!!•«•<•-
arf1 a Ministry of Agricul
1ST a t d_ o n a. X Agricul ies
ilizer Use Recommendation Project (Phase X)
Annex XXX
Description of tln^ FdLirsti: Priority
Sites in tln.^ Various Distiricrts
Volume 21
Murang'a District
District No.: 21
Nairobi, June 1987 ilizer TUse ion
Pro j
Pro j Tee», in Team of Consultants1) Professional Staff from NAL2)
Project Coordination H. Strobel (ed.) G.Hinga Project Coordinator Director NAL
S.W.Nandwa Counterpart Coordinator
Aaro-Climatoloaists 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 J.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 Fer-ti X d_ zeur Use Recommendation Project C Phase X )
Report:Methodology and Inventory of Existing Information
: Compilation of results from Former Fertilizer Trials In Kenya (2 Volumes)
. 1 : Inventory of Farming Systems Research in Kenya
X . 2 : Influence of Fertilizer Application on Ruminant Production
Annex XX . 3 : Maintaining Soil Fertility with Little or No Use of Fertilizers
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
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 soil.isrictBwur.nl indicating the item reference number concerned. District: Murang'a General Aspects 21.0
Gontents
Annex XXI- Volume 2X
Page
Chapter 2X - O s
General Aspects 0.1
Legend of the Soil Map of Murang'a District 0.27
Chapter 2X - X s
Description of the Kandara-Kareti Trial Site 1.1
ar 2 X - 2 =
Description of the Makuyu 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 Ma,p within Chapter.
- 0.1 - District: Murang'a General Aspects 21.0
Contents of Chapter 21.0:
General Aspects
Page
1. Climate and Soils of the District 0.3
2. Location of the Trial Sites and Criteria for their Final Position 0.13
3. Names and Addresses of Government Officers Involved in FURP Activities 0.15
4. Trial Design and Execution Plan 0.16
5. Areas in Murang'a District Represented by FURP Trial Sites 0.17
List of Tables
Table 21.0.1 Climate in the Agro-Ecological Zones of Murang'a District 0.6
Table 21.0.2 Agro-Ecological Zone and Soil Classification of the Trial
Sites 0.9
Table 21.0.3 Ratings of Criteria Used for Trial Site Selection 0.14
Table 21.0.4 Names and Addresses of Government Officers in the District 0.15 Table 21.0.5 Major Soil Properties and Climatic Conditions of the
Agro-Ecological Units in Murang'a District 0.23
List of Maps'
Map 21.0.1 66% Reliability of Rainfall in First Rains 0.4
Map 21.0.2 66% Reliability of Rainfall in Second Rains 0.5
Map 21.0.3 Agro-Ecological Zones and Trial Sites of the District 0.7
Map 21.0.4 Soils and Trial Sites in Murang'a District 0.11
Map 21.0.5 Groupings of Soil Mapping Units Represented by Trial
Sites in Murang'a District 0.21
Map 21.0.6 Agro-Ecological Units in Murang'a District 0.25
Legend of the Soil Map of Murang'a District 0.27 - 0.2 - District: Murang'a General Aspects 21.0
1. Climate and Soils of the District
Murang'a District, situated on the eastern slopes of the Nyandarua Range, has due to the south eastern Trade Winds a climate which is typical for increasing altitudes in the area and which is characterized by high rainfall and distinctive agro-humid periods.
The average annual rainfall in the District is variable, ranging from >800 mm in the south-east (Zone UM and LM 4) to >2600 mm in the north-west (Zone UH 0). The rainfall pattern is bimodal and rainy seasons are clearly separated. The first rains start at about the end of March, with their peaks in April and May while the second rains start any time from the beginning of October with the peak in November, as shown in Figures 21.1.5 and 21.2.5. The 66% reliability of rainfall, i.e. amount surpassed in 20 out of 30 years, is shown in Map 21.0.1 for the first rains and in Map 21.0.2 for the second rains. Evaporation, varying with altitude, ranges between 1800 mm. at 1400 m, and 1300 mm. at 2500 m. The mean annual temperature is about 20°C at 1400 m and 12.5°C at 2500 m. A summary of climatic data is compiled in Table 21.0.1, which can be used as a key to the Agro-Ecological Zones Map 21.0.3.
