) Soil Representativeness Code C is only indicated if it involves a "mappable" area. If not, the scattered hills and narrow elon-

gated valleys of the minor physiographic units should be considered inclusions of Representativeness Code C within Groupingswith a Representativeness Code A, B+ or B-.

MAP 8.0.5 GROUPINGS OF SOIL MAPPING UNITS REPRESENTED BY TRIAL SITES

IN NANDI DISTRICT35° E

• Site of first Priority

8.1 Baraton

8.2 Chepkumia

soil groupings mapping codesoil groupings boundary

For ÈJil'LrhV-ïlI t< ',"J bc'ïr ï ttü-ï n.'U^ i ACE

\

,o30'

N

02-

KEYum soil mapping code— soil boundary% • towns and major villages~ — tarmac road===== other all-weather roads

district boundary

nrrn scarp

- river


SOURCE

LBDA Reconnaissance Soil Map of theLake Basin Development AuthorityArea, Western Kenya, 1985 (scale1:250,000)

F E R T I L I Z E R USE RECOMMENDATION P R O J E C T ( 1 9 8 7 ) Ministry of AgricultureNational Agricultural LaboratoriesGerman Agricultural .Team

10 15 20 25 km

Table 8.0.5: Hajor Soil Properties and Cliiatic Conditions of the Agro-Ecological Units in the Nandi District

Agro-Ecological Unit

Site SoilHo. Code

1.1 . 8-

1.2. B-

2.4. A

B-

3 . 1 . A

6 . 1 . A

6 .1 . 8»

6.2. A

(7.4).A

8 . 1 . A

8 . 1 . Bt

8 . 1 . 8-

8.2. A

8.2. 8«

8.2. B-

9 . 1 . A

11.1. A/C

11.2. A

Cli iateCode

ab-tb-

b-x

b-b-x

b*-b-bx*

bx-bx»

b«b-x

a

b*-b«xb-

b«b-«b-b«x

a

a-b

a

b»-b«

b»-

b*-bt-b*x

a

b«tbu

b«

a

b*-b-t

ab«-

a

b*-b--

b-b*-b-x

b«tb*xb»i

ab-*b-»b-X

drai-nage

»

i-p

N

*

N

N

a

•

N

N

II

*

II

N

eff .depth

vd-ed

vd-ed

id-d

sh-d

d-vd

d-vd

d-vd

vd-ed

vd-ed

ed

d-ed

d-vd

ed

•d-d

ed

sh-d

d-vd

Soil

nutr.avail.

h

h

h

l-i

1

1

1

1

i

h

1

1

1

1

h

1

1

properties

top- w i s t .soil st.cap.

lh-2h

lh

lh

0

0

0

0

0

2ah

2ah

lah-2ah

lah-2ah

lah-2ah

lah

lah

0

0

vh

vh

i-h

l- i

h

h-vh

h

vh

vh

vh

h-vh

h-vh

vh

i-h

vh

l - i

h-vh

classi-fication

•o Hi

dy-io Ni

lu Ph («ha Ph)

ve-eu PI (*ch Ve],(+ sodic subsoil)

rh Fe (• fe-ch Ac)

ni-rh Fe •fe-or Ac

or Fe • fe-or Ac

fe-or Ac •ni-rh Fe

huid

hu Hi

hu • fe-hu Ac

hu 4 fe-hu Ac

hu Ac

hu Ac

hu Hi

rh Fe • fe Ca (A)gl Ca • io Gl (C)

or • fe-or •fe-ch Ac

tetp.l)lean ann.

18-2115-1815-18

15-18

15-1815-18

21-2418-2115-18

15-18 •15-18

21-2418-21

18-21

18-2118-2115-18

21-2415-1815-1818-21

18-21

Cliiatic

teip.l)•ean u n .

11-148-118-11

8-11

8-118-11

14-1711-148-11

8-118-11

14-1711-14

11-14

11-1411-148-11

14-178-118-11

U-14

11-14

Conditions

rainfall Agro-Ec.66* prob.2) Subione3)

765-9Î5 4765-9J5 4680-765 4

595-680 4

660-740 4580-660 4

6B0-765 5680-765 5765-935 5

680-765 5765-935 5

605-660660-715

610-750 6

540-610 6470-540 6540-610 6

610-750610-750540-610 6470-540 6

540-660

Cliiatic representativeness is goodepending on

15-18

15-1818-21

18-21

15-1818-2118-21

15-18

15-1B18-21

18-21

18-21

18-2115-18

18-2118-21

18-21

18-2115-18

15-1818-2115-18

15-1815-1815-18

18-2115-1815-1815-18

the situation of the

Jl-14

U-1414-17

14-17

11-1414-1714-17

11-14

U-1414-17

14-17

14-17

14-17U-14

14-1714-17

14-17

14-17U-14

U-1414-17U-14

U-14U-14U-14

14-17U-14U-14U-14

600-740

530-600600-740

530-600

530-600530-600460-530

600-740

740-810740-810

600-740

765-935

680-765765-935

765-935680-765

765-935

680-765680-765

670-740 7670-740 7600-670 8

475-520 8520-565 8565-645 8

520-640 8520-640 9640-700 9700-760 9

p or tNOvl i or tHOvl/1 or txo

Agro-Ec.Zone

UN 1LH 1IH 2-3

to 1/vl or tNO1/vl or tdo IH 3

1/vl or Uo1/vl or tHO

l/ i - -( i /s)l / i - - ( i /svl/1 or tNO

LH 3LH 3

LH 2UN 2-4LH 2 -1

to vl i or tNO1/vl or tNOvl i or tNO

1/|"(|/S)vl/1 or tHO

vl/1 or tNOto 1/vl or1/vl or tNO1/vl or two1/vl or tNO

p or tNOvl /1 or tNO1/vl or tNO1/vl or tNO

1/vl or tNO

1 to loderate,trial site

vl /1 or tNOto 1/vl or1/vl or tNOvl i or v l /or tNO1/vl or tNO

1/vl or tNO1/vl or tiio1/vl or tNO

p or tNO tov i / i or n op or tNOp or tNO

LH 3LH 1-2

LH 2UM 2-3

UN 3-4NO

UN 4UN 4LH 3

LH 1IH 2-3LH 3UN 4

UN 4

LH 2-3INO

LH 3I UN 1 -

LH 2UN 4

LH 3UN 4UN 4

LH 1-2

IH 1UN 1

vl /1 i or tNOp or tNO to

p or tNo/three

p or tNop or tito

p or tHOvl i or tNO

p or tNo/ihr Q0micep or tNOvl i or tNO

1 vl i or tNO1 p or tNo1 vl /1 or tNO

1/vl or tNO1/vl or tNO1/vl or tNO

1/vl or tNOvl /1 or tNOp or tNop or tNo

UN 1-2

UN 1

UN 1LH 1

UN 1UN 1

UN 1

UN 1-3LH 1-2

LH 1-2UN 1IH 2

LH 3LH 3LH 3

UN 4LH 2LH 1LH 1

( continued next page )

- 0.23 -

Table 8.0.5 cont: Major Soil Properties and Cliaatic Conditions of the Agro-8cological Units in the Mandi District

Agro-geological Doit

Site Soil CliaateMo. Code Code

12.1. B-b Mb H

C

0

Soil properties

drai- «ff. nutr. top- aoist. dassi-nage depth avail, soil st.cap. ficatioa

v ad-d l-i lab a-h hu Ac » hu Ca

Cliaatic Conditions

teip.l) teip.l) rainfall Agro-Kc. Agro-Sc.aean ann. aean a m . 661 prob.2) SubioneJ) Zone

15-18 11-14 635-690 9) vl i or U o IB 118-21 M-1T 635-690 9) vl i or U o UM 1-3

to vl/1 i or tvo

soil tot representative

soil and/or cliaate are not representative

ley:

Drainage Moisture storage eapacitv

se soaevhat excessive vh very high > 160 aa.v «ell b hieb 120-160 aa.a« aoderatelj «ell a aoderate 80-120 aa.i iaperfect 1 lo» < 80 aa.p poor

Effective soil depth Butrient availabiliti

ed eitreaely deep > 180 ca. h highvd vet; deep 120-180 ca. a aoderated deep 80-120 ca. 1 lovad aoderately deep SO- 80 ca. vl very lovsh shallow 25- SO ca.V8h ver; shallow < 25 ca.

Specification givenin Chapter IV.2(aain report)

Topaoil properties Soil classification

i huaic (base Hi Hitisols ao aollic fe ferraiic'saturation >S0 I] Pb Phaeoteas hu huaic fe-hu ferralo-huaic

ah acid huaic (base Ca Caabisols or orthic fe-ch ferralo-chroaicsaturation (SOt) ftc Acrisols rh rhodic fe-or ferralo-orthic

! thick (30-60 ca.) Fe Ferralsols ch cbroaic dv-ao dvstro-aollicthin (<30 ca.) Gl Gleisols ha haplic m-rh nito-rbodic

0 non-huaic Ve Vertisols lu luvic ve-eu verto-eutricPI Plaoosols gl gle;ic

1) Teiperature I'C)(differentiated acccording to ABZ belts)

21 Rainfall 661 probability (in aa.)-referring to agro-huaid period oflong rains onl;(and of F. - beg. of July)

-for definition of rainfall ranges aeeexplanation to Hap 8.0.6;-661 probability aeans that aaount ofrainfall «ill Be eiceeded in at least20 out of 30 years.

3) Agro-Ecological Subtone-approxiaative indication only, sincesubtones are not directly related toaaouot of rainfall;-'--' in foriula aeans "follo»ed by";-for further explanation of subionessee Chapter IV on lethodology;

-Agro-ecological tones and subconesare shown in Kap 8.O.3.

4) Coaparable tile: Mid Feb.-beg. of August.

5) Coaparable tile: Kid Feb.-iid August.

6) Coaparable tiae: March - July.

7) Coaparable tile: aid Feb.-aid July.

8) Coiparable tine: end of Feb.-aid July430 aa in 11.1. - .

9) Coaparable tilt: March - July, 580 ••ia 11.1, 5TS ii. in U.I.

- 0.24 -

E X P L A N A T I O N TO H A P 8 . 0 . 6

S o i l Codes Climatic Codes

= A =

= B+ =

= B- =

I

O

(V)en

highly representative

moderately representative(soils of map unit are slightly morefavourable than soils at the trial site)

moderately representative(soils of map unit are slightly lessfavourable than soils at the trial site)

highly representative,i.e. same Agro-Ecol.ZonesBelt and long rains (+/-10%) as at trial site

moderately representative

Trial sites

1.1 Otamba (Kisii District)1.2 Kiamokatna (Kisii District)2.4 Oyugis-Ober (South Nyanza)3.1 Paponditi (Kisumu District)6.1 Kamokoiwa (Bungoma District)6.2 Tongaren (Bungoma District)(7.4) between Butere and Kaimosi (Kakamega District)8.1 Baraton (Nandi District)8.2 Chepkutnia (Nandi District)9.1 Sosiot (Kericho District)11.1 Eldoret Moi TC (Uasin Gishu District)11.2 Turbo (Uasin Gishu District)12.1 Kapenguria (West Pokot District)

XXXXm

1 AEZ Belt warmer,1 AEZ Belt warmer,1 AEZ Belt warmer,1 AEZ Belt cooler,1 AEZ Belt cooler,1 AEZ Belt cooler,AEZ Belt the same,AEZ Belt the same,2 AEZ Belts warmer,2 AEZ Belts cooler,

long rains 10-20% higherlong rains similar (+/-10%)long rains 10-20% lowerlong rains 10-20% higherlong rains similar (+/-10%)long rains 10-20% lowerlong rains 10-20% higherlong rains 10-20% lowerlong rains 20-30% higherlong rains 20-30% lower

= long rains 30-50% higer (more mm.)

Area not represented

0 = not represented by soils and/or climate

For further explanation see Table 8.0.5

MAP 8.0.6 AGRO-ECOLOGICAL UNITS REPRESENTED BY TRIAL SITES

IN IMANDI DISTRICT

35° E

• Site of first Priority8.1 Baraton

8.2 Chepkumia

agro-ecological units boundary

For EXPLANATION see PREVIOUS PAGE

and TABLE S .O.5

11 2.a

N

6 t b+*

KEY«UN! soil mapping code—. soil boundary% • towns and major villages— — tarmac road

===== other all-weather roadsdistrict boundary

fiH u scarp

riverforest reserve boundary


SOURCE

LBDA Reconnaissance Soil Map of theLake Basin Development AuthorityArea, Western Kenya, 1985 {scale1:250,000)

FERTILIZER USE RECOMMENDATION PROJECT (1987) Ministry of AgricultureNational Agricultural LaboratoriesGerman Agricultural .Team

10 15 20 25 km


LEGEND TO THE SOIL MAP OF NANDI DISTRICT

1—Explanation of first character (physiography)

M Mountains and Major Scarps (steep; slopes predominantly over 301; relief intensity more than 300 ra(Mountains) or more than 100 m (Major Scarps); altitudes up to 4250 m)

H Hills and Minor Scarps (hilly to steep; slopes predominantly over 16%; relief intensity up to 100(Minor Scarps) to 300 m (Hills); altitudes up to 2850 i)

L Plateaus (very qently undulating to undulating; slopes less than 8S; altitudes between 1200 and1600 m - Maseno/Kisumu/Muhoroni/Sondu - and between 2000 and 2500 i - üasin Gishu and Siria Plateaus)

R Volcanic Footridges (dissected lower slopes of major older volcanoes and older lava flows, undulatingto hilly; slopes between 5 and 301; altitudes between 2000 and 3000 m; Mount Elgon/TinderetMountains/Hau Forest)

F Footslopes (at the foot of Hills and Mountains; gently undulating to rolling; slopes between 2 and161; various altitudes)

V Piedmont Plains (nearly flat to gently undulating; slopes between 0 and 5%; altitudes between 1150and 1500 m; in Lambwe Valley, Kano Plains and near Lake Victoria shoreline)

Ü UplandsUh upper Middle-Level uplands (undulating to rolling; slopes between 5 and 161; altitudes

between 1650 and 2650 ra)Um Lower Middle-Level uplands (gently undulating to undulating; slopes between 2 and 81;

altitudes between 1200 and 2200 m)B Bottomlands (flat to gently undulating; slopes between 0 and 51; various altitudes; seasonally

ponded)S Swamps (almost flat; slopes between 0 and 2%; various altitudes; permanently waterlogged if not

reclaimed)V Minor Valleys (V or ü-shaped valleys; slopes mainly up to 161, exceptionally up to 301; width mainly

250-500 ra, up to about 1000 m; depth up to about 100 m; various altitudes)

2—Explanation of second character (litholoqy);

A Recent Alluvial Sediments from Various SourcesB Basic Igneous Rocks (basalts, nepheline phonolites? older basic tuffs included)D Hudstones and ClaystonesF Gneisses Rich in Ferromagnesian Minerals and Hornblende GneissesG Granites and GranodioritesI Intermediate Igneous Rocks (andesites, phonolites, syenites, etc.)N Biotite GneissesR Quartz-Feldspar Gneissesü Dndifferentiated Basement System Rocks (predominantly Gneisses)V Undifferentiated or Various Igneous RocksX undifferentiated or Various Rocks

3 — S o i l descriptions

MB3 Well drained shallow to moderately deep, dark reddish brown, friable, gravelly clay loam toclay, with an acid humic topsoil; in places stony and rocky, or deephumic CAHBISOLS, partly lithic, stony phase; with Rock Outcrops

HB4 Somewhat excessively drained, shallow, dark reddish brown to dark brown, very stony, clayloam to clay, with a humic or acid humic topsoil; in places moderately deep to deephaplic PHAEOZEMS and RANKERS, lithic and stony phases

- 0.29 -

District : Nandi General Aspects 8.0

KU2 Well drained, very shallow to shallow, brown to reddish brown, stony and rocky, gravelly tovery gravelly sandy loan to sandy clay loanLITHOSOLS and dystric REGOSOLS, rocky and stony phases

HB1 Somewhat excessively to well drained, very shallow to moderately deep, dark reddish brown,friable, gravelly clay; in many places with an acid humic topsoil; in places stony and rockydystric and humic CAKBISOLS, partly lithic and stony phases, and LITHOSOLS; with RockOutcrops

HGC Complex of:Somewhat excessively drained, shallow, stony and rocky soils of varying colour, consistencyand texturedystric REGOSOLS and RANKERS, with ferralic and hunic CAHBISOLS, lithic, rocky and stonyphases, LITHOSOLS and Rock Outcrops

HIC Complex of:Well drained, shallow to deep, dark red to strong brown, friable, gravelly sandy clay; overpetroplinthite or rock; in many places very shallow, stony and rockyferralo-chromic CAHBISOLS and orthic and rhodic FERRALSOLS, partly lithic, stony and rockyphases, with LITHOSOLS

HNl Well drained, moderately deep to deep, yellowish red, friable clay, with an acid humictopsoil; over pisoferric material or rockferralo-humic ACRISOLS, partly pisoferric phase

HUC1 Complex of:Excessively to well drained, shallow, dark red to brown, sandy clay loam to clay; in manyplaces stony, bouldery and rocky; in places with an acid humic topsoil and/or moderatelydeep to deepdystric REGOSOLS, with humic CAHBISOLS, lithic, bouldery and rocky phases, with LITHOSOLSand Rock Outcrops

LI3 Well drained, very deep, dark reddish brown to dark red, friable claynito-rhodic FERRALSOLS

