(Elgeyo) Marakwet

MJLri is-fcry of Agricultun

&&L -ti-onal Acjr ici-aX tiara X Laboratories

FertXX i zer Use :R.eooimmencä.at ion Project (Phase X)

FJL:raaX Report

A.nne:>c XXI

De scr ipt ion of the First Priority Sites iin the Va.riou.s Districts

Volume 13

Keiyo Marakwet District

District No.: 13

ISRJC LIBRARY

^ 8>«grk Wageningen, The Netherlands

Nairobi, June 1987

13% Scanned from original by ISRIC - World Soil Information, as ICSU World Data Centre for Soils. The purpose is to make a safe depository for endangered documents and to make the accrued information available for consultation, following Fair Use • Guidelines. Every effort is taken to respect Copyright of the , materials within the archives where the identification of the Copyright holder is clear and, where feasible, to contact the originators. For questions please contact snilisricOwur.nj indicating the item reference number concerned. Fexriz-d.1 i zeir TJse Recommendation

Project (Phase X)

Project Team Team of Consultants1) Professional Staff from NAL2)

Project Coordination H. Strobel (ed.) G.Hinga Project Coordinator Director NAL S.W.Nandwa Counterpart Coordinator

Agro-Climatoloqists R. Jätzold J.W. Onyango R. Rötter

Soil Scientists / Surveyors R.F. van de Weg F.N. Muchena E.M.A. Smaling C.K.K. Gachene Ü.M. Kibe

Soil Chemists P. Pietrowicz J.N. Qureshi P.O.S. Oduor

Agronomists A.Y. Allan J.O. Owuor

Data Processing H. Mayr R.L. Milikau R. Dölger D.K. Wamae A. Muliro

Land Surveyors R. Rötter B. Mwangi S. Wataka

Animal Production W. Bayer

1)^ German Agency for Technical Cooperation (GTZ) (German Agricultural Team (GAT))

2) National Agricultural Laboratories Feart d_ 1 ô_ zeir Use Recommendation Project C E>na.:se X )

Contents of tne Fj-na.1 Report

Ma.±n Report:Methodology and Inventory of Existing Information frnnex X : Compilation of results from Former Fertilizer Trials In Kenya (2 Volumes)

^.r\x\Gt>c X X . 1 : Inventory of Farming Systems Research in Kenya

&>.T\T\&>C X X - 2 : Influence of Fertilizer Application on Ruminant Production

Annex XX . 3 : Maintaining Soil Fertility with Little or No Use of Fertilizers

Annex XXX : Detailed Description of the First Priority Sites in the Various Districts :

1. Kisii 17. Narok 2. South Nyanza 18. Samburu 3. Kisumu 19. Nyandarua 4. Siaya 20. Kiambu 5. Busia 21. Muranga 6. Bungoma 22. Nyeri 7. Kakamega 23. Kirinyaga 8. Nandi 24. Embu •• 9. Kericho 25. Meru .10. Trans Nzoia 26. Machakos 11. Uasin Gishu 27. Kitui 12. West Pokot 28. Lamu 13. Keyo Marakwet 29. Kilifi 14. Baringo 30. Taita Taveta 15. Laikipia 31. Kwale 16. Nakuru 32. Nairobi

Annex XV : Description of Computer Programmes Established in Phase I District: Keiyo Marakwet General Aspects 13.0

Annex III. Volume 13

Page

Chapter 13 - O s 0.1 General Aspects 0.27 Legend of the Soil Map of Keiyo Marakwet District

Cna-ip-teir 1 3 - I z Description of the Tot Trial Site 1.1

Cliapter- 13 - 2 =

Description of the Bugar Trial Site 2.1

Please note the following numbering mode of Tables and Maps: First Number : District Number Second Number: Trial Site Number Third Number : Number of Table or Map within Chapter.

- 0.1 - District: Keiyo Marakwet General Aspects 13.O

Contents of Chapter 13.0:

General Aspects

Page

1. Climate and Soils of the District 0.3

2. Location of the Trial Sites and Criteria for their Final Position 0.10

3. Names and Addresses of Government Officers Involved in FURP Activities 0.15

4. Trial Design and Execution Plan i 0.16 ! 5. Areas in Keiyo Marakwet District Represented by FURP Trial Sites 0.17

List of Tables

Table 13.0.1 Climate in the Agro-Ecological Zones of Keiyo Marakwet District 0.6

Table 13.0.2 Agro-Ecological Zone and Soil Classification of the

Trial Sites 0.10

Table 13.0.3 Ratings of Criteria Used for Trial Site Selection 0.11

Table 13.0.4 Names and Addresses of Government Officers in the District 0.15 Table 13.0.5 Major Soil Properties and Climatic Conditions of the Agro-Ecological Units in Keiyo Marakwet District 0.23

Ligt of Haps

Map 13.0.1 66% Reliability of Rainfall in First Rains 0.4

Map 13.0.2 66% Reliability of Rainfall in Second Rains 0.5

Map 13.0.3 Agro-Ecological Zones and Trial Sites in the District 0.7

Map 13.0.4 Soils and Trial Sites in Keiyo Marakwet District 0.13

Map 13.0.5 Groupings of Soil Mapping Units Represented by Trial

Sites in Keiyo Marakwet District 0.21

Map 13.0.6 Agro-Ecological Units in Keiyo Marakwet District 0.25

Legend of the Soil Map of Keiyo Marakwet District 0.27

- 0.2 - District: Keiyo Marakwet General Aspects 13.0

1. Climate and Soils of the District

The Keiyo (formerly Elgeyo) Marakwet District is dominated by the steep Elgeyo Escarpment which rises to over 2700 m, and the Kerio Valley, a part of the Great Rift Valley at about 1200 m. The contrasts between the agricultural potential of the higher and the lower areas are, therefore, tremendous. The Cherangani Hills are the highest part. This is an area of undulating plateau about 2800 m high, with some higher ridges up to 3365 m and is mainly on the upper limit of the arable Upper Highland Zones with transitions to the open mountain grasslands of the Tropical Alpine Zones. Thus the Agro-Ecological Zonation is not very distinct. Many areas are transitional, ranging from UH to TA, as shown on Map 13.0.3. Large parts of the Cherangani Hills are Forest Reserve; the forests include open spaces of tropical alpine and other grassland vegetation, and outside the reserves grassland is dominant. The potential given for UH 1 in the Farm Management Handbook, Vol. II/B, refers mainly to the lower and wetter plateaus in the southern parts of the District. On the Cherangani Hills, the micro-climate must be considered well before new crops are grown, since night frosts are frequent. Some areas in the rain shadow also seem to be too dry for most high altitude crops such as potatoes, pyrethrum, cabbages and carrots. The long but narrow zones near the edge of the escarpment have the best natural potential in the District. Maize is thriving except in some higher parts in the south. The zone suitable for tea cultivation is unfortunately very small because many areas with sufficient rainfall are too high. The same applies to coffee, for the rainfall at suitable altitudes is unreliable and most decades of the agro-humid period have only a weak performance (water supply between 40% and 80% of the potential evaporation). The climatically defined Maize-Sunflower Zone (UM 4) and the Marginal Cotton Zone (LM 4) are mainly on the middle and lower slopes of the escarpment, and only a few places are really suitable for these crops. Too many steep slopes have already been cleared and cultivated (mainly with maize), causing tremendous soil erosion. Soil conservation is the most urgent problem in this easily unbalanced ecological environment. On the footslopes of the escarpment it is possible to grow some cotton and maize. Coast composite maize was found to do much better here than Katumani Composite B. mainly due to the relatively high temperatures. In Zone LM 5, additional irrigation is essential, since the rainfall is not only low but also unfavourably distributed, as shown in Figure 13.1.5. The first rains create only a very short agro-humid period. Unfortunately, there is a break in May/June during which time crops like maize Pwani, planted in March, have their peak water requirements. The second peak in July/August could probably be better utilised if water from April was conserved and planting started in May. The October/November rains are normally too short and weak to support another cropping season.

- 0.3 - KEIYO (ELGEYO) MARAKWET

1" N

66% RELIABILITY OF RAINFALL IN AGROHUMID PERIOD OF FIRST AND MIDDLE RAINS (March - end of Sept.or less) o- Amounts in mm, surpassed norm, in 20 out of 30 years

Broken boundaries are uncertain

because ol lack of rainlall records

o 25 km sa Nil! Agi Ltlbs üoimun Agi Team. H JflettotrJ

- 0.4 - 35WE

KEIYO (ELGEYO) 100 MARAKWET

more than 600

Map 13.0.2 66% RELIABILITY OF RAINFALL IN AGROHUMID PERIOD OF MIDDLE AND SECOND RAINS — (end of June -Jan. or less) Amounts in mm, surpassed norm, in 20 out of 30 years

Broken boundaries are uncertain because ol lack ol rainlnll records

t^T^TÎfTFEn Nal Agr. Labs.. German Agr. Team. R Jaeliotd

- 0.5 - Table 13.0.1 : Climate in the Agro-Ecological Zones of Keyo District

Agro-Ecological Subzone Altitude Annual mean Annual av. 66 % reliability 66 % reliability Zone in m temperature rainfall of rainfall'' of growing period in°C in mm 1st rains 2nd rains 1st rains2' 2nd rains Total3' in mm in mm in days in days in days TA 1 u. TA 11 Tropical Alpine Rough natural grazing, unimportant Zones

TA1-1I-UH2-3 Cattle and Sheep transitional 2 800-3 150 12.4- 9.7 1 050-1 250 350-400 500-610 110 or more 190-200 300-310 Zone

UH 1 vl i or two 1 200-1700 400-630 550-700 110 or more 200-220 310-330 Sheep and Dairy 2 370-3 100 14.8-10.1 Zone (vi) i or two 1 200-1400 420-480 560-650 110 or more 170-210 280-320 UH1-2 (vl)iortwo 2 350-3 000 15.0-11.2 1 200-1 350 400-450 >600 110 or more 170-210 280-320 UH 2 Pyrethrum- (vl) i or two 2 350-2 880 15.0-11.9 1 150-1 250 { 360-420 550-600 110 or more 170-200 280-310 Wheat Zone LH 1 ^ „ . _ (vi) i or two 2 100-2 350 16.6-15.0 1 250-1 350 400-420 >600 110 or more 180-210 290-320 Tea-Dairy Zone LH 2 vi i or two 1 200-1 .50 400-420 >600 110 or more 170-200 280-310 Wheat/Maize- (vl/1) i or two 2 000-2 400 17.2-14.8 1 150-1300 340-450 500-600 100 or more 160-180 260-280 Pyrethrum Zone fvl i or 1.-. (s)i 1 100-1 400 320-K600 500-700 100 or more 140-200 240-300 LH 3 Wheat/(Maize)- 1/vl 2 010-2 350 17.3-15.1 900-1 200 320-400 380-550 100 or more 120-140 220-240 i Barley-Zone i UM 3 Marginal Coffee Very small and steep, see Baringo District Zone UM 4 Sunflower-Maize f(l) i or two 1 500-1 900 20.5-18.0 900-1 100 240-500 320-450 80 or more 100-150 180-230 Zone LM4 (m/1) l or Marginal Cotton 1 120-1 500 22.6-20.6 800- 900 200-250 280-360 70 or more 80-110 150-180 two/three Zone

LMS ,(vs.- . s/vs/ )> i• 700- 800 180-200 250-^330 50 or more 70-100 110-150 Lower Midland 1 000-1 300 23.5-21.7 Livestock-Millet 680- 750 150-180 200-250 45 or more 45- 75 90-120 (VS r, fvs) 1 Zone 1L6 Lowland u r i 950- 990 23.8-23.6 <680 80-150 140-200 <40 <40 Ranching Zone

' Amounts surpassed normally in 6 out of 10 years, falling during the agro-humid period which allows growing of most cultivated plants 2' More if growing cycle of cultivated plants continues into the period of second rains 3' Agro-humid conditions continue from 1st to 2nd rains nearly in the whole district Source: Jaetzold R., and H. Schmidt, eds. (1982): Farm Management Handbook of Kenya, Volume Il/B Central Kenya, page 236.

- 0.6 - District: Keiyo Marakwet General Aspects 13.0

Annual rainfall in the District ranges from less than 700 mm in the Kerio Valley to >1600 mm near Chepkorio. The rainfall pattern is trimodal, as shown in Figures 13.1.5 and 13.2.5. First rains start in mid-March with a second increase in July/August and a third in October/November.

The 66% probability of rainfall, i.e. amount surpassed in 20 out of 30 years, is shown in Map 13.0.1 for the first and middle rains and in Map 13.0.2 for the "second" or third rains.

Agro-Ecological Zone LH 2, one of the best areas for agriculture in the District, is represented by the Bugar Trial Site (No. 13.2). Zone LM 5 in the Kerio Valley is represented by the Tot K.V.D.A. Trial Site, where two separate blocks have been selected: one for irrigated cropping and the other, for comparison, without irrigation.

A summary of climatic data is compiled in Table 13.0.1, which can be used as a key to the Agro-Ecological Zones Map 13.0.3.

The soils of Keiyo Marakwet District are shown on Map 13.0.4. This elongated district is discussed according to a sub-division into three areas : a. Kerio Valley (Piedmont, Sedimentary and Alluvial Plains) b. Cherangani Hills and Escarpment (Mountains) c. Keiyo Marakwet West (Uplands)

a. Kerio Valley.

= Soils developed on colluvium and alluvium from various, mainly igneous rocks.

Piedmont plain units YU1 and YU4: deep, eutric and calcic Cambisols and chromic Luvisols, occasionally (YU4) or predominantly (YU1) sodic phase, with a texture of sandy loam to sandy clay. Unit YU4 also has cambic Arenosols. Sedimentary plain unit PtUl with de-ep eutric Cambisols and chromic Luvisols (Trial Site 13.1) . Alluvial plain unit AA4: calcaric Fluvisols. b. Cherangani Hills and Escarpment.

= Soils mainly developed on gneisses.

Unit MFC constitutes the steep escarpment to Kerio Valley. This unit, the northern unit MU2 and the southern unit MV5, all have shallow Lithosols and Regosols and patches of moderately deep to deep humic and/or chromic Cambisols. c. Keiyo Marakwet West.

= Soils developed on various gneisses (North and West of Cheptongei).

- Units UF2, UN2 (cf. Trial Site 12.1. West Pokot District) and UUC3 all have moderately deep to deep humic Cambisols.

- 0.9 - District: Keiyo Marakwet General Aspects 13.0

\ In addition, unit UF2 has humic Nitisols, unit UN2 has humic Acrisols and unit UUC3 has Rankers. In places a lithic phase occurs.

= Soils developed on intermediate igneous rocks.

Unit UI2 (South of Iten, and extending into Uasin Gishu District) has eutric Nitisols, unit UI3 (North'of Iten) has humic Nitisols and Acrisols (Trial Site 13.2).

= Soils developed on basic igneous rocks.

Unit UB1 near Kamwosor, bordering the Baringo District in the south, has eutric Nitisols to nito-chromic Luvisols (cf. Trial Site 14.2. Baringo District). t * The basic climatic and soil designations referring to trial sites in Keiyo Marakwet District are summarized in Table 13.0.2.

Table 13.0.2: Agro-Ecological Zone and Soil Classification of Trial Sites in Keiyo Marakwet District

Site Site Agro-Ecological Soil Classification No. Name Zone i

13.1 Tot K.V.D.A Livestock- chromic LUVISOL Millet Z. (LM 5)

13.2 Bugar Wheat/Maize- humic NITISOL Pyrethrum Zone (LH 2)

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

In Keiyo Marakwet District, two first priority sites were selected as shown in Map 13.0.4.

Trial Site 13.1 is on the Kerio Valley Development Authority farm. Two rectangular blocks of one and two acres respectively were demarcated in order to compare crop response to fertilizers on both irrigated and non- irrigated land. The soils have a limited representativeness and the accessibility of the site is very poor; notably in the rainy season. It takes more than two hours to drive down from Iten to Tot whenever the road is passable. K.V.D.A. should therefore take full responsibility for the experiments. The nearest rainfall recording station: 08835049, Tot Primary School is 5 km SW of the trial plot, but only has five years of recordings (up to 1986). The nearest suitable long-term rainfall recording station: 08835029, Kapenguria/Sigor is located in West Pokot District, 35 km NW of the trial site.

Between Iten and Chebiemit, ample land appeared to be available.

- 0.10 - District: Keiyo Marakwet General Aspects 13.0

Site 13.2 is situated along the Iten/Chebiemit main road. A rectangular and uniform trial plot was demarcated. Accessibility and demonstration effect are good and the soils of the farmers' fields, which are within walking distance, adequately resemble those of the trial plot. There are two long-term rainfall recording stations close to the Bugar trial site: 08935106, Elgeyo Forest Station is located 1.5 km NE, and 08935064, Kapkaboi Karuna Farm is 3.5 km WSW of the trial site.

The criteria for the final position of the trial sites are listed in Table 13.0.3, which is self-explanatory. Criteria have been rated very good (1), good (2), moderate (3), poor (4) or non-relevant (nr).

Table 13.0.3: Ratings of Criteria Used for Trial Site Selection in Keiyo Marakwet District

Criterion Site number

13.1 13.2

1. Representativeness of Agro-Ecological Zones 2 2 2. Representativeness of soils 3 2 3. Representativeness of topography 1 1

4. Adequacy of size and shape of the trial plot 1 2 5. Absence of trees and hedges 3 1 6. Absence of rocks arid boulders 1 1 7. Absence of termite mounds 1 1 8. Uniformity of previous land use 3 2

9. Accessibility 4 2 10. Demonstration effect 4 2 11. Proximity to a long-term rainfall station 4 2

12. Availability of storage facilities 1 4 13. Availability of s(turdy fences 4 2 14. Availability of Housing facilities for T.A.s 2 2

15. Farmer's willingness to cooperate 1 2 16. Security - theft 4 2 17. Security - intruding animals 3 2

18. Proximity of on-farm trials nr 2 19. Representativeness of soils at on-farm trials nr 2

- 0.11 - MAP 13.0.3 AEZS AND TRIAL SITES IN ELGEYO MARAKWET DISTRICT

35>l30 E • Site of first priority 13.1 co-operation site) 13 2

\ \

\ 'A \

-v Kap

ibte

0' 30' N

i TA m

.•• L H

i LH

'M 3

f, iv»

soil boundary, see Map 4

FERTILIZER USE RECOMMENDATION PROJECT (1987) Ministry of Agriculture National Agricultural Laboratories German Agricultural Team 25 km 10 15 2Ü District : Keiyo tiarakwet General Aspects 13.0

The 66% probability of rainfall, i.e. amount surpassed in 20 out of 30 years, is shown in Map 13.0.1 for the first and middle rains and in Map 13.0.2 for the "second" or third rains.

A summary of climatic data is compiled in Table 13.0.1, which can be used as a key to the Agro-Ecological Zones Map 13.0.3.

=== Soils developed on colluvium and alluvium from various, mainly igneous rocks.

Piedmont plain units YU1 and YU4: deep, eutric and calcic Cambisols and chromic Luvisols, occasionally (YU4) or predominantly (YU1) sodic phase, with a texture of sandy loam to sandy clay. Unit YU4 also has cambic Arenosols. Sedimentary plain unit PtUl with deep eutric Cambisols and chromic Luvisols (Trial Site 13.1). Alluvial plain unit AA4: calcaric Fluvisols. b. Cherangani Hills and Escarpment. i == Soils mainly developed on gneisses.

- Unit MFC constitutes the steep escarpment to Kerio Valley. This unit, the northern unit MU2 and the southern unit MV5, all have shallow Lithosols and Regosols and patches of moderately deep to deep humic and/or chromic Cambisols. c. Keiyo Marakwet West.

= Soils developed on various gneisses (North and West of Cheptongei).

- Units UF2, UN2 (cf. Trial Site 12.1. West Pokot District) and UUC3 all have moderately deep to deep humic Cambisols.

- 0.9 - District: Keiyo Marakwet General Aspects 13.0

\ In addition, unit UF2 has humic Nitisols, unit UN2 has humic Acrisols and unit UUC3 has Rankers. In places a lithic phase occurs.

=== Soils developed on intermediate igneous rocks.

Unit UI2 (South of Iten, and extending into Uasin Gishu District) has eutric Nitisols, unit UI3 (North of Iten) has humic Nitisols and Acrisols (Trial Site 13.2).

===== Soils developed on basic igneous rocks.

Unit UBl near Kamwosor, bordering the Baringo District in the south, has eutric Nitisols to nito-chromic Luvisols (cf. Trial Site 14.2. Baringo District). i

The basic climatic and soil designations referring to trial sites in Keiyo Marakwet District are summarized in Table 13.0.2.