The annual average rainfall reaches a maximum of 2700 mm at 2500 m. From this altitude up to the forest line and down to about 2150 m, it is so wet, cold and steep that the area is not recommended for agriculture (UH 0). A strip of UH 1 extends further down to the frost line and the 15° C isotherm, (here due to heavy cloud cover exceptionally low at about 2050 m) and is generally known as the Sheep and Dairy Zone, though in view of the population pressure, vegetable cultivation would be more appropriate.
The next zones are found in descending order on the eastern slopes of the Nyandarua Range: the Tea-Dairy Zone LH 1, the Coffee-Tea Zone UM 1, the Main Coffee Zone UM 2, the Marginal Coffee Zone UM 3, and the Sunflower- Maize Zone (UM 4) which is actually partly a sisal and pineapple zone due to the presence of large estates. A strip of UM 3-4 occurs towards the east in the Kakuzi Hills, although on less suitable soils which are very marginal for coffee. Additional irrigation is essential here.
Down on the plains where cotton production is feasible - the limit is reached at about 1300 m where a decrease in cloudiness leads to reduced insulation - the climate becomes so dry within short distances (annual average 800-900 mm) that the Cotton Zone LM 3 is little more than a small transitional strip to the Marginal Cotton Zone LM 4.
Agro-Ecological Zones UM 2 and UM 4 are represented by the Kareti (21.1) and Makuyu (21.2) Trial Sites, as shown on Map 21.0.3.. Zones LH 1, UM 1 and LM 3-4 are represented by Trial Sites in Nyeri, Kiambü, Embu and Meru Districts. The Marginal Coffee Zone (UM 3) is not yet represented by any of the FURP first priority trial sites.
- 0.3 - 37°|E Map 21.0.1 MURANG'A 66% RELIABILITY OF RAINFALL IN AGROHUMID PERIOD OF FIRST RAINS (March-Sept. or less) Amounts in mm, surpassed 9N norm. in 20 out of 30 years
Broken boundaiies are uncertain because ol lack ol rainlall records
Nal Agr Labi. German Agr Team. R Jaeliotd
- 0.4 - 37°|E
Map 21.0.2 MURANG'A
66% RELIABILITY OF RAINFALL IN AGROHUMID PERIOD OF SECOND RAINS (Oct.-Feb. or less) Amounts in mm, surpassed f norm, in 20 out of 30 years
THIKAV
Broken boundaries arc uncertain because ol lack of rainlall records
Nai Agr Labs German Agr Team. R JaeUold
-0.5- Table 21.0.1 : climate in the Agro-Ecological Zones of Muranga District
Agro-Ecological Subzone Altitude Annual mean Annual av. 66 % reliability 66 % reliability Zone in m temperature rainfall of rainfall1' of growing period in°C in mm 1st rains 2nd rains 1st rains2' 2nd rains Total^' in mm in mm in days in days in days
TA I + 11 Tropical National Park Alpine Zones
UMO Forest Reserve Forest Zone
Uli 1 Sheep and 3 or 1/vl " m 2 130-2 430 14.9-13.0 2 200-2 500 1 100-1 400 650-700 210 or more 140-155 350-365 Dairy Zone
LH 1 Tea - Dairy p or 1/vl - m 1 730-2 130 18.0-15.0 1 700-2 400 850-1 300 480-680 210 or more 140-155 350-365 Zone
UM 1 p or f 1 ^ m 1 700-1 900 800-1 100 500-580 210 or more 140-155 350-365 Coffee - Tea 1 670-1 800 18.8-18.0 flim 1 500-1 700 700- 900 400-520 180 or more 130-140 310-340 Zone
UM 2 m/l i m/s 1 300-1 620 550- 820 320-480 160 or more 110-130 270-300 Main Coffee 1 500-1 670 19.7-18.8 m + s/m 1 180-1 400 450- 650 280-400 130-160 105-115 Zone
UM 3 m/s + s 900-1 350 350- 650 230-380 110-130 90-100 Marginal 1 340-1 500 20.7-19.7 s/m + s/m 900- 950 350- 410 260-310 105-115 100-110 Coffee Zone
UM 4 s/m + s 900-1 100 320- 450 230-300 100-110 90-100 Sunflower - s + s 1 340-1 520 20.7-19.5 850- 950 280- 380 220-280 90-105 90-100 Maize Zone s + s/vs 800- 850 200- 280 200-230 85-100 75- 85
LM 3 s/m + s 1 160-1 340 21.7-20.8 Very small, see Kirinyaga District Cotton Zone s + s 980-1 100 390- 490 270-320 85-105 85-100
LM4 s + s/vs 900-1 000 350- 450 230-280 85-100 75- 85 Marginal s/vs + s/vs 1060-1 160 22.3-21.7 790- 980 320- 400 250-300 75- 85 75- 85 Cotton Zone s/vs + vj/s Very small, see Kirinyaga District
Amounts surpassed normally in 6 out of 10 years, falling during the agro-humid period which allows growing of most cultivated plants. More if growing cycle of cultivated plants continues into the period of second rains.