LIAI Association of:well drained, moderately deep to deep, dark red, "9ry friable clay; over petroplinthite; onrelatively higher parts (601)rhodic FERRALSOLS, partly petroferric phaseand:well to imperfectly drained, shallow to moderately deep, dark red to brown, friable clay;over petroplinthite or rock; in many places mottled, in places very shallow and/or rocky;near depressions and valley sides (201)ferralic and gleyic CAHBISOLS, petroferric and lithic phases, with LITHOSOLS and RockOutcropsand:poorly drained, moderately deep to deep, dark grey to grey, mottled, firm clay, with a humictopsoil; in many places over petroplinthite; in depressions (201)mollic GLEYSOLS, partly petroferric phase

RB2 Well drained, extremely deep, dusky red to dark reddish brown, very friable clay, with anacid humic topsoilhumic NITISOLS

- 0.30 -


RB5 Well drained, moderately deep to deep, dark reddish brown to brown, friable to f i n clay,with a humic topsoil; in places shallow and fairly boulderyluvic PHAEOZEHS, with haplic PHAEOZEHS, lithic phase

FB7 Moderately well to imperfectly drained, very deep, very dark grey to very dark greyishbrown, friable to very firm, clay loan to cracking clay; predominantly with a thick humictopsoil; in places with a calcareous deeper subsoilverto-luvic and haplic PHAEOZEHS, with chromic VERTISOLS

FG2 Well drained, moderately deep to deep, dark yellowish brown, friable sandy clay; in manyplaces with an acid humic topsoil, rocky and/or stonydystric and humic CAHBISOLS, stony and rocky phases

FIA Association of:well drained, very deep to extremely deep, dark red, friable clay; on sloping land (601)eutric NITISOLSand:somewhat excessively drained, shallow to deep, dark reddish brown, friable to firm,bouldery, fairly rocky clay; on steep slopes (40%)ferralo-chromic LUVISOLS and ferralo-chronic CAHBISOLS, partly lithic phases

FÜ2 Well drained, deep, yellowish red to dark reddish brown, friable to firm, fairly rocky,sandy clay loam to clay; in places moderately deeporthic LUVISOLS and eutric CAHBISOLS

FÜC Complex of:well drained, deep, dark reddish brown to dark yellowish brown soils of varying consistencyand texture; in places moderately deep, gravelly and/or stonyorthic FERRALSOLS, orthic ACRISOLS and ferralic ARENOSOLS, partly stony phases

YÜ1 Imperfectly drained, very deep, dark greyish brown to very dark grey, mottled, very firm,cracking clay, with a calcareous and slightly sodic deeper subsoil; in many places abruptlyunderlying a firm topsoil of sandy claychromic VERTISOLS and verto-eutric PLANOSOLS

Y03 Imperfectly to poorly drained, deep to very deep, very dark grey to dark greyish brown,mottled, firm to very firm, saline and sodic, sandy clay loam to cracking clay; in manyplaces abruptly underlying a topsoil of firm sandy loam to sandy clay loamvertic SOLONETZ and solodic PLANOSOLS, saline phase and chromic VERTISOLS, saline-sodicphase

YÜ4 Poorly drained, very deep, dark greyish brown to very dark grey, mottled, firm to very firm,cracking clay, abruptly underlying a topsoil of friable sandy clay loam, in places with asodic subsoilverto-eutric PLANOSOLS, with solodic PLANOSOLS

ÏÜC Complex of:moderately well to poorly drained, very deep, dark brown to very dark grey, firm to veryfirm sandy clay to cracking clay; in places stratified, sodic, or gravellyPLANOSOLS, GLEYSOLS, SOLONETZ, VERTISOLS and FLUVISOLS

ühBl Well drained, very deep to extremely deep, dark red to dark reddish brown, friable clay,with a hunic topsoilnollic NITISOLS

- 0.31 -


UhDl Well drained, very deep, dark reddish brom to yellowish red, friable clayferralo-orthic ACRISOLS

ühFl Well drained, extremely deep, dark reddish brown, friable clay, with a thick acid humictopsoilhumic NITISOLS

UhGl Well drained, deep, yellowish red to dusky red, friable sandy clay to clay; in placesshallow (on steeper slopes and rocky)ferralo-chromic ACRISOLS, partly lithic phase; with Rock Outcrops

DhG2 Well drained, deep to very deep, yellowish red to dark reddish brown, friable to firm sandyclay, with an acid humic to thick acid humic topsoilhumic and ferralo-humic ACRISOLS

UhG4 Well drained, deep to very deep, brown to strong brown, friable to firm, bouldery and fairlyrocky, gravelly sandy clay to clay, with an acid humic to thick acid humic topsoil; inplaces stonyhumic ACRISOLS, bouldery and partly stony phase

UhG5 Well drained, moderately deep to deep, strong brown, friable to firm, bouldery and fairlyrocky sandy clay, with an acid humic topsoilhumic ACRISOLS, bouldery phase

UhGAl Association of:well drained, moderately deep to deep, brown, friable to firm, fairly bouldery and fairlyrocky, gravelly coarse sandy clay; on moderate slopes (60%)dystric CAMBISOLSand:somewhat excessively drained, very shallow to shallow, brown, friable, bouldery andextremely rocky, gravelly coarse sandy clay loam; in places with an acid humic topsoil; onsteep slopes (401)LITHOSOLS and RANKERS, rocky and bouldery phase

UhI3 Well drained, very deep to extremely deep, dark red to dark reddish brown, friable clay,with a humic topsoildystro-mollic NITISOLS

UhI5 Well to moderately well drained, shallow to moderately deep, dark red to brown, friable tof i n clay, with a humic topsoil; over rock or pisoferric materialhaplic and luvic PHAEOZEHS, partly lithic or pisoferric phases

UhNl Well drained, very deep to extremely deep, dusky red to dark reddish brown, friable clay,with a thick acid humic topsoilhumic NITISOLS

UhN2 Well drained, moderately deep to very deep, dark reddish brown, friable sandy clay, with athick humic topsoil; in places shallow and fairly rockyluvic PHAEOZEHS, partly lithic phase

0hN3 Well drained, deep to very deep, dark reddish brown to dark brown, friable to firm clay,with a thick acid humic topsoilhumic ACRISOLS, with humic CAHBISOLS

- 0.32 -


ühH4 Well drained, very deep to extremely deep, dark red, friable to f i n clay, with an acidhumic topsoil . .ferralo-humic ACRISOLS

UhU4 Well drained, shallow to moderately deep, dark brown to yellowish brown, friable sandy clayloam to sandy clay, with an acid humic topsoil; in places very bouldery and rocky; withinclusions of very deep, dark reddish brown, friable clayhumic CAHBISOLS and ACRISOLS, partly lithic and bouldery phases, with Rock Outcrops andhumic NITISOLS

UhV2 Well drained, extremely deep, dusky red to dark red, friable clay, with a thick humictopsoilraollic NITISOLS

0mF2 Well drained, moderately deep to very deep, yellowish red to strong brown, friable to firmclayferralo-orthic ACRISOLS

UmN2 Well drained, deep to very deep, red to dark red, friable clay; in places moderately deeprhodic FERRALSOLS, with ferralo-chromic ACRISOLS

UmRl Well drained, deep to very deep, dark red to brownish yellow, friable clay; in placesmoderately deeporthic FERRALSOLS and ferralo-orthic ACRISOLS

ümü4 Well drained, shallow to moderately deep, very dark greyish brown, friable, gravelly sandyclay; in places with a humic topsoïl; in places stony and very shalloweutric CAHBISOLS, with haplic PHAEOZEMS, partly stony and lithic phases and with LITHOSOLS,partly stony phase

BX1 Imperfectly to poorly drained, deep to very deep, dark grey to greyish brown, mottled, firmsandy clay to cracking clay; in places with a peaty topsoil; in places with a calcareoussubsoileutric and vertic GLEYSOLS, with lollic GLEYSOLS

SA1 Very poorly drained, deep, dark grey to black, half ripe clay, with a humic or histictopsoil; in many places peatymollic GLEYSOLS and eutric HISTOSOLS

VXC Complex of:well drained, shallow to deep soils of varying colour, consistency and texture (on valleysides)CAHBISOLS, ACRISOLS and FERRALSOLS, partly lithic phases, with Rock Outcropsand:imperfectly to poorly drained, deep, mottled soils with predominantly greyish colours, firmconsistency and fine textures (in valley bottoms)GLEYSOLS, with VERTISOLS and HISTOSOLS

- 0.33 -


NOTES

1 Dollic Nitisols and chrono-luvic Phaeozems: soils are equally important2 mollic Nitisols, with chromo-luvic Phaeozems: Nitisols are prevalent3 in places: in <30$ of the area4 in many places; in 30-501 of the area5 predominantly: in >50% of the area6 deeper subsoil: below 80 cm.

- 0.34 -

District: Nandi Trial Site 8.1: Baraton


Detailed Description of the Baraton Trial Site

Page

1. Geographical and Additional Technical Information 1.41.1 Final Position of the Trial Site 1.41.2 Sketch of Trial Sites 1.51.3 Physiography 1.71.4 Vegetation, Past and Present Land Use 1.81.5 Names and Addresses of> Government Officers from the

Division and Farmers Involved in FURP Activities 1.9

2. Climate 1.102.1 Prevailing Climatic Conditions 1.10

2.1.1 Agro-Climatic Classification of the Area Represented 1.102.1.2 Relevant Meteorological Data 1.112.1.3 Crop Suitability from the Climatic Point of View 1.16

2.2 Proposal for the Monitoring of Agro-Climatic Conditions inPhase II 1.20

3. Soils 1.213.1 Survey Data 1.21

3.1.1 Brief Soil Description and General Information onthe Soil 1.21

3.1.2 Detailed Profile Description and Soil Classification 1.223.1.3 Soil Sampling 1.24

3.2 Laboratory Data 1.243.3 Evaluation of Soil Data 1.29

3.3.1 Literature References and Soil Correlation 1.293.3.2 Representativeness 1.293.3.3 Variability of Soil Properties within the Trial Site 1.303.3.4 Fertility Status of the Soil 1.31

3.3.4.1 Soil Profile and Global Fertility Rating 1.313.3.4.2 Soil Fertility Assessment of Composite Samples 1.32

3.4 Sampling Programme for Laboratory Analysis 1.343.4.1 Soil Samples 1.343.4.2 Plant Samples - 1.343.4.3 Other Samples 1.34

4. Conclusions from the Analyses of Climate and Soils 1.354.1 Moisture Availability 1.354.2 Nutrient Availability in Relation to Possible Fertilizer

Requirement 1.354.3 Other Relevant Land Qualities 1.37


- 1.1 -


Table

Table

Table

Table

Table

Table

Table

Table

Table

Table

Table

Table

Table

Table

Table

8.1.1

8.1.2

8.1.3

8.1.4a

8.1.4b

8.1.5

8.1.6

8.1.7

8.1.8

8.1.9

8.1.10

8.1.11

8.1.12

8.1.13

8.1.14

List of Tables1)

Page

Physiography of the Baraton Trial Site 1.7

Vegetation, Past and Present Land Use 1.8

Names and Addresses of the Divisional Staff Members and

Farmers of the Baraton Trial Site 1.9

Data of the Nearest Long-Term Rainfall Station 1.12

Data of the Nearest Long-Term Rainfall Station 1.13

Temperature 1.14

Potential Evaporation (Eo) 1.14

Agro-Climatological Crop List for Baraton 1.16

Crop Development Stages and Crop Coefficients 1.18

Detailed Profile Description of the Baraton Trial Plot 1.23

Analytical Results (physical and chemical analyses) 1.25

Analytical Results (chemical analysis.trial plot) 1.26

Analytical Results (chemical analysis, farmers' fields) 1.28

Soil Correlation with Respect to the Baraton Trial Site 1.29

Evaluation of Mehlich Analysis Data According to NAL

Standards " 1.33

1) See Footnote next page.

- 1.2 -


List of Figures1)

Page

Figure 8.1.1 Demarcation of the Baraton Trial Site 1.4

Figure 8.1.2 Access Map of the Trial Site Baraton 1.5

Figure 8^1.3 Map of the Trial Plot Baraton 1.6

Figure 8.1.4 Location of Farmers' Fields for On-Farm Trials, Baraton 1.7

Figure 8.1.5 Rainfall and Potential Evaporation 1.15

Figure 8.1.6 Water Requirement and Availability for Maize H 625,

First Rains 1.19

Figure 8.1.7 Location of Composite Sampling Blocks and ProfilePit at the Baraton Trial Plot 1.24

1) Numbering mode of Tables and Figures:First Number: District NumberSecond Number: Trial Site NumberThird Number: Number of Table or Figure within Chapter.

- 1.3 -


1, Geographical and Additional Technical Information

1.1 Final Position of the Trial Site

position of the site at Baraton is shown in Figure 8.1.1 ^ " a c ^ d

" i/\rtrt ' t* B^^ IÖY" Ho^â î T Q OT1 ttlG f ÎTlâJ- pOSl-tiOXl a i e

Shown Figurf^î.^and the sketch map of the trial plot in Figure 8.1.3.

733

I

735

I

736

I

737 738 s 7:

r\:^"Kï>J CÜ/#^C

Figure 8.1.1: Demarcation of the Baraton Trial Site on the 1:50,000

Topographic Map

- 1.4 -


1.2 Sketch Of the Trial Site.

The location of and the access route to the Baraton site are shown inFigures 8.1.2 and the map of the trial plot in Figure 8.I.3.

05 I

Figure 8.1.2: Access Map of the Trial Site, Baraton

- 1.5 -


O 10 20 30 40 50m

Figure 8.1.3: Map of the Trial Plot, Baraton

- 1.6 -


The approximate location of the on-farm trials is indicated in Figure8.1.4.

Figure 8.1.4: Location of Farmers' Fields for On-Farm Trials, Baraton

1.3 Physiography

Information on the physiography of the trial site and its surroundings issummarized in Table 8.1.1 below.

Table 8.1.1: Physiography of the Baraton Trial Site

Elevation

Landform

Physiographic position of

Topography of surrounding

Slope on which trial plot

Aspect

Microtopography

the site

country

is sited

2000 m.

Upper middle-level uplands

convex upper and middleslope

undulating to rolling(slopes 5-16%)

5-8%

NE

terraces/contour-lines

- 1.7 -


1.4 Vegetation, Past and Present Land Use

Information on vegetation and on past and present land use is summarized inTable 8.1.2 below:

Table 8.1.2: Vegetation, Past and Present Land Use of the Baraton TrialSite

Vegetation

Cropping svstem

(a) cleared since:(b) crops grown:

(c) fallow periods:(d) present land use:

Inputs

(a) mineral fertilizers:

(b) organic manure:(c) means of land preparation:(d) means of weeding:(e) frequency of weeding:(f) other capital inputs:(g) level of know-how:

Produce

(a) maize

Livestock

Montane Acacia vegetationfrom moist intermed. forest

1982maize/beans (1982);maize sole crop since 1983nonemaizemaize var: H 613,614,625

SSP or TSP or 20:20:0;DAP in 1986only in home gardentractormanualonce per crop standnonemoderate

15-20 bags/acre(90 kg-bags)

21 cows ; milk productionimportant source of income

Remarks

Farmer, a T.A., was not impressed by effect SSP, TSP, 20:20:0

- 1.8 -

1.5


Names and Addresses of Government Officers Involved in FURPActivities

Names and addresses of the divisional staff members and of all farmersinvolved are given in Table 8.1.3.

The codes used for the additional "on-farm" farmers refer to the locationof their farms as indicated in Figure 8.1.4.

Table 8.1.3: Names and Addresses of Divisional Staff Members and ofFarmers of the Baraton Trial Site

DivisionalStaff

D.E.OL.E.OT.A.

Farmers

Trial plot

On-Farm trials

8.1.A8.1.B8.1.C8.1.D8.1.E8.1.F8.1.G8.1.H

Name

P. Kichwennot metNdege Kogoo

Name

Ndege Kogoo

LOCATION:SUB-LOCATION:

Name

George BometSimeon MutaiJoseph ChirchirEsther KoteKundule BusienieKipkene RabarnoFlorence CheruiyotEric Korir

Address

Box 60, Kapsabet

Box 60, Kapsabet

Address

Box 60, Kapsabet

ChemunduBaraton

Remarks

Period of site selection: March 1986.

- 1.9 -


2. Climate

2.1 Prevailing Climatic Conditions

2.1.1 Agro-Climatic Classification of the Area Represented by theBaraton Trial Site

The following brief climatic description refers to the existinginformation:

ACZ : 115 (H.M.H. BRAUN, 1982)1)

AEZ : LH 2, vl/1 or two (R. JÄTZOLD, 1983)2)

Next long-term rainfall stations: 08935062, University of East AfricaBaraton, and 08935018, Kapsabet D.O.

Agro-Climatic Zone (ACZ):

Moisture availability Zone II (r/Eo): annual average precipitation is 65-80% of the potential evaporation (Eo).

Temperature Zone 5: mean annual temperature is 16-18°C

Agro-Ecological Zone (AEZ):

LH 2 = Wheat/Maize - Pyrethrum Zone

LH = Lower Highland Zone: mean annual temperature 15-18°C, mean minimum

2 = sub-humid; annual average precipitation is 65-80% of the potentialevaporation (Eo)

Sub-zone according to growing periods for annual crops (calculated for a"normal" crop in 60% probability)

vl/1 or two = with a very long to long cropping season, which can bedivided into two variable cropping seasons.

1) According to H.M.H. BRAUN in: W.G. SOMBROEK et al. (1982):Exploratory Soil Map and Agro-Climatic Zone Map of Kenya, scale1:1,000,000. - Rep. El, Nairobi

2) According to R. JÄTZOLD and H. SCHMIDT, eds. (1983): FarmManagement Handbook of Kenya, Vol. II/B CENTRAL KENYA - Nairobiand Trier.

- 1.10 -


Formula Cropping season Lengths of growing period(exceeded in 6 out of 10 years)

vl/1 very long to long 235-284 days

2.1.2 Relevant Meteorological Data for the Baraton Trial Site

In this section a breakdown is given of the following climatic parameters:rainfall, potential evaporation and temperature.