Table 13.0.2: Agro-Ecological Zone and Soil Classification of Trial Sites in Keiyo Marakwet District

Site Site Agro-Ecological Soil Classification No. Name Zone i i 13.1 Tot K.V.D.A Livestock- chromic LUVISOL Millet Z. (LM 5)

13.2 Bugar Wheat/Maize- humic NITISOL Pyrethrum Zone (LH 2)

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

In Keiyo Marakwet District, two first priority sites were selected as shown in Map 13.0.4.

Between Iten and Chebiemit, ample land appeared to be available.

- 0.10 - District: Keiyo Marakwet General Aspects 13.0

Table 13.0.3: Ratings of Criteria Used for Trial Site Selection in Keiyo Marakwet District

Criterion Site number

13.1 13.2

1. Representativeness of Agro-Ecological Zones 2 2 2. Representativeness of soils 3 2 3. Representativeness of topography 1 1

4. Adequacy of size and shape of the trial plot 1 2 5. Absence of trees and hedges 3 1 6. Absence of rocks and boulders 1 1 7. Absence of termite mounds 1 1 8. Uniformity of previous land use 3 2

9. Accessibility 4 2 10. Demonstration effect 4 2 11. Proximity to a long-term rainfall station 4 2

12. Availability of storage facilities 1 4 13. Availability of sturdy fences 4 2 14. Availability of housing facilities for T.A.s 2 2

15. Farmer's willingness to cooperate 1 2 16. Security - theft 4 2 17. Security - intruding animals 3 2

18. Proximity of on-farm trials nr 2 19. Representativeness of soils at on-farm trials nr 2

- 0.11 - MAP13.0.4 SOILS AND TRIAL SITES IN ELGEYO MARAKWET DISTRICT

35° 30' E • Site of first priority 13.1 Tot K.V.D.A. (co-operation site 13 2 Bugar

0 30' N

SOURCES Ç1 Exploratory Soil Map of Kenya,1980 (scale 1:1,000,000) P7 5 Soil Resources Map of the Sangurur-Kapsowar-Chesoi Area (scale 1:50,000)

KEY UUC3 soil mapping code . soil boundary #• towns and major villages • tarmac road other all-weather roads district boundary — river 'inn scarp

For LEGEND See APPENDIX SB*

FERTILIZER USE RECOMMENDATION PROJECT (1987) Ministry of Agriculture National Agricultural Laboratories German Agricultural Team 5 10 15 20 25 km - ! District: Keiyo Marakwet General Aspects 13.0

3. Names and Addresses of Government Officers Involved in FURP Activities in Keiyo Marakwet District

The names and addresses of the agricultural staff members in the district are listed in Table 13.0.4.

Table 13.0.4: Names and Addresses of Government Officers in the District

OFFICER SITE NAME P.O. BOX TEL. NO.

DISTRICT D.C. Harry Wamubeyi* 200-Iten D.A.O. B.M. Matemo 279-Iten 6-Iten D.C.O. G.W. Kinyagiah 279-Iten 6-Iten D.E.C. F. Kambo 279-Iten 6-Iten

DIVISION Div. Ext. 13.1 N. Kisiero 249-Iten 6-Iten Officer 13.2 E. Chibole 249-Iten 6-Iten

Loc. Ext. 13.1 not met Officer 13.2 not met

Technical 13.1 not met Assistant 13.2 not met

K.V.D.A. Deputy 13.1 J: Kwambai 2660- Director Eldoret Project 13.1 Chandra Sekhara II Manager Farm 13.1 P.K. Mutungwa n Manager Farm 13.1 John K. Mutai n Assistant

Period of site selection in the District: March 1986.

- 0.15 - District: Keiyo Marakwet General Aspects 13.0

\ 4. Trial Design and Execution Plan, Keiyo Marakwet.

(Full details of the methodology for carrying out the trials are shown in Chapter IV of the main report.)

Selection of Crops. The proposed crop sequences in each of the three modules, in the two Keiyo Marakwet trials are:

Site 13.1, Tot RAINY SEASONS K.V.D.A. 1st, Long, Feb. 2nd, Short, Oct.

51 Standard Maize Coast Composite Fallow 52 Maize & Beans C.C.+ Beans, GLP 1004 Fallow 53 Sorghum, Ratooned Sorghum Seredo Fallow

The 1st sequence or module is continuous, pure maize, once/year. The 2nd is intercropped maize and beans, also once/year. The 3rd is sorghum planted in the 1st rains.

Site 13.2 Bugar, RAINY SEASONS Near Iten. 1st, Long, Feb. 2nd, Short, Aug.

51 Standard Maize Hybrid 625' Fallow 52 Maize & Beans Hybrid 625 + GLP 2 Fallow 53 Pot./Cabb.; For.Oats B 53/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, and forage oats in the 2nd 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 2NP x 2K x 2L x 2 FYM factorial, also with 2 replications in each module, at the Tot site. At the Bugar site, the standard design has been modified to a 2N x 2P x 4 FYM design in accordance with the soil analyses.

Each module thus consists of 64 plots, and the total for the 3 modules is 192 plots.

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

- 0.16 - District : Keiyo Marakwet General Aspects 13.0

5. Areas in Keiyo Marakwet 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 of Kenya. This consideration constituted the backbone for making decisions as to where to establish these FURP trial sites.

Two representativeness maps are drawn per District. One refers to the soils only (Map 13.0.5: Groupings of Soil Map Units), and in the second one (Map 13.0.6) Agro-Ecological Units (AEUs) are shown in which, according to the information available, the soils and the climate can be considered homogeneous.

Map 13.0.5 shows the representativeness of FURP trial sites for Keiyo Marakwet District only as far as soils are concerned. Since FURP can only cover major physiographic units (mainly uplands, plateaus and plains), minor units such as mountains, hills, floodplains and bottomlands indicated in the Soil Map (Map 13.0.4) and described in the accompanying Legend (cf. Appendix: M, H, A and B units), are beyond consideration when it comes to representativeness.

The explanation for Map 13.0.5 shows eight generalized "Groupings of Soil Mapping Units". These groupings have the same or similar soil properties and, as such, represent a specific soil environment, typified by one of the FURP trial sites.

The codes in the explanation to Map 13.0.5 refer to a specific trial site (13.1, 13.2, etc.) and to a specific degree of representativeness of soils (A, B+, B-). The combination of both forms a "Soil Representativeness Code". Unit 13.1.A, for instance, covers an area which is highly represented (A) by the Tot K.V.D.A. Trial Site (13.1). Unit 13.2.B+ covers an area which is moderately represented (B) by the Bugar Trial Site, also in Keiyo Marakwet District (13.2), although information on soil properties reveals slightly better conditions in the represented area than at the trial site itself (B+).

The explanation to Map 13.0.5 also lists those units of the Soil Map (Map 13.0.4) which are considered in the various groupings. A breakdown of soil properties referring to the Groupings of Soil Map Units is given as part of Table 13.0.5.

The soils of Keiyo Marakwet District are partly represented by the FURP trial sites. "A" cover (high representativeness) is mainly provided by District Sites 13.1 and 13.2, and Site 14.2 from neighbouring Baringo District.

For the Tot KVDA site, a combined Grouping 13.1.A/B- is given, since differences with respect to subsoil salinity and sodicity are to be expected within short distances. The Grouping refers to soil map units YU1 and PtUl (Cambisols and Luvisols, sodic phase, and partly saline phase).

The Bugar Trial Site is representative of the mainly humic Nitisols of so.il map units UI3, in which the site is situated (Grouping 13.2. A) and UF2 (Grouping 13.2.B+, richer parent material, thicker, acidic, humic topsoil).

- 0.17 - District: Keiyo Marakwet General Aspects 13.0

The Eldama Ravine Trial Site (14.2) mainly represents the Nitisols which do not have a humic or acidic humic topsoil. As the parent rock at Eldama Ravine is basically igneous, the southern part of Keiyo Marakwet District is coded 14.2.A (soil map unit UB1), and the central western fringes, which consist of poorer parent rock, are coded 14.2.B-(soil map unit UI2).

Areas which are not represented by any one trial site with respect to soils are coded C. This involves the shallow soils of the Cherangani Hills and its footslopes and part of the piedmont plains.

The second representativeness map, Map 13.0.6, shows the integrated representativeness of FURP trial sites involving both soils and climate. The map units are named "Agro-Ecological Units", and represent a specific soil-climate environment, typified by FURP trial sites. ! All combinations of the different soil-climate environments occurring in Keiyo Marakwet District are shown in the Agro-Ecological Unit Map (Map 13.0.6) and are explained in Table 13.0.5. The codes for the Agro- Ecological Units consist of three parts: site, soil representativeness and climatic representativeness. Site and soil representativeness are taken from Map 13.0.5. In addition, Map 13.0.6 and Table 13.0.5 indicate the codes which refer to the representativeness of the climatic environment (small letters). Several degrees of representativeness are given according to the prevailing temperature regime and the rainfall in the agro-humid period of the long rains.

All areas in Map 13.0.6 which are marked with code "a" (highly representative) are within the same temperature belt and receive the same amount of rainfall (± 10%) in the agro-humid period of the long rains as the trial site the code refers to.

The map units marked with code "b" (e.g.: b++, b+- ,b+*) are only modera tely represented by trial sites. In the AEU 13.1.A.b-H-, for instance, the soils are highly represented by the Tot K.V.D.A. Trial Site (13.1.A), but the climate (b++) indicates that this Agro-Ecological Unit belongs to the next warmer temperature belt and receives 10-20% more rainfall than the Tot K.V.D.A. Trial Site.

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

The criteria set for sub-division of the various degrees of represen tativeness with respect to soils and climate are further elaborated upon in Chapter IV.2 of the main report.

- 0.18 - XI o o r-H

in sr X5 c ro d r-H ro E O Ul *— • 4-> •U Q 4-1 • M ro O C S X) 3 ~ |" ,_ .. m Q.T3 3 Ul ro ai +J 1—1 •o Ul i-H c s -Do a U •H ro r-H i-H ai x: •M a t— CM r-» ro CM T- 3 > r> 3 r> r> o ai m aui Ul 4-> » 4-> 4-> < •H ro Ul C a ai D in Ul X) Ul o D ai >s o H) E aci i- rco Ul > E Ul t—i •H ~ ai 'H +j in i ai c O ro • x: ai Ul +-> o 4J c • * '>H +-> ai < < à < m «c • M ro M a •—t ai CM ,_ ,_ CM CM CM CM 4-> O O •M XI ro -M ai a E-. o o NO CM n ro ro •* •* o 4J XJ DS CS en o C C < ai -M Ul x4-:1 s ai 4-1 •H u o 3 ai c Ul o U Ul 4-1 1 •M 'H H •M C O o 3 ai ai 'M ai x) O JE ai ai t. o 4-> +j 00 o Ul O •M •H +j ai c ai ui Ul U) o Xi Ul o M Ul •M •H Ou r-\ ai •—i +J t. +J -H ai mai Ul H S ra r-l ro cj -H ci a 4-< c 3 •H •M •M Ul 'M -M ro ai i-H < >S t. >N M fc'H fc (, Cl > o •-H -t-" r-H 4-" •M Q +J +J •M -H c Z 4-> +J 4-1 Ul Ul Ul XI 4-1 •H x: ai JC ai O 'H 4-" 'M -H C ro < ta x: •M Q ai Q Q •H +J XI •nMo +xJ: •H +J b 3 C ai ai •-! ai i—i ff^f o ui ai M > Ul -H > Ul 4-> ui o ro ai DO M Ul ai a •H ro •M ro •H ;* fn 3 C ai ai X) •H ai +j ai Q O ro ^ 'M 4-> u •H x Ul ai ro U Ul ro U Ul a S ro M 4-> a Ul 1/1 > •+-> ra -—i P IDH ro b m ai ai c M ai •H C 'H C -H E 4-> o ro 00 r-H CK o 4J ai -p o ai -H o ai O Ul >> s Cl (cU m m 'M m Ul -M Ul 00 ai ai • - .—I •H ai c ai c •>H C 3 00 O i U 'H ai •>H c t-.DC M 3 c +J 3 <-i >> ai o X) •H a ro ro co ui ai xi en tu ai a ra ai ax; 4-> i oo ai E XI •H ami ua i raax 4->: M ro 4J C •M C D - r-H C M E E ai 1 t W -M C Ul 3 (U a >% ai >. ai m ro > C O Ul Ol i-H 'M r-H i-H ro •H ro ai D Q •M ro >> ro Ul L, ro m t, ai M 00 > ro ui ai m ai •-H M 'M D t. i-H D M m cy t. E ro M x: ai 'H o ai 'H o Ul 00 ai ro (0 1—1 u ai OO T3 o > •o o > c ai c a 4-j ooTi ro rj f-, 1 'M M o m ro o Ul ro o 4- O ro o 3 <-\ •M .H ro o x: B ^ 'M E v «M c • M H^HOM M x: Ul 4-1 a ru ai ro m ai •—i 3 u ai f- ro CM i- »- CM CM •M o ooxH : aoci i M MJ CM PO ro NT •mÇ 4°J a < c+a u H ^ V— 1^ T~ t* m Ut ro U•l 4-> a •M •cH 00 L ro • M o f-H Q U. a

0. 20 MAP 13.0.5 GROUPINGS OF SOIL MAPPING UNITS REPRESENTED BY TRIAL SITES IN ELGEYO MARAKWET DISTRICT

35' 30 E • Site of first priority 13.1 Tot K.V.D.A. (co-operation site 13.2 Bugar soil goupings mapping code soil groupings boundary

30' 0 N

SOURCES El Exploratory Soil Map of Kenya,1980 (scale 1:1,000,000) P75 Soil Resources Map of the Sangurur-Kapsowar-Chesoi Area { (scale 1:50,000) \

KEY UUC3 soil mapping code soil boundary towns and major villages tarmac road other all-weather roads district boundary river •"TTm scarp

~*7 For LEGEND See APPENDIX ,%7

FERTILIZER USE RECOMMENDATION PROJECT (1987) Ministry of Agriculture National Agricultural Laboratories German Agricultural Team 25 km 10 15 20 Table 13.0.5: Hajor Soil Properties and Cliiatic Conditions of the Ag ro-Kco log Lei1 Units in the Slgeyo Harakwet District

Agro-Ecological Unit Soil properties CI initie Conditions Site Soil Cliiate drai- eft. nutr. too- loist. classi- teip,l| tenp.l) rainfall Agro-Sc. Agro-Kc. No. Code Code nage depth avail, soil st.cap. fication lean ann. lean nin. 66X prob,2) Subconel) Zone 6,2.* d 1 h or Fe (• (e Ca) 15-18 8-11 720-810 1/ïl LH 3 b-i 15-18 8-11 630-120 1/vl LH 3 12.1,A l-i 2ah hu Ca t hu Ac a 15-18 8-11 730-890 »1 l LH 1-2 vi) b-» 10-15 3-8 130-890 vi Uli 1-2 13.I.A/B- eu t ca Ca * ch U, Bodic subsoil 22-25 15-18 Irrigation (vs--s/vs| i LH 5 to ur i IL 6

13.2. A vd-ed l-i lah-2ah vh hu Ni It hu Ac) 15-18 8-1 630-110 HM) i to LH 2-3 1/vl bM 15-18 8-1 110-8(0 'vil i b-* 10-15 3-8 770-810 vl i UH 1 13.2.B» d-vd 2ah h-vh hu Ni t hu Ca b»» 15-18 8-1 770-8(0 LH 1-2 b-t 10-15 3-8 770-8(0 UH 1 H. 2. A d-ed i-h h-vh eu Ni (» ni-ch Lu) a 15-18 8-1 600-7(0 f vi i or LH 2 1-ls] btt 15-18 8-1 710-810 [ vl i or M 2 Mil b-t 10-15 3-8 810-880 vl l UH 1-2 b-t 10-15 3-8 880-1020 vl i H.2.B- vd-ed vh eu Ni Uli 1 a 15-18 8-1 600-740 vl/1 i to 1/vl LU 2-3 b«t 15-18 7(0-810 t vl i U 1/vl LH 2-1 b-x 10-15 3-8 810-880 vl i b-n 10-15 3-8 880-1020 vl i Uli 1 Uli I soil not representative soil and/or cliiate are not representative ley: Drama» Koisture atotagc capacity 1| TeineraUre (*C) (differentiated according to A82 belts) se soievhat excessive vh very high > 160 n. v »ell h hied 120-160 ». 2) Rainfall 66X probability (in ••.) o* loderately «ell • loderatt 80-120 na. -referring to agro-huiid period of i iipertect 1 low < 80 ii. long and liddle rains only (e.of Harch-Septeiber, p poor if not otherwise larked in Hap 13.01); -for definition of rainfall ranges see explanation to Hap 13.0,6: -66* probability leans that aiount of Effective soil depth Nutrient availability rainfall will be eiceeded in at least 20 out of 30 years, ed eitreiely deep ) 180 ci. h high vd very deep 120-180 ci. • loderate 3) Agro-geological Subtone id loderately deep 50- 80 ci. vl very low -approxiiativapproxiiative indicatioindicate n only, since sh shallow 25- 50 c». Specification given subtones are not directldirec y relaatet d' t o' vsh very shallow < 25 ». in Chapter IV,2 aiount of rainfall; (lain report) -"--"in fomula leans 'followed by; -for further explanation of subtones see Chapter IV on lethodology; -Agro-ecological tones and subtones Toosoil properties Soil classification are shown in Kap 13.0,3. h huiic (base Hi Hitisols nu huiic eu eutric saturation )50 I) Ca Canbisols Ce ferralic ca calcic ah acid huiic (base Lu Luvisols or orthic ni-ch nito-chroaic saturation (5011) Ac Acrisols ch chroiic thick (30-60 ci.) Fe Ferralsols thin (<30 ci.| non-huiic

- 0.23 - Ul ** 1* 01 o o EH c ai JH.T- u T- IH ai (H O 4-> ai i (H ai i (H ai u x: ai N 'H x: v. ai x: s. ai x: ai 00 3 in • 1/1 00 3 •H o • r-1 • 0H0 ^+ 3O 'DHO »+^ 3o •rH O x: r-l ai \ o O fi £ HX; r-l x: r-i 4-1 u ro U u r* tt ro ro W 'H ftf.ro .^f .N' ro ** ** ft O O E t— 1 IH o O ro to ••"> •ri O +J COM 'r-HH COM COM 'r-Hl CMO CM CM i 1 • r-i ai u 1 E i E i I 1 O o E U r-H 00 4-> O 'H O O -ri O O o CM CM E XI < 0) r- Ul T- i- U) i- T— T-* U ro Ul Ul ai O H ai in Ul Ul Ul Ul U) Ul Ul Ul c c IH \ c c c c c c C C •H •H O TD ai S" 'r-l >H 'H 'H 'iH 'H •H •H ro ro E C ai m ~ ro ro ro ro ro ro ro ro u u \^ ro U) ** (L, u u u u u (H u • o 00 00 IH Ul c ai t- ai M M HO M M M 00 c c ai •—i o • i > C C C C C C c ë" o o x: •rH •ri 'H \ • H o o o o o o o o r-H r-H 00 o 4-1 - + +-> •rH Ul ro ai ~ ro •• -x: c > fi IH >. ro +-< r-H •H ui c PH f* U u u u ai ai ai ai *4 X) •H c ai ai ai ai ai ai ai E E E r-H O a ro -H Ul E E EHHH ro ro JH o m TD X •H ro ai t, CH CH O O O Ul Ul ro o i ai ai C U U ro ro ro o o o 3 u o 4-1 ai a 3 3 3 a u u ai ai n c u U) 00 ai x: jz Ul Ul ai ai ai c u 4-> 4-> 4-> 4-< 4-1 +J 4-1 +j 4-1 +-> Ul Ul x: (H O l—l r-l r-l 1—1 r-i r-i r-H r-H c ai +j an >> ai ai a> ai ai ai +j +j ai 01 •H (H (H Ul ai H CQ CQ CQ CQ CO DQ r-H r-l m CQ ro a 3 ai f-, TD ai ai ai u ai > ro ro (H o i—i u < g < < < < N NI 2 < g TD 4-> o x: 4-1 ai w O Ol o IX CJ aOr-H TD r- ^- T-- *— *— T— ä < CM CN r-H 4-> c SO •rH •H ai o c 4-> x: m II II II II II II u n II II M ai o' 03 e m II + * 1 •T * 1 +• i s eu rö s + + 4 * u •ri 1 1 1 * sä r— a 1 ai o ro A 1 a o 4-> 1 < o s c Ul ro ^v r^ ai o ai ai 1 u 4-1 4-> 1 < H •H •rH ai ui Ul U) u Ul 0) rH S ro r-i ro z •rH •rH ^ U rH fn o r-i 4-1 r-l +J 4-1 4-1 M j- ai x: ai *•% MX: oo x: 4-> H •ri 4J •H 4-> CJ ai r-H Ol rH r*> •H *-% ^> > Ul 4J > Ul 4J 4-1 f-, 4-1 4-> •ri ro •H ro U 4-1 a u < 4-> ai 4-1 ai •rH Ul •rH •H ai ro f-, m ro u ui C-r •H IH CH > •H ID r-l 4J (O rH *•* 4-r a 4J 4-1 •H c •ri c -n 4-1 Ul Ul Ul < •H ai 4-1 O «PO a •H •H •ri ro Ul •H tfl Ul 'H Ul • H a +-a>i O a ai ai c 3 c u JU 3 c 4J 4-1 4-1 o a ai a §s a ro Ul O ro ai 00 m 01 ax: ai ax: •rH ^ t-, 3 c X ai u ro 4-> t. ro 4J a o ro -* •ri M u E E a s ro u a >> ai >. ai ro f-i ro ai r-i •H rH r-H «H r-H E 4-1 o ro m t. ai O XI ai o xi o Ul >» ro Ul U ro m u 3 00 o eu t-i (.H3 g «»*• r-H >< G ai • rt o «'ri O ai ai •rH Ul 00 TD o > TD O > ro ^-» 00 > ai •H o m ro o ui m •H r-H ro TD x: E <-» «M B ^ "w C IH < M CM o ai D a «h** o U > ro ro S v; SH E r-i n u II Ul 00 ai ro ro •ri ai c a4J QO TD o 1 4-1 O ro o D rH en < a+ ta •ri H v: H m M Ul

n u n r-H CM CM CM ro i • t •ri CM ro < .-.•.•Y.- // H J / ^ // S^

- 0.24 - MAP 13.0.6 AGRO-ECOLOGICAL UNITS REPRESENTED BY TRIAL SITES IN ELGEYO MARAKWET DISTRICT

35° 30- E • ST te of first priority 13.1 Tot K.V.D.A. (co-operation site 13.2 Bugar YU1 esegon — agro-ecological units boundary

13.1.a

1° N

0 30' N

SOURCES El Exploratory Soil Map of Kenya, 1980 (scale 1:1,000,000) Chepkorio(l P7 5 Soil Resources Map of the Sangurur-Kapsowar-Chesoi Area (scale 1 :50,000) 14.2. b"

KEY UUC3 soil mapping code soil boundary 9 • towns and major villages „' tarmac road other all-weather roads 14.2.b-*_L district boundary - river 142 b inn scarp '"^

14.2b" "3*7 For LEGEND See APPENDIX Fox EXPLANATION see PREVIOUS PAGE and TABLE

FERT1LIZER USE RECOMMENDATION PROJECT (1987) Ministry of Aqriculture National Agricultural Laboratories German Agricultural Team 25 km 10 15 20 District: Keiyo Marakwet General Aspects 13.0

LEGEND TO THE SOIL MAP OF KEIYO MARAKWET DISTRICT

1—Explanation of first character ( physiography )

M Mountains and Major Scarps H Hills and Minor Scarps F Footslopes Y Piedmont Plains Ö uplands, upper, Middle and Lower Levels Pt Sedimentary Plains of upper River Terraces A Floodplains

2—Explanation of second character (litholoqy):

A Alluvial Sediments from Various Sources B Basic and Ultra-Basic Igneous Rocks (basalts, nepheline phonolites; older basic tuffs included) F Gneisses Rich in Ferromagnesian Minerals and Hornblende Gneisses I Intermediate Igneous Rocks (andesites, phonolites, syenites, etc.) N Biotite Gneisses R Quartz-Feldspar Gneisses U Undifferentiated Basement System Rocks (predominantly Gneisses) V undifferentiated or Various Igneous Rocks

3—Soil descriptions

HFC Complex of: well drained soils, ranging from shallow, rocky and stony to deep, non-rocky and non-stony, dark red to dark brown, friable to firm, sandy loam to sandy clay chronic CAMBISOLS, partly lithic phase; with eutric REGOSOLS and Rock Outcrops

MÜ2 Well drained, moderately deep, reddish brown to brown, friable, stony sandy clay loam, with an acid humic topsoil humic CAMBISOLS; with humic NITISOLS, dystric REGOSOLS and Rock Outcrops

MV5 Well drained, shallow to moderately deep, dark reddish brown to dark brown, friable, rocky and bouldery, clay loam to clay; in places with a humic topsoil nito-chromic CAMBISOLS; with haplic PHAEOZEMS, lithic phase, LITHOSOLS, eutric REGOSOLS and Rock Outcrops

HOC Complex of: excessively drained to well drained, shallow, dark red to brown, friable, sandy clay loam to clay; in many places rocky, bouldery and stony and in places with an acid humic topsoil dystric REGOSOLS, lithic phase; with LITHOSOLS, humic CAMBISOLS, lithic phase and Rock Outcrops

HV1 Well drained, shallow, dark reddish brown, friable, very calcareous, bouldery or stony, loam to clay loam; in many places saline LITHOSOLS; with calcic XEROSOLS, lithic, bouldery and saline phase and Rock Outcrops

- 0.27 - District : Keiyo Marakwet General Aspects 13-u

FVC Complex of: . well drained to moderately well drained, deep, reddish brown to very dark greyish brown, firm, sandy clay loan to clay; in many places with a humic topsoil and/or cracking and/or moderately calcareous undifferentiated LUVISOLS, luvic PHAEOZEHS and chromic VERTISOLS YUl well drained deep, dark brown, friable, moderately calcareous clay loam, with a sodic deeper subsoil calcic CAHBISOLS, sodic phase

YU4 well drained, moderately deep to very deep, yellowish red to dark brown, friable, loamy sand to sandy clay loan - chromic LUVISOLS, eutric CAHBISOLS and cambic ARENOSOLS

OBI wen drained extremely deep, dark reddish brown, friable clay; in places deep to very deep eutric NITISOLS; with nito-chromic LUVISOLS

ÖF2 well drained deep to very deep, dark red to dark reddish brown, friable clay, with 40 to 50 cm acid humic topsoil; in places shallow to moderately deep - humic NITISOLS and humic CAHBISOLS, partly lithic phase

012 well drained very deep to extremely deep, dark red to dark reddish brown, friable clay eutric NITISOLS ,

ÜI3 Well drained very deep to extremely deep, dusky red to dark reddish brown, friable clay, with a (thick) acid humic topsoil humic NITISOLS, with humic ACRISOLS

ÜI4 Well drained deep, üisky red to dark reddish brown, friable clay; in places shallow, fairly rocky and stony . . . chromic ACRISOLS, partly lithic phase

ÜN1 Well drained moderately deep to deep, brown to dark yellowish brown, firm sandy clay loan orthic LUVISOLS 0N2 Well drained moderately deep to deep, dark reddish brown to dark brown, friable, sandy clay loam to clav' with a thick acid humic topsoil; in places shallow and rocky humic ACRISOLS and humic CAHBISOLS, partly lithic phase; with Rock Outcrops

UR1 Well drained deep, strong brown to reddish yellow, very friable, sandy clay loam to sandy

clay . „.mTr,n.„ — orthic FERRALSOLS; "** ferralic CÀMBIS0LS ÖU6 Well drained deep to very deep, dark reddish brown to dark brown, friable sandy clay loan to clav in ólaces shallow to moderately deep, rocky and stony — orthic LUVISOLS and eutric CAHBISOLS, partly lithic phase

- 0.28 - District: Keiyo Marakwet General Aspects 13.0

ÜÜC3 Complex of: well drained, shallow, black to very dark brown, very friable loan, with an acid humic topsoil; in places rocky RANKERS and: well drained, moderately deep, dark brown, friable clay loam, with a very thick acid humic topsoil humic CAHBISOLS

PtUl Vieil drained to moderately well drained, deep, dark brown, friable to firm, slightly calcareous, clay loam to clay, in many places slightly saline-sodic eutric CAHBISOLS and chromic LUVISOLS, partly saline-sodic phase

AÀ4 Well drained to imperfectly drained, very deep, dark brown to yellowish brown, stratified, micaceous, strongly calcareous, predominantly loamy soils calcaric FLÜVISOLS

NOTES:

1. mollic Nitisols and chromo-luvic Phaeozems: soils are equally important 2. mollic Nitisols, with chromo-luvic Phaeozems: Nitisols are prevalent 3. in places: in <30% of the area 4. in many places: in 30-501 of the area 5. predominantly: in >50l of the area 6. deeper subsoil: below 80 cm.

-0.29 District: Keiyo Marakwet Trial Site 13.1: Tot

Contents of Chapter 13.1:

Detailed Description of the Tot Trial Site

Page

1. Geographical and Additional Technical Information 1.4 1.1 Final Position of the Trial Site 1.4 1.2 Sketch of the Trial Site 1.5 1.3 Physiography 1.7 1.4 Vegetation, Past and Present Land Use 1.8

2. Climate 1.9 2.1 Prevailing Climatic Conditions 1.9 2.1.1 Agro-Climatic Classification of the Area Represented 1.9 2.1.2 Relevant Meteorological Data 1.10 2.1.3 Crop Suitability from the Climatic Point of View 1.15 2.2 Proposal for the Monitoring of Agro-Climatic Conditions in Phase II 1.19

3. Soils 1.20 3.1 Survey Data 1.20 3.1.1 Brief Soil Description and General Information on the Soil 1.20 3.1.2 Detailed Profile Description and Soil Classification 1.21 3.1.3 Soil Sampling' 1.23 3.2 Laboratory Data 1.23 3.3 Evaluation of Soil Data 1.27 3.3.1 Literature References and Soil Correlation 1.27 3.3.2 Representativeness 1.28 3.3.3 Variability of Soil Properties within the Trial Site 1.29 3.3.4 Fertility Status of the Soil 1.29 3.3.4.1 Soil Profile and Global Fertility Rating 1.29 3.3.4.2 Soil Fertility Assessment of Composite Samples 1.30 3.4 Sampling Programme for Laboratory Analysis 1.32 3.4.1 Soil Samples 1.32 3.4.2 Plant Samples 1.33 3.4.3 Other Samples 1.33

4. Conclusions from the Analyses of Climate and Soils 1.33 4.1 Moisture Availability 1.33 4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement 1.34 4.3 Other Relevant Land Qualities 1.35

5. Trial Design and Execution Plan 1.36

- 1.1 - District: Keiyo Marakwet Trial Site 13.1: Tot

List of Tables1)

Page

Table 13.1.1 Physiography of the Tot Trial Site 1.7

Table 13.1.2 Vegetation, Past and Present Land Use 1.8

Table 13.1.3 Names and Addresses of the Divisional Staff Members (No On-

and Farmers at the Tot Trial Site Farm Trials) Table 13.1.4a Data of the Nearest Long-Term Rainfall Station 1.11 Table 13.1.4b Data of the Nearest Long-Term "Rainfall Station 1.12 Table 13.1.5 i

Table 13.1.6 Temperature 1.13

Table 13.1.7 Potential Evaporation (Eo) 1.13

Table 13.1.8 Agro-Climatological Crop List for Tot 1.15

Table 13.1.9 Crop Development Stages and Crop Coefficients 1.17

Table 13.1.10 Detailed Profile Description of the Tot Trial Plot 1.22

Table 13.1.11 Analytical Results (physical and chemical analyses) 1.24

Table 13.1.12 Analytical Results (chemical analyses, trial plot) 1.25

Analytical Results (chemical analyses, (No On-Farm Table 13.1.13 farmers' fields) Trials) Table 13.1.14 Soil Correlation with Respect to the Tot Trial Site 1.28

Evaluation of Mehlich Analysis Data According to NAL Standards 1.32

1) See Footnote next page.

- 1.2 - District: Keiyo Marakwet Trial Site 13.1: Tot

List of Figures1)

Page

Figure 13.1.1 Demarcation of the Tot Trial Site 1.4

Figure 13.1.2 Access Map to the Tot Trial Site 1.5

Figure 13.1.3 Map of the Trial Plot, Tot 1.6

Figure 13.1.4 Location of Farmers' Fields for On-Farm (No On-

Trial s , Tot Farm Trials)

Figure 13.1.5 Rainfall and Potential Evaporation 1.14

Figure 13.1.6 Water Requirement and Availability for Maize Pwani, First Rains 1.18 Figure 13.1.7 Location of Composite Sampling Blocks and Profile Pit at the Tot Trial Plot 1.23

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

- 1.3 - District: Keiyo Marakwet Trial Site 13.1: Tot

1. Geographical and Additional Technical Information

1.1 Final Position of the Trial Site

The position of the site at Tot Kerio Valley Development Authority (K.V.D.A) farm is shown in Figure 13.1.1, extracted from Map No. 76/3 - Tot. Its UTM grid coordinates are E 98.6 and N 36.2. The elevation is 960 m. Further details on the final position are shown in Figure 13.1.2 and the sketch map of the trial plot in Figure 13.1.3.

Figure 13.1.1: Demarcation of the Tot K.V.D.A. Trial Site on the 1:50,000 Topographic Map

- 1.4 - District: Keiyo Marakwet Trial Site 13.1: Tot

1.2 Sketch of the Trial Site.

The location of and the access route to the Tot K.V.D.A. site are shown in Figures 13.1.2 and the map of the trial plot in Figure 13.1.3.

Trial site 13.1

.5 2Km.

Figure 13.1.2: Access Map of the Trial Site, Tot K.V.D.A.

1.5 District: Keiyo Marakwet Trial Site 13.1: Tot

Irrig, canal m Trees 4 & * *

O 20 40 60m.

Figure 13.1.3: Map of the Trial Plot, Tot K.V.D.A.

- 1.6 District: Keiyo Marakwet Trial Site 13.1: Tot

As trial site 13.1 is a co-operation site, no farmers' fields were selected. As a result, Figure 13.1.4, Table 13.1.3 and Table 13.1.12 have been omitted.

1.3 Physiography

Information on the physiography of the trial site and its surroundings is summarized in Table 13.1.1 below.

Table 13.1.1: Physiography of the Tot K.V.D.A. Trial Site

Elevation 960 m.

Landform sedimentary plain

Physiographic position of the site plain

Topography of surrounding country very gently to gently undulating (slopes 0-5%)

Slope on which trial plot is sited < 1%

Aspect Nil

Microtopography , two blocks separated by a 1 drainage depression; small block close to irrig.canal

- 1.7 - District: Keiyo Marakwet Trial Site 13.1: Tot

1.4 Vegetation, Past and Present Land Use

Information on vegetation, past and present land use is summarized in Table 13.1.2 below:

Table 13.1.2: Vegetation, Past and Present Land Use of the Tot K.V.D.A. Trial Site

Vegetation Acacia thicket with Capparidaceae

Cropping system

(a) cleared since: 3,983 (b) crops grown: maize (Coast Composite); sorghum (Serena and IS 76) cowpeas, beans, sunflowers, cotton, groundnuts, veget. (c) fallow periods: none (d) present land use: sorghum

Inputs

(a) mineral fertilizers: not applied (b) organic manure: not applied (c) means of land preparation: tractor (d) means of weeding: manual (e) frequency of weeding: twice per crop stand (f) other capital inputs: pesticides (stalk borer) (g) level of know-how: high

Produce

(a) maize 8 bags/acre (90 kg bags) (b) sunflowers 4.5 bags/acre (50 kg bags)

Livestock none Remarks

Crop residues are given to Pokot pastoralists to feed their cattle. Waterlogging reportedly affects crop yields markedly.

Period of site selection: March 1986.

- 1.8 - District: Keiyo Marakwet Trial Site 13.1: Tot

2 Climate

2.1 Prevailing Climatic Conditions

2.1.1 Agro-Climatic Classification of the Area Represented by the Tot K.V.D.A. Trial Site

The following brief climatic description refers to the existing information:

ACZ : V 2 (H.M.H.BRAUN, 1982)1)

AEZ : LM 5, (vs - fvs)i (R.JÄTZOLD, 1983)2)

Next long-term rainfall station: 08835029, Kapenguria/Sigor District Office

Agro-Climatic Zone (ACZ):

Moisture availability Zone V (r/Eo): annual average precipitation is 25-40% of the potential evaporation (Eo)

Temperature Zone 2 : mean annual temperature is 22-24°C

Agro-Ecological Zone (AEZ):

LM 5 = Livestock-Millet Zone

LM = Lower Midland Zone: mean annual temperature is 21-24°C, mean minimum >14°C ''

5 = semi-arid; annual average precipitation is 25-40% of the potential evaporation (Eo)

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

(vs - fvs)i = with a (weak) very short cropping season followed by a (weak) very'short but full (i.e. no subdivision of the growing period) one.

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

2) According to R. JÄTZ0LD and H. SCHMIDT, eds. (1983): Farm Management Handbook of Kenya, Vol. II/B CENTRAL KENYA - Nairobi and Trier

- 1.9 - District: Keiyo Marakwet Trial Site 13.1: Tçt

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

vs very short 45 - 54 days (in LM)

i = intermediate rains (at least 5 decades more than 0.2 Eo); that means moisture conditions are above wilting point for most crops. f = full, i.e. no subdivision of growing periods, for instance fvs means 45 - 74 days (in LM) ( )= weak performance of growing periods (most decades less than 0.8 Eo)

2.1.2 Relevant Meteorological Data for the Tot K.V.D.A. 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 long-term rainfall station: 08835029 Kapenguria/Sigor Divisional Office (elevation: 1050 m), 35 km NW of the Tot K.V.D.A. Trial Site (elevation: 960 m), and the nearest rainfall recording station 08835049 Tot Primary School (elevation: 1030 m), 5 km SW of the trial site. The data are listed in Tables 13.1.4a and 13.1.4b. At the trial site, rainfall amounts are probably lower than those recorded at Kapenguria/Sigor and higher than those recorded at Tot Primary School : in 20 out of 30 years the Tot K.V.D.A. Trial Site gets more than 300 mm of rain in the period from March to September, i.e. first and middle rains. The methods of rainfall data analysis are described in Chapter IV.2.2 of the main report. At Tot, a part of the trial plot is within the irrigated area.

Temperature and potential evaporation(Eo):

Temperature data are extrapolated from Marigat, Perkerra Irrigation Scheme (elevation:1070 m), 90 km SE of the trial site (elevation: 960 m). The temperature gradient in this area is on average 0.7°C. Potential evapora tion (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 the Marigat Perkerra Irrigation Scheme Meteorological Station: 08935163.

Temperature and evaporation data are given in Tables 13.1.5 and 13.1.6. The rainfall pattern and potential evaporation are shown in Figure 13.1.5. For more detailed information on the methodology of climatic description see Chapter IV.2.2 of the main report.

- 1.10 - Table 13.1.4a : Data of the Nearest Long-Term Rainfall Station Station No.: 08835029 Total years for calculation: 22 Kapenguria, Sigor D.0, First year included: 1963 Elevation: 1050 m Last year included: 1985

Average annual rainfall 944 mm

Rainfall surpassed in 20 out of 30 years (s66X Probability) 1st rains: 240 mm 2nd rains: 100 mm (mid Apr. - end of May) (beg. of Oct. - mid Nov.)

Decades Arithmetic Average Number of Rainy s66% Probabi Years and Mean Days with Rainfall lity of ex anal- Month (mm) >= 1 mm >= 5 mm ceeding ... mm ized

1 JAN 6.1 0.8 0.7 2.4 22 2 4.4 0.8 0.8 0.8 22 3 11.5 1 .5 1 .5 1 .6 22 4 FEB 7.3 0.8 0.8 0.4 20 5 8. 1 1 .0 1 .0 3.1 20 6 14.5 1 .3 1 .3 2.9 20 7 MAR 12.0 1 .5 1 .4 3.9 21 8 28.9 2.1 2.0 9.7 21 9 38.7 2.6 2.5 16.6 21 10 APR 43.6 3.2 3.2 27.6 21 1 1 51 .4 4.3 4.2 28.3 21 12 55.0 | 3.5 3.4 34.7 21 13 MAY 54.7 4.3 4.1 29.8 22 14 51 .4 4.1 4.0 35.0 22 15 32.5 3.5 3.5 21 .8 22 16 JUN 21 .2 1 .8 1 .7 10.1 20 17 21 .5 2.3 2.2 11.6 20 18 27.1 2.5 2.4 16.3 20 19 JUL 33.8 3.1 3.0 22.7 20 20 29.2 2.5 2.3 18.8 20 21 43.0 3.6 3.6 29.5 20 22 AUG 35.2 3.3 3.2 21 .1 22 23 29.4 2.7 2.5 16.8 22 24 31 .6 2.7 2.6 17.3 22 2 5 SEP 26.0 2.6 2.5 15.4 21 26 15.6 2.0 2.0 7.8 21 27 24. 1 1 .7 1 .6 12.3 21 28 OCT 12.6 2.4 2.3 6.8 21 29 23.0 3. 1 3.0 13.6 21 30 22.9 3.0 2.8 12.8 21 31 NOV 39.6 3.0 2.9 22.0 19 32 27.0 2.1 2. 1 13.9 19 33 27.1 2.2 2.2 12.7 19 34 DEC 15.7 1 .2 1 .2 0.0 19 35 8.3 0.8 0.8 1 .9 19 36 10.0 0.8 0.8 3.4 19 \

- 1.11 - Table 13.1.4b : Data of the Nearest Long-Term Rainfall Station

Station No.: 08835049 Total years for calculation: 5 Tot, Pr. School First year included: 1973 Elevation: 1030 m Last year included: 1985

Average annual rainfall: 649 mm

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

1st rains: 230 mm 2nd rains: 70 mm (beg. of Apr. - end of May) (beg. of Oct. - mid Nov.)