Rainfall :

Rainfall data are obtained from the nearest long-term rainfall stations:08935062, University of East Africa, Baraton (elevation: 1960 m), 3.5 km NWof the trial site (elevation: 2000 m ) , and 08935018, Kapsabet D.O.(elevation: 1980 m), 3.5 km S of Baraton Trial Site. The data are listed inTable 8.1.4a and 8.1.4b. At the trial site rainfall amounts are almostsimilar: in 20 out of 30 years Baraton gets about 670 mm during the agro-humid period of the first rains (end of February - mid July, see Map8.0.1), and about 580 mm during the second rains (mid July - November, seeMap 8.0.2). In the growing season from March to September the site getsmore than 900 mm in 20 out of 30 years. The methods of rainfall-data anal-ysis are described in Chapter IV.2.2 of the main report.

Temperature and potential evaporationfEo^:

Temperature data are obtained from temperature-recording station 08935018,Kapsabet (operating up to 1954) 3.5 km S of the trial site (elevation: 2000m). Potential evaporation (Eo) is calculated using the PENMAN formula,modified by MC CULLOCH (1965). The input parameters employed - windrun,sunshine hours and relative humidity - are obtained from 08935133, Moi T.C.Meteorological Station (elevation: 2140 m ) , 45 km NE of the trial site.

Temperature and evaporation data for the Baraton site are given in Tables8.1.5 and 8.1.6, and the rainfall pattern and potential evaporation areshown in Figure 8.1.5.

For more detailed information on the methodology of climatic descriptionsee Chapter IV.2.2 of the main report.

- 1.11 -

Table 8.1 .4a : Data of the Nearest Long-term Rainfall Station

Station No.: 08935018Kapsabet, 0.0.Elevation: 1980 m

Total years for calculation: 52First year included: 1926Last year included: 1985

Average annual rainfall: 1511 mm

Rainfall surpassed in 20 out of 30 years (~66% Probability):

1st rains: 675 mm(beg. of Mar. - beg. of July)

2nd rains: 620 mm(mid Jul. - beg. of Dec.)

Decadesand

Months

1 JAN234 FEB567 MAR89

10 APR1 11213 MAY141516 JUN17181 9 JUL202122 AUG232425 SEP262728 OCT293031 NOV323334 DEC3536

ArithmeticMean(mm)

12.917.320. 117.328.626.528.233.638.664.972.868.681 .570.852.555.855.656. 554. 145. 562. 164.659.463. 453.349.036.933.529.930.427.825.822. 121 .017.512.7

Average Number of RainyDays with Rainfall> = 1 mm

1 .21.61 .91 .62.22.02. 12.72.74.04.74.95.95.14.44.64.55.34.74.55.25. 15.45.84.94.23. 13. 12.73.03. 12.62.21 .71 .61 .4

>= 5 mm

1 .21 .61 .91 .62. 12.02. 12.72.73.94.74.85.95.04.34.54.45.24.74.45.25. 15.35.74.84.23.03.12.72.93.02.62. 11 .71 .51 . 4

=66% Probabi-lity of ex-

ceeding . . .mm

3.46.48.97. 1

12.413.415.118.224.431 .749.644.064.454. 139.641 .739.945.839.133.646.551 .247.251 .639.533.224.122.918.418.816.912.010.98.36.84.9

Yearsanal-ized

515151525252515151525252505050505050494949515151505050515151494949484848

- 1.12 -

Table 8.1.Ab : Data of the Nearest Long-term Rainfall Station

Station No.: 08935062 Total years for calculation: 22Univers, of E. Afr. Baraton First year included: 1962Elevation: 1960 m Last year included: 1985


Rainfall surpassed in 20 out of 30 years (z66X Probability):

1st rains: 670 mm(beg. of Mar. - beg. of July)

2nd rains: 470 mm(mid Jul. - beg. of Dec.)

Decadesand

Months

1 JAN234 FEB567 MAR89

10 APR1 11 213 MAY1 41 516 JUN17181 9 JUL202122 AUG232425 SEP262728 OCT293031 NOV323334 DEC3536

ArithmeticMean(mm)

21 .429.129.832.028.227.320.639. 146.555.863.374.385.374.272.051 .655.957. 254.463.065.560.369.762.554.739.651 .339.232.944.534.522.933.119.61 4. 51 5.8

Average Number of RainyDays with Rainfall> = 1 mm

1 .81 .82.52.42.52.21 . 93.03.24.04.74.56.05.75.54.55.5

• 5.45. 15. 15.25.36.26.45.74.33.53.93.43.93.52.82. 51 .81 .72.0

> = 5 mm

1 .71 .7

2.52.32.42.21 .92.93.23.84.44.45.95.65.44.35.35. 25. 14. 95. 15.25.96.25.5 •4.23.53.83.33.93. 42.72.51 .71 .61 .8

~66% Probabi-lity of ex-

ceeding ... mm

8.113.29.8

14.716.816.013.423.332.238.347.253.867.960. 553. 539.745.642.542.351 .451 .649.453.151 .939.830.034.225.024.328.620.812.919.48.65.95.6

Yearsanal-ized

22222221212121212121212122222222222219191 9212121212121202020202020202020

- 1.13 -


Table 8.1.5: Temperature (°

MeanMeanMean

MeanMeanMean

temp.max.temp.min.temp.


JAN.

18.125.510.7

JUL.

16.222.010.4

FEB.

18.325.710.8

AUG.

16.122.110.1

annual mean: 17.4 mean max

C)

MAR.

18.625.911.3

SEPT.

16.122.210.0

.: 24.1

APR.

18.8 ~26.111.5

OCT.

17.524.410.6

mean

MAY

17.123.410.8

NOV.

18.125.410.8

min. :

JUN.

16.722.810.5

DEC.

17.524.310.6

10.7

Table 8.1.6: Potential

1st decade2nd decade3rd decadeTotal :


average annual

JAN.

565662174

JUL.

3131

_3597

Evaporation

FEB.

616149171

AUG.

3333

_36102

MAR.

626268192

SEPT

4141_41123

(Eo) in

APR.

555555165

. OCT.

5151

_56_158

potential evaporation: 1730

mm per

MAY

414146128

NOV.

5151

_51153

mm.

Decade :

JUN.

33333399

DEC.

5454

_60168

For all the climatic data published in this Section, a data bank has beenestablished by FURP on Personal Computers at the National AgriculturalLaboratories in Nairobi.

-1.14 -

co

ö

m

LUM—

O

wQ)

iv v v v v v

cID(NCDOLOroCD00O

CO

-4—l

D

CO—O

c'oer

• *co

• —-f->J3CO

"5o

OO

O<ü

CO•

, 1 1

•

o•

o

roT —

roen00O

CO

ininro

oIO

COCM

CM

(OCM

mCM

it;IOCM

üLUQ

>oIZ

1—oo

CLLUCO

—\

CM

oCM

O»"~

CO

CO

m

n

o

a>

CO

CD

m

• * •

Kl

CM

1 '

<

01CL.

o:

mLU

<

co

•H

oo.

LU

i—1

(Ö• H+ j

CCD

OCL

-occti

all

c•H

<r

io•

00

0

co• H

LL

- 1.15 -


2.1.3 Crop Suitability from the Climatic Point of View

A summary of the agro-climatic suitability of the most important seasonalfood crops is given in Table 8.1.7. below. Additional information on othercrops, considered suitable from the agro-climatic viewpoint, is given inthe Farm Management Handbook, Vol. II/B, Central Kenya1).

Table 8.1.7: Agro-Climatological Crop List for Baraton

Crop/variety(or place ofbreeding)e = earlym = medium1 = late

Maize/1.mat.like H625

Maize/1.mat.like H613

Barley/m. mat.

Garden Peaslike meteor

Potatoes/m.mat.

Av.No.ofdays tophysiol.maturity

170-200

160-180

120-140

90-130

140-170

Altitudes2)accordingto growingperiod

(m.)

1500-2100

1500-2100

2100-2400

1800-2700

1800-2900

Requirem.ofwell distri-buted rain-fall 3) ingrow.period

(mm. )

600-950

600-950

400-600

250-400

450-750

Yieldpotential ace.to water avai-lability 4)a = 1st rainsb = 2nd rains

a) good/verygood(Mar-Sep)

a) good/verygood (Mar-Sep)

b) good(Jun.-Oct.)

a) goodb) good/fair

good(May - Sep.)

1) R. JÄTZOLD and H. SCHMIDT, eds.(1983): Farm Management Handbook ofKenya, Vol. II/B, Central Kenya - Nairobi and Trier.

2) Most suitable altitudes; the length of the growing periodincreases with altitude; growth is also possible beyond theindicated altitude range, as long as the ecological limits havenot been reached.

3) Lower figure for fair results, higher for very good results withsome corrections due to rainfall distribution, evaporation andrun-off losses.

4) Estimated yield potential: very good >80%, good = 60-80%, fair =40-60% and poor <40% of the expected., yield under optimum wateravailability adapted from R. JÄTZOLD and H. SCHMIDT, eds. (1982):Farm Management Handbook of Kenya, Vol. II/A, West Kenya

- 1.16 -


For the most important food crops in the area around the Baraton TrialSite, the crop coefficients (kc) are shown in Table 8.1.8, differentiatedaccording to decades (10 day periods) of the growing season which is thetime between planting or sowing and the physiological maturity.Furthermore, four crop development stages are distinguished in Table 8.1.8.

The crop coefficients for the climatic conditions at the Baraton Trial Sitewere estimated on the basis of data obtained from DOORENBOS and PRUITT(1977)1) and DOORENBOS and KASSAM (1979)2).

The data on the duration of each of the growing seasons and on the variousdevelopment stages of each crop were assessed on the basis of localobservations made under average climatic conditions.The crop coefficients estimated for the various decades of the growingseasons were used to estimate the maximum (potential) evapotranspiration(ETm) under the prevailing climate, assuming that water is not a limitingfactor for plant growth. For this calculation the following approximativeformula was employed:

ETm = kc • * Eo

whereby: ETm= maximum (potential) evapotranspirationkc = crop coefficientEo = potential evaporation (climatic evaporative demand)

In Figure 8.1.6 the ETm-values are used to indicate the estimated maximumwater requirements of the maize crop for optimum growth. Furthermore, therainfall data at 66% reliability shown in Figure 8.1.6 give an indicationof the water availability. However, when reading these figures, it must beborne in mind that the actual availability of water for the plants alsodepends, to a large degree, on factors such as the run-off, the moisturestorage capacity of the soil, the deep percolation of water etc.The placement of the growing seasons of the various crops on the time axisas presented in Figure 8.1.6 was mainly based, on the pattern of rainfall,whereby the peak water requirements of the plants should be met by high,reliable rainfall.

Detailed information on the calculation procedures and references are givenin Chapter IV.2.2 of the main report. The interpretation of the diagrammentioned above follows in Section 4 of this Volume (Conclusions from theAnalyses of Climate and Soils).

1) FAO (1977): Crop Water Requirements - (= Irrigation and DrainagePaper, 24), Rome

2) FAO (1979): Yield Response to Water - (= Irrigation and DrainagePaper, 33), Rome

- 1.17 -

Table 8.1.8 : Crop development stages 1) and crop coefficients (Kc) 2) for approx. nxiiui (potential) crop evapotranspiration of the nst importantseasonal crops grom at Baraton (site no. 8.1)

00

I

Crop/Variety

MAIZEH625

MAIZEH511

BEAISRose coco

GARDENPEAS

POTATOES

1

0.55I

0.55I

0.6I

0.6I

0.61 I

Umber2

0.6I

0.6I

0.6I

0.6I

0.6I

of decades3

0.65I

0.65I

0.68II

0.68II

0.65I

4

0.69II

0.71II

0.83II

0.91II

0.71II

from s5

0.77II

0.81II

0.98II

1.05III

0.81II

«eding6

0.85II

0.91II

1.05III

1.05III

0.91II

resp.7

0.93II

1.01II

1.05III

1.05HI

1.01II

planting to8

1.01II

1.05III

1.05III

1.05HI

1.05HI

9

1.05III

1.05III

1.05III

0.92IV

1.05III

(physiological) ntarity10

1.05III

1.05III

1.05III

0.67IV

1.05III

11

1.05III

1.05III

0.92IV

0.43IV

1.05III

12

1.05III

1.05HI

0.67IV

1.05HI

13

1.05 1III

1.05 0III

0.43IV

1.05 0III

14

.05III

.97IV

.99IV

15

1.05III

0.8IV

0.89IV

16 17 18 19 20 21 22 23 24

0.97 0.88 0.74 0.61IV IV IV IV

0.63IV

0.76IV

1) Crop development stages as defined in chapter IV 2.2 (lain report)I = initial stage II = development stage III = lid season IV = late season

2) Kc = crop coefficient as defined in chapter IV 2.2 (nin report)

Figure 8.1.6: Water requirementsand availability for cropMaize H 625, first rains

Rainfall Station: 08935062University of E. A., Baraton

mm

CO

I

Trial Site 8.1 Baraton

66% Probability

16 17 18 19 20 21 22 23 24 25 26

MAR APR MAY JUN JUL AUG SEP


2.2 Proposal for the Monitoring of Agro-Climatic Conditions in PhaseII

For Phase II the agro-climatic recording programme should include:

1) Rainfall records :

A rain gauge has to be installed at the Baraton Trial Site to measureactual precipitation on the spot. Subsequently, the data can be comparedwith both rainfall for a particular year and the long-term average from thenearest rainfall recording stations of the Meteorological Department:08935062, University of East Africa, Baraton and 08935018, Kapsabet D.O.

2) Records on other relevant meteorological parameters :

Data on temperature, relative humidity, windrun and sunshine hours can beobtained from 08935133 Moi Teachers College Meteorological Station(elevation: 2140 m), in order to calculate Eo (climatic evaporativedemand). The temperature data have to be adjusted to the altitude of thetrial site (elevation: 2000 m). The temperature gradient in this area is onaverage 0.7°C.

3) Phenological records :

Dates of planting or seeding of each crop, emergence, start of tasselling(for maize crop), budding (for bean or pea crop), flowering, ripeness orphysiological maturity and harvest have to be recorded. Additionally theleaf area index (LAI) has to be determined every week (at least for thecereal crops) in order to provide a sound basis for water balancecalculations. Other important features should also be recorded, above allrolling and wilting leaves, which indicate water stress and wilting pointrespectively before physiological maturity has been reached.

Moreover, soil moisture checks and observations on rooting depth at theabove-mentioned growing stages and run-off measurements would be needed toestimate the actual evapotranspiration of the various crops correctly.

For most of the data to be recorded, official forms from the MeteorologicalDepartment are available.

Detailed information on calculation procedures, as proposed for themonitoring of agro-climatic conditions, is given in Chapter IV.2.2 of themain report.

- 1.20 -


3. Soils

In this Section, survey and laboratory data concerning the trial site and,more specifically, the soil profile are given. The evaluation of these datais shown in Sub-Section 3.3.

3.1 Survey Data

3.1.1 Brief Soil Description and General Information on the Soil

The brief description of the soils of the trial plot is followed by arating of relevant soil-related land factors. The classes for these ratingshave been adapted from Andriesse and van der Pouw (1985) and a key for themis to be found in Chapter IV. 2.3 of the main report.

Brief soil description

The soils are very deep to extremely deep, dark reddish brown to dark brownin colour, and consist of friable clay, with a thick acid humic topsoil.The soils have a moderate, sub-angular biocky structure and a highbioporosity throughout the profile.

Rating of soil-related land factors

- Parent rock

- Drainage

- Effective soil depth

- Inherent fertility

- Topsoil properties

1 rich2 moderately rich:

biotite gneisses3 poor

1 (somewhat) excessively drained2 well drained3 moderately well drained4 imperfectly drained5 (very) poorly drained

1 extremely deep to2 very deep3 deep4 moderately deep5 shallow6 very shallow

1 high2 moderate3 poor4 very poor

0 non-humic1 humic2 thick humicla acid humic2a thick acid humic

- 1.21 -


- Salinity 0 non-saline1 slightly saline2 saline

- Sodicity 0 non-sodic1 slightly sodic2 sodic

- Stoniness

- Rockiness

- Consistency (moist)

- Moisture storage capacity

0 non-stony1 slightly stony2 stony3 very stony

0 non-rocky1 slightly rocky2 rocky3 very rocky

1 half-ripe2 loose3 very friable4 friable5 firm6 very firm

1 very high2 high3 moderate4 low

- Excess surface water 0 none1 occasional2 seasonal3 permanent

3.1.2 Detailed Profile Description and Soil Classification

Detailed information on the various soil properties as they occur in thedifferent horizons are given in Table 8.1.9.The location of the profile near the trial plot is shown in Figure 8.1.7.

The soil profiles are classified according to two systems, which areexplained in Chapter II.2.2 of the main report.

1. Legend to the Soil Map of the World (FAO-Unesco, 1974), with adjustmentsaccording to the Kenya Concept (Siderius and van der Pouw, 1980): humicNitisol.

2. USDA Soil Taxonomy (Soil Survey Staff, 1975): typic Palehumult. veryfine-clavev family.

- 1.22 -

Table 8.1.9: Detailed Profile Description of Trial Plot Baraton

CO

I

Profile nuiber:Date of eiaiination:Authors:

Saiple80.

8.1.1

J 8.1.2111! 8.1.31

1

1

{ 8.1.4I

1

j 8.1.5

| 8.1.6

1

8.122-1-1986Gacheue/Kibe

1

H o r i z o n

Genetic Depth | Boundary

Ahl1

Ah2

AB

Bti

Bt2

, Akl(controlsaiple)

0 - 15

1 5 - 5 4

5 4 - 9 0

90 - 116

116 - 158

gradualsiooth

graduaiSlOOth

clearsiooth

gradaalsiooth

Coionr(Hoist)

5 ÏI 2.5/2dark redd,

brown

5 n 2.5/2dark redd.

brova

7.5 II 3/2dark brom

2.5 Tl 3/4dark redd,

brovn

2.5 TE 3/4dark redd.

brown.