Decades Arithmetic Average Numh f s66% Probabi Years and Mean Days with Rainfal>er of lRain y lity of ex anal- Month (mm) >= 1 mm >= 5 mm ceeding ... mm ized

1 JAN 0. 4 0.3 0.3 0.1 3 2 0.0 0.0 0.0 0.0 3 3 10.0 1 . 1 1 . 1 4.3 3 4 FEB 1 . 1 0. 1 0. 1 0.3 3 5 0.0 0.0 0.0 0.0 3 6 1 .6 0.4 0.3 0.8 3 7 MAR 2. 1 1 .0 h .0 0.6 3 8 4.7 0.9 0.7 2. 9 3 9 34.4 2. 1 1 .9 10.7 3 10 APR 25. 1 2.6 2.6 17. 5 4 1 1 15.7 2.6 2.4 8. 1 4 12 12.5 1 .6 1 . 1 5.5 4 13 MAY 40.8 3. 1 3. 1 28.8 4 14 54. 1 2.4 2.4 33.4 4 15 20.4 1 .6 1 .6 16.2 4 16 JUN 10.7 1 .3 1 .3 6.2 4 17 40.0 2. 1 2.0 24.2 4 18 8.0 1 .4 1 .4 3.2 4 19 JUL 20.6 1 .6 1 .6 11.8 5 20 34.3 2.3 2. 1 21 .6 5 21 37.5 3. 1 3.0 23.1 5 22 AUG 32.7 2.3 2.3 15.3 5 23 11.7 0.9 0.9 3.9 5 24 21 .5 1 .6 1 .6 9.8 5 25 SEP 13.1 1 .3 1 .3 8.0 5 26 14. 1 1 .7 1 .7 8. 1 5 27 22.3 2.0 2.0 10. 1 5 28 OCT 17.6 3.0 2.7 10.1 5 29 7.4 1 .0 1 .0 2.6 5 30 12.2 3.3 3.3 9.0 5 31 NOV 7. 1 1 . 1 1 . 1 6.0 3 32 28.3 0.9 0.9 16.1 3 33 36.7 2.0 2.0 17.9 3 34 DEC 15.3 1 .4 1 .4 10.1. 4 35 20. 1 2.0 2.0 9.0 4 36 15.2 1 .4 1 .4 3.7 4

- 1.12 - District: Keiyo Marakwet Trial Site 13.1: Tot

Table 13.1.5: Temperature ( 'C' )

JAN. FEB. MAR. APR. MAY JUN.

mean temp. 25.5 26.1 26.5 26.1 25.6 24.9 mean max.temp. 34.0 34.5 34.4 33.4 33.2 32.8 mean min.temp. 17.0 17.8 18.6 18.8 18.0 17.1

JUL. AUG. SEPT. OCT. NOV. DEC.

mean temp. 24.5 24.3 25.2 25.6 25.0 24.7 mean max.temp. 31.8 31.8 33.9 33.7 32.1 32.2 mean min.temp. 17.9 16.9 16.5 17.6 18.0 17.3

annual mean: 'i15. 3 mean max : 33.1 mean min. : 17.6

Table 13.1.6: Potenti al Evaporation (Eo) in -mm per Decade :

JAN. FEB. MAR. APR. MAY JUN. i1 1st decade 66 71 71 62 58 57 2nd decade 66 71 71 62 58 57 3rd decade 73 57 78 62 64 57 Total : 205 199 220 186 180 171

JUL. AUG. SEPT OCT. NOV. DEC.

1st decade 52 55 63 65 59 61 2nd decade ,52 55 63 65 59 61 3rd decade +51 61 . _63 _Z2 59 67 Total : 161 171 189 202 177 189

av. annual pc)tentia l evaporation: \>25 0 mm

For all climatic data published in this Section, a data bank has been established by FURP on Personal Computers at the National Agricultural Laboratories in Nairobi.

- 1.13 - O Ld ro O

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- 1 . M+ - District: Keiyo Marakwet Trial Site 13.1: Tot

2.1.3 Crop Suitability from the Climatic Point of View

A summary of the agro-climatic suitability of the most important seasonal food crops under non-irrigated conditions is given in Table 13.1.7. below. Additional information on other crops which are considered suitable from the agro-climatic viewpoint is given in the Farm Management Handbook, Vol. II/B, Central Kenya1).

Table 13.1.7: Agro-Climatological Crop List for Tot K.V.D.A.

Crop/variety Av.No.of Altitudes2) Requirem.of Yield (or place of days to according well distri potential ace. breeding) physiol. to growing buted rain to water avai e = early maturity period fall 3) in lability ") m = medium (m.) grow.period a = 1st rains (mm. ) b = 2nd rains

Maize/e.mat. 100-120 0 - 1200 550-700 a) poor 1ike Pwani 3 (Mar.-Jul/Aug)

Foxtail 65-80 800-1300 220-320 a) fair Millet

Sorghum/ a) poor e.mat. like 85-110 0 - 1500 220-480 b) fair/poor Serena (ratoon.)

Cowpeas/ a) fair e. mat. 70-90 \ 0 - 1500 200-400 b) fair like Katuli (for leaves)

Tepary Beans 60-75 600-1500 180-300 a) fair very e.mat. b) fair/poor

1) R. JÄTZ0LD and H.i SCHMIDT, eds. (1983): Far-m Management Handbook of Kenya, Vol. II/B, Central Kenya - Nairobi and Trier

2) Most suitable altitudes; the length of the growing period increases with altitude; growth is also possible beyond the indicated altitude range, as long as the ecological limits have not been reached.

3) Lower figure for fair results, higher for very good results with some corrections due to rainfall distribution, evaporation and run-off losses.

4) Estimated yield potential: very good >80%, good = 60-80%, fair = 40-60% and poor <40% of the expected yield under optimum water availability, adapted from R. JÄTZ0LD, and H. SCHMIDT, eds. \ (1982): Farm Management Handbook of Kenya, Vol. II/A, West Kenya.

- 1.15 - District: Keiyo Marakwet Trial Site 13.1: Tot

For the most important food crops in the area around the Tot K.V.D.A. Trial Site, the crop coefficients (kc) are shown in Table 13.1.8, differentiated according to decades (10 day periods) of the growing season which is the time between planting or sowing and the physiological maturity.

Furthermore, four crop development stages are distinguished in Table 13.1.8. The crop coefficients for the climatic conditions at the Tot K.V.D.A. Trial Site were estimated on the basis of data obtained from D00RENB0S and PRUITT (1977)1) and D00RENB0S and KASSAM (1979)2).

The data on the duration of each of the growing seasons and on the various development stages of each crop were assessed on the basis of local observations made under average climatic conditions.

The crop coefficients estimated for the various decades of the growing seasons were used to estimate the maximum (potential) évapotranspiration (ETm) under the prevailing climate, assuming that water was not a limiting factor for plant growth. For this calculation the following approximative formula was employed:

ETm = kc * Eo whereby: ETm= maximum (potential) évapotranspiration kc = crop coefficient j Eo = potential evaporation (climatic evaporative demand)

In Figure 13.1.6, the ETm-values are used to indicate the estimated maximum water requirements of the maize crop for optimum growth. Furthermore, the rainfall data at 66% reliability are shown in Figure 13.1.6 to give an indication of the water availability. However, when reading these figures, it must be borne in mind that the actual availability of water for the plants also depends, to a large degree, on factors such as the run-off, the moisture storage capacity of the soil, the deep percolation of water.

The placement of the growing seasons of the various crops on the time axis as presented in Figure 13.1.6 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 given in Chapter IV. 2.2 of the main report. The interpretation of the diagrams mentioned above follows in Section 4 of this Volume (Conclusions from the Analyses of Climate and Soils).

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

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

- 1.16 - «# 1 CM

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- 1.18 - District: Keiyo Marakwet Trial Site 13.1: Tot

2.2 Proposal for the Monitoring of Agro-Climatic Conditions in Phase II

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

1) Rainfall records:

A rain gauge has to be installed at the Tot K.V.D.A. Trial Site to measure actual precipitation on the spot. Subsequently, data can be compared with both rainfall for the particular year and the long-term average of the nearest rainfall recording station of the Meteorological Department: 08835029 Kapenguria Sigor Divisional Office.

2) Records on other relevant meteorological parameters:

Temperature and relative humidity data could be obtained from Chesongoch Mission (No. 08835046). Data on windrun and sunshine hours could be obtained from 08935163 Marigat, Perkerra Irrigation Scheme Meteorological Station, in order to calculate Eo (climatic evaporative demand). For this purpose a computerized PENMAN formula, modified by MC CULLOCH (1965) is available on PC. The calculated Eo-values could subsequently be compared with the Class-A Pan readings taken at Chesongoch Mission. Finally, it would be desirable to have "irrigated" and "non-irrigated trials". In this case the discharge of irrigation water has to be measured in co-operation with the K.V.D.A., and a meteorological station should be established at the trial plot (containing minimum and maximum thermometers, dry and wet bulb thermometers, an anemometer, a sunshine recorder and soil thermometers), in order to carry out detailed crop-water relationship studies. I 3) Phenologi r.«1 records : Dates of planting or sowing of each crop, emergence, start of tasselling (for maize crop), budding (for bean/cowpea crop), flowering, ripeness or physiological maturity and harvest have to be recorded. Additionally the leaf area index (LAI) has to be determined every week (at least for the cereal crops) in order to provide a sound basis for water balance calculations. Other phenological features, above all rolling and wilting leaves have to be recorded in order to determine water stress and wilting point respectively before physiological maturity has been reached. Moreover, soil moisture checks and observations on rooting depth at the above-mentioned growing stages and run-off measurements would be needed to estimate the actual évapotranspiration of various crops correctly.

For most of the data to be recorded, official forms of the Meteorological Department are available.

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

- 1.19 - District: Keiyo Marakwet Trial Site 13.1: Tot

3. Soils i 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 a rating of relevant soil related land factors. The classes for thesevfactors have been adapted from Andriesse and van der Pouw (1985), and a key for them is to be found in Chapter IV.2.3 of the main report. t Brief soil description

The soils are deep, dark red to dark reddish brown in colour, and consist of firm sandy clay to clay. They have a moderate, angular blocky structure and a low (Btl) to moderately high (Bt2) biopórosity. The deeper subsoil is calcareous and slightly saline-sodic.

Rating of soil-related land factors

Parent rock 1 rich * 2 moderately rich: colluvial. mainly derived from hornblende and biotite gneisses 3 poor

Drainage 1 (somewhat) excessively drained 2 well drained 3 moderately well drained 4 imperfectly drained 5 (very) poorly drained

Effective soil depth 1 extremely deep 2 very deep 3 deep 4 moderately deep 5 shallow 6 very shallow

Inherent fertility high moderate 3 poor 4 very poor

Topsoil properties 0 non-humic 1 humic 2 thick humic la acid humic 2a thick acid humic

- 1.20 - District: Keiyo Marakwet Trial Site 13.1: Tot

Salinity 0 non-saline 1 slightly saline 2 saline

Sodicity 0 non-sodic 1 slightly sodic 2 sodic

Stoniness 0 non-stony 1 slightly stony 2 stony 3 very stony

- Rockiness 0 non-rocky 1 slightly rocky 2 rocky 3 very rocky

Consistency (moist) 1 half-ripe 2 loose 3 very friable 4 friable 5 firm 6 very firm

- Moisture storage capacity 1 very high 2 high 3 moderate 4 low

- Excess surface water 0 none 1 occasional 2 seasonal 3 permanent

3.1.2 Detailed Profile Description and Soil Classification

Detailed information on the various soil properties as they occur in the different horizons is given ,in Table 13.1.9. The location of the profile near the trial plot is shown in Figure 13.1.7.

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

1. Legend to the Soil Map of the World (FAO-Unesco, 1974), with adjustments according to the Kenya Concept (Siderius and van der Pouw, 1980): chromic Luvisol. saline-sodic phase.

2. USDA Soil Taxonomy (Soil Survey Staff, 1975): aquic Haplustalf. fine- clayey family .

- 1.21 - er

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- 1 .22 - District: Keiyo Marakwet Trial Site 13.1: Tot

3.1.3 Soil Sampling

Soil samples (profile, composite, pF rings) are listed in Sub-Section 3.2.

Figure 13.1.7 shows the location of the composite sampling blocks (I to VI) as well as the location of the profile pit.

J>2___jüo to {o »Qo

track' VI IV V 3 TTI II is "~ 148m. 3 Ki^ <0=> -fc I K£ i0=> *<=

Figure 13.1.7: Location of Composite Sampling Blocks and Profile Pit at the Tot K.V.D.A. Trial Plot

3.2 Laboratory Data

The soil samples from the profile and the composite samples from the various blocks of the main trial site and from the farmers' fields were analyzed in the laboratory. The results are compiled in Tables 13.1.10 and 13.1.11. The methodology applied for obtaining these results is described in detail in Chapter IV. 2 of the main report.

- 1.23 - District: Keyo Haraknet Trial Site: 13.1 Tot K.V.D.A.

Table 13.1.10 : Analytical Jtôults (physical and cheiical analysis, results on air dry soil basis) Profile Saiples froi Trial Site v

Horizon Depth Field Lab. ) 2 H. Sand Silt Clay Texture pH PH Diff. Cond. ci. No. No. Z Z I Z Class KCl H20 PH H20

1 Ah 0-13 13.1.1 3954/86 — 45 14 41 SC 5.1 6.0 0.9 0.4 2 BU 13-41 13.1.2 3955 — 35 8 57 C 4.1 5.9 1.8 0.3 3 Bt2 41-89 13.1.3 3956 — 31 10 59 C 4.7 6.2 1.5 0.6

4 Btk 89-120 13.1.4 3957 •- 29 14 57 C 6.4 7.1 0.7 1.6 5 6 Ah Control 13.1.5 3958 — 47 12 41 SC 5.2 6.3 1.1 0.4 7

Saturation Extract Na K Hg Ca Hn ECEC Bases AI Al H+Al Z Mater pH El.Cond. ie./100gi. AgTU— Z Z ie./100gi. KCl

NA NA NA 0.28 1.89 5.25 9.60 0.23 15.70 108.41 0.38 0.06 0.14 NA NA NA 0.47 1.39 6.00 9.20 0.23 16.70 102.16 1.08 0.18 0.46 NA NA NA 0.14 0.32 56.7 7.6 4.50 0.08 0.20

NA NA NA 0.06 0.14

'. 105 deg.C Na K Hg Ca CEC pH8.2 Bases Bases+Al AI Org. C N C/N f Olsen in rel.to —-—te ./lOOgi. Acetate Z ie./100gi Z Z Z ppi. air dry 1 0.38 0.92 2.45 3.60 19.50 37.69 7.41 0.81 0.85 0.13 6.5 0.96 2 0.65 1.38 3.39 5.00 24.30 42.88 10.60 1.70 0.47 0.07 6.7 0.93 3 0.87 1.32 2.43 4.70 20.80 44.81 9.46 1.48 0.31 0.06 5.2 0.93 4 2.00 1.88 5.75 14.20 25.50 93.45 23.91 0.33 0.31 0.05 6.2 0.92 5 6 0.43 1.27 3.71 4.30 19.50 49.79 9.77 0.61 0.89 0.13 6.8 0.96 7 8 0.00

Hoisture Retention Capacity Horizon Depth Vol.Z Hoisture Avail. Hoisture Bulk Dens CI. bar 0 1/10 1/3 5 15 Capacity gi./cc. PF 0 2 2.5 3.7 4.2 n./10ci. 105 deg.C

no saiples

NA = not applicable ie./100gi. : lilliequivalents per 100 gi. of soil AgTU : Silver Thio Urea Extraction Acetate : Bases by Anoniui Acetate of pH 7, CEC by Sodiui Acetate pH 8.2 pH and conductivity in suspension 1:2.5 v/v

- 1.24 - District: Keyo Harakwet Trial Site: 13.1 lot K.V.D.A.

fable 13.1.11 : Analytical Results (chemical analysis, results on air dry soil basis) Trial Site Composite Samples

Depth Bloch number X s Max. cm. I II III IV V VI VII diff.

! 1 Lab. No. /86 20 3896 3898 3900 3902 3904 3906 ! 2 50 3897 3899 3901 3903 3905 3907 ! 3 ! 4 Fine earth I 20 100 100 100 100 100 100 100 0.00 0.00 ! 5 50 100 100 100 100 100 100 100 0.00 0.00 ! é Vol.weight gi./cc. 20 1.18 1.15 1.14 1.10 1.11 1.11 1.13 0.03 0.08 ! 7 50 1.12 1.18 1.21 1.11 1.12 1.12 1.14 0.04 0.10 : 8 105 deg.C / air dry 20 0.96 0.94 0.93 0.94 0.95 0.95 0.95 0.01 0.03 r 9 50 0.94 0.93 0.93 0.92 0.93 0.93 0.93 0.01 0.02 ! 10 ! 11 pH H20 1/1 20 5.6 6.2 6.5 6.2 6.3 6.9 6.28 0.43 1.30 ! 12 50 5.6 6.4 6.5 6.4 6.5 6.9 6.38 0.43 1.30 ! 13 pH H20 1/2.5 20 6.2 6.8 7.6 7.3 6.9 7.4 7.03 0.51 1.40 ! 14 50 6.2 7.6 7.4 7.3 7.2 7.9 7.27 0.58 1.70 ! 15 pH N KCl 1/2.5 20 5.1 5.7 5.9 5.5 5.4 5.6 5.53 0.27 0.80 ! 16 50 4.3 5.9 5.9 5.7 5.4 6.1 5.55 0.66 1.80 ! 17 i ! 13 C org. Z 20 0.57 0.33 0.48 0.56 0.76 0.58 0.55 0.14 0.43 ! 20 N tot. : 20 0.08 0.05 0.08 0.09 0.13 0.07 0.08 0.03 0.08 ! 22 C/N 20 7 7 6 6 6 8 6.64 0.94 2.44 ! 24 ! 25 Mod.Olsen Abs. 260m 20 115 126 108 155 160 98 127.00 25.38 62.00 : 26 (1/1000) 50 70 104 97 116 110 52 91.50 25.11 64.00 ! 27 ! 25 S04 soluble ppm. 20 10 ! 26 50 9 ! 27 ! 28 P Meh.1/5 ppm. 20 12 12 14 14 14 12 13.00 1.10 2.00 ! 29 50 9 J4 14 14 14 14 13.17 2.04 5.00 ! 30 P Olsen ppn. 20 6.80 ! 31 50 6.80 ! 32 P mod.Olsen ppn. 20 5.50 2.80 2.30 3.30 4.00 2.00 3.32 1.29 3.50 ! 33 50 2.30 2.20 3.20 1.80 2.20 2.50 2.37 0.47 1.40 I 34 P Citric ac. ppm. 20 28 ! 35 50 21 ! 36 ! 37 ECEC AgTU me./100g». 20 13.9 15.7 ! 38 Bases Z 20 108.9 118.5 ! 39 A1Z 20 NA ; NA ! 40 1 ! 41 Hp BaCl2 me./100g«. 20 not applicable ! 42 50 not applicable ! 43 H & Al KCl me./lOOgm 20 not applicable ! 44 50 not applicable ! 45 Al 3- KCl me./lOOgm. 20 not applicable ! 46 50 not applicable ! 47 Al 3- AgTU me./100ga 20 not applicable ! 48 ! 49 Sat.Ext. Z H20 20 not applicable ! 50 50 not applicable ! 51 Sat.Ext. El.Cond. 20 not applicable ! 52 50 not applicable ! 53 Sat.Ext. pH 20 not applicable ! 54 50 not applicable ! 55

- 1.25 - con t.

District: Keyo Harakwet Triai Site: 13.1 Tot K.V.D.A.

Table 13.1.11 : Analytical Results (chemical analysis, results on air dry soil basis) Trial Site Coaposite Samples N

Depth Block number X s Hax. cm. 1 II III IV V VI VII diff.

1 1 'Lab. No. /86 20 3896 3898 3900 3902 3904 3906 ! 2 50 3897 3899 3901 3903 3905 3907 3 j 56 Na Hen.1/5 ae./100ga 20 0.60 1.04 1.00 0.67 0.64 1.04 0.83 0.22 0.44 ' 57 50 0.86 1.70 1.28 1.36 1.46 1.64 1.38 0.30 0.84 ! 53 Na Ag-TU «e./100gm. 20 0.32 0.53 0.43 0.15 0.21 59 ! 60 'K Heh.1/5 me./lOOgm. 20 1.20 1.20 0.86 1.08 1.04 0.96 1.06 0.13 0.34 61 50 0.78 1.00 0.70 0.86 0.92 0.56 0.80 0.16 0.44 ! 62 K mod.01. ae./lOOgo. 20 0.97 0.97 0.72 0.97 1.02 0.69 0.89 0.15 0.33 ! 63 50 0.77 0.77 0.67 0.72 0.77 0.38 0.68 0.15 0.38 i 64 !K Ag-TU aie./lOOga. 20 1.77 1.63 i 1.70 0.10 0.14 ! 65 ! 66 !Hg Heh.1/5 me./lOOga 20 4.60 5.00 5.30 5.40 ' 4.50 4.80 5.02 0.50 1.30 ' 67 50 4.20 5.80 4.90 6.20 4.60 5.40 5.18 0.75 2.00 ! 63 Hg sod.01. me./lOOga 20 5.84 6.99 7.57 7.57 6.17 6.34 6.75 0.74 1.73 69 50 6.75 6.50 7.16 7.90 7.74 6.67 7.12 0.59 1.40 ! 70 !Hg Ag-TU »e./lOOgm. 20 5.45 5.65 5.55 0.14 0.20 71 ! 72 Ca Heh.1/5 «e./lOOga 20 4.00 4.40 6.40 5.20 3.60 4.40 4.67 1.00 2.80 73 50 2.80 5.20 4.40 4.80 2.40 5.60 4.20 1.31 3.20 74 Ca nod.Ol. Be./lOOgm 20 5.00 10.00 13.00 12.00 8.00 10.00 9.67 2.88 8.00 75 50 6.00 11.00 14.00 13.00 10.00 13.00 11.17 2.93 8.00 76 Ca Ag-TU me./lOOga. 20 7.60 10.80 \ 9.20 2.26 3.20 77 78 Hn Heh.1/5 ne./iOOga 20 0.56 0.88 0.61 1.00 1.10 1.03 0.87 0.24 0.54 79 50 0.66 0.98 0.84 0.86 0.56 1.00 0.82 0.13 0.44 80 Hn nod.01. me./lOOgm 20 0.06 0.04 0.04 0.09 0.06 0.06 0.05 0.02 0.06 81 50 0.06 0.04 0.06 0.02 0.02 Trace 0.03 0.02 0.06 82 Hn Ag-TU ae./100gm. 20 0.57 0.22 0.40 0.25 0.35 83 84 In HCl pp«. 20 2.80 85 50 2.00 86 In tod. 01. ppo. 20 2.00 1.00 1.00 2.00 2.00 1.00 1.50 0.55 1.00 87 50 1.00 1.00 1.00 1.00 1.00 0.00 0.83 0.41 1.00 88 89 Cu HCl ppm. 20 1.00 90 50 1.50 91 , Cu sod. 01. pps. 20 1.00 1.00 1.00 2.00 1.00 2.00 1.33 0.52 1.00 92 50 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.00 0.00 93 ! 94 Fe HCl ppm. 20 29 95 ! 50 .21 96 Fe nod. Ol. ppœ. 20 115 50 20 55 95 75 68.33 34.01 95.00 97 ! 50 140 30 35 35 80 25 57.50 45.03 115.00 93 99 ! Fe Oxalate I 20 0.17 100 50 0.22 101 ! AI Oxalate I 20 0.90 102 , 50 0.90

HA : not applicable me./lOOgm. = oiilliequivalents per 100 gm. of soil Heh. ; Hehlich Analysis mod. Ol. : Hodified Olsen Extraction AgTU - Silver Thio Urea Extraction

- 1 .26 - District: Keiyo Marakwet Trial Site 13.1: Tot

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 other agencies. A complete list of soil survey reports is given in Chapter II.2 of the main report. Those reports that refer to the area in which the trial site is situated are listed below.

Literature references:

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

J.J. Vleeshouwer, and D.O. Michieka (1974). P17 Irrigation Suitability of the Soils and Waters of the Flood Plain of the Kerio River NE of Lokori (Turkana D.)

W. Siderius, (1975). P24 The Soils Resources of the Upper Kerio Valley - A Preliminary Investigation (with map, scale 1:100,000).

F.M. Muchena, and J.M. Kibe (1984). P75 The Soils of the Sangurur-Kapsowar-Chesoi Area (Elgeyo Marakwet District; with map, scale 1:50,000).

B.N. Ita, (1986). D40 Detailed Soil Survey of the K.V.D.A. Farm, Tot (Elgeyo Marakwet District; with map, scale 1:5,000).

In order to correlate existing information with findings at the trial site, the map units and classification units in the above-mentioned reports have been grouped in Table 13.1.13. Moreover, the FURP soil map unit (Map 13.0.4) and the classification of the soil of the profile at the trial plot are given.

- 1.27 - District: Keiyo Marakwet Trial Site 13.1: Tot

\ Table 13.1.13: Soil Correlation with Respect to the Tot K.V.D.A. Trial Site

Reference Map unit Soil Classification

El Pt 2 eutric Cambisols

P24 PAT dark reddish brown clay loam

P75 YX 1 eutric Cambisols and cambic Arenosols

D40 YX 1 chromic Cambisols, sodic and partly saline phase

eutric Cambisols and chromic FURP PtUl Luvisols, partly saline-sodic phase

Trial plot profile chromic LUVISOL, saline-sodic phase

The various sources indicate Arenosols and Cambisols. The profile, however, had clear features of clay illuviation and keys out as a Luvisol. Throughout the trial plot, the subsoil has an Electrical Conductivity >4 and an Exchangeable Sodium Percentage >6. These saline- sodic conditions are only recognized by detailed survey D40. Moreover, the trial site area is a sedimentary plain rather than a piedmont plain.

3.3.2 Representativeness

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

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

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

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

- 1.28 - District: Keiyo Marakwet Trial Site 13.1: Tot

Distinction is made between high representativeness - code A - and moderate representativeness - code B if soil conditions are slightly more favourable than at the trial site and code B- if soil conditions are slightly less favourable than at the trial site. Code C is applied for the remaining parts of the District, where none of the FURP trial sites are representative.

Within Keiyo Marakwet District, the Tot K.V.D.A. Trial Site has high to moderate representativeness (13.1.A/B-) for piedmont and sedimentary plains which have Cambisols and Luvisols that are just slightly saline and slightly sodic. It refers to soil map units YU1 and PtUl, in which the site is situated.

The Tot K.V.D.A. Trial Site is also representative of parts of sedimentary and piedmont plains of the Kerio River in Baringo and West Pokot Districts.

3.3.3 Variability of Soil Properties within the Trial Site

The trial plot Tot K.V.D.A. is not 100% uniform for the following reasons: 1--variability with respect to the degree of salinity and sodicity of the subsoil

2--variability with respect to nutrient availability in an irrigated and thus alternately aerobic/anaerobic environment

3--variability with respect to geogenesis and pedogenesis of piedmont plains and sedimentary plains in general.

Tables 13.1.10 and 13.1.11 show the soil test values at the trial plot. Exchangeable sodium (ESP, indicative for sodicity) appears to vary among the four composite sampling blocks.

In this Sub-Section, a breakdown is given for pH-KCl and organic carbon content of the upper 20 cm. of the soils. pH-KCl: profile pit: 5.1 composite samples: 5.1 (Block I) - 5.9 (Block III) organic carbon content : profile pit: 0.9% composite samples: 0.33% (Block II) - 0.76% (Block V)

3.3.4 Fertility Status of the Soil

The criteria applied for the interpretation of the analytical data are outlined 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 side of Block I (see Figure 13.1.7), are presented in Table 13.1\. 10 and are interpreted in the following paragraphs.

- 1.29 - District: Keiyo Marakwet Trial Site 13.1: Tot

The entire profile has a moderate CEC (pH 8.2) increasing with depth from 19 to 25 me./100 gm.. The base saturation increases with depth. It is moderate in the Ah and Bt horizons (35 - 40 %) and high in the Btk horizon (85 %). Clay and bases are leached from the upper horizons and accumulate to some extent in the (deeper) subsoil.

The exchangeable Na percentage (ESP) rises from 2 % in the Ah to 8 % in the Btk, and Na contributes less than 8 % of the exchangeable bases. These amounts are tolerated by almost all crops but have a negative effect on the structural stability of the soil and enhance deflocculation of clay. In all horizons, exchangeable K and Mg occupy very high portions of the exchange complex (>1, »2.5 me./100 gm.' respectively). The two methods used to extract exchangeable bases produced very different results. Mg and Ca were probably significantly underestimated in the'NH4-Acetate extract, whereas K analysed using silver-thiourea is too high when compared with the "available" nutrients in Block I.

The Ah horizon is strongly to moderately acid (pH KCl 5.1). There is a remarkable decrease of 1 pH (KCl) unit from this horizon to the underlying Btl, which is not shown by the pH in water. This is probably due to a sharp increase in (partly dispersed) fine clay, which will be a major source of exchangeable Al when more bases are leached and the soil pH decreases further. I

The Ah horizon is moderately humic (0.85 % C), whereas the organic matter content of the underlying soil is low (>0.5 % C). The N contents in the soil reflect the organic matter content and the C/N ratio is narrow. In the underlying soil below 40 cm., which is poor in humus, N is low. The topsoil composite samples of Blocks I and VI, which are close to the profile pit, show considerably lower C and N values than the profile; the reason for this probably being the sampling depth, which is 13 cm. in the profile and 20 cm. in the trial site composite samples. In the latter, the Ah and Btl material is mixed.

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 13.1.11. There are no farmers' fields around this trial site and therefore no Table 13.1.12.

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

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

- 1.30 - District: Keiyo tiarakwet Trial Site 13.1: Tot

The following interpretation of analytical data assumes that the nutrients found in the soil are accessible to plant roots, meaning that the roots may freely grow and penetrate the soil. This may, however, be doubted at the Tot Trial Site (see Chapter 4.3) and the true nutrient availability may be less than indicated by the soil tests, depending on the depth of the soil layer actually exploited by the roots.

The total N content of the on average slightly humic soils is low to medium (0.05 - 0.13 % N). The C/N ratios are medium to narrow in all samples and similar to those found in the profile. This and other prevailing soil conditions indicate that N availability is probably low to moderate. The UV absorption of the modified Olsen extract also indicates a low to moderate N supplying capacity of the soils.

In Block I of the trial site S04 solubility was found to be just above the critical level (<10 ppm.).

The "available" P, as determined by both methods (Mehlich analysis and modified Olsen method), is always in the low range. P availability is probably slightly inadequate to the N supplying capacity of the soil as indicated by the ratios of C/P (m.01.) and N/P (m.01.)., which are on average, 1600 and 300 respectively. These ratios are approximately eight times the optimum level for good crop performance.

The "available" quantities of K are constantly high or, in places, even very high. The "available" amounts of Mg and Ca are all in the high and very high range. Similar to the NH4-0-Ac exchangeable bases in the profile, the cations are adequately balanced with respect to plant nutrition, although the Mg/Ca ratio is rather narrow.

According to the Mehlich analysis, "available" Mn is in the sufficient range (<0.5 me./100 gm.), whereas the modified Olsen method shows only low Mn values.

According to the modified Olsen method, the micro-elements Zn and Cu are available in low amounts only and micro-element deficiencies may be expected in some places. In Block I of the trial site the HCl extractable Zn and Cu are at or below Che critical value.

The modified Olsen method extracted moderate to high amounts of Fe which vary in a wide range from 20 ppm. (Block III, topsoil) to 140 ppm. (Block I, subsoil). The Fe values are inversely related to the bases extracted by the same method, and particularly to Ca. The oxalate extraction for amorphous oxides and hydroxides yielded low amounts of Fe and low to moderate quantities of Al.

Almost all trial site composite samples are in the slightly acid range (pH KCl 5-6), which is favourable for the growth of most crops.

The evaluation of the Mehlich Analysis data according to NAL standards is given in Table 13.1.14.

- 1.31 - District: Keiyo Marakwet Trial Site 13.1: Tot

Table 13.1.14: Evaluation of the Mehlich Analysis Data According to NAL Standards

Parameter Trial Site Farmers' Fields

Soil reaction (pH) Moderately acid to slightly acid Acidity (Hp) Low

Available nutrients Sodium Adequate Potassium High Calcium Adequate Magnesium High Manganese Adequate Phosphorus Low

Total Nitrogen Very low Organic Carbon Very low

C / N Ratio Favourable Ca / Mg Ratio Favourable Ca / K Ratio Favourable \ K / Mg Ratio Favourable

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

3.4 Sampling Programme for Laboratory Analyses

3.4.1 Soil Samples

Soil samples will be collected once a year at the beginning of the long rains in March/April 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 only from the plots in Module 2 with maize/beans mixed cropping.

The treatments to be sampled are :

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

Trial II: 0 FYM 1 (2.5 t/ha) FYM 3 (7.5 t/ha) FYM 1 + P FYM 3 + P N + P FYM 1 + N + P

- 1.32 - District: Keiyo Marakwet Trial Site 13.1: Tot

3.4.2 Plant Samples

Harvest samples from the maize/beans mixed crop include individual samples of grain and straw from maize and beans respectively. Samples will be collected separately from each replication of the treatments where soil samples were collected, i.e.:

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

Trial II: 0 FYM 1 (2.5 t/ha) FYM 3 (7.5 t/ha) FYM 1 + P FYM 3 + P N + P FYM 1 + N + P

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 availability during the growing periods. Other parameters of the water balance such as moisture storage capacity, run-off, and deep percolation also have to be considered in order to obtain a comprehensive picture of the moisture availability.

For example, the water requirements and the water availability for Maize/Pwani, planted at the end of March at the Tot K.V.D.A. Trial Site, can be interpreted as follows : Figure 13.1.6 shows that the maximum water requirements (ETm) of the maize crop are not at all in line with the rainfall pattern at the 66% probability level.

Run-off is low. The trial site is located on almost flat land (slopes: <1%), and the maximum rainfall intensity in April/May is normally not very high. '(

•v. Deep percolation, lateral sub-surface flow and run-on could be estimated, but can be omitted, since they are low. There is some uncertainty that lateral sub-surface flow from the irrigation channels might bring additional water to the plots.

For the Tot K.V.D.A. Trial Site, the moisture storage capacity is rated moderate to high (i.e. 100-140 mm.), but there is no surplus water, which could be stored to extend the very short agro-humid periods.

Summarizing the evaluation of the climatic factors, the yield potential from the climatic point of view can, for the "non-irrigated" maize crop (planted at the end of March), be rated poor on a "20 out of 30 year" basis. With additional irrigation and the favourable temperature, however, \

- 1.33 - District: Keiyo Marakwet Trial Site 13.1: Tot

\ the potential for maize as well as for many other crops (especially vegetables) is good or even very good.

4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement

In all samples analyzed the N supplying capacity appeared low to moderate. S is similarly released from organic matter as N and the soil test carried out for Block I indicated a low SO« solubility. Therefore, a shortage of S might be feared in a good growing crop. P availability appears very low and inadequate to the expected N supply from the soil. K, Mg and Ca were extracted in appreciable amounts. A suspected shortage of the micro elements Zn and Cu will have to be verified by trials and Fe and B (not tested) should also be monitored.

The main rooting zone may hardly exceed the Ah horizon (depth 13 cm.) as root development is impeded by the compact Btl, the hampered drainage and the erratic air and moisture regime. This is a severe drawback on the accessibility of the nutrients for the soil. While the soil is waterlogged, the roots will not develop because of lack of air, or, in the opposite case, due to occasional water shortage in the topsoil, nutrients from either the soil or from fertilizers may not be used efficiently.

The poor physical conditions of the soil may be improved slowly but persistently by lay farming systems. The regular occurrence of selected deep rooting shrubs in the crop rotation may considerably deepen the soil volume exploited by crops and in this way enhance moisture and nutrient availability. Green manuring with appropriate lay crops is also an efficient N fertilizer. It is very likely, however, that roots will not exploit a deep soil volume as long as the topsoil offers a much richer environment than the subsoil following mineral fertilizer applications.

A high standard of ploughing and land preparation will be of particular importance at this site. Mulching is recommended to protect the soil surface from sealing, to reduce unproductive evaporation, and to enhance the development of a favourable soil structure.

Fertilizer applications should first of all consider the most relevant plant nutrients which include N, P, S and possibly micro-nutrients as well.

For sustained high yields regular N fertilization will probably be necessary, either from FYM or green manure or in mineral form. Mineral N should be supplemented with mulch and other organic amendments to raise the humus content of the soil over the present low level. Humus plays an essential role in stabilizing the soil structure, infiltration rate, soil aeration and moisture retention capacity and prevents applied nutrients from leaching too quickly.

When high rainfall occurs or when soil aeration is impeded due to inappropriate irrigation, N losses by denitrification may be very high and may exceed 50% of the applied N in a few days. Denitrification losses from N03 sources occur in greater amounts than from NH4 sources. For a more reliable estimate of the extent to which denitrification may occur, more precise data on soil moisture and air regime and its effects on N losses are required.

- 1.34 - District: Keiyo Marakwet Trial Site 13.1: Tot

N applications in whatever form should be supplemented by P. In most places P application will probably be necessary in order to obtain reasonable responses to N. P in the form of TSP or superphosphate will be superior to rock phosphate. Only in acid soils will rock phosphate be readily available to plants. The tendency of P to become unavailable by immediate fixation is probably low. The efficiency of P application may be enhanced by the addition of fresh FYM to stimulate soil biological activity.

Superphosphate contains about 12% S and therefore may act as two-element fertilizer. Under farmers' conditions this might be very useful when limited S availability is feared.

Liberal applications of N and P may induce or intensify deficiencies of micro-elements, notably Zn and Cu in this trial site.

K applications are not required at the present stage and response to K may not be obtained at first. Although the analytical data provide no infor mation on the reserves of K beyond the exchangeable pool, this should be sufficient to support high yields, at least for some years. However, the limited effective soil depth necessitates close monitoring of K avail ability and a K treatment should be introduced to the trial whenever signs of K impoverishment are observed.

Under the present soil conditions liming is not required at all and may even have detrimental effects on the availability of P and micro-elements. The acidifying effects of the applied mineral fertilizers will be sufficiently buffered by the soil and should not be counterbalanced in advance. I 4.3 Other Relevant Land Qualities

In addition to an assessment of moisture and nutrient availability, the following land qualities are relevant in the context of fertilizer use: a) Oxygen availability. This land quality is important for the Tot K.V.D.A. Trial Site. Excess water due to inappropriate irrigation can easily lead to temporarily impeded soil aeration, which jls a constraint to plant metabolism, notably at the crop emergence stage. Moreover, it is a major cause of low nitrogen fertilizer recovery. The predominantly low permeability of the soils (compacted Bt horizon) increases the risk of water logging. Improvement of topsoil structure by careful seed-bed preparation can alleviate this problem to some extent. b) Rootability. The soils provide a moderately suitable environment for root development and tuber expansion. The structure of the subsoil is coarse, angular blocky and porosity is low. In addition, bulk density, which is more or less inversely related to soil rootability, is high. Careful land preparation, yet again, is an important amelioration practice to increase the rootability of the topsoil.

- 1.35 - District: Keiyo Marakwet Trial Site 13.1: Tot

c) Resistance to erosion. Gully erosion plays a important role in the area around Tot. Run-off from the Cherangani Hills accumulates into torrential streams during periods of heavy rainfall, devastating pieces of land and further eroding existing gullies. The process is enhanced by a high livestock density in the area.

d) Ease of cultivation and scope for agricultural implements. Land preparation is rather demanding. Only the upper 10-15 cm are tilled without too strenuous efforts, but the lower layers are quite firm.

The scope for agricultural implements is good, as oxen and machines can cope with these soils, as long as the land is level. When the soil is wet, however, mechanical tillage can diminish the permeability and porosity of the soils of the trial plot further. i

5. Trial Design and Execution Plan, Tot K.V.D.A. (Full details of the methodology for carrying out-the trials are shown in Section IV. of the main report).