1

Mottling

...

...

I1

Teitnre

clayloai

clay

clay

~*clay

clay

day

1

Cotans

—

verypatchyclay

brokenloderately

thickclay

brokenloderately

thickclay

1

Strnctare

weakfine

snbangniarblocky

loderateledini

subangniarblocky

loderatelediu

snbangnlarblocky

loderateledini

snbangnlarblocky

loderateledini

snbangnlarblocky

Biopores

lany v.f.•any f.coiion 1.

few c.

•any v.f.•any f.few i.no c.

m y v.f.•any f.coiion 1.

no e.

•any v.f.•any f.coiion 1.

no c.

•any v.f•any f.coiion 1.

no c.

1

Consistence

friable;si.sticky-si.plastic

friable;sl.sticky-si.plastic


friable;sticky-plastic

friable;sticky-plastic

1

Field'P8

3.5

4.2

4.4

4.4

3.9

1

Concretions

...

—

—

OtherPeatnres

1

1

1111

coipactiondue totractor

ploughing

I

—

—

1 1

Reiarks: High biological activity (teriites)Clay entans not continuons; pale faces not shiny ("weak" Ritisol)Colour: redd. : reddishBiopores: v.f. = very fine; f. = fine; 1. = lediui; c. = coarseConsistence: si. = slightly


3.1.3 Soil Sampling

Soil samples (profile, composite, farmers' fields, pF rings) are listed inSub-Section 3.2.Figure 8.1.7 shows the location of the composite sampling Blocks (I to IV)as well as the location of the profile pit.

Y ^

Baraton

Kapsabet

ma}or aust roa

Figure 8.1.7: Location of Composite Sampling Blocks and Profile Pit at theBaraton Trial Plot

3.2 Laboratory Data

The soil samples from the profile and the composite samples from thevarious blocks of the main trial site and from the farmers' fields wereanalyzed in the laboratory. The results are compiled in Tables 8.1.10 to8.1.12. The methodology applied for obtaining these results is described indetail in Chapter IV.2 of the main report.

- 1.24 -

District: Nandi Trial Site: 8.1 Baraton

Table 8.1.10 : Analytical Results (physical and chemical analysis, results on air dry soil basis)Profile Samples from Trial Site

Horizon Depthcm.

FieldNo.

Lab.No.

) 2 mm.

zSand

ZSilt

ZClay Texture

Z ClassPHKCl

PHH20

Diff.PH

Cond.H20

12345

678

12345(j

78

12345b

78

AhlAh2BABtlBt2

Ahl

0-1515-5454-9090-116116-158

Control

Saturation ExtractZ water

NANANANANA

NA

Na

0.130.160.170.200.17

0.13

PH

NANANANANA

NA

K

0.470.310.300.360.38

0.46

8.1.18.1.28.1.38.1.48.1.5

8.1.6

El.Cond.

NANANANANA

NA

Hg

3933/863934393539363937

3938

Na

0.050.03

Ca•me./lOOgin. Acetate

2.102.112.273.071.63

1.95

Moisture Retention Capacity

1234

Horizon

Ah2BA/Btl

Depthen.

20-2550-55

5.006.705.603.001.80

5.30

Vol.*bar 0pF 0

54.355.3

————

--

Kme

0.340.20

CEC pH8.2

24.3031.0031.5024.5022.80

25.80

Moisture1/10

2

37.538.2

4430302624

42

Mg./lOOgm

1.951.95

BasesZ

31.6929.9426.4827.0617.46

30.39

1/32.5

31.731.4

20121044

18

Ca

. Agiu

8.6011.40

Bases+Alœe./100gm.

8.569.528.546.815.74

8.76

53.7

21.220.4

3658607072

40

Mn

0.410.11

AlZ

10.052.522.342.6430.66

10.50

154.2

19.518.8

CLCCCC

C/CL

ECEC

12.5014.40

Org. CZ

3.572.362.281.030.77

3.29

4.74.95.15.24.5

4.7

BasesZ

87.5294.31

NZ

0.360.230.200.110.08

0.39

5.66.16.36.56.1

5.6

AlZ

6.881.67

C/N

9.910.311.49.89.6

8.4

Avail. MoistureCapacitymm./10cm.

18.019.4

0.91.21.21.31.6

0.9

Al

0.10.10.00.00.0

0.1

H+Alme./100giD. KCl

0.860.240.200.181.76

0.92

P OlsenPPIB.

1.180.460.380.382.38

1.00

105 deg.Cin rel.toair dry

0.930.930.930.940.94

0.93

Bulk Densga./cc.105 deg.C

0.950.89

NA : not applicablesie./lOOgn. : milliequivalents per 100 giB. of soilAgTU ; Silver Thio Urea ExtractionAcetate ; Bases by Aononiua Acetate pH 7,CEC by Sodium Acetate pH 8.2ph and conductivity in suspension 1:2.5 v/v

- 1 .25 -


Table 8.1.11 : Analytical Results (cheaical analysis, results on air dry soil basis)Trial Site Coiposite Sasples

I 1: 21 71 J

: 4! 5: 6! 7

: s! 9: io: ii! 12! 13! 14: is: i6

! 17: is! 19! 20' 011 Ci

1 22! 23! 24! 25! 261 n-j1 2/

! 28! 29! 30! 31! 32! 33! 34! 35! 36! 37

i 38! 391 in1 4U

: 4i: 42! 43: 44! 45: 46! 47: 48! 49: 50: 5i! 52! 53! 54! 55

Depth

lLab. No. /861111

IFine earth Iii

iVol.weight gm./cc.ii

!105 deg.C / air dryiii .i

IpH H20 1/1I1

ipH H20 1/2.511

IpH N KC1 1/2.51I|1

iC org. :IN tot. ZiC/Hi

IMod.Olsen Abs. 260na! (1/1000)I1

IS04 soluble ppffl.fi

ii

IP Hen. 1/5 ppm.11

IP Olsen ppo.ii

IP mod.Olsen PPJO.Ii

'P Citric ac. ppœ.ii

»i .

IECEC AgTU «e./lOOg«.! Bases ZJAIZ

!Hp BaCl2 me./lOOgn.II

!H & Al KC1 Bte./lOOgm1

!A1 3- KCl «e./lOOg«.I1

!A1 3- AgTU ne./100giD11

ISat.Ext. Z H20ii

ISat.Ext. El.Cond.ii

ISat.Ext. pH•iii

CD.

2050

205020502050

205020502050

202020

2050

2050

20502050205020

202020

20502050205020

205020502050

Block nusberI II

3848 38503849 3851

100 100100 100

0.95 0.940.94 0.980.93 0.930.93 0.93

6.1 6.26.6 6.55.4 6.86.0 5.84.4 4.44.8 4.5

3.66 3.420.33 0.32

11 11

180 190120 170

4Trace

12 107 10

4.703.006.50 4.002.00 5.00147

11.6 8.8121.0 85.9

NA NA

not applicable. not applicablenot applicablenot applicablenot applicablenot applicablenot applicable

not applicablenot applicablenot applicablenot applicablenot applicablenot applicable

III

38523853

100100

0.990.960.940.94

6.36.65.55.84.34.5

3.250.2613

190110

107

4.502.00

IV V

38543855

100100

1.000.980.950.94

6.46.65.75.84.64.6

2.450.2311

180100

1010

6.003.50

VI1

VIIX

100100

0.970.970.940.94

6.256.585.855.854.434.60

3.200.2911.23

185.00125.00

10.508.50

5.253.13

e

0.000.000.030.020.010.01

0.130.050.650.100.130.14

0.520.050.87

5.7731.09

1.001.73

1.191.44

HiX. 1diff. I

0.00 10.00 10.06 I0.04 10.02 I0.01 1

0.30 10.10 11.40 I0.20 !0.30 I0.30 1

1.21 10.10 11.85 1

10.00 !70.00 1

2.00 !3.00 1

2.503.00 1

cont 'd next page

- 1 .26 -

cont 'd District: Nandi Trial Site: 8.1 Baraton

Table 8.1.11 : Analytical Results (chemical analysis, results on air dry soil basis)Trial Site Coœposite Samples

! 1: 2( ?

1 0

: 56! 57! 58i 59: 60! 61! 62! 63! 64! 65! 66! 67i 68! 69! 70! 71! 72! 73! 74! 75! 76! 77! 78! 79I 80! 81! 82! 83! 84! 85! 86! 871 QQI 00

! 89! 90! 91! 92! 93! 94! 95! 96! 97! 98! 991100!1O11102

Depth

Lab. No. /86

-- -Na Heh.1/5 ue./lOOgm

Na Ag-TU oe./lOOgo.

K Heh.1/5 oe./100gi.

K Bod.ûl. me./lOOgffl.

K Ag-TU ne./lOOgn.

Hg Heh.1/5 me./lOOgm

Hg nod.01. oe./lOOgm

Hg Ag-TU me./lOOgm.

Ca Heh.1/5 ae./lOOgm

Ca mod.01. me./lOOgo

Ca Ag-TU se./lOOgo.

Hn Heh.1/5 me./lOOgœ

Hn aiod.Ol. ie./100gs)

Hn Ag-TU me./lOOgm.

Zn HCl ppm.

Zn mod. 01. ppa.

Cu HCl ppa.

Cu mod. 01. ppn.

Fe HCl ppn.

Fe mod. 01. ppm.

Fe Oxalate Z

Al Oxalate :

cm.

2050

205020

2050205020

2050205020

2050205020

2050205020

20502050

20502050

20502050

20502050

Block numberI

38483849

0.050.070.09

0.640.180.690.130.80

3.203.202.662.152.75

3.605.6010.0012.0010.40

0.900.780.330.160.44

2.302.501.002.00

0.301.202.902.10

5.511.5161103

3.000.351.801.00

II

38503851

0.070.070.09

0.240.140.150.080.19

2.002.602.342.182.10

4.004.0011.0011.007.00

1.100.820.400.280.44

1.002.00

2.602.20

177146

III

38523853

0.070.07

0.180.140.200.10

1.902.401.992.67

1.605.208.0010.00

1.001.040.500.28

2.002.00

2.602.50

195128

IV V

38543855

0.070.14

0.320.140.460.13

1.702.802.292.11

2.406.807.009.00

1.280.900.330.25

2.002.00

2.602.10

203147

VI VIIX

0.070.090.09

0.350.150.380.120.50

2.202.752.322.282.43

2.905.409.0010.508.70

1.070.890.390.240.44

1.502.00

2.682.23

184.00131.00

s

0.010.030.00

0.200.020.250.040.43

0.680.340.270.260.46

1.101.151.831.292.40

0.160.110.080.060.00

0.580.00

0.150.19

18.8020.61

Hax. !diff. !

0.02 !0.07 !0.00 !

0.46 !0.04 !0.54 !0.10 !0.61 !

1.50 !0.80 !0.67 !0.56 !0.65 !

2.40 !2.80 !4.00 !3.00 :3.40 !

0.38 !0.26 !0.17 !0.12 !

o.oo :

1.00 !0.00 !

0.30 !0.40 I

42.00 i44.00 !

NA : not applicableae./lOOgm. = œilliequivalents per 100 gm. of soilHeh. : Hehlich Analysismod. 01. : Hodified Olsen ExtractionAgTU : Silver Thio Urea Extraction

- 1.27 -


Table 8.1.12 : Analytical Results (chemical analysis, results on air dry soil basis)Farmers' Fields Composite Samples

; !

1 21 31 41 r1 J

1 6I 71 81 n1 1

1 10! 11

CSI

! 13! 14' 1 Q1 Ij

1 161 171 181 i91 201 211 221 231 241 25! 261 271 281 291 301 311 321 331 341 351 361 37l -rn1 JO

1 391 401 41

lLab. No. /86IFine earth ïIVol.weight gm./cc.1105 deg. C / air dry11

IpH:pHIpH

leIN

H20 1/1H20 1/2.5N KCl 1/2.5

org. Ztot. Z

IC/N1

iHod.Olsen Abs.260nm.11

IPIPi

.'Na1t

IKIK11

IHgIHg11

ICaICaI

iHn!Hn11

,'ZnI1

,'Cu11

IFe

iHpIHIA1

Heh. 1/5 ppm.mod.Olsen ppm.

Heh.1/5 Bie./lOOgm

Heh.1/5 me./100gm.mod.01. me./100gm.

Heh.1/5 me./lOOgmmod.01. me./lOOgm



mod.01. ppm.

mod.01. ppm.

mod.01. ppm.

BaCl2 me./100gm.& Al KCl me./lOOgmKCl me./lOOgm.

Depthcm.

20202020

202020

202020

20

2020

. 20

2020

. 20

. 20

. 20

. 20

. 20

. 20

20

20

20

20. 20

20

FarmersA

38561001.010.94

6.105.504.40

2.900.31

9

257

10.002.50

0.07

0.180.26

1.201.15

Trace6.00

0.78Trace

1.00

1.00

215

' fieldsB

38571000.960.94

6.505.604.60

3.550.35

10

231

10.004.50

0.18

1.501.43

4.001.56

7.6013.00

0.92Trace

4.00

1.00

180

not applicablenot applicablenot applicable

(code)C

3853100

1.000.95

6.706.105.20

3.510.35

10

272

22.005.80

0.14

1.601.74

4.001.56

10.0020.00

0.70Trace

9.00

1.00

95

D

3859100

0.940.94

6.306.104.90

3.780.41

9

420

10.002.90

0.18

0.780.90

3.602.06

4.0013.00

0.82Trace

4.00

1.00

175

E

3860100

1.000.95

6.506.104.90

3.040.32

10

229

14.003.80

0.10

0.961.07

2.801.89

2.8013.00

0.80Trace

6.00

2.00

180

F

3861100

0.990.95

6.405.904.80

3.690.41

9

282

10.003.60

0.10

1.081.18

3.301.56

10.4019.00

0.85Trace

7.00

2.00

160

G

38621001.000.95

6.305.804.70

3.620.41

9

285

7.002.80

0.10

0.610.82

1.701.15

4.8017.00

1.160.06

7.00

2.00

150

H

3863100

0.980.95

6.505.904.90

2.840.31

9

233

12.005.10

0.32

1.461.23

2.201.15

3.4018.00

0.92Trace

5.00

2.00

185

Trial siteaverage

1000.970.94

6.255.354.43

3.200.29

11

185

10.505.25

0.07

0.350.38

2.202.32

2.909.00

1.070.39

1.50

2.68

134

X

100.000.980.95

6.395.874.76

3.350.359.61

271.56

11.724.03

0.14

0.951.00

2.781.60

5.6614.22

0.890.05

4.94

1.63

169.33

s

0.000.020.01

0.180.220.26

0.360.050.75

64.63

4.281.19

0.03

0.510.47

1.020.42

3.604.71

0.150.13

2.63

0.64

33.15

Hax. Idiff. 1

0.00 !0.07 I0.01 1

0.60 10.60 10.30 1

0.94 !0.12 !2.40 1

235.00 J

15.003.30 1

0.25

1.421.48 ,

2.801.17 ,

10.4014.00

0.460.39

8.00

1.68

120.00

NA : not applicableme./100gm. = milliequivalents per 100 gm. of soilppm. : parts per millionHeh. = Hehlich AnalysisHod. 01. : Hodified Olsen Extraction

- 1 .28 -


3.3 Evaluation of Soil Data

3.3.1 Literature References and Soil Correlation

Since 1972, the Kenya Soil Survey has carried out many soil surveys and

site evaluations and, in addition, some surveys were conducted by otheragencies.A complete list of soil survey reports is given in Chapter II.2 of the mainreport. Those reports which refer to the area in which the trial site issituated are listed below.

Literature references:

ElW.G. Sombroek, H.M.H. Braun and B.J.A. van der Pouw(1982). Exploratory Soil Map and Agro-Climatic ZoneMap of Kenya, 1980, scale 1:1,000,000.

LBDAW. Andriesse and B.J.A. van der Pouw (1985).Reconnaissance Soil Map of the Lake Basin DevelopmentAuthority Area, Western Kenya, scale 1:250,000.

In order to correlate existing information with findings at the trial site,the map units and classification units in the above-mentioned reports havebeen grouped in Table 8.1.13. Moreover, the FURP soil map unit (Map 8.0.4)and the classification of the soil of the profile at the trial plot aregiven.

Table 8.1.13: Soil Correlation with Respect to the Baraton Trial Site

Reference

El

LBDA

FURP

Map unit

Uh 11

UhNl

UhNl

Trial plot profile

Soil Classification

humic Nitisols

humic Nitisols

humic Nitisols

humic NITISOL

Total agreement exists on humic Nitisols as the proper classification ofthe soils of Trial Site 8.1. The "nitic" properties, however, are not aspronounced as for example in Kisii District.

3.3.2 Representativeness

For two reasons, statements about the representativeness of the soils ofthe trial site should be made with care.Firstly, soil classification units are mainly based on properties of arelatively permanent nature, i.e. those of the sub-surface horizons and notthose of the topsoil.

- 1.29 -


Secondly, the generally high variability of topsoil properties within shortdistances is not reflected in relatively small- scale reconnaissance soilmaps (1:100,000 to 1:1,000,000).

In this report, soils of a map unit considered to be within the "area ofrepresentativeness" must meet the following requirements:

(a) the soil-related land factors must have the same or similarratings ;

(b) soil classification must be the same or similar.