Selection of Crops. The proposed crop sequences in each of the 3 modules, in the Tot trial are :

I Site 13.1 Tot, K.V.D.A GROWING (RAINY) SEASONS Keiyo Marakwet. 1st, Long, March 2nd, Short, Oct.

51 Standard maize Coast Composite Fallow 52 Maize & beans C.C.+ Beans, GLP 1004 Fallow 53 Sorghum, ratooned Sorghum Seredo Fallow

The 1st sequence or module is continuous, pure maize, 1 once a year. The 2nd is intercropped maize and beans, also once a year. The 3rd is sorghum planted in the 1st 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 4 FYM factorial, also with 2 replications in each module.

Each module thus consists of 64 plots, and the total for the 3 modules is 192 plots.

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

- 1.36 - District: Keiyo Marakwet Trial Site 13.2: Bugar

Contents of Chapter 13.2:

Detailed Description of the Bugar Trial Site

Page

1. Geographical and Additional Technical Information 2.4 1.1 Final Position of the Trial Site 2.4 1.2 Sketch of the Trial Site 2.5 1.3 Physiography 2.7 1.4 Vegetation, Past and Present Land Use 2.8 1.5 Names and Addresses of Government Officers from the Division and Farmers Involved in FURP Activities 2.9

2. Climate 2.10 2.1 Prevailing Climatic Conditions 2.10 2.1.1 Agro-Climatic Classification of the Area Represented 2.10 2.1.2 Relevant Meteorological Data 2.11 2.1.3 Crop Suitability from the Climatic Point of View 2.16 2.2 Proposal for the Monitoring of Agro-Climatic Conditions in Phase II 2.20

3. Soils 2.21 3.1 Survey Data 2.21 3.1.1 Brief Soil Description and General Information on the Soil 2.21 3.1.2 Detailed Profile Description and Soil Classification 2.22 3.1.3 Soil Sampling 1 2.24 3.2 Laboratory Data 2.24 3.3 Evaluation of Soil Data 2.29 3.3.1 Literature References and Soil Correlation 2.29 3.3.2 Representativeness 2.30 3.3.3 Variability of Soil Properties within the Trial Site 2.30 3.3.4 Fertility Status of the Soil 2.31 3.3.4.1 Soil Profile and Global Fertility Rating 2.31 3.3.4.2 Soil Fertility Assessment of Composite Samples 2.32 3.4 Sampling Programme for Laboratory Analysis 2.34 3.4.1 Soil Samples ' 2.34 3.4.2 Plant Samples 2.35 3.4.3 Other Samples 2.35

4. Conclusions from the Analyses of Climate and Soils 2.35 4.1 Moisture Availability 2.35 4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement 2.36 4.3 Other Relevant Land Qualities 2.37

5. Trial Design and Execution Plan 2.38

- 2.1 - District: Keiyo Marakwet Trial Site 13.2: Bugar

\ List of Tables1)

Page

Table 13.2.1 Physiography of the Bugar Trial Site 2.7

Table 13.2.2 Vegetation, Past and Present Land Use 2.8

Table 13.2.3 Names and Addresses of the Divisional Staff Members and

Farmers at the Bugar Trial Site 2.9

Table 13.2.4a Data of the Nearest Long-Term Rainfall Station . 2.12

Table 13.2.4b Data of the Nearest Long-Term Rainfall Station 2.13 } Table 13.2.5 Temperature 2.14

Table 13.2.6 Potential Evaporation (Eo) 2.14

Table 13.2.7 Agro-Climatological Crop List for Bugar 2.16

Table 13.2.8 Crop Development Stages and Crop Coefficients 2.18

Table 13.2.9 Detailed Profile Description pf the Bugar Trial Plot 2.23 t Table 13.2.10 Analytical Results (physical and chemical analyses) 2.25

Table 13.2.11 Analytical Results (chemical analysis, trial plot) 2.26

Table 13.2.12 Analytical Results (chemical analysis, farmers' fields) 2.28

Table 13.2.13 Soil Correlation with Respect to the Bugar Trial Site 2.29

Table 13.2.14 Evaluation of Mehlich Analysis Data According to NAL Standards 2.34

1) See Footnote next page.

- 2.2 - District: Keiyo Marakwet Trial Site 13.2: Bugar

List of Figures1)

Page

Figure 13.2.1 Demarcation of the Bugar Trial Site 2.4

Figure 13.2.2 Access Map to the Bugar Trial Site 2.5

Figure 13.2.3 Map of the Trial Plot, Bugar 2.6

Figure 13.2.4 Location of Farmers' Fields for On-Farm Trials, Bugar 2.7

Figure 13.2.5 Rainfall and Potential Evaporation 2.15

Figure 13.2.6 Water Requirement and Availability for Maize H 625, First Rains 2.19 Figure 13.2.7 Location of Composite Sampling Blocks and Profile Pit at the Bugar Trial Plot 2.24

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

- 2.3 - District: Keiyo Marakwet Trial Site 13.2: Sugar

1. Geographical and Additional Technical Information

1.1 Final Position of the Trial Site

The position of the site at Bugar is shown in Figure 13.2.1, extracted from Map No. 90/3 - Tambach. Its UTM grid coordinates are E 80.2 and N 82.7. The elevation is 2320 m. Further details on the final position are shown in Figure 13.2.2 and the sketch map of the trial plot in Figure 13.2.3.

780 I 5'30'E IT'- 'Jum&uti elm

Figure 13.2.1: Demarcation of the Bugar Trial Site on the 1:50,000 Topographic Map

- 2.4 - District: Keiyo Marakwet Trial Site 13.2: Bugar

1.2 Sketch of the Trial Site.

The location of and the access route to the Bugar site are shown in Figure 13.2.2 and the map of the trial plot in Figure 13.2.3. 1

a Elgeyo Forest a Station

0.5 1.5 2.5Km

Figure 13.2.2: Access Map of the Trial Site, Bugar

- 2.5 - District: Keiyo Marakwet Trial Site 13.2: Bugar

30 «)

Figure 13.2.3: Map of the Trial Plot, Bugar

- 2.6 - District : Keiyo Marakwet Trial Site 13.2: Bugar

The approximate location of the on-farm trials is indicated in Figure 13.2.4.

ajor dust road

Figure 13.2.4: Location of Farmers' Fields for On-Farm Trials, Bugar

1.3 Physiography

Information on the physiography of the trial site and its surroundings is summarized in Table 13.2.1 below.

Table 13.2.1: Physiography of the Bugar Trial Site

Elevation 2320 m.

Landform high-level plateau

Physiographic position of the site slightly concave middle slope

Topography of surrounding country gently undulating to undu lating (slopes 2-8%)

Slope on which trial plot is sited 3-4%

Aspect W

Microtopography nil

- 2.7 District: Keiyo Marakwet Trial Site 13.2: Bugar

1.4 Vegetation, Past and Present Land Use

Information on vegetation and on past and present land use is summarized in Table 13.2.2 below:

Table 13.2.2: Vegetation, Past and Present Land Use of the Bugar Trial Site

Vegetation Podo and moist Cedar grassland

Cropping system

(a) cleared since: 1965 (b) crops grown: wheat, maize, maize/beans (c) fallow periods: none (d) present land use: maize (2/3), wheat (1/3)

Inputs

(a) mineral fertilizers: DAP or 20:20:0 and CAN (b) organic manure: not applied (c) means of land preparation: tractor (d) means of weeding: manual (e) frequency of weeding: twice per crop stand (f) other capital inputs: none (g) level of know-how: moderate

Produce

(a) maize 60 bags/acre (! ) (90 kg bags) (b) wheat 35-40 bags/acre

Livestock 14 cows; sheep, goats

Remarks

Fertilizer application: DAP and CAN are mixed and applied at planting.

- 2.8 - District: Keiyo Marakwet Trial Site 13.2: Bugar

1.5 Names and Addresses of Government Officers Involved in FURP Activities

Names and addresses of the divisional staff members and of all farmers involved are given in Table 13.2.3. The codes used for the additional "on-farm" farmers refer to the location of their farms as indicated in Figure 13.2.4.

Table 13.2.3: Names and Addresses of Divisional Staff Members and Farmers of the Bugar Trial Site

Divisional Name Address Staff

D.E.O. E. Chibole Box 249, Iten L.E.O. not met T.A. Mr. Rutto Box 249, Iten

Farmers Name Address

Trial plot Kimais Changwany Box 300, Iten

LOCATION : Kapchemtua SUB-LOCATION: Bugar

On-Farm trials Name Remarks

i 13.2.A Daniel T. Sawel 13.2.B John Chelimo 13.2.C Chelal Chepkieng 13.2.D Francis Kwambai 13.2.E Kilemen Kiplagat upper part 13.2.F Kangoko Kipkorir 13.2.G Alois Limo 13.2.H Paul Kiptoo ! Period of site selection: March 1986.

- 2.9 - District: Keiyo Marakwet Trial Site 13.2: Bugar

2. Climate

2.1 Prevailing Climatic Conditions

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

The following brief climatic description refers to the existing information:

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

AEZ : LH 2-(3), (vl/l)i or two (R. JÄTZOLD, 1983)2)

Next long-term rainfall stations: 08935106, Elgéyo Forest Station, and 08935064, Kapkaboi Karuna Farm.

Agro-Climatic Zone (ACZ):

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

Temperature Zone 5: annual mean temperature is 16-18°C. i Agro-Ecological Zone (AEZ):

LH 2 = (Wheat)/Maize - Pyrethrum Zone

LH «= Lower Highland Zone: annual mean temperature is 15-18°C, mean minimum 8-ll°C

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

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

(vl/1) i or two = with a (weak) very long to long cropping season, which can be divided 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, scale 1:1,000,000 - Rep. El, Nairobi

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

- 2.10 - District: Keiyo Marakwet Trial Site 13.2: Bugar

Formula Cropping season Lengths of growing period (exceeded in 6 out of 10 years) vl/1 very long to long 235-284 days

( ) = weak performance of growing period (most decades less than 0.8 Eo);

i = intermediate rains (at least 5 decades more than 0.2 Eo), which means moisture conditions are above wilting point for most crops.

2.1.2 Relevant Meteorological Data for the Bugar 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: 08935106, Elgeyo Forest Station (elevation: 2340 m), 1.5 km NE of the trial site (elevation: 2320 m), and 08935064, Kapkaboi Karuna Farm (elevation: 2220 m), 3.5 km WSW of the Bugar Trial Site. The data are listed in Tables 13.2.4a and 13.2.4b. At the trial site, rainfall amounts are slightly less than at Elgeyo Forest Station. In 20 out of 30 years Bugar gets more than 700 mm during the agro-humid period of the first and middle rains (March - September). The methods of rainfall data analysis are described in Chapter IV.2.2 of the main report.

Temperature and potential evaporation(Eo):

Temperature data are obtained from temperature recording station 08935133, Eldoret Experimental Farm (elevation: 2140 m, recorded period: 1961-1968), 30 km SW of the trial site (elevation: 2320 m). The temperature gradient in this area is on average 0.6°C. 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 Teachers' College Meteorological Station (elevation: 2140 m), 30 km SW of the trial site.

Temperature and evaporation data for the Bugar site are given in Tables 13.2.5 and 13.2.6, and the rainfall pattern and potential evaporation are shown in Figure 13.2.5.

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

- 2.11 - Table 13.2.4a : Data of the Nearest Long-Term Rainfall Station Station No.: 08935106 Total years for calculation: 25 Elgeyo Forest St. First year included: 1961 Elevation: 2340 m Last year included: 1985

Average annual rainfall: 1383 mm

Rainfall surpassed in 20 out of 30 years (=66% Probability): 1st rains: 790 mm 2nd rains: 250 mm (mid Mar. - end of Sep.) (beg. of Oct. - beg. of Dec.)

Decades Arithmetic Average Number of Rainy z66% Probabi Years and Mean Days with Rainfall I lity of ex anal- Month (mm) >= 1 mm >= 5 mm ceeding . . .mm ized 1 JAN 5.8 0.9 0.9 0.9 25 2 7.5 1 .1 1 .0 0.9 25 3 23.2 2.2 2.2 5.8 25 4 FEB 16.2 1 .9 1 .8 7.2 23 5 20.5 2. 1 2.0 9.6 23 6 21 .5 1 .9 1 .8 4.3 23 7 MAR 16.9 1 .9 1.? 8. 1 24 8 37.4 3.0 2.9 21 .0 24 9 44.8 3.8 3.8 24.8 24 10 APR 58.0 4.8 4.8 41 .9 24 1 1 85.2 6.0 5.9 60.4 24 12 71 . 1 4.8 4.7 47.5 24 13 MAY 89.2 5.9 5.8 63. 1 25 14 73.2 5.5 5.4 51 .2 25 15 38.5 3.6 3.5 23. 1 25 16 JUN 22.4 2.6 2.5 15.5 24 17 25.4 2.6 2.5 17.0 24 18 31 .6 3.5 3.5 18.7 24 19 JUL 45.8 4.2 4.1 29.6 25 20 36.5 3.9 3.8 23.4 25 21 46.2 4.5 4.5 31 .2 25 22 AUG 56.8 5.3 5.2 42.8 25 23 40.8 4.0 3.9 29.7 25 24 34.3 3.5 3.5 21 .3 25 25 SEP 35.5 2.8 2.8 21 .2 24 26 20.6 2.5 2.5 10.7 24 27 18.4 2.0 1 .9 10.5 24 28 OCT 23.0 3.4 3.3 13.4 25 29 45.9 4.1 4. 1 27.2 25 30 54.9 5.5 5.5 35.9 25 31 NOV 59.8 4.5 4.5 40.1 23 32 56.5 3.8 3.8 31 .4 23 33 49.5 3.3 3.3 25.0 23 34 DEC 37.5 2.8 2.8 15.6 24 35 18. 1 1 .8 1 .8 6.5 24 36 14.3 1 .3 1 .3 7.2 24

- 2.12 - Table 13.2.4b : Data of the Nearest Long-Term Rainfall Station Station No.: 08935064 Total years for calculation: 19 Kapkaboi, Karuna Farm First year included: 1961 Elevation: 2220 m Last year included: 1981

Average annual rainfall: 954 mm

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

1st rains: 600 mm 2nd rains: 110 mm (mid Mar. - end of Sept.) (beg. of Oct. - end of Nov.)

Decades Arithmetic Average Number of Rainy 266% Probabi Years and Mean Days with Rainfall lity of ex anal- Month (mm ) >= 1 mm >= 5 mm ceeding . . .mm ized

1 JAN 7.9 0.7 0,7 2.1 18 2 8.9 0.7 0.6 0.1 18 3 13.2 1 .4 1 .4 4.0 18 4 FEB 7.8 1 .0 7.0 0.1 18 5 9.3 1 .1 1 .1 2.2 18 6 17.4 1 .4 •1 .4 0.0 18 7 MAR 18.9 1 .5 1 .5 10.6 19 8 22.9 2.0 2.0 12.1 19 9 29.4 2. 5 2.5 14.8 19 10 APR 48.0 3.2 3.2 25.2 17 1 1 62.8 4. 1 4.1 44.3 17 12 58.7 ) 3.5 3.5 39.0 17 13 MAY 57.9 ' 4.1 4.1 36.3 18 14 29.9 3. 1 3.1 21 .3 18 15 18.0 2.2 2.2 11.7 18 16 JUN 14.4 1 .4 1 .4 5.5 19 17 20.2 2.3 2.3 13.4 19 18 26.9 3.0 3.0 15.4 19 19 JUL 50.0 3.5 3.5 35.9 18 20 37.9 3.0 3.0 23.3 18 21 39.1 4.0 4.0 27.7 18 22 AUG 46.6 3.6 3.6 33.6 18 23 30.0 3. 1 3.1 21 .2 18 24 31 .4 3.0 3.0 19.8 18 25 SEP 25.2 2.4 2.4 14.2 18 26 15.9 2.2 2.1 8.8 18 27 8.9 1 . 1 1 .0 4.6 18 28 OCT 16.5 2. 1 2.1 8.7 17 29 23.9 2.3 2.3 13.2 17 30 26.1 3.1 3.0 14.8 17 31 NOV 24.4 2.5 2.5 9.3 17 32 32.6 2.2 2.2 10.8 17 33 38.7 2.4 2.4 17.5 17 34 DEC 12.1 1 .2 .1 .2 0.5 18 35 13.8 1 .4 1 .4 7.5 18 36 8.3 1 .0 1 .0 3.6 18 \

- 2.13 - District: Keiyo Marakwet Trial Site 13.2: Bugar

Table 13.2.5: Temperature ( 'C)

JAN. FEB. MAR. APR. MAY JUN.

Mean temp. 15.0 15.1 15.6 15.5 14.8 14.2 Mean max.temp. 22.6 22.9 23.1 21.5 21.1 20.6 Mean min.temp. 7.4 7.2 8.1 9.5 8.4 6.7

JUL. AUG. SEPT. OCT. NOV. DEC. f Mean temp. 14.4 13.5 13.7 14.9 15.0 14.5 Mean max.temp. 19.3 19.9 21.1 21.2 20.6 20.9 Mean min.temp. 7.4 7.1 6.2 8.6 9.3 8.0

annual mean : 14.5 mean max : 21.2 mean min. : 7.8

Table 13.2.6: Potential Evaporation (Eo) in mm per Decade :

JAN. FEB. MAR. APR. MAY JUN.

1st decade 51 56 56 50 37 30 2nd decade 51 56 56 50 37 30 3rd decade 56 45 62 50 41 30 Total : 158 157 174 150 115 90

JUL. AUG. SEPT. OCT. NOV. DEC.

1st decade 28 30 37 46 46 49 2nd decade 28 30 37 46 46 49 3rd decade 31 33 37 51 46 54 Total : 87 93 111 143 138 152

average annuoi. 1 potenti al evaporation: 1568 mm.

For all the climatic data published in this section, a data bank has been established by FURP on Personal Computers at the National Agricultural Laboratories in Nairobi.

- 2.14 - c o •*->

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- 2.15 - District: Keiyo Harakwet Trial Site 13.2: Bugar

2.1.3 Crop Suitability from the Climatic Point of View

A summary of the agro-climatic suitability of the most important seasonal food crops is given in Table 13.2.7 below. Additional information on other crops considered suitable from the agro-climatic viewpoint, is given in the Farm Management Handbook, Vol. II/B, Central Kenya1).

Table 13.2.7: Agro-Climatological Crop List for Bugar

Crop/variety Av.No.of Altitudes2) Requirem.of Yield (or place of days to according well distri potential ace. breeding) physiol. to growing buted rain to water avai e = early maturity period fall 3) in lability *) m = medium On.) grow.period a = 1st rains 1 = late (mm. ) b = 2nd rains

Maize/1.mat. 170-200 1500-2100 600-950 a) good like H 625 (Mar.- Nov.)

Maize/1.mat. 160-180 1500-2100 600-950 a) good like H 613 (Mar.- Oct.)

Barley/ i b) good/fair m. mat. 120-140 2100-2400 400-600 (Jun.- Oct.)

Garden Peas a) good like meteor 90-130 1800-2700 250-400 b) fair (Jun.- Sep.)

Potatoes/ 140-170 1800-2900 450-750 good m.mat. (Mar.- Jul.)

1) R. JÄTZ0LD and H. SCHMIDT, eds.(1983): Farm Management Handbook of Kenya, Vol. II/B, Central Kenya - Nairobi and Trier.

3) Lower figure for fair results, higher for very good results with some corrections due to rainfall distribution, evaporation and run-off losses.

4) Estimated yield potential: very good >80%, good = 60-80%, fair = 40-60% and poor <40% of the expected yield under optimum water availability, adapted from R. JÄTZ0LD and H. SCHMIDT, eds. (1982): Farm Management Handbook of Kenya, Vol. II/A, West Kenya.

- 2.16 - District: Keiyo Marakwet Trial Site 13.2: Sugar

For the most important food crops in the area around the Bugar Trial Site, the crop coefficients (kc) are shown in Table 13.2.8, differentiated according to decades (10 day periods) of the growing season which is the time between planting or sowing and the physiological maturity. Furthermore, four crop development stages are distinguished in Table 13.2.8.

The crop coefficients for the climatic conditions at the Bugar Trial Site were estimated on the basis of data obtained from D00RENB0S and PRUITT (1977)1) and D00RENB0S and KASSAM (1979)2).

The data on the duration of each of the growing seasons and on the various development stages of each crop were assessed on the basis of local observations made under average climatic conditions.

ETm = kc * Eo whereby: ETm= maximum (potential) évapotranspiration kc = crop coefficient Eo = potential evaporation (climatic evaporative demand)

In Figure 13.2.6 the ETm-values are used to indicate the estimated maximum water requirements of the maize crop for optimum growth. Furthermore, the rainfall data at 66% reliability are shown in Figure 13.2.6 give an indication of the water availability. However, when reading these figures, it must be borne in mind that the actual availability of water for the plants also depends, to a large degree, on factors such as the run-off, the moisture storage capacity of the soil, the deep percolation of water etc.

The placement of the growing seasons of the various crops on the time axis as presented in Figure 13.2.6 was mainly based on the pattern of rainfall, whereby the peak water requirements of the plants should be met by high, reliable rainfall. ' i Detailed information on the calculation procedures and references are given in Chapter IV.2.2 of the main report. The interpretation of the diagram mentioned above follows in Section 4 of this Volume (Conclusions from the Analyses of Climate and Soils).

1) FAO (1977): Crop Water Requirements - (- Irrigation and Drainage Paper, 24), Rome

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

- 2.17 - I S3

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~~- 2.19 - District: Keiyo Marakwet Trial Site 13.2: Bugar~~

~~2.2 Proposal for the Monitoring of Agro-Climatic Conditions in Phase II~~

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

~~1) Rainfall records:~~

A rain gauge has to be installed at the Bugar Trial Site to measure actual precipitation on the spot. Subsequently, the data can be compared with both rainfall for a particular year and the long-term average from the nearest rainfall recording stations of the Meteorological Department: 08935106, Elgeyo Forest Station, and 08935064, Kapkaboi Karuna Farm. The latter, however, made no recordings during the period u.984-86.

~~2) Records on other relevant meteorological paraim>ters:~~

Temperatures and relative humidity have to be recorded at the trial site. Consequently, minimum and maximum thermometers as well as dry and wet bulb thermometers have to be installed in a weather hut at the trial plot. Additionally the minimum grass temperature should be recorded. Data on windrun and sunshine hours can be obtained from the Moi Teachers' College Meteorological Station: 08935133, (elevation: 2140 m), in order to calc ulate Eo (climatic evaporative demand). >

~~3) Phenological records:~~

Dates of planting or sowing of each crop, emergence, start of tasselling (for maize crop), budding (for bean or pea crop), flowering, ripeness or physiological maturity and harvest have to be recorded. Additionally the leaf area index (LAI) has to be determined every week (at least for the cereal crops) in order to provide a sound basis for water balance calculations. Other important features should also be recorded, above all rolling and wilting leaves, which indicate water stress and wilting point respectively before physiological maturity has been reached.

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

~~For most of the data to be recorded, official forms from the Meteorological Department are available.~~

~~Detailed information on calculation procedures, as proposed for the monitoring of agro-climatic conditions, is given in Chapter IV.2.2 of the main report.~~

~~- 2.20 - • District: Keiyo Marakwet Trial Site 13.2: Bugar~~

~~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 a rating of relevant soil-related land factors. The classes for these factors have been adapted from Andriesse and van der Pouw (1985), and a key for them is to be found in Chapter IV.2.3 of the main report.

~~Brief soil description~~

The soils are very deep to extremely deep, dark red to dusky red in colour, and consist of friable clay. The topsoil is acid humic and about 30 cm thick. Soil structure is weak, sub-angular blocky, and a high bioporosity is prevalent.

~~Rating of soil-related land factors~~

~~- Parent rock 1 rich 2 moderately rich: intermediate igneous rocks 3 poor~~

~~- Drainage 1 (somewhat) excessively drained 2 well drained 3 moderately well drained 4 imperfectly drained 5 (very) poorly drained~~

~~- Effective soil depth 1 extremely deep to 2 very deep 3 deep 4 moderately deep 5 shallow 6 very shallow~~

~~- Inherent fertility high moderate 3 poor 4 very poor~~

~~Topsoil properties 0 non-humic 1 humic 2 thick humic la acid humic 2a thick acid humic~~

~~- 2.21 - District: Keiyo Marakwet Trial Site 13.2: Bugar~~

~~Salinity 0 non-saline 1 slightly saline 2 saline~~

~~- Sodicity 0 non-sodic 1 slightly sodic 2 sodic~~

~~Stoniness 0 non-stony 1 slightly stony 2 stony 3 very stony~~

~~Rockiness 0 non-rocky 1 slightly rocky 2 rocky I 3 very rocky~~

~~Consistency (moist) 1 half-ripe 2 loose 3 very friable 4 friable 5 firm 6 very firm~~

~~- Moisture storage capacity 1 very high 2 high 3 moderate 4 low~~

~~Excess surface water 0 none 1 occasional 2 seasonal 3 permanent~~

~~3.1.2 Detailed Profile Description and Soil Classification~~

~~Detailed information on the various soil properties as they occur in the different horizons is given in Table 13.2.9. The location of the profile near the trial plot is shown in Figure 13.2.7.~~

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

~~1. Legend to the Soil Map of the World (FAO-Unesco, 1974), with adjustments according to the Kenya Concept (Siderius and van der Pouw, 1980): humic Nitisol.~~

~~2. USDA Soil Taxonomy (Soil Survey Staff, 1975): orthoxic Palehumult. very fine-clayey family.~~

~~- 2.22 - *%~~

~~s- 5e?~~

~~I O I o eu JBTUJ —4 O OQ .—< o to III •s sca 3a- • •-3 co o. -r-4 ca cOo-~~

~~&&&.B IIP HI* 111 till life UB nil nil IJlt iî^ 135~~

~~1 s .3 g ^ a5 'S CS* »'S fcO 04-M ' e. 3 a» 5p 1~~

~~S& 13 .J I Î1 fl S ..,~~

~~2â '-s «Nes eu • i Ü COO» .r-1 3 5 ,|f~~

~~C^3 III CO~~

~~- 2.23 - District: Keiyo Harakwet Trial Site 13.2: Bugar~~

3.1.3 Soil Sampling ( file composlte farmers fieids sut-s::tfor3 r ' • ' > * ^^ «• ***« m Figure 13.2.7 shows the location of the composite sampling Blocks (I to VTÏ as well as the location of the profile pit. C }

~~track~~

~~iwpil BT-—" ~~~~

~~IV III Remark: Block I and IV are outside the trial plot. I II Ä ,_*_ profile ____- 1 pit V VI~~

~~So«] m J~~

~~« * H~~

~~Figure 13.2.7; Location of Composite Sampling Blocks and Profile Pit at the Bugar Trial Plot~~

~~3.2 Laboratory Data~~

The soil samples from the profile and the composite samples from the various blocks of the main trial site and from the farmers' fields were U 2y!2 ÎLt«tîa^at0ry- J*6 reSUltS a" COm*iled in Tables Ï3 2"S to ,.2, 2: T^e »fthodology applied for obtaining these results is described in detaiil in Chapter IV.2 of the main report. described

~~- 2.24 - District: Keyo Harakwet Trial Site: 13.2~~

~~Table 13.2.10 : Analytical Results (physical and cheiical analysis, results on air dry soil basis) Profile Saiples fro» Trial Site~~

~~Horizon Depth Field Lab. > 2 II. Sand Silt Clay Texture PH pH Diff. Cond. CI. No. No. Z X Z Z Class KCl H20 pH H20~~

1 Ah 0-20 13.2.1 3959/86 — 15 16 69 C 4.0 5.2 1.2 0.20 2 AB 20-35 13.2.2 3960 ~ 15 18 67 C 4.2 5.2 1.0 0.10 3 Btl 35-57 13.2.3 3961 ~ 15 14 71 C 4.1 5.4 1.3 0.06 4 Bt2 57-96 13.2.4 3962 — 13 14 73 C 4.0 5.4 1.4 0.03 5 Bt3 96-130 13.2.5 3963 "~ 13 12 75 C 4.0 4.9 0.9 0.06 6 7 Ah Control 13.2.6 3964 15 16 69 3.9 4.8 0.9 0.18

~~Saturation Extract Na K Ng Ca Hn ECEC Bases Al Al H+Al Z Mater pH El.Cond. —le./lOOgi. AgTU- Z Z le./lOOgi. KCl~~

~~NA NA NA 1.50 2.10 4.80 1.12 12.0 70.7 6.33 0.76 1.44 NA NA NA 08 0.64 2.55 5.00 0.64 10.6 78.0 5.66 0.60 0.90 NA NA NA 0.90 1.38 NA NA NA 1-.56 2.16 NA NA NA 1:50 2.24~~

~~NA NA NA 0.88 1.50~~

~~105 deg.C Na Hg Ca CEC pH8.2 Bases Bases+Al Al O«. C N C/NP Olsen in rel. to -ie./100gi. Acetate Z ie./100gi Z Z Z ppi. air dry~~

0.10 1.34 1.47 2.30 24.50 21.27 5.97 12.73 1.93 0.19 10.2 0.94 0.12 0.86 2.11 3.20 22.50 27.96 6.89 8.71 1.54 0.16 9.6 0.93 0.11 0.62 2.00 2.30 20.30 24.78 5.93 15.18 1.30 0.14 9.3 0.93 0.05 0.55 1.23 1.40 21.80 14.82 4.79 32.57 1.13 0.16 7.1 0.93 0.08 0.54 1.23 1.40 20.50 15.85 4.75 31.58 0.76 0.15 5.1 0.93

~~0.04 0.90 1.15 1.80 20.30 19.16 4.77 18.45 1.97 0.22 8.95 0.93~~

Moisture Retention Capacity Horizon Depth Vol.Z Moisture Avail. Moisture Bulk Dens Cl. bar 0 '1/10 1/3 5 15 Capacity gi./cc. pF 0 ' 2 2.5 3.7 4.2 ii./lOci. 105 deg.C •9 1 AB 20-25 53.6 43.6 40.1 28.5 26.6 16.0 1.06 2 Bt2 60-65 52.1 44.8 38.8 27.9 26.0 18.1 1.04 3 4

NA : not applicable •e./100gi. : lilliequivalents per 100 gi. of soil AgTU : Silver Thio Urea Extraction Acetate = Bases by Anoniui Acetate pH 7, CEC by Sodiui Acetate pH 8.2 pH and conductivity in suspension 1:2.5 v/v

~~- 2.25 - District: Keyo Harakwet Trial Site: 13.2 Sugar~~

~~Table 13.2.11 : Analytical Results (chemical analysis, results on air dry soil basis) Trial Site Composite Samples~~

~~Depth Block nunber X s Max. en. I II III IV V VI VII \ diff.~~

! 1 Lab. No. /86 20 3908 3910 3912 3914 3916 3918 ! 2 50 3909 3911 3913 3915 3917 3919 ! 3 ,' 4 Fine earth HI 20 100 100 100 100 100 100 100 0.00 0.00 ! 5 50 100 too 100 100 too too 100 0.00 0.00 ! 6 Vol.weight gn./cc 20 1.02 1.02 0.99 1.03 1.00 t.00 1.0t 0.02 0.04 ! 7 50 0.98 0.98 0.99 0.98 1.02 1.03 1.00 0.02 0.05 ! 8 105 deg.C / air dry 20 0.93 0.93 0.94 0.93 0.93 0.94 0.93 0.01 0.01 ! 9 50 0.93 0.93 0.93 0.93 0.94 0.94 0.93 o.of 0.01 ! 10 ! 11 pH H20 1/1 20 5.2 5.3 5.2 5.4 5.3 5.2 5.27 0.08 0.20 ! 12 50 5.4 5.6 5.5 5.6 5.2 5.3 5.43 0.16 0.40 ! 13 pH H20 1/2.5 20 5.8 6.0 5.9 5.8 6.0 6.8 6.05 0.38 1.00 ! H 50 5.9 6.0 5.9 6.0 , 5.8 6.3 5.98 0.17 0.50 : i5 pH N KCl 1/2.5 20 4.4 4.5 4.4 4.3 '• 4.4 5.0 4.50 0.25 0.70 1 : i6 50 4.5 4.5 4.5 4.5 4.4 4.8 4.53 0.14 0.40 ! 17 ! 18 C org. % 20 1.79 1.85 1.81 2.09 1.87 1.94 1.89 0.11 0.30 : i9 N tot. X 20 0.18 0.20 0.21 0.23 0.24 0.26 0.22 0.03 0.08 ! 20 C/N 20 10 9 9 9 8 7 8.69 0.93 2.48 : 21 ! 22 Hod.Olsen Abs. 260nn 20 136 122 122 136 136 142 132.33 8.33 20.00 ! 23 (1/1000) 50 82 75 75 73 128 12t 92.33 25.20 55.00 ! 24 ; ! 25 S04 soluble 20 3 ' 26 50 2 127 ' 28 PHeh.1/5ppn. 20 9 6 44 9 12 12 15.33 14.22 38.00 29 50 12 9 9 12 12 9 10.50 1.64 3.00 30 P Olsen ppn. 20 31 50 ' 32 P nod.Olsen ppn. 20 2.90 2.30 1.90 1.30 3.30 1.30 2.17 0.83 2.00 33 50 1.20 0.60 Trace Trace 0.50 0.10 0.40 0.47 1.20 34 P Citric ac. ppn. 20 10 1 35 50 10 4fi 36 37 ECEC AgTU ne./100gn. 20 10.60 11.60 ! 38 Bases X 20 80.38 77.93 ' 39 A1X 20 7.92 5.52 ! 40 ! 41 Hp BaC12 ne./100gn. 20 .0.40 0.40 0.20 0.20 0.40 0.30 0.32 0.10 0.20 ! 42 50 0.40 0.40 0.40 0.20 0.35 0.10 0.20 ! 43 H i AI KCl ne./100gn 20 1.16 0.80 0.96 0.94 1.60 1.00 t.08 0.28 0.80 ! 44 50 1.08 0.78 0.72 0.76 0.84 0.17 0.36 ! 45 Al 3- KCl ne./IOOgn. 20 0.84 0.64 0.80 0.76 0.84 0.70 0.76 0.08 0.20 ! 46 50 0.84 0.52 0.52 0.54 0.61 0.16 0.32 ! 47 Al 3- AgTU ne./100gn 20 ! 48 ! 49 Sat.Ext. % H20 20 not applicable ! 50 50 not applicable ! 51 Sat.Ext. El.Cond. 20 not applicable ! 52 50 not applicable ! 53 Sat.Ext. pH 20 not applicable ! 54 50 not applicable ;1 5te5 District: Keyo Marakwet Trial Site: 13.2 Bugar

~~Table 13.2.11 : Analytical Results (chemical analysis, results on air dry soil basis) Trial Site Composite Samples~~

~~Depth Block number X S Max. cm. I II III IV V VI VII diff.~~

: i Lab. Mo. /86 20 3908 3910 3912 3914 3916 3918 ! 2 50 3909 3911 3913 3915 3917 3919 ! 3 ! 56 Ha Melt. 1/5 me./IOOgm 20 0.10 0.14 0.10 0.07 0.14 0.14 0.12 0.03 0.07 ! 57 50 0.07 0.14 0.10 0.10 0.10 0.10 0.10 0.02 0.07 ! 58 Na Ag-TU me./IOOgm. 20 0.06 0.08 1 59 ! 60 KMeh. 1/5 me./IOOgm. 20 0.96 1.12 0.92 0.78 1.08 1.00 0.98 0.12 0.34 I 61 50 0.52 0.74 0.74 0.50 0.78 0.82 0.68 0.14 0.32 : 62 K mod.01. me./IOOgm. 20 1.15 1.26 1.26 0.88 1.15 0.93 1.11 0.16 0.38 : 63 50 0.63 0.66 0.75 0.46 0.69 0.89 0.68 0.14 0.43 : 64 K Ag-TU me./IOOgm. 20 1.21 1.41 : 65 ! 66 MgMeh. 1/5 me./IOOgm 20 2.30 2.30 2.20 2.30 2.50 2.10 2.28 0.13 0.40 : 67 50 2.30 2.50 2.80 2.00 2.80 2.50 2.48 0.31 0.80 : 6e Mg mod.01. me./IOOgm 20 2.88 2.88 3.05 2.72 3.05 2.88 2.91 0.12 0.33 : 63 50 2.72 2.80 3.05 2.39 3.21 2.72 2.81 0.29 0.82 : 70 Mg Ag-TU me./IOOgm. 20 2.45 2.55 ! 71 ! 72 Ca Meh.1/5 me./IOOgm 20 1.60 1.60 0.80 0.80 2.00 1.60 1.40 0.49 1.20 ! 73 50 0.40 0.80 0.40 Trace 1.60 0.80 0.67 0.55 1.60 ! 74 Ca mod.01. me./IOOgm 20 4.00 3.00 3.00 2.00 4.00 3.00 3.17 0.75 2.00 1 75 50 2.00 2.00 2.00 1.00 4.00 3.00 2.33 1.03 3.00 ! 76 Ca Ag-TU me./IOOgm. 20 4.80 5.00 ! 77 ! 78 Mn Meh.1/5 me./IOOgm 20 1.30 1.10 1.20 1.06 0.16 0.18 0.83 0.52 1.14 ! 79 50 1.23 1.23 1.26 0.13 0.46 0.40 0.79 0.51 1.13 ! 80 Mn mod.Ol. me./IOOgm 20 0;26 0.24 0.20 0.18 0.15 0.16 0.20 0.04 0.11 ! 81 50 oil 3 0.13 0.15 0.11 0.55 0.46 0.25 0.20 0.44 ! 82 Mn Ag-TU me./IOOgm. 20 1.01 1.01 ! 83 ! 84 Zn HCl ppffl. 20 3.00 ! 85 50 1.90 ! 86 Zn mod. 01. ppm. 20, 3.00 3.00 2.00 2.00 3.00 4.00 2.83 0.75 2.00 ! 87 50 1.00 2.00 1.00 1.00 3.00 2.00 1.67 0.82 2.00 ! 88 ., ! 89 Cu HCl ppm. 20 1.60 ! 90 50 j 1.90 ! 91 Cu nod. 01. ppm. 20 1 2.00 3.00 2.00 2.00 2.00 2.00 2.17 0.41 1.00 ! 92 50 2.00 2.00 2.00 1.00 3.00 3.00 2.17 0.75 2.00 ! 93 ! 94 Fe HCl ppm. 20 24 I 95 50 25 ! 96 Fe mod. Ol. ppm. 20 150 170 155 140 140 160 152.50 11.73 30.00 ! 97 50 120 115 115 105 170 150 129.17 25.18 65.00 ! 98 ! 99 Fe Oxalate % 20 0.55 MOO 50 0.63 : toi Al Oxalate % 20 2.25 1102 50 1.05 , NA : not applicable me./IOOgm. : mi 11îequivalents per 100 gm.o f soil Men. : Hehl ich Analysis mod. 01. : Modified Olsen Extraction AgTU : Silver Thio Urea Extraction District: Keyo Harakwet Trial Site: 13.2 Bugar

~~Table 13.2.12 : Analytical Results (chemical analysis, results on air dry soil basis) Farmers' Fields Composite Samples~~

~~Depth Farmers '•field« (code Trial site X s Hax. ! cm. A B C D E F G H average diff. !~~

! 1 Lab. No. /86 20 3920 3921 3922 3923 3924 3925 3926 3927 ! 2 Fine earth Ï 20 100 100 100 100 100 100 100 100 100 100.00 0.00 0.00 ! ! 3 Vol.weight gm./cc. 20 1.05 1.03 1.06 1.03 0.99 1.04 1.04 1.02 1.01 1.03 0.02 0.07 ! ! 4 105 deg. C / air dry 20 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.94 0.93 0.94 0.00 0.01 ! ! 5 ! 6 pH H20 1/1 20 5.00 5.20 5.00 5.10 6.00 5.90 5.20 5.00 5.27 5.30 0.38 1.00 ! 7 pH H20 1/2.5 20 6.00 6.00 5.70 5.80 66.00 6.80 6.10 5.60 6.05 12.67 20.00 60.40 ! ! 3 pH H CCI i/2.5 20 4.50 4.60 4.60 4.50 5.50 5.20 4.60 4.60 4.50 4.73 0.36 1.00 ! ! 9 ! 10 C org. I 20 2.03 2.25 2.03 2.10 2.88 2.20 2.17 2.69 1.89 2.25 0.33 . 0.99 ! 11 N tot. X 20 0.21 0.22 0.21 0.21 0.27 0.18 0.24 0.38 0.22 0.24 0.06 0.20 : ! 12 C/N 20 10 10 10 10 11 12 9 7 9 9.68 1.42 5.14 ! ! 13 . : ! 14 Hod.Olsen Abs.260nm. 20 135 148 126 132 144 124 1 155 155 132 139.04 11.84 31.00 : is ! 16 P Heh. i/5 ppiB. 20 12.00 14.00 9.00 9.00 14.00 12.00 9.00 26.00 15.33 13.37 5.31 17.00 1 17 P «od.Olsen ppm. 20 0.30 0.90 1.50 3.20 5.40 3.10 1.90 1.20 2.17 2.19 1.54 5.10 ! : is ! 19 Na Heh.1/5 me./lOOgm. 20 0.07 0.07 0.50 0.07 0.21 0.18 0.10 0.10 0.12 0.16 0.14 0.43 ! 20 ! 21 K Heh.1/5 me./100gm. 20 0.78 1.24 1.12 0.96 1.46 1.84 1.00 1.28 0.98 1.18 0.32 1.06 1 22 K mod.01. me./100g». 20 0.69 1.18 1.05 0.87 1.41 1.37 0.77 0.90 1.11 1.09 0.36 1.18 ! 23 ! 24 Hg lieh. 1/5 me./lOOgm. 20 2.00 2.40 2.80 2.50 4.20 4.00 2.30 3.70 2.28 2.91 0.83 2.20 ! 25 Hg mod.01. me./lOOgm. 20 2.80 3.46 2.88 3.21 1.81 5.51 2.96 3.37 2.91 3.21 0.99 3.70 , ! 26 ! 27 Ca Heh.1/5 me./lOOgm. 20 0.40 1.60 0.80 1.60 16.00 3.20 2.40 2.80 1.40 3.36 4.83 15.60 , ! 23 Ca mod.Ol. ne./100gm. 20 3.00 4.00 3.00 4.00 19.00 7.00 4.00 4.00 3.17 5.69 5.14 16.00 ! 29 ! 30 Hn Heh.1/5 ae./lOOgm. 20 0.21 0.16 1.13 1.14 1.43 0.93 0.80 1.06 0.83 0.87 0.44 1.32 ! 31 Hn mod.01. me./lOOgm. 20 0.24 0.11 0.20 0.15 Trace 0.04 0.16 0.16 0.20 0.14 0.08 0.24 ! ! 32 33 Zn mod.Ol. ppm. 20 4.00 4.00 4.00 5.00 9.00 6.00 5.00 6.00 2.83 5.09 1.79 6.17 ! ! 34 35 Cu mod.Ol. ppm. 20 2.00 2.00 2.00 2.00 Trace 2.00 3.00 2.00 2.17 1.91 0.79 3.00 ! ! 36 37 Fe mod.Ol. ppm. 20 160 145 150 155 45 135 200 . 225 153 151.94 49.37 180.00 ! ' 33 39 Ilp BaCl2 me./lOOgm. 20 0.50 0.30 0.20 0.20 0.20 0.32 0.29 0.12 0.30 ! 40 H & AI KCl me./lOOgm. 20 1.78 0.74 1.04 1.08 1.00 0.74 1.08 1.07 0.35 1.04 ! 41 AI KCl me./lOOgm. 20 0.96 0.52 0.74 0.78 0.68 0.44 0.76 0.70 0.17 0.52 !