The extent to which all the FURP trial sites are representative of thesoils of Nandi District is shown in Map 8.0.5: "Groupings of Soil MappingUnits Represented by Trial Sites in Nandi District". This map is discussedin Sub-Section 8.0.5.Distinction is made between high representativeness - code A - and moderaterepresentativeness - code B if soil conditions are slightly morefavourable than at the trial site and code B- if soil conditions areslightly less favourable than at the trial site. Code C is applied for theremaining parts of the District, where none of the FURP trial sites isrepresentative.

Within Nandi District, the Baraton Trial Site has high representativeness(8.1.A) for an extensive area of humic Nitisols, developed on biotitegneisses in the central parts of the District (soil map unit UhNl, Grouping8.1.A).

Moderate representativeness (B-) holds for soil map units UhN3 and UhN4(Grouping 8.1.B-). Soils are poorer and shallower than those of the trialsite.

Soil map unit UhFl (Grouping 8.1.B+) shows moderate representativeness(B+). Soils are developed on richer parent rock.

The Baraton Trial Site is also representative of a small area in BungomaDistrict (soil map unit UhNl: Grouping 8.1.A).Humic Nitisols developed on biotite gneisses in Uasin Gishu, ElgeyoMarakwet and West Pokot Districts are represented by Trial Site 13.2,Elgeyo Marakwet District, which has soils that strongly resemble those atBaraton.

3.3.3 Variability of Soil Properties within the Trial Site

The trial plot and the farmers' fields have uniformly very deep toextremely deep humic Nitisols with a thick, acidic, humic topsoil. Tables8.1.10 to 8.1.12 show the following relatively narrow ranges with respectto the soil fertility parameters pH-KCl and organic carbon content of theupper 20 cm:

pH-KCl: profile: 4.7composite samples: 4.3-4.6farmers' fields: 4.4 (field A) - 5.2 (field C)

- 1.30 -


organic carbon: profile: 3.6%composite samples: 2.5% (Block IV) - 3.2% (Block III) -

3.4% (Block II) - 3.7% (Block I)farmers' fields: 2.8%-3.0% (fields A, E, H)

3.5%-3.8% (fields B, C, D, F, G)

3.3.4 Fertility Status of the Soil

The criteria applied for the interpretation of the analytical data areoutlined in Chapter IV.2 of the main report.

3.3.4.1 Soil Profile

The analytical data of the soil samples taken from the profile pit,situated on the side of the site and close to Blocks I and IV (see Figure8.1.7) are presented in Table 8.1.10 and are interpreted in the followingparagraphs.

The rooting depth of the soil is not limited by physical or chemicalobstacles in the subsoil. The capacity for plant available moisture in theupper 100 cm. of the profile may be estimated from the pF analysis ofhorizons Ah2 and BA/Btl; it attains almost 200 mm.. This is a very highvalue and confirms the field estimate for the available moisture capacity.

All horizons down to 160 cm. depth have a moderate to high CEC (pH 8.2) of22 to 32 me./100gm.. The base saturation is moderate (29-32%) in the Ahhorizons, low to moderate (26%) in the BA and Btl horizons, and low (16%)in the Bt2. This appears somewhat low in view of the slightly to moderatelyacid soil reaction, but is supported by the amount and distribution ofhumus in the soil.

The K saturation of the exchange complex is in the medium range (0.3-0.5me./100gm.) in all horizons. Exchangeable K decreases from the topsoil tothe BA, which shows the lowest K level, and increases again with depth. Inthe entire profile, Mg is very high and, in contrast to K, increases withdepth to reach a maximum in the Btl horizon. In comparison to the otherbases, Ca is low and in absolute terms low to moderate (1.6 - 6.8 me./100gm.) with a maximum in the Ah2 horizon and decreasing quickly with depth.Exchangeable bases by AgTU (Silver-thiourea) are available for the Ahhorizons only.

In the entire profile the Ca/Mg ratio is narrow, particularly the valuesobtained by the Ammonium Acetate method, and is in the range of 3:1 (Ahl)to 1:1 (Btl). The K/Mg ratio is quite variable, but never close to criticalvalues. The distribution of bases indicates a moderate leaching intensity.

The soil reaction of the upper horizons is in the moderately acid range (pHKC1 4.7 - 4.9) favourable for the growth of most plants. Consequently onlyvery limited amounts of Al are exchangeable (<0.86 me./100gm. and <10 % ofexchangeable bases plus Al in the topsoil), which may hardly affect evensensitive plants.

- 1.31 -


The organic matter content of the three top horizons (Ahl, Ah2, BA) is inthe high range; the humus content decreases continuously with depth from3.5% C (Ahl) to 0.8% C (Bt2) The N content reflects the C content and ishigh in the three top horizons. The C/N ratio is about 10.

3.3.4.2 Soil Fertility Assessment of Composite Samples

The analytical results for the composite samples from the trial site(depths 0-20 cm. and 20-50 cm.) are presented in Table 8.1.11., those forthe farmers' fields (depth 0-20 cm. only) are shown in Table 8.1.12.

The composite samples were analyzed to assess the chemical fertility statusof the soil, with special emphasis on the availability of the importantnutrient elements to the plants. The "available nutrients" were estimatedby means of two complementary methods, the "Mehlich" diluted double-acidmethod (NAL routine) and a "modified Olsen" bicarbonate + EDTA extraction.

The interpretation of the analytical data presented is in so far tentativefor both methods, as the validity of the applied ratings (ranges for Low,Medium, High) has not yet been verified by field trials in the variousregions of Kenya.

The trial site soil samples investigated are all slightly more acid thanthe profile and in the strongly to moderately acid range (around pH KC14.4), while the farmers' fields show a generally moderately acid soilreaction.

The total N content of the generally very humic soils is high (0.2-0.4 % ) .The moderate to wide C/N ratios and other prevailing soil propertiesindicate a slightly hampered mineralisation of the organic matter in thesoil. Thus, the N availability is probably moderate. The UV absorption ofthe modified Olsen extract on average indicates a low to moderate N supply-ing capacity from both the top and the subsoil in the trial site, so that amoderate N supply may be expected from the deep soils. In almost allsamples from farmers' fields, UV absorption was considerably higher and inthe moderate range.

Soluble S04 was determined in Block I of the trial site only. The reportedvalues are very low (4 ppm. and traces) and a shortage of SO4 may thereforebe feared in a good growing crop.

The "available" P as determined by both methods (Mehlich and modifiedOlsen) is in the low range (<15 ppm. and <7 ppm. respectively) for allsamples except Mehlich-P in farmer's field C. These quantities are far fromreaching adequacy to the N supplying capacity. The inadequate P availabi-lity is corroborated by the extreme wide ratios of C/P (m.01.) approx-imately 7000, and N/P (m.01.) over 600. These values are about 20 times thesuggested optimum for plant growth.

The "available" quantities of K are on average high in the topsoil andmoderate in the underlying 20 - 50 cm., with a considerable variation fromplace to place. K availability decreases with the downward slope and ishigher in Blocks I and II than in Blocks III and IV. Additionally, Blocks I

- 1.32 -


and IV of the trial site may have received K fertilizer earlier; K may alsohave been transported by erosion from Block I to Block IV. K levels arevery high in all the farmers' fields except field A where they are low.

The "available" amounts of Ca and particularly Mg are always in the highrange. The composite samples from Block I of the trial site contain more Mgthan the other blocks. Similar to the exchangeable bases the cations areadequately balanced with respect to plant nutrition.

According to the Mehlich analysis, "available" Mn is well within theadequate range; the modified Olsen method shows comparatively low values,similar to exchangeable Mn.

According to the modified Olsen.method, Zn and. Cu are very low and oftenclose or below the (tentative) deficiency levels in the trial site and, asfar as Cu is concerned, also in the farmers' fields. Only in farmer's fieldA is Zn in the low range. For Block I of the trial site, this is confirmedby the ratings for the HC1 extractable micro-nutrients.

Fe was extracted in high to very high amounts from all samples by the modi-fied Olsen method. The oxalate extraction for amorphous oxides andhydroxides, carried out on the composite samples of Block I, yielded highto very high amounts of Fe in the topsoil, whereas only low levels werefound in the 20-50 cm. layer. This method extracted moderate quantities ofAl. '

The evaluation of the Mehlich Analysis data according to NAL standards isgiven in Table 8.1.14.

Table 8.3.14: Evaluation of the Mehlich Analysis Data According to NALStandards

Parameter

Soil reaction (pH)Acidity (Hp )

Available nutrientsSodiumPotassiumCalciumMagnesiumManganesePhosphorus

Total NitrogenOrganic Carbon

C / N RatioCa / Mg RatioCa / K RatioK / Mg Ratio

Trial Site

Slightly acidLow

LowModerateAdequateAdequateAdequateVery low

HighHigh

FavourableFavourableFavourableFavourable

Farmers, Fields

Slightly acidLow

LowModerateAdequate to highAdequate to highAdequateVery low

HighHigh


- 1.33 -


Remarks on Trial Site:The soil reaction is favourable.Positive yield responses to P applicationare expected. Responses to lime, manure, K and N applications areunlikely. However, with continuous cropping K and JST responses are likely.

Remarks on Farmers' fields :Soil reaction is favourable. Positive yield responses to P application areexpected. Responses to lime, manure, K and N applications are unlikely.

3.4 Sampling Programme for Laboratory Analyses during Phase II

3.4.1 Soil Samples

Soil samples will be collected once a year at the beginning of the longrains in March just after ploughing and before the fields are planted. Thesamples will be taken individually from two depths (0 - 20 cm and 20 - 50cm) for each replication of the selected fertilizer treatments, and onlyfrom the plots in Module 2 with maize/beans mixed cropping.

The treatments to be sampled are:

Trial I: N0:P0 N75:P75 N0:P75 . N75:P0

Trial II: 0 N+P FYM FYM+P FYM+N+P N+P+K

Farmers' Fields A, C and D are proposed

3.4.2 Plant Samples

Harvest samples from the maize/beans mixed crop include individual samplesof grain and straw from maize and beans respectively. Samples will becollected separately from each replication of the following treatments:

Trial I: N0:P0 N75:P75 N0:P75 N75:P0


Farmers' fields: Harvest samples will only be collected from those farmers'fields from which soil samples were taken. Individual samples of grain andstraw are only required from the maize crop.

3.4.3 Other Samples.

From every batch of applied FYM three representative samples will be taken.

- 1.34 -


4. Conclusions from the Analyses of Climate and Soils

4.1 Moisture Availability

The amount of rainfall, which is surpassed in 20 out of 30 years (i.e. 66%probability), constitutes the basis for estimating moisture availabilityduring the growing periods. Other parameters of the water balance such asmoisture storage capacity, run-off, and deep percolation also have to beconsidered in order to obtain a comprehensive picture of the moistureavailability.

For example, the water requirements and thé water availability for maizeH 625, planted in mid-March at the Baraton Trial Site, can be interpretedas follows:

Figure 8.1.6 shows that the maximum water requirements (ETm) of themaize crop are in line with the rainfall pattern at the 66% probabilitylevel.

Run-off is moderate. The trial site is located on sloping land (slope:5-8%) and although the crop does not provide adequate ground-cover atthe time of already high rainfall-intensity in April and May, the soilshave a very high moisture storage capacity.

Deep percolation, lateral sub-surface flow and run-on could beestimated, but can be omitted, since they are generally low.

For the Baraton Trial Site, the moisture storage capacity is rated veryhigh (i.e. >160 mm.). Thus, the surplus of water, which is likely tooccur from April to August, can to a large extent be stored, leading toa continuous agro-humid period from at least March to December.

Summarizing the evaluation of the climatic factors, the yield potentialfor the maize crop (planted in mid-March) can, from the climatic point ofview, be rated good to very good on a "20 out of 30 year" basis.

4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement

Except for P, nutrient availability and soil reaction appear moderatelyfavourable for plant production. A suspected shortage of S, Zn, and Cushould be verified by trials.

Fertilizer applications should first of all involve P in the form of TSP orfinely ground soft rock phosphate (e.g. Hyperphos). Under the moderatelyacid soil conditions the rock phosphate should be almost as effective asTSP even in the first season. P from rock phosphate is less subject tofixation than P from TSP. Despite the high amounts of extractable Fe, therisks of fast P fixation into non available forms are considered to be onlymoderate due to the high humus content of the soil. The efficiency of Papplication may be enhanced by the addition of small amounts of fresh FYMto stimulate soil biological activity.

- 1.35 -


Mineral N applications are considered useful only in combination withadequate P supply, in which case reasonable responses to N application maybe expected. Top dressings may prove more efficient than broadcastapplications at planting time. The N supply from the soil should besufficient to make starter N unnecessary in most places.

High mineral N applications at planting time may lead to losses throughdenitrification, especially if high rainfall occurs and soil aeration is(even slightly) restricted. During the periods of high rainfall inApril/May and in July/August this may occasionally be expected. Denitri-fication losses from N03 sources occur in greater amounts than from NH4sources. Proper incorporation of the fertilizer into the soil can, to someextent, reduce denitrification losses. For a more reliable estimate of theextent to which denitrification may occur, more precise data on the soil,air and moisture regime and its effects on N losses are required. N lossesdue to leaching seem rather low, as the base saturation of the profileindicates only a moderate leaching intensity.

The application of FYM will only have limited effect if not combined withP. Green manuring with leguminous plants will depend even more on Pfertilization.

K applications are not needed at the present stage and response to K maynot be obtained at first. However, over prolonged periods of intensivefarming with high N and P inputs, at least the amounts of K removed withthe harvests should be replaced to avoid depletion of the soil. The analy-tical data give no estimate of the K reserves beyond the exchangeable pool.

As K fertilizer, K2SO4 should generally be preferred to KC1 (both contain50% K20), as the S04-ion enhances P availability. The form in which K isapplied should also take into account crop requirements (e.g. KC1 tocabbages, but not to Irish potatoes).

Under the present soil conditions liming is not needed at all and theacidifying effects of the applied mineral or organic fertilizers will besufficiently buffered by the soil for the duration of the trials over fiveyears. But over long periods of chemical fertilizer use, the increasingsoil acidity should be counterbalanced by liming. N-fertilizers have parti-cularly high lime requirements, i.e. approximately 1.8 Kg. of CaCO, per Kg.of applied N; in the case of CAN, which contains Ca, only about 0.8 Kg.CaCOj per Kg. N or 0.2 Kg. lime per Kg. of CAN will be needed. TSP does notcontribute substantially to the Ca budget of the soil ; soft rock phosphate(30% P2O5) contains about 2.7 Kg. CaCO, equivalents per Kg. of P2O5.

If lime is applied, availability of Zn, Cu and possibly also Mn will becomelow and plant uptake should be monitored, at least in sensitive crops.

- 1.36 -


4.3 Other Relevant Land Qualities

In addition to an assessment of moisture and nutrient availability, thefollowing land qualities are relevant in the context of fertilizer use:

a) Oxygen availability.With sustained heavy downpours, not uncommon in the area, temporarilyimpeded soil aeration may occur, which is a constraint to plant metabolism,notably at the crop emergence stage. The high structure stability andinfiltration capacity of the topsoil prevents this from occurring toooften.

b) Rootability.The very deep to extremely deep soils with stable blocky structures providean outstanding environment for unhampered root development and tuberexpansion.

c) Resistance to erosion.The area has a moderate resistance to erosion. The negative influence ofthe high rainfall intensity and the rolling topography are offset by a veryhigh structure stability (low erodibility) of the surface soil and thequick establishment of crop cover.

d) Ease of cultivation and scope for agricultural implements.Although the soils impose no limitations on manual land preparation, therolling topography restricts the use of oxen ploughs and heavy machinery inthe steeper parts of the area around Baraton.

5. Trial design and Execution Plan, Baraton

(The full details of the methodology for carrying out the fertilizer trialsare given in Chapter IV of the main report.)

Selection of Crops. The proposed crop sequences for the three modules atBaraton are :

Site 8.1 Baraton,Nandi.

SI Standard maizeS2 Maize & beansS3 Potat/Cabb.;Forage

RAINY SEASONS1st, Long, March 2nd, Short, Aug.

Hybrid 625Hybrid 625 + BeansAnnet/Copenhagen Forage oats

The 1st sequence or module is continuous, pure maize, once/year.The 2nd is intercropped maize and beans, also once/year.The 3rd is potatoes or cabbages in the 1st rains, followed by a forage cropof oats in the August rains.

Each module contains 2 experiments, namely Experiment 1 and Experiment 2.

- 1.37 -


Experiment 1 is a 4N x 4P factorial, with 2 replications in each module.Experiment 2 is a 2N x 2P x 2K x 2 FYM factorial, also with 2 replicationsin each module.


Fertilizer and FYM will be applied only to crops during the first rains.Where maize and beans are intercropped, the fertilizer will go on themaize. The beans will not receive any fertilizer directly, but will"scavenge" from the maize, and from residual fertilizer left in therelevant plots after the first season. Similarly, in the second rains theforage oats will not receive any fertilizer directly.

- 1.38 -

District: Nandi Trial Site 8.2: Chepkumia


Detailed Description of the Chepkumia Trial Site

Page

1. Geographical and Additional Technical Information 2.41.1 Final Position of the Trial Site 2.41.2 Sketch of the Trial Site 2.51.3 Physiography 2.71.4 Vegetation, Past and Present Land Use 2.81.5 Names and Addresses of Government Officers from the

Division and Farmers Involved in FURP Activities 2.9

2. Climate , 2 . 1 02.1 Prevailing Climatic Conditions 2.10

2.1.1 Agro-Climatic Classification of the Area Represented 2.102.1.2 Relevant Meteorological Data 2.112.1.3 Crop Suitability from the Climatic Point of View 2.15

2.2 Proposal for the Monitoring of Agro-Climatic Conditionsin Phase II 2.19

3. Soils 2.203.1 Survey Data 2.20

3.1.1 Brief Soil Description and General Information onthe Soil 2.20

3.1.2 Detailed Profile Description and Soil Classification 2.213.1.3 Soil Sampling 2.23

3.2 Laboratory Data . 2.233.3 Evaluation of Soil Data 2.27

3.3.1 Literature References and Soil Correlation 2.273.3.2 Representativeness 2.273.3.3 Variability of Soil Properties within the Trial Site 2.283.3.4 Fertility Status of the Soil 2.29

3.3.4.1 Soil Profile and Global Fertility Rating 2.293.3.4.2 Soil Fertility Assessment of Composite

Samples 2.293.4 Sampling Programme for Laboratory Analysis 2.31

3.4.1 Soil Samples 2.313.4.2 Plant Samples 2.323.4.3 Other Samples 2.32

4. Conclusions from the Analyses of Climate and Soils 2.324.1 Moisture Availability 2.324.2 Nutrient Availability in Relation to Possible Fertilizer

Requirement 2.334.3 Other Relevant Land Qualities 2.34


- 2.1 -


IA at of Tables11)

Page

Table 8.2.1 Physiography of the Chepkumia Trial Site 2.7

Table 8.2.2 Vegetation, Past and Present Land Use 2.8

Table 8.2.3 Names and Addresses of the Divisional Staff Members and

Farmers of the Chepkumia Trial Site 2.9

Table 8.2.4 Data of the Nearest Long-Term Rainfall Station 2.12

Table 8.2.5 Temperature 2.13

Table 8.2.6 Potential Evaporation (Eo) 2.13

Table 8.2.7 Agro-Climatological Crop List for Chepkumia 2.15

Table 8.2.8 Crop Development Stages and Crop Coefficients 2.17

Table 8.2.9 Detailed Profile Description of the Chepkumia Trial Plot 2.22

Table 8.2.10 Analytical Results (physical and chemical analyses) 2.24

Table 8.2.11 Analytical Results (chemical analysis, trial plot) 2.25Table 8.2.12 Analytical Results (chemical analysis, farmers' (No Samples

fields) Taken)

Table 8.2.13 Soil Correlation with Respect to the ChepkumiaTrial Site 2.27

Table 8.2.14 Evaluation of Mehlich Analysis Data According to NALStandards 2.31

1) See Footnote next page.

- 2.2 -


List of Figures1)

Page

Figure 8.2.1 Demarcation of the Chepkumia Trial Site 2.4

Figure 8.2.2 Access Map of the Trial Site Chepkumia 2.5

Figure 8.2.3 Map of the Trial Plot Chepkumia 2.6

Figure 8.2.4 Location of Farmers' Fields for On-Farm Trials, Chepkumia 2.7

Figure 8.2.5 Rainfall and Potential Evaporation 2.14

Figure 8.2.6 Water Requirement and Availability for Maize H 625,

First Rains 2.18

Figure 8.2.7 Location of Composite Sampling Blocks and Profile Pitat the Chepkumia Trial Plot 2.23

1) Numbering mode of Tables and Figures:First Number: District NumberSecond Number: Trial Site NumberThird Number: Number of Table or Figure within Chapter.

- 2.3 -


1. Geographical and Additional Technical Information

1.1 Final Position of the Trial Site

The position of the site at Chepkumia is shown in Figure 8.2.1, extractedfrom Map No. 102/4 - Kaimosi. Its UTM grid coordinates are E 16.5 and N16:6. The elevation is 1750 m. Further details on the final position areshown in Figure 8.2.2 and the sketch map of the trial plot in Figure 8.2.3.

Figure 8.2.1: Demarcation of the Chepkumia Trial Site on the 1:50,000Topographic Map

- 2.4 -


1.2 Sketch of the Trial Site.

The location of and the access route to the Chepkumia site are shown inFigure 8.2.2 and the map of the trial plot in Figure 8.2.3.

Figure 8.2.2: Access Map of the Trial Site, Chepkumia

- 2.5 -


Eucolyptice Forest

0 10 20 30 40 SOm.

Figure 8.2.3: Map of the Trial Plot, Chepkumia

- 2.6 -


The approximate location of the on-farm trials is indicated in Figure8.2.4.

Since the selection of farmers' fields had not been finalized, Figure 8.2.4was not drawn.

Figure 8.2.4: Location of Farmers' Fields for On-Farm Trials, Chepkumia

•1.3 Physiography

Information on the physiography of the trial site and its surroundings issummarized in Table 8.2.1 below.

Table 8.2.1: Physiography of the Chepkumia Trial Site

Elevation

Landform

Physiographic position of

Topography of surrounding

Slope on which trial plot

Aspect

Microtopography

the site

country

is sited

1750 m

upper middle-level uplands

convex middle slope

undulating (slopes 5-8%)

3-6X

WSW

Nil

- 2.7 -


1.4 Vegetation, Past and Present Land Use

Information on vegetation and on past and present land use is summarized inTable 8.2.2 below:

Table 8.2.2: Vegetation, Past and Present Land Use of the Chepkumia TrialSite

Vegetation

Cropping system

(a) cleared since:(b) crops grown:(c) fallow periods:(d) present land use:

Inputs

(a) mineral fertilizers:(b) organic manure:(c) means of land preparation:(d) means of weeding:(e) frequency of weeding:(f) other capital inputs:(g) level of know-how:

Produce

(a) maize

Livestock

Croton megalocarpus type

1974maize/beansnonemaize/beans

formerly 11:52; 1986: DAPonly in the home gardentractormanualtwice per crop standnonemoderate to high

25-35 bags/acrè(90 kg bags)

cows and goats

Remarks

Yields reported have been fairly constant since land was openedup.

- 2.8 -

1.5


Names and Addresses of Government Officers Involved in FURPActivities

Names and addresses of the divisional staff members and of all farmersinvolved are given in Table 8.2.3.The codes used for the additional "on-farm" farmers refer to the locationof their farms as' indicated in Figure 8.2.4.

Table 8.2.3: Names and Addresses of Divisional Staff Members and Farmersof the Chepkumia Trial Site

DivisionalStaff

D.E.O.L.E.O.T.A.

Farmers

Trial plot

On-Farm trials

8. 2. A8.2.B8.2.C8.2.D8.2.E8.2.F8.2.G8.2.H8.2.18.2.J

Name

P. Kichwennot metK. Lang'at

Name

Joash Barno

Address

Box 60, Kapsabet

II • : -

Address

Box 76, Kaimosi

LOCATION : KapkanganiSUB-LOCATION: Chepkumia

Name

Joel KorirObot Matayo KoskeiDavid CheruiyotHenry CheruiyotPaul KimetoDavid KiraetoSolomon SongokElijah RonoJoash KoskeiSamwel Langat

R e m a r k s ••'

Period of site selection: March 1986.

- 2.9 -


2. Climate

2.1 Prevailing Climatic Conditions

2.1.1 Agro-Climatic Classification of the Area Represented by theChepkumia Trial Site

The following brief climatic description refers to the existinginformation:

ACZ : 14 (H.M.H. BRAUN, 1982)1)

AEZ : UM1, p or two/three (R. JÄTZOLD, 1983)2)

Next long-term rainfall station: 08934072, Kaimosi Tea Estate.

Agro-Climatic Zone (ACZ):

Moisture availability Zone I (r/Eo): annual average precipitation is >80%of the potential evaporation (Eo).

Temperature Zone 4: mean annual temperature is 18-20°C

Agro-Ecological Zone (AEZ):

UM 1 = Tea-Coffee Zone

UM = Upper Midland Zone: mean annual temperature 18-21°C, mean minimum11-14°C

1 = humid; annual average precipitation is >80% of the potentialevaporation (Eo)

Sub-zone according to growing periods for annual crops (calculated for a"normal" crop in 60% probability)

p or two/three = with permanent cropping possibilities, which can bedivided into two or three cropping seasons

Formula Cropping season Lengths of growing period(exceeded in 6 out of 10 years)

p normally permanent more than 364 days

1) According to H.M.H. BRAUN in: W.G. SOMBROEK et al. (1982):Exploratory Soil Map and Agro-Climatic Zone Map of Kenya, scale1:1,000,000. - Rep. El, Nairobi

2) According to R. JÄTZOLD and H. SCHMIDT, eds. (1983): FarmManagement Handbook of Kenya, Vol. II/B Central Kenya - Nairobiand Trier.

- 2.10 -


2.1.2 Relevant Meteorological Data for the Chepkumia Trial Site

In this Section a breakdown is given of the following climatic parameters:rainfall, potential evaporation and temperature.

Rainfall :

Rainfall data are obtained from the nearest long-term rainfall station:08934072, Kaimosi Tea Estate; (elevation: 1770 m), 2 km NW of the ChepkumiaTrial Site (elevation: 1750m). The data are listed in Table 8.2.4. At theTrial Site rainfall amounts are similar: in 20 out of 30 years Chepkumiagets about 850 mm during the agro-humid period of the first rains (see Map8.0.1),and about 720 mm during the second rains (see Map 8.0.2). Themethods of rainfall-data analysis are described in Chapter IV.2.2 of themain report.

Temperature and potential evaporation(Eo):

Temperature data are extrapolated from 08934009, Kaimosi MissionTemperature Recording station (elevation: 1620 m), 2km SW of the trialsite. The temperature gradient in this area is on average 0.6°C per 100 m.Potential evaporation (Eo) is calculated using the PENMAN formula, modifiedby MC CULLOCH (1965). The input parameters employed - windrun, sunshinehours and relative humidity - are obtained from Kisii N.A.R.S.Meteorological Station (elevation: 1750 m ) , 95 km SSW of the trial site.

Temperature and evaporation data for the Chepkumia Trial Site are given inTables 8.2.5 and 8.2.6, and the rainfall pattern and potential evaporationare shown in Figure 8.2.5.

For more detailed information on the methodology of climatic descriptionsee Chapter IV.2.2 of the main report.

- 2.11 -

Table 8.2.4 Data of the Nearest Long-term Rainfall Station

Station No.: 08934072Kaimosi Tea Estate Ltd.Elevation: 1770 m

Total years for calculation: 26First year included: 1960Last year included: 1985


Rainfall surpassed in 20 out of 30 years (~66% Probability):

1st rains: 850 mm(end of Feb. - beg. of July)

2nd rains: 720 mm(mid July - mid Feb. )

Decadesand

Month«

1 JAN234 FEB567 MAR8910 APR1 11213 MAY1 41516 JUN171819 JUL202122 AUG232425 SEP262728 OCT293031 NOV323334 DEC3536

ArithmeticMean(mm)

24.030.435.437. 538.634.429.446.675.487.296.8

116.195. 177. 176. 557.856. 447.464.859.655.795.774.785.477. 166.056.658.560.850. 559.347.848.323.733.024.3

Average Number of RainyDays with Rainfall>= 1 mm

2.72.93.13.63.83.03. 14.65.26.57. 16.57.77.57.85.76.26.56.56.37.06.26.97.77.47.06.36.46.56.76.05.24.43.03.23.0

>= 5 mm

2.52.93.03.53.52.92.94.54.96.47.06. 47.57. 27.55.56. 16.26.36.26.66.06.87.67. 26.76.16.26.36.45.85.04. 12.73.02. 9

=66% Probabi-lity of ex-

ceeding ... mm

12.514.917.821 .821 .016.516.630.948.665.574.991 .275.561 .161 .845.240.537.549. 145.343.374.264. 170.064. 453.037.644.045.634. 442.630.028. 910.320.313.5

Yearsanal-ized

262626252525262626262626262626252525262626252525262626262626252525262626

- 2 . 1 2 -


Table 8.2.5: Temperature (°C)

MeanMeanMean

MeanMeanMean



JAN.

20.326.014.5

JUL.

18.523.014.0

FEB.

20.826.614.9

AUG.

19.024.113.9

annual mean: 19.8 mean max.:

MAR.

20.626.314.9

SEPT.

19.625.114.1

25.1

APR.

20.325.714.8

OCT.

19.624.914.2

mean

MAY

19.725.214.1

NOV.

19.824.615.0

min. :

JUN.

19.324.514.0

DEC.

20.025.414.6

14.4

Table 8.2.6: Potential



average annual

JAN.

5050

_55155

JUL.

454549139

Evaporation

FEB.

5151

_41143

AUG.

505055155

MAR.

5252

_5Z161

SEPT

565656168

(Eo) in

APR.

4444

_44132

. OCT.

585864180

potential evaporation: 1760

mm per

MAY

4141_45127

NOV.

444444132

mm.

Decade :

JUN.

4242

-42126

DEC.

464650142

For all the climatic data published in this Section, a data bank has beenestablished by FURP on Personal Computers at the National AgriculturalLaboratories in Nairobi.

- 2.13 -

O

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tn-4-Î

O)00o.,

tion

oC/)

M—

'5rv

cO

öLD

"5'5>OooQ)

*Q)"5

*

Kis

ii

0000or-ooeno

- 2.14 -


2.1.3 Crop Suitability from the Climatic Point of View

A summary of the agro-climatic suitability of the most important seasonalcrops is given in Table 8.2.7 below. Additional information on other cropsconsidered suitable from the agro-climatic viewpoint is given in the FarmManagement Handbook, Vol. II/B, Central Kenya1).

Table 8.2.7: Agro-Climatological Crop List for Chepkumia

Crop/variety(or place ofbreeding)e = earlym = medium1 = late

Maize/1.mat.like H 625

Maize/m.mat.like H 511

FingerMillet m.matlocal

Beans/e.matlike RoseCoco (GLP 2)

Sweet Pota-toes/m.mat

Av.No.ofdays tophysiol.maturity

170-200

130-160

100-160

90-120

120-130

Altitudes2)accordingto growingperiod

(m.)

1500-2100

1000-1700

0 - 2400

1200-1900

0 - 1800

Requirem.ofwell distri-buted rain-fall 3) ingrow.period

(mm. )

600-950

500-750

500-900

250-450

500-900

Yieldpotential ace.to water avai-lability 4)a = 1st rainsb = 2nd rains

a) good

good/fair(Jun.-Nov.)

a) goodb) good

a) good/fairb) good/fair

a) goodb) good

1) R. JÄTZOLD and H. SCHMIDT, eds.(1983): Farm Management Handbook ofKenya, Vol. II/B, Central Kenya - Nairobi and Trier.

2) Most suitable altitudes; the length of the growing periodincreases with altitude; growth is also possible beyond theindicated altitude range, as long as the ecological limits havenot been reached.

3) Lower figure for fair results, higher for very good results, withsome corrections due to rainfall distribution, evaporation andrun-off losses.

4) Estimated yield potential: very good >80%, good = 60-80%, fair =40-60% and poor <40% of the expected yield under optimum wateravailability adapted from R. JÄTZOLD and H. SCHMIDT, eds. (1982):Farm Management Handbook of Kenya, Vol. II/A, West Kenya .

- 2.15 -


For the most important food crops in the area around the Chepkumia TrialSite, the crop coefficients (kc) are shown in Table 8.2.8, differentiatedaccording to decades (10 day periods) of the growing season which is thetime between planting or sowing and the physiological maturity.

Furthermore, four crop development stages are distinguished in Table 8.2.8.The crop coefficients for the climatic conditions at the Chepkumia TrialSite were estimated on the basis of data obtained from DOORENBOS and PRUITT(1977)1) and DOORENBOS and KASSAM (1979)2).The data on the duration of each of the growing seasons and on the variousdevelopment stages of each crop were assessed on the basis of localobservations made under average climatic conditions.

The crop coefficients estimated for the various decades of the growingseasons were used to estimate the maximum (potential) evapotranspiration(ETm) under the prevailing climate, assuming that water is not a limitingfactor for plant growth. For this calculation the following approximativeformula was employed:

ETm = kc * Eo

whereby: ETm= maximum (potential) evapotranspirationkc = crop coefficientEo = potential evaporation (climatic evaporative demand)

In Figure 8.2.6, the ETm-values are used to indicate the estimated maximumwater requirements of an important food crop for optimum growth.Furthermore, the rainfall data at 66% reliability are shown in Figure 8.2.6to give an indication of the water availability. However, when readingthese figures, it must be borne in mind that the actual availability ofwater for the plants also depends to a large degree, on factors such as therun-off, the moisture storage capacity of the soil, the deep percolation ofwater etc.

The placement of the growing season of the crop on the time axis aspresented in Figure 8.2.6 was mainly based on the pattern of rainfall,whereby the peak water requirements of the plants should be met by high,reliable rainfall.

Detailed information on the calculation procedures and references are givenin Chapter IV.2.2 of the main report. The interpretation of the diagramsmentioned above follows in Section 4 of this Volume (Conclusions from theAnalyses of Climate and Soils).

1) FAO (1977): Crop Water Requirements - (= Irrigation and DrainagePaper, 24), Rome

2) FAO (1979): Yield Response to Water - (= Irrigation and DrainagePaper, 33), Rome

- 2.16 -

Table 8.2.8 : Crop development stages 1) and crop coefficients (Kc) 2) for approx. Mxiiui (potential) crop evapotranspiration of the lost importantseasonal crops grown at Chepkuiia (site no. 8.2)

Crop/Variety

MAIZEH625

MAIZEH511

BEARSKose coco

FINGERMILLET

1

0.6I

0.6I

0.6I

0.6I

Number2

0.7I

0.7I

0.7I

0.7I

of decades3

0.75I

0.75I

0.79II

0.79II

0

0

0

0

4

.79II

.79II

.88II

.88II

from5

0.86II

0.86II

0.98II

0.98II

seeding6

0.94II

0.94II

1.05III

1.05III

resp7

1.01II

1.01II

1.05III

1.05III

. planting to8

1.05III

1.05HI

1.05III

1.05III

9

1.05III

1.05HI

1.05III

1.05HI

(physiological) maturity10

1.05HI

1.05III

0.92IV

1.05III

11

1.05HI

1.05III

0.67IV

0.94IV

12

1.05III

1.05HI

0.43IV

0.76IV

13

1.05III

0.97IV

0.57IV

14

1.05III

0.8IV

0.39IV

15

0.97IV

0.63IV

16

0.86IV

17

0.74IV

18 19 20 21 22 23 24

0.61IV

1) Crop development stages as defined in chapter IV 2.2 (lain report)I = initial stage II = development stage H I = lid season IV = late season

2) Kc : crop coefficient as defined in chapter IV 2.2 (nin report)

Figure 8.2.6: Water requirementsand availability for cropMaize H 625, first rains

Rainfall Station: 08934072Kaimosi Tea Estate

00

I

mm

Trial Site 8.2 Chepkumia

8 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

MAR APR MAY JUN JUL AUG SEP


2.2 Proposal for the Monitoring of Agro-Climatic Conditions in PhaseII

For Phase II the agro-climatic recording programme should include:

1) Wai Tifal 1 records :

A rain gauge has to be installed at the Chepkumia Trial Site to measureactual precipitation on the spot. Subsequently, the data can be comparedwith both rainfall for a particular year and the long-term average of thenearest rainfall recording station of the Meteorological Department:08934072 Kaimosi Tea Estate.