~~NA : not applicable me./lOOgm. : ailliequivalents per 100 gm. of soil ppm. : parts per million Heh. : Hehlich Analysis Hod. Ol. : Hodified Olsen Extraction~~

~~- 2.28 - District: Keiyo Marakwet Trial Site 13.2: Bugar~~

~~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 other agencies. A complete list of soil survey reports is given in Chapter II.2 of the main report. Those reports referring to the area in which the trial site is situated are listed below.

~~Literature references:~~

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

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

~~F.M. Muchena, and J.M. Kibe (1984). P75 The Soils of the Sangurur-Kapsowar-Chesoi Area (Elgeyo Marakwet District; with map, scale 1:50,000).~~

In order to correlate existing information with findings at the trial site, the map units and classification units in the above-mentioned reports have been grouped in Table 13.2.13. Moreover, the FURP soil map unit (Map 13.0.4) and the classification of the soil of the profile at the trial plot are given.

~~Table 13.2.13: Soil Correlation with Respect to the Bugar Trial Site~~

~~Reference Map unit Soil Classification~~

~~El Uh3 eutric Nitisols~~

~~LBDA UhNl humic Nitisols i P75 LIr humic Nitisols and Acrisols~~

~~FURP UI3 humic Nitisols, with humic Acrisols~~

~~Trial plot profile humic NITISOL \~~

The trial site is located in a transitional "humic-eutric-dystric" area. Topsoil colours differ considerably in the area around the trial site. At the trial plot, the colour requirements of a humic Nitisol were just met. The "nitic" properties (clay illuviation causing shiny ped faces) were also not very pronounced. \

~~- 2.29 - District: Keiyo Marakwet Trial Site 13.2: Bugar \~~

~~3.3.2 Representativeness~~

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

~~(a) the soil-related land factors must have the same or similar ratings ;~~

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

The extent to which all the FURP trial sites are representative of the soils of Keiyo Marakwet District is shown in Map 13.0.5: "Groupings of Soil Mapping Units Represented by Trial Sites in Elgeyo Marakwet District". This map is discussed in Sub-Section 13.0.5. Distinction is made between high representativeness - code A - and moderate representativeness - code B if soil conditions are slightly more favourable than at the trial site and code B- if soil conditions are slightly less favourable than at the trial site. Code C is applied for the remaining parts of the district, where none of the FURP trial sites is representative.

Within Keiyo Marakwet District, the Bugar Trial Site has high representa tiveness (Grouping 13.2.A) for soil map unit UI3 (humic Nitisols, with humic Acrisols), between Bugar and Cheptongei. It has moderate représentât iveness (Grouping 13.2.B+) for soil map unit UF2 (humic Nitisols, with humic Cambisols), North of Cheptongei. The parent rock consists of rich gneisses and the acid humic topsoil is thicker than at Bugar.

The Bugar Trial Site is also representative of areas outside Keiyo Marakwet District, in particular in the North-East of Uasin Gishu District (soil map unit UhNl). Regarding soils, the site overlaps more or less with Trial Site 8.1 (Baraton, Nandi District).

~~3.3.3 Variability of Soil Properties within the Trial Site~~

The trial plot is quite homogeneous as to thickness of the topsoil, effective soil depth and inherent fertility. The pH-KCl and organic carbon content of the composite topsoil samples are within a narrow range. The farmers' fields tend to have slightly better chemical properties.

~~Tables 13.2.10 to 13.2.12 list the soil test values for the various samples. A breakdown of data on pH-KCl and organic carbon content of the upper 20 cm. is given below.~~

~~- 2.30 - District : Keiyo Marakwet Trial Site 13.2: Bugar~~

~~pH-KCl: profile pit: 4.0 composite samples: 4.3 - 4.5 (Blocks I-V); 5.0 (Block VI) farmers' fields: 4.5 - 4.6 (fields A,B,C,D(G,H) 5.2 - 5.5 (fields E and F)~~

~~organic carbon content : profile pit: 1.9% composite samples: 1.8% - 2. L% farmers' fields: 2, 0% - 2 3% (fields A B,C D,F G) 2, 7% - 2 .9% (fields E and H)~~

~~3.3.4 Fertility Status of the Soil~~

~~The criteria applied for the interpretation of the analytical data are outlined 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 are presented in Table 13.2,10 and are interpreted in the following paragraphs. The pit is situated approximately 50 or 60 m up-slope of the final trial site, at the outer edge of Block I which is no longer part of the actual plot (see Figure 13.2.7).

The rooting depth of the soil is not limited by physical or chemical obstacles in the subsoil. The capacity for plant available moisture in the profile was estimated in the field as being very high (>160 mm.). This was confirmed by the results of the| pF analysis carried out on horizons AB and Bt2.

All horizons down to a depth 130 cm. have a moderate CEC (pH 8.2) of more than 20 me./100 gm. The base saturation is low (20%) in the Ah horizon, low to moderate (around 26%) in the AB and Bt horizons, and low in the soil below 57 cm. This is in accordance with the strongly to very strongly acid soil reaction.

With respect to the moderate CEC, the exchangeable K is extremely high (1.3 me./100 gm.) in the Ah horizon and very high to high (0.86 - 0.54 me./100 gm.) in all underlying horizons. Exchangeable K decreases continuously with depth. Mg is high to very high in the entire profile, with an expressed maximum in the AB horizon. The Ca levels are in the low range (>5 me./100 gm.) throughout, with a less expressed maximum in the AB horizon.

The soil reaction of the entire profile is in the strongly to very strongly acid range (pH KCl 3.9 - 4.2), which is at the lower limit acceptable for the good performance of most crops. However, only low amounts of Al are exchangeable (<1 me./100 gm. and <15 % of exchangeable bases plus Al) in the upper 57 cm. of the soil. In the underlying soil a moderate Al saturation was observed. As these percentages are based on the sum of cations extracted by NH4-0-Acetate and because Ca seems to be underestimated by approximately 50% (see Ca by AgTU or mod.01sen-Ca in Block I of the

~~- 2.31 - District: Keiyo tiarakwet Trial »Site 13.2: Bugar~~

trial site), the exchangeable Al percentage is probably even lower. This level of Al will only affect very sensitive plants. The trial site compo site samples are less acid, and exchangeable Al does not reach any critical levels.

The organic matter content of the topsoil (Ah and AB) is in the high range; the humus content decreases continuously with depth from almost 2 % C (Ah) to 0.76 % C (Bt3, low to medium). N is medium to high (0.2 % N) in the Ah horizon and appears almost constant in the underlying soil with approximately 0.14 % N. The C/N ratio is about 10 and moderate to wide in the topsoil. It becomes narrower with depth.

~~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 13.2.11. Those for the farmers' fields (depth 0-20 cm. only) are shown in Table 13.2.12. Blocks I and IV are no longer part of the trial' site.

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

As the soil pH increases down-slope, the trial site soil samples investigated are slightly less acidic than the profile and moderately to strongly acid (pH KCl 5 - 4.4). Block VI as the lowermost is slightly to moderately acid (pH KCl 5). The farmers' fields are slightly to moderately acid (pH KCl 5.5 - 4.5). As stated above, soil acidity is in a range well tolerated by all relevant agricultural crops.

The total N content of these very humic soils (1.8 -2.9 % C) is medium to high (0.18 - 0.38 % N). While N is at the same level in the trial site and the farmers' fields, organic matter is slightly higher in the farmers' fields. Farmers' fields E and H show a particularly high humus content. The generally medium to wide C/N ratios and other prevailing soil characteris tics indicate a moderate rate of N release through mineralisation of soil organic matter. The UV absorption of the modified Olsen extract on average indicates a low to moderate N supplying capacity.

~~Soluble S04 was determined in Block I of the trial site only. The values reported are far below the critical level (<3 ppm.) and a shortage of S0t may therefore be feared for a good growing crop.~~

~~- 2.32 - District : Keiyo Marakwet Trial Site 13.2: Bugar~~

In all composite samples, "available" P is very low and inadequate for plant nutrition. Only in Block III of the trial site and in farmer's field H, is Mehlich-P high or moderate, but, in contrast, the modified Olsen method indicates a very low P status for both places.

~~The "available" quantities of K are high to very high in all samples analyzed. For example, in the topsoils Mehlich-K is in the range 0.8 - 1.8 me./100 gm.~~

The "available" amounts of Mg are always far in the high range, whereas Ca is generally in the moderate (Mehlich analysis) or low (modified Olsen method) range. Only farmer's field E shows very high Ca values. Both ele ments have almost constant values over the present trial site according to the modified Olsen method, while the Mehlich analysis produced more erratic values. Similar to the NH4-0-Ac exchangeable bases the cations are ade quately balanced with respect to plant nutrition. However, the Ca/Mg ratio is very narrow in many places.

According to the Mehlich analysis, "available" Mn is well within the adequate range. In contrast, the modified Olsen method shows only low and erratic values, and in farmer's field E Mn traces are reported. The Mn values, to some extent, inversely reflect the Ca status.

According to the modified Olsen method, Zn is available in low to moderate amounts (2-6 ppm.) throughout. For farmer's field E an exceptionally high value of 9 ppm. is reported. The Cu levels are similarly low to moderate in all samples except for farmer's field E, where Cu was found in traces only. The HCl extractable Zn and Cu were determined in Block I of the trial site. Zn is definitely below the critical value, whereas Cu is above the limit.

Fe was extracted in high amounts from all samples by the modified Olsen method. The oxalate extraction for amorphous oxides and hydroxides yielded low amounts of Fe and moderate quantities of Al (Block I only).

~~The evaluation of the Mehlich Analysis data according to NAL standards is given in Table 13.2.14.~~

~~2.33 District: Keiyo Marakwet Trial Site 13.2: Bugar~~

~~Table 13.2.14: Evaluation of the Mehlich Analysis Data According to NAL Standards~~

~~Parameter Trial Site Farmers' Fields~~

~~Soil reaction (pH) Moderately acid Moderately acid Acidity (Hp ) Low Low~~

~~Available nutrients Sodium Low Low Potassium Adequate Adequate Calcium Low Low to adequate Magnesium Adequate i Adequate Manganese Adequate j Adequate Phosphorus Low Low~~

~~Total Nitrogen Adequate Adequate Organic Carbon Moderate Adequate~~

~~C / N Ratio Favourable Favourable Ca / Mg Ratio Not favourable Not favourable Ca / K Ratio Not favourable Not favourable K / Mg Ratio Favourable ! Not favourable~~

~~Remarks on Trial Site : Soil reaction is not very favourable. Positive yield responses to manure, lime, N and P application are expected. Responses to K applications are unlikely.~~

~~Remarks on Farmers' fields : Same as for Trial Site.~~

~~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 long rains in March 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 only from the plots in Module 2 with maize/beans mixed cropping. The treatments to be sampled are :

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

~~Trial II: FYM 1 (2.5 t/ha) FYM 3 (7.5 t/ha) FYM 1 + P FYM 3 + P N + P FYM 1 + N + P~~

~~Farmers' Fields A, E, and H are proposed~~

~~- 2.34 - District: Keiyo Marakwet Trial Site 13.2: Bugar~~

~~3.4.2. Plant Samples~~

Harvest samples from the maize/beans mixed crop include individual samples of grain and straw from maize and beans respectively. Samples will be collected separately from each replication of the same treatments where soil samples were collected, i.e.:

~~Trial I: NO: PO N75:P0 NO: N75:P75~~

~~Trial II: 0 FYM 1 (2.5 t/ha) FYM 3 (7.5 t/ha) FYM 1 + P FYM 3 + P N + P FYM 1 + N + P~~

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

~~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~~

For example, the water requirements and the water availability for Maize H 625, planted in mid-March at the Bugar Trial Site, can be interpreted as follows: Figure 13.2.6 shows that the maximum water requirements (ETm) of the maize crop are quite in line with the rainfall pattern at the 66% probability level. i Run-off is moderate. The trial site is located on gently sloping land (slopes: 3-4%), but the crop does not provide adequate ground-cover at the time of maximum rainfall-intensity in April/ May. Deep percolation and lateral sub-surface flow could be estimated, but can be omitted, since they are generally low. Some run-on from the upper slope to the southern part of the plot probably offsets to a large extent the run-off losses on this part of the trial plot.

For the Bugar Trial Site, the moisture storage capacity is rated very high (i.e. >160 mm.). Thus the surplus water likely to occur in April and May, can to a large extent be stored and offset the deficits of June.

~~- 2.35 - District: Keiyo Marakwet Trial Site 13.2: Bugar~~

\\ Summarizing the evaluation of the climatic factors, the yield potential from the climatic point of view can, for the maize crop (planted in mid- March), be rated good on a "20 out of 30 year" basis. In extreme years, low night temperatures might hamper plant growth (particularly the maize crop), but generally the minimum temperatures are still tolerable for high altitude crops. -

~~4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement~~

Nutrient availability and soil reaction generally appear moderately favourable for plant production. The most limiting factors for successful crop production are probably P and N availability, whereas K and Mg should be available in sufficient quantities. A suspected shortage of S, Zn and perhaps Cu should be verified by trials. j

Fertilizer applications should first of all involve P in the form of TSP or finely ground soft rock phosphate (e.g. Hyperphos or from Minjingu). Under the moderately to strongly acid soil conditions, rock phosphate should be almost as effective as TSP even in the first season. P from rock phosphate is less subject to fixation than P from TSP. Nevertheless, the risks of P fixation into non-available forms are considered to be only moderate. The efficiency of P application may be enhanced by the addition of small amounts of fresh FYM to stimulate soil biological activity.

Superphosphate contains about 12% S and therefore may act as a two-element fertilizer. Under farmer's conditions this might be very useful because a limited S availability may be expected in some fields.

For sustained high yields regular N fertilization will be necessary, either from FYM or green manure or in mineral form. N applications are considered useful only in combination with adequate P supply, in which case repeated reasonable responses to N may be expected. When mineral N is applied regularly, it should be supplemented with mulch and other organic amendments to maintain the humus content of the soil at least at the present level. The humus plays an essential role in stabilizing the soil structure, infiltration rate, soil aeration and moisture retention capacity, and also prevents applied nutrients from leaching too quickly.

During excessively high rainfall, which is not uncommon in the area, soil aeration may be restricted and losses of N by denitrification may occur, but this is probably only of minor intensity. Denitrification losses from N03 sources occur in greater amounts than from NH4 sources. For a more reli able estimate of the extent to which denitrification may occur, more precise data on the soil moisture regime and its effects on N losses are required.

~~N losses due to leaching may be moderate, as the base saturation of the profile indicates moderate leaching intensity. N03-N is leached more quickly than NEi-N.~~

~~Liberal applications of N and P may cause secondary deficiencies, particularly of Zn and Cu.~~

~~- 2.36 - District: Keiyo Marakwet Trial Site 13.2: Bugar~~

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

K applications are not needed at the present stage and response to K may not be obtained over the trial period of five years. The analytical data give no estimate of the reserves of K beyond the exchangeable pool. In the long run, however, it might become necessary to replace the amounts removed with the harvests.

Under the present soil conditions liming is not needed and the acidifying effects of the applied mineral or organic fertilizers will probably be buffered sufficiently by the soil for the duration of the trials over five years. But as some of the soils tested are already in the strongly acid range (below pH KCl 4.5), the increasing soil acidity will have to be corrected by liming over longer periods of fertilizer use. As a general rule, 2 t./ha. of agricultural lime will be needed to compensate each me./100 gm. of exchangeable Al in the topsoil. The soil should not be limed to a pH (KCl) above 5, to avoid negative effects on nutrient availability.

Another possibility might be to counterbalance fertilizer acidity with lime. N fertilizers have particularly high lime requirements, i.e. approximately 1.8 Kg. of CaC03 per Kg. of applied N. In the case of CAN, which contains Ca, only about 0.8 Kg. CaC03 per Kg. N or 0.2 Kg. lime per Kg. of CAN will be needed. TSP does not contribute substantially to the Ca budget of the soil. Soft rock phosphate (30% P205) contains about 2.7 Kg. CaC03 equivalent per Kg. of P205.

~~If lime is applied excessively, the availability of Zn and possibly also Cu will become low and plant uptake should be monitored, at least for sensi tive crops.~~

~~4.3 Other Relevant Land Qualities~~

In addition to ah assessment of moisture and nutrient availability, the following land qualities are relevant in the context of fertilizer use: a) Oxygen availability! With sustained heavy downpours, not uncommon in the area, temporarily impeded soil aeration may occur, which is a constraint to plant metabolism, notably at the crop emergence stage. The high structure stability and infiltration capacity of the topsoil prevent this from occurring too often. b) Rootability. The very deep to extremely deep soils with stable blocky structures provide an outstanding environment for unhampered root development and tuber expansion.

~~- 2.37 - District: Keiyo Marakwet Trial Site 13.2: Bugar~~

\ c) Resistance to erosion. The area has a high resistance to erosion. The negative influence of the high rainfall intensity is offset by a high structure stability (low erodi- bility) of the surface soil, the gently undulating topography and the quick establishment of a crop cover.

d) Ease of cultivation and scope for agricultural implements. There are no limitations to any method of land preparation although compaction and decreased porosity of the topsoil may result from the mechanical tillage of moist soils.

~~5. Trial Design and Execution Plan, Bugar~~

~~i (Full details of the methodology for carrying out jthe trials are shown in Chapter IV of the main report).~~

~~Selection of Crops. The proposed crop sequences in each of the three modules, in the Bugar trial are:~~

~~Site 13.2 Bugar, RAINY SEASONS Keiyo Marakwet 1st, Long, March 2nd, Short, Aug.~~

~~51 Standard maize Hybrid 625 ( 52 Maize & beans Hybrid 625 + GLE 2 53 Potat./Cabb.; Forage B 53/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 crop of forage oats in the August 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 4 FYM factorial, also with 2 replications in each module.~~

~~Each module thus consists of 64 plots, and the total for the 3 modules is 192 plots.~~

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

~~- 2.38 -~~