2) Records on other relevant meteorological

Temperature data can be taken from temperature recording station: 08934072,Kaimosi Tea Estate (elevation: 1770 m) .Data on windrun, sunshine hours and relative humidity can be obtained fromKisii N.A.R.S. Meteorological Station, in order to calculate Eo (climaticevaporative demand).For this purpose a computerized PENMAN formula, modified by MC CULL0CH(1965) is available on PC.

3) Phenological records :

Dates of planting or seeding of each crop, emergence, start of tasselling(for maize crop), budding (for bean crop), flowering, ripeness orphysiological maturity and harvest have to be recorded. Additionally theleaf area index (LAI) has to be determined every week (at least for thecereal crops) in order to provide a sound basis for water balance ocalculations. Other important features should also be recorded, above allrolling and wilting leaves, which indicate water stress and wilting pointrespectively before physiological maturity has been reached.

Moreover, soil moisture checks and observations on rooting depth at theabove-mentioned growing stages and run-off measurements would be needed toestimate actual evapotranspiration of the various crops correctly. Soilmoisture checks are mainly proposed to reveal excess water.

For most of the data to be recorded, official forms from the MeteorologicalDepartment are available.

Detailed information on calculation procedures, as proposed for themonitoring of agro-climatic conditions, is given in Chapter IV.2.2 of themain report.

- 2.19 -


3. Soils

In this Section, survey and laboratory data concerning the trial site and,more specifically, the soil profile are given.The evaluation of these data is shown in Sub-Section 3.3.

3.1 Survey Data

3.1.1 Brief Soil Description and General Information on the Soil

The brief description of the soils of the trial plot is followed by arating of relevant soil-related land factors. The classes for these factorshave been adapted from Andriesse and van der Pouw (1985), and a key forthem is to be found in Chapter IV.2.3 of the main report.

Brief soil description

The soils are very deep, dark reddish brown to red in colour, and consistof friable to firm clay, with a thick acid humic topsoil.They have a weak to moderate, sub-angular blocky structure and a moderateto high bioporosity.

Rating of soil-related land factors

- Parent rock

- Drainage

- Effective soil depth

- Inherent fertility

- Topsoil properties

1 rich2 moderately rich3 poor :

granites and granodiorites

1 (somewhat) excessively drained2 well drained3 moderately well drained4 imperfectly drained5 (very) poorly drained

1 extremely deep2 very deep3 deep4 moderately deep5 shallow6 very shallow

1 high2 moderate3 poor4 very poor

0 non-humic1 humic2 thick humicla acid humic2a thick acid humic

- 2.20 -

District: Nandi Trial Site 8.2: Chepkwnia

- Salinity 0 non-saline1 slightly saline2 saline

- Sodicity 0 non-sodic1 slightly sodic2 sodic

- Stoniness

- Rockiness

- Consistency (moist)

- Moisture storage capacity

0 non-stony1 slightly stony2 stony3 very stony

0 non-rocky1 slightly rocky2 rocky3 very rocky

1 half-ripe2 loose3 very friable4 friable to5 firm6 very firm

1 very high2 high3 moderate4 low

- Excess surface water 0 none1 occasional2 seasonal3 permanent

3.1.2 Detailed Profile Description and Soil Classification

Detailed information on the various soil properties as they occur in thedifferent horizons is given in Table 8.2.9.The location of the profile near the trial plot is shown in Figure 8.2.7.

The soil profile is classified according to two systems, which areexplained in Chapter II.2.2 of the main report.

1. Legend to the Soil Map of the World (FAO-Unesco, 1974), with adjustmentsaccording to the Kenya Concept (Siderius and van der Pouw, 1980): humicAcrisol.

2. USDA Soil Taxonomy (Soil Survey Staff, 1975): typic Palehumult. veryfine-clavev familv.

- 2.21 -

Table 8.2.9: Detailed Profile Description of Trial Plot Chepkuia

IMrv>

Heiarks: Upon angering graiite fragieots «ere fond froi ISO ci downwards.Coloar: v. = very; d. = dark; redd. - reddishBiopores: v.f. : very fine; f. = fine; i. - tedins; c. = coarseConsistence: si. = slightly

Profile naiber: 8.2Date of eiaiinatioa: 24-3-1986Authors: Gachene/ïibe/Sialing

SaipleBo.

8.2.1

1

8.2.2

8.2.3

1

8.2.4

1

8.2.5

8.2.6

i

H o r i z o n

Genetic Depth | Boundary

Ahi

Ah2

AB

Bti

Bt2

Ahi(controlsaiple)

0-25

25-40

iO-52

52-90

90 - 135

clearsiootn

cleartongsing

clearwavy

ciearsiooth

Coloar(Hoist)

10 U 2/2v.d.brown

10 YR 3/3dark brown

5 ÏR 3/4dark redd,

brown

5 ÏR 3/4dark redd,

brown

2.5 ÏR 4/6red

Mottling

—

...

îeïtnre

clayloai

clay

clay

clay

clay

Cntans

...

patchythinclay

brokenloderateiy

thickclay

brokenloderateiy

thickclay

Strnctare

weaklediai

snbangnlarblocky

weakfine

snbangnlarblocky

weakfine

snbangnlarblocky

•oderate•edini

sibangnlarbiocky

loderatelediaiangnlarblocky

Biopores


•any v.f..any f.few i.no c.

•any v f.•any f.few i.no c.


•any v.f•any f.few i.no c.

Consistence

friable;$1. sticky-si, plastic

friable-fin:

si.sticky-si.plastic

friable-fin:


friable-fir«:



FieldPB

3.8

3.9

3.5

3.4

n.d

Concretions

...

...

Other !Features

|I

11

1

1

—

j

i


3.1.3 Soil Sampling

Soil samples (profile, composite, farmers' fields, pF rings) are listed inSub-Section 3.2.Figure 8.2.7 shows the location of the composite sampling blocks as well asthe location of the profile pit.

Water Tank • W& House

profilePit

• Slope 3.3*/!

I I

I I I

lOOn

IV

90n

Figure 8 . 2 . 7 : Location of Composite Sampling Blocks and Profile Pit at theChepkumia Trial Plot

3.2 Laboratory Data

The soil samples from the profile and the composite samples from thevarious blocks of the main trial site and from the farmers' fields wereanalyzed in the laboratory. The results are compiled in Tables 8.2.10 to8.2.12. The methodology applied for obtaining these results is described indetail in Chapter IV.2 of the main report.

- 2.23 -

District: Nandi Trial Site: 8.2 Chepkuia

Tab)« 8.2.10 : Analytical Results (physical and dMical analysis, results on air dry soil basis)Profile Sables fr« Trial Site

1234Sa0

78

Horizon

AhiAh2ABBtiBt2

Ahi

Deptha.

0-2525-4040-5252-9090-130

Control

FieldNo.

8.2.18.2.28.2.38.2.48.2.5

8.2.6

Lab. > 2 a .No. I

3939/86 -3940394139423943

3944

SandI

3533352525

37

SiltI

28221888

24

ClayI

3745476767

39

TextureClass

aCCCC

a

PHKC1

4.95.04.74.54.1

4.4

PHH2O

5.55.85.75.85.3

5.1

Diff.PH

0.60.81.01.31.2

0.7

Cord.H2O

0.10.20.10.00.1

0.2

Saturation ExtractI nter ph El. fond.

K Hg Ca— M . / I O O p . AgTU—

Hn ECEC BasesI

AlI

AI HtAln./IOOa. KC1

NANANANANA

NA

NANANANANA

NA

NANANANANA

NA

0.050.05

0.810.24

1.70 12.802.15 13.60

0.770.29

14.8 103.814.8 108.4

1.61.8

0.240.260.340.800.76

0.360.400.380.721.10

0.26 0.94

Ng Ca CEC pH8.2 Bases Bases+Al Al Org. C Ne./tOOga. Acetate I M./IOOp I X t

105 dsg.CC/N P Olsen in rei.to

pp. air dry

0.100.080.100.150.10

0.690.250.150.100.09

1.471.792.272.031.45

5.65.63.424

26.828.32S.124.620.0

29.3327.2823.5918.4717.20

8.107.986.265.384.20

2.963.265.4314.8718.10

3.782.931.870.980.62

0.450.310.180.090.06

0.15 0.76 1.63 5.9 26.0 32.46 8.70 2.99 3.63 0.44

8.49.510.410.910.3

8.3

0.950.940.950.940.95

0.95

Noisturt Retention CapacityHorizon Depth

a .Vol.! Moisturebar 0 1/10pFO 2

1/32.5

53.7

154.2

Avail. NoistureCapacity•./10a.

Bulk Densp./cc.105 oeg.C

1 Mil2 Afl/Bti34

20-2550-55

47.547.1

38.837.4

35.034.2

20.721.6

19.420.0

19.417.4

1.151.28

NA : not applicable•./lOOp. : •illiequivalants per 100 p . of soilAgTU : Silver Thio Urea ExtractionAcetate : Bases by Aaoniui Acetate pH 7, CEC by Sodiui Acetate pH 8.2pH and conductivity in suspension 1:2.5 v/v

- 2.24 -

District: Nandi Trial Site: 8.2 Chepkuiia

Table 8.2.11 : Analytical Results (chenical analysis, results on air dry soil basis)Trial Site Coiposite Saiples

! !

1 21 71 0

: 4I 51 6I 71 8I 91 101 11I 12I 13! 141 15

1 171 1/

1 181 191 201 21I 221 23I 24! 251 261 071 ll

1 28! 29! 30I 311 32I 33! 341 351 T/1 00

I 371 381 39i 401 411 42! 431 441 451 461 471 48I 491 50I 511 521 531 54I 55

Depth

lLab. No. /86

i _

iFine earth Z

I! Vol.Height ga./cc.i

1105 deg.C / air dryi

IpH N20 I/Ii

IpH H20 1/2.5i

IpH N KC1 1/2.5i

i

'C org. ZIN tot. ZIC/N11

!Mod.Olsen Abs. 260no1 (1/1000)i

IS04 soluble ppfl.i

i

iP Heh.1/5 ppa.[IP Olsen ppa.jIP aod.Olsen ppi.!IP Citric ac. ppa.ti

IECEC AgTU le./lOOgn.I Bases Z,'AIII1

!Hp BaCl2 oe./100ga.

!H & Al KC1 me./lOOgfli

IA1 3- KCi me./lOOgm.1

IA1 3- AgTU me./lOOgai

ISat.Ext. Z H20i

ISat.Ext. El.Cond.|iSat.Ext. pHij

CO.

2050

205020502050

205020502050

202020

2050

2050

2050205020502050

202020

20502050205020

205020502050

Block nuaberI

38643865

100100

0.981.020.950.95

6.46.67.27.05.65.4

3.680.36

10

302302

65

V.

1715

5.502.60487

15.3107.7

II

38663867

100100

0.990.940.950.95

6.45.66.46.65.25.3

3.590.39

9

309222

1012

4.601.70

14.8104.7

not applicablenot applicablenot applicablenot applicablenot applicablenot applicable

III

38683869

1001001.000.980.950.95

5.45.65.96.34.95.1

3.740.39

10

452286

1210

3.901.80

0.40

0.320.12

IV V

38703871

1001001.001.000.950.96

4.65.65.35.94.65.2

3.220.38

8

303218

2712

22.003.50

0.50

0.360.20

VI VII

•

. . . . . . . . .

X

1001000.990.990.950.95

5.705.856.206.455.085.25

3.560.387.40

341.50257.00

16.5012.25

9.002.40

s

0.000.000.010.030.000.00

0.870.500.800.470.430.13

0.230.014.22

73.7343.25

7.592.06

8.690.84

Hax.diff

0.0.0.0.0.0.

1.1.1.1.1.0.

0.0.10.

150.84.

17.5.

18.1.

00 !

oo :02 :08 100 101 !

80 !00 190 I10 100 130 !

52 !03 I00 i

00 !00 !

0000

10

so :

- 2.25 -

District: Nandi Trial Site: 8.2 Chepkuaia

Table 8.2.11 : Analytical Results (cheiical analysis, results on air dry soil basis)Trial Site Coiposite Saiples

: i: 2i î1 0

! 56! 57! 58! 59! 60! 61: 62: 63! 64: 65! 66! 67! 68! 69! 70! 71! 72! 73! 74! 75! 76i 77! 78! 79! 80! 81! 82: 83: 84: 85: 86! 871 001 00

: 89! 90i 91! 92! 93! 94! 95! 96! 97! 98! 9911001101,'102

Depth

Lab. No. /86

Na Heh.1/5 le./lOOgi

Na Ag-TU le./lOOgi.

K Heh.1/5 ie./100g».

X iod.01. ie./100gi.

K Ag-TU ae./lOOgi.

Hg Heh.1/5 se./lOOga

Hg iod.01. ie./100gi

Hg Ag-TU ne./100gi.

Ca Heh.1/5 ie./100gi

Ca iod.01. ae./lOOgi

Ca Ag-TU oe./100ga.

Hn Heh.1/5 ne./lOOgi

Hn aod.Ol. ae./lOOgi

Hn Ag-TU ne./lOOg».

Zn HC1 ppo.

2n nod. 01. ppa.

Cu HCl ppi.

Cu lod. 01. ppi.

Fe HCl ppi.

Fe iod. 01. ppi.

Fe Oialate I

Al Oialate Z

CI.

2050

205020

2050205020

2050205020

2050205020

2050205020

20502050

20502050

20502050

20502050

Block nuiberI

38643865

0.380.610.12

1.080.541.180.51 .1.61

3.002.201.231.231.95

9.206.8018.0015.0012.80

1.100.920.04

Trace0.73

5.202.156.002.00

0.650.603.003.00

13.011.0240205

0.570.500.900.95

II

38663867

0.140.210.09

0.640.520.870.361.06

2.003.501.231.812.15

6.8010.4017.0017.0012.20

1.190.640.04

Trace0.66

5.001.00

3.002.00

220175

III

38683869

0.180.10

0.670.240.670,15

2.102.400.991.32

6.807.60

17.0015.00

0.900.610.07Trace

5.00Trace

3.001.00

255210

IV V

38703871

0.140.10

0.460.420.380.38

1.802.300.911.65

8.407.60

16.0016.00

1.230.880.130.15

4.00Trace

3.002.00

265195

VI VIII

.. ...

0.210.260.11

0.710.430.770.351.34

2.23! 2.60' 1.09! 1.50

2.05

7.8a1 8.10

17.0015.7512.50

1.110.760.070.040.70

5.000.75

3.002.00

245.00196.25

S

0.110.240.02

0.260.140.330.150.39

0.530.610.170.270.14

1.201.580.820.960.42

0.150.160.040.070.05

0.820.96

0.000.82

19.5815.48

Haï. !diff. !

0.24 i0.51 !0.03 i

0.62 i0.30 !0.79 !0.36 !0.55

1.201.300.330.58 ,0.20

2.403.60 !2.00 !2.00 i0.60

0.330.31 ,0.09 ,0.15 ,0.07 ,

2.002.00

0.00 i2.00 i

45.00 !35.00 !

NA : not applicableae./100go. : lilliequivalents per 100 gi. of soilHeh. : Hehlich Analysisiod. 01. : Hodified Olsen EitractionAgTU : Silver Thio Urea Eitraction

- 2.26 -


3.3 Evaluation of Soil Data

3.3.1 Literature References and Soil Correlation

Since 1972 the Kenya Soil Survey has carried out many soil surveys and siteevaluations and in addition, some surveys were conducted by other agencies.

A complete list of soil survey reports is given in Chapter II.2 of the mainreport. Those reports referring to the area in which the trial site issituated are listed below.

Literature references:

El

LBDA

W.G. Sombroek, H.M.H. Braun and B.J.A. van der Pouw(1982). Exploratory Soil Map and Agro-Climatic ZoneMap of Kenya, 1980, scale 1:1,000,000.

W. Andriesse and B.J.A. van der Pouw (1985).Reconnaissance Soil Map of the Lake Basin DevelopmentAuthority Area, Western Kenya, scale 1:250,000.

In order to correlate existing information with findings at the trial site,the map units and classification units in the above-mentioned reports havebeen grouped in Table 8.2.13. Moreover, the FURP soil map unit (Map 8.0.4)and the classification of the soil of the profile at the trial plot aregiven.

Table 8.2.13 Soil Correlation with Respect to the Chepkumia Trial Site

Reference

El

LBDA

FURP

Map unit

Uh 9

UhG2

UhG2

Trial plot profile

Soil Classification

humic Cambisols, with humicAcrisols

ferralo-humic Acrisols

humic and ferralo-humic Acrisols

humic ACRISOL

Reasonable agreement exists on soil classification among the varioussources. El mentions Cambisols as the major soil order, but clayilluviation was obvious at the trial plot profile.

3.3.2 Representativeness

For two reasons, statements about the representativeness of the soils ofthe trial site should be made with care. •>Firstly^ soil classification units are mainly based on properties of arelatively permanent nature, i.e. those of the sub-surface horizons and notthose of the topsoil.Secondly, the generally high variability of topsoil properties within shortdistances is not reflected in relatively small-scale reconnaissance soilmaps (1:100,000 to 1:1,000,000).

- 2.27 -


In this report, soils of a map unit considered to be within the "area ofrepresentativeness" must meet the following requirements:

(a) the soil-related land factors must have the same or similarratings ;

(b) soil classification must be the same or similar.

The extent to which all the FURP trial sites are representative of thesoils of Nandi District is shown in Map 8.0.5; "Groupings of Soil MappingUnits Represented by Trial Sites in Nandi District". This map is discussedin Sub-Section 8.0.5.Distinction is made between high representativeness - code A - and moderaterepresentativeness - code B if soil conditions are slightly morefavourable than at the trial site and code B- if soil conditions areslightly less favourable than at the trial site. Code C is applied for theremaining parts of the Distict, where none of the FURP trial sites isrepresentative.

Within Nandi District, the Chepkumia trial site has high representativeness(8.2.A) for an extensive area in the south-western part of the Distict,south of Tindinyo. It refers to soil map units UhG2 and UhG4: deep to verydeep humic Acrisols.Moderate representativeness (B+) holds for soil map unit UhG7, north ofNdurio, where extremely deep humic Acrisols prevail.Moderate representativeness (B-) holds for soil map unit UhG5, which hasmoderately deep to deep humic Acrisols.

The Chepkumia Trial Site is also representative of vast areas outside NandiDistrict, in particular:

in Kisumu District, small area bordering Nandi District,in Busia District, small area bordering Bungoma District,in Bungoma District, north of Malakisi, soil map unit UmGl: Grouping8.2.A,in Kakamega District, large areas mainly in the central parts, soil mapunit UhG2: Grouping 8.2.A, and unit UhG5 and UmG5: Grouping 8.2.B-, andin Kericho District, small area south-west of Sosiot.

3.3.3 Variability of Soil Properties within the Trial Site

The soils of the trial plot are quite uniform. A thick, acidic, humictopsoil is prevalent and an effective depth of at least 120 cm isencountered throughout the plot. Chemical data confirm field observationsconcerning land uniformity, although there is a range of 1 pH-unit amongthe composite sampling blocks.

DH-KCI (0-20 cm.): composite samples: 4.6 (Block IV) - 4.9 (Block III) -5.2 (Block II) - 5.6 (Block I),profile: 4.7.

Organic carbon (0-20 cm.): composite samples: 3.2% (Block IV) - 3.7% (BlockI and III),profile: 3.8%.

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3.3.4 Fertility Status of the Soil

The criteria applied for the interpretation of the analytical data areoutlined in Chapter IV.2 of the main report.

3.3.4.1 Soil Profile

The analytical data of the soil samples taken from the profile pit,situated at the outer edge of the trial site and close to Block II (seeFigure 8.2.7) are presented in Table 8.2.10 and are interpreted in thefollowing paragraphs.

The rooting depth of the soil is not limited by physical or chemicalobstacles in the subsoil. The capacity for plant available moisture in theupper 100 cm. of the profile may be estimated from the pF analysis carriedout for horizons Ah2 and AB/Btl and it attains approximately 180 mm. This avery high value and in line with the field estimate.

All horizons down to a depth of 130 cm. have a moderate to high CEC (pH8.2) of 20 to 28 me./100gm. The base saturation is moderate (27-30%) in theAh horizons, low to moderate (23%) in the AB, and low (<19%) in the Bthorizons. This appears to be somewhat low in view of the moderate to strengacid soil reaction, but is supported by the amount and distribution ofhumus in the soil.

The K saturation of the exchange complex is high (0.7 me./lOOgm-) in tbsAhl horizon, but in the low to very low range (0.09-0.25 me./100gm.) ±n. £.11underlying horizons. Exchangeable K decreases continuously with deptli. !_:.the entire profile Mg is very high and increases with depth to reach amaximum in the Btl horizon. Ca is low in comparison to the other basas, e:.:..~..the Ca levels are moderate in the topsoil (5.6 me./100gm.) and decreesswith depth to very low levels in the Bt2 (1.8 me./100gm.). Exchangeablabases by AgTU (Silver-thiourea) are available for the Ah horizons only. Kand Mg are slightly higher than by Ammonium Acetate, but Ca is more thantwice as high (13 me./100gm.). This higher value is supported by theanalysis of available nutrients.

The soil reaction of the upper horizons down to 50 cm. is in the moderatelyacid range (pH KC1 4.7 - 4.9) favourable for the growth of most plants. „Consequently only very limited amounts of Al are exchangeable (<0.34me./100gm. and <6 % of exchangeable bases plus Al in the topsoil) which mayhardly affect even sensitive plants.

The organic matter content of the three top horizons (Ahl, Ah2, AB) is inthe high range; the humus content decreases continuously with depth from3.8% C (Ahl, high to very high C) to 0.6% C (Bt2, low C). The distributionof N with depth reflects the C contents of the different horizons; and N ishigh in the three top horizons. The ratio C/N is about 10.

3.3.4.2 Soil Fertility Assessment of Composite Samples

The analytical results for the composite samples from the trial site(depths 0-20 cm. and 20-50 cm.) are presented in Table 8.2.11. There wereno samples collected from the farmers' fields around this trial site and as

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a result, Table 8.2.12 has been omitted.

The composite samples were analyzed to assess the chemical fertility statusof the soil, with special emphasis on the availability of the importantnutrient elements to the plants. The "available nutrients" were estimatedby means of two complementary methods, the "Mehlich" diluted double-acidmethod (NAL routine) and a "modified Olsen" bicarbonate + EDTA extraction.

The interpretation of the analytical data presented is in so far tentativefor both methods, as the validity of the applied ratings (ranges for Low,Medium, High) has not yet been verified by field trials in the variousregions of Kenya.

The trial site soil samples investigated are all less acid than the profileand in the slightly to moderately acid range. In the topsoil the pHdecreases from Block I to Block IV (pH KC1 5.6-4.6), while in the subsoilthe pH varies only little (5.4-5.1).

The total N content of these very humic soils is high (0.36-0.39% N). Themoderate to wide C/N ratios and other prevailing soil properties indicatethat N availability is probably moderate. The UV absorption of the modifiedOlsen extract on average indicates a moderate N supplying capacity fromboth the top and the subsoil in the trial site, so that a moderate to highN supply may be expected from the deep soil.

Soluble S04 was determined^ in Block I of the trial site only. The reportedvalues are low (6 ppm. ) and a shortage of S04 may therefore be feared, atleast for a good growing crop. \\

In Blocks I, II, and III the "available" P is in the low range (<5.5 ppm.)..by the modified Olsen method; while P is high in the topsoil of Block IV •(22 ppm.). The Mehlich analysis corroborates a low P status for Blocks IIand III (10-12 ppm.), but indicates a moderate P-status for Blocks I and IV(17 and 27 ppm.). The analytical results show similar tendencies, althoughthe ratings of the two methods are not fully consistent. Most probably Pavailability is not adequate to the N supplying capacity of the soil,except perhaps in Block IV.

The "available" quantities of K are on average high in the topsoil andmoderate in the underlying 20 - 50 cm., with a considerable decrease fromBlock I to Block IV.

The "available" amounts of Mg and Ca are always in the high range. Bothelements decrease slightly from Block I to Block IV. Similar to theexchangeable bases, the cations are adequately balanced in respect of plantnutrition.

According to the Mehlich analysis, "available" Mn is well within theadequate range. In contrast, the modified Olsen method shows only very lowvalues (0.13 to traces).

According to the modified Olsen' method, Zn is available in sufficientquantities in the topsoil, while the subsoil values are very low. The Culevels are low, but a Cu deficiency may not be expected immediately. For

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Block I of the trial site this is confirmed by the ratings for the HC1extractable micronutrients.

Fe was extracted in high amounts from all samples by the modified Olsenmethod, whereas the oxalate extraction for amorphous oxides and hydroxidesyielded only low amounts of Fe and Al.

The evaluation of the Mehlich Analysis data according to NAL standards isgiven in Table 8.2.14.

Table 8.2.14: Evaluation of the Mehlich Analysis Data According to NALStandards

Parameter

Soil reaction (pH)Acidity (Hp )

Available nutrientsSodiumPotassiumCalciumMagnesiumManganesePhosphorus

Total NitrogenOrganic Carbon

C / N RatioCa / Mg RatioCa / K RatioK / Mg Ratio

Trial Site

Slightly moderate acidLow

AdequateAdequateAdequateAdequateAdequateLow

HighHigh


Farmers' Fields

Remarks on Trial Site:The soil reaction is favourable. Positive yield responses to P applicationare expected. Responses to lime, manure, K and N applications are unlikely.Responses to K and N are expected later.

3.4 Sampling Programme for Laboratory Analyses during Phase II

3.4.1 Soil Samples

Soil samples will be collected once a year at the beginning of the longrains in February just after ploughing and before the fields are planted.The samples will be taken individually from two depths (0 - 20 cm and 20 -50 cm) for each replication of the selected fertilizer treatments, and onlyfrom the plots in Module 2 with maize/beans mixed cropping.

The treatments to be sampled are:

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Trial I: NO:PO N75:P75 N0:P75 N75:PO

Trial II: 0 N+P FÏM FYM+P FYM+N+P N+P+K

3.4.2 Plant Samples

Harvest samples from the öaize/beans mixed crop include the individualsamples of grain and straw from maize and beans respectively. Samples willbe collected separately from each replication of the following treatments:

Trial I: N0:P0 N75:P75 N0:P75 N75:P0


3.4.3 Other Samples

From every batch of applied FYM three representative samples will be taken.

4. Conclusions from the Analyses of Climate and Soils

4.1 Moisture Availability

The amount of rainfall which is surpassed in 20 out of 30 years (i.e. 66%probability) constitutes the basis for estimating moisture availabilityduring the growing periods. Other parameters of the water balance such asmoisture storage capacity, run-off, and deep percolation also have to beconsidered in order to obtain a comprehensive picture of the moistureavailability.

For example, the water requirements and the water availability for maizeH 625, first rains, at the Chepkumia Trial Site, can be interpreted asfollows :

Figure 8.2.6 shows that the maximum water requirements (ETm) of themaize crop are in line with the rainfall pattern at the 66% probabilitylevel. The ratio of reliable rainfall (i.e. 66% probability) to maximumevapotranspiration (ETm) for maize H 625 is >0.8 for the total length ofthe growing period.

Run-off is considered to be moderate. The trial site is located onsloping land (5 - 8%). Although the crop does not provide adequateground cover at the time of maximum rainfall intensity in April and May,the soil is deep, well drained and has a very high moisture storage .capacity.

Deep percolation and lateral sub-surface flow occur to some extent, butare not easily estimated (roughly: 10-20% loss during the peak of therainy seasons). Run-on is less relevant for the site and can be omitted.

For the Chepkumia Trial Site, the moisture storage capacity is very high(i.e. >160mm.). Therefore, to a large extent, the water surplus of Apriland May is stored which leads to a permanent agro-humid period from at

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least March to January for annual crops. Moisture deficits are notlikely to occur, but in most years excess water might be a problem. Itmay for instance favour the spread of disease or limit oxygenavailability.

Summarizing the evaluation of the climatic factors, the yield potentialfrom the climatic point of view can, for the maize crop, be rated good on a"20 out of 30 year" basis.

4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement

Except for P, nutrient availability and soil reaction appeared favourablefor plant production; the N supplying capacity of the soil was estimated atmoderate while the solubility of S in Block 1 was very low. The soil testmight therefore have limited significance, although S is similarly releasedfrom organic matter as N. As a result, a shortage of S might be feared in agood growing crop. This and a suspected shortage of Zn and possibly also Mnand Cu should be verified by trials.

Fertilizer applications should first of all involve P in the form of TSP orfinely ground soft rock phosphate (Hyperphos). P in the form of TSP orsuperphosphate will probably be superior to rock phosphate ; under the soilconditions of Blocks I and II, the solubility of rock phosphate will beslow. The moderately acid soil reaction of Blocks III and IV, however,enhances the availability of P from rock phosphate. P from rock phosphateis less subject to fixation than P from TSP. Nevertheless, the risks of Pfixation into non-available forms may only be moderate. The efficiency of Papplication may be enhanced by the addition of small amounts of fresh FYMto stimulate soil biological activity.

Superphosphate contains about 12% S and therefore may act as two-elementfertilizer. Under farmers' conditions this might be very useful becauselimited S availability was found.

Mineral N applications are considered useful only in combination withadequate P supply, in which case reasonable responses to N application maybe expected.

Top dressings may prove more efficient than broadcast applications atplanting time. The N supply from the soil should be sufficient to makestarter N unnecessary.

High mineral N applications at planting time may lead to losses throughdenitrification, especially if high rainfall occurs and soil aeration is(even slightly) restricted. This may be expected during the high rainfallin April/May and in August/September.

For a more reliable estimate of the extent to which denitrification mayoccur, more precise data on soil air and moisture regime and its effects onN losses are required.

N losses due to leaching seem to be rather low, as the base saturation ofthe profile indicates only a moderate leaching intensity.

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The application of FYM will have only limited effect if not combined withP, except in Block IV of the trial site. Green manuring with leguminousplants will depend even more on P fertilization.

Liberal applications of N and P may lead to a significant deficiency of Zn,and possibly of Cu and S as well. The effect on Mn availability will haveto be checked.

K applications are not needed at the present stage and response to K maynot be obtained. It is doubtful that any response to K will be obtainedover the trial period of five years. Nevertheless, it is imperative that inthe long-term the amounts removed with the harvests should be replaced, atleast in Blocks III and IV. Although the analytical data give no estimateof the reserves of K beyond the exchangeable pool, its limitations areindicated by the rather low K levels of the subsoil.

As K fertilizer, K2SO4 should generally be preferred to KC1 (both contain50% KjO) as the S04-ion enhances P availability. The form in which K isapplied should also take into account crop requirements (e.g. KC1 tocabbages but not to Irish potatoes).

Under the present soil conditions liming is not required at all and theacidifying effects of the applied mineral or organic fertilizers will besufficiently buffered by the soil at least for the duration of. the trialsover five years. But over long periods of chemical fertilizer use, theincreasing soil acidity should be compensated by liming. N fertilizers haveparticularly high lime requirements - approximately 1.8 Kg. of CaCO3 per Kg-.,of applied N. In the case of CAN, which contains Ca, only about 0.8 Kg.CaCOj per Kg. N or 0.2 Kg. lime per Kg. of CAN will be needed. TSPfertilizer does not contribute substantially to the Ca budget of the soil.Soft rock phosphate (30% P2O5) contains about 2.7 Kg. CaC03 equivalents perKg. of P A .

If lime is applied, the availability of P, Zn, Cu and possibly Mn will bereduced and may consequently induce or intensify deficiencies in plantnutrition.

4.3 Other Relevant Land Qualities

In addition to an assessment of moisture and nutrient availability, thefollowing land qualities are relevant in the context of fertilizer use:

a) Oxygen availability.In wet years, the excess rainfall can lead to temporarily impeded soilaeration, which is a constraint to plant metabolism, notably at the cropemergence stage. The high structure stability of the topsoil prevents thisfrom occurring too often.

b) Rootability.The very deep soils with stable blocky structures, heterogenous pore sizedistribution and high organic matter content provide an outstandingenvironment for unhampered root development and tuber expansion.

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District: Nandi Trial Site 8.2: Chepkwnia

c) Resistance to erosion.The area has a moderate resistance to erosion, as long as the organicmatter content remains as high as it is at present. The negative influenceof high rainfall intensity and rolling topography are to some extent offsetby high structure stability (low erodibility) of the surface soil and thequick establishment of a crop cover.

d) Ease of cultivation and scope for agricultural implements.Although in general the soils allow any method of land preparation,topography restricts the use of oxen ploughs and heavy machinery on thesteep slopes around Chepkumia.

5. Trial Design and Execution Plan, Chepkumia

(The full details of the methodology for carrying out the fertilizer trialsare given in Chapter IV of the main report.)

Selection of Crops. The proposed crop sequences for the three modules inthe Chepkumia trial are :

Site 8.2 Chepkumia,Kaimosi.

SI Standard MaizeS2 Maize & BeansS3 Pot./Cabb; Beans

RAINY SEASONS1st, Long, March 2nd, Short,Sept

Hybrid 625 Hybrid 511Hybrid 625 + GLP 2 Hybrid 511 +GLP 2B 53/Copenhagen Beans GLP 2

The 1st sequence or module is continuous, pure maize, twice/year.The 2nd is intercropped maize and beans, also twice/year.The 3rd is maize and beans in 1st rains, and potatoes or cabbages in the2nd rains.

Each module contains 2 experiments, namely Experiment 1 and Experiment 2.

Experiment 1 is a 4N x 4P factorial, with 2 replications in each module.Experiment 2 is a 2N x 2P x 2K x 2 FYM factorial, also with 2 replicationsin each module.


FYM will be applied only in the first rainy season. The other fertilizerswill be applied in both rainy seasons at Chepkumia. Where maize and beansare intercropped, the fertilizer will go on the maize. The beans will notreceive any fertilizer directly, but will "scavenge" from the maize, andfrom residual fertilizer left in the relevant plots after the first season.Similarly, the crops during the second rains will not receive anyfertilizer directly.

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t&jüw'iä - WUR · 3_ d. Use Recomm « Project (Phase X) ... Map 8.0.1 66% Reliability of Rainfall...

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