Only added if rainfall continues at least for survival (> 0.2 Eo) of most long term crops. Source: Jaetzold R., and H. Schmidt, eds. (1982): Farm Management Handbook of Kenya, Volume Il/B Central Kenya, page 568.
- 0.6 - MAP 21.0.3 AEZS AND TRIAL SITES IN MURANGÄ DISTRICT
37° E • Site of first priority 21.1 Kareti 21.2 Makuyu
ofl
LM3 mts
S
AGRO-ECOLOGICAL ZONES
Forest Reserve Nat Park Unsuitable steep slopes soil boundary, see Map 4 (only marked outside Nat. Parks or Forest Res.)
Belt of A. E. Zones •" » ^ Broken zonal boundaries are uncertain or A. E. Zones — — — mean transitional strips Subzones Climatic data for AEZ formulas see tables II. 1-2 ||. 1. 4 and 21.0.1
üAS
Ministry of Agriculture FERTILIZER USE RECOMMENDATION PROJECT (19871 National Agricultural Laboratories German Agricultural Team
15 20 25 km m
g eu er
V*»-
C\) District: Murang'a General Aspects 21.0
The soils of Murang'a District are shown in Map 21.0.4.
Apart from the eastern-most part, the soils of Murang'a District corres- pond entirely with the typical Aberdares-Mount Kenya Toposequence, which occurs in all districts from Meru down to Kiambu and Nyandarua. The mountain unit MV2 (humic Andosols, partly lithic phase) gradually gives way to extensive volcanic footridges (units RB 1,2 and 3), which account for more than 50% of the area of the District. East of the Murang'a-Makuyu line, the plateaus and high-level structural plains (units LB 1, 2 and 8) occur. All these soils are developed on basic igneous rocks.
The major mapping units are given below.
=== Soils developed on basic igneous rocks.
- Unit RBI: ando-humic Nitisols, with humic Andosols (Trial Site 22.1. Nyeri District); - Unit RB2: humic Nitisols (Trial Site 21.1): - Unit RB3: eutric Nitisols, with shallower inclusions (Trial Site 21.2'): - Unit LB1: nito-rhodic Ferralsols (Trial Site 24.2. Embu District).
In the eastern-most part of the District shallow Regosols and Cambisols (unit HUC), deep Arenosols and Luvisols (unit FUC) and moderately deep to deep orthic and rhodic Ferralsols (unit UU1) prevail.
The basic climatic and soil designations referring to trial sites in Murang'a District are summarized in Table 21.0.2.
Table 21.0.2: Agro-Ecological Zone and Soil Classification of Trial Sites in Murang'a District
Site Site Agro-Ecological Soil Classification No. Name Zone
21.1 Kareti Main Coffee humic NITISOL Zone (UM 2)
21.2 Makuyu Sunflower-Maize eutric NITISOL Zone (UM 4)
- 0.9 - MAP 21.0.4 SOILS AND TRIAL SITES IN MURANG'A DISTRICT 37° E
• Site of first priority 21.1 Kareti 21.2 Makuyu
0°30'
r ABERDAR NATIONAL/ PARKI ,'MVI,
S
SOURCE
El Exploratory Soil Map of Kenya,1980 (scale 1:1,000,000) KEY LB1 soil mapping code — soil boundary W# towns and major villages — -=: tarmac road •==r other all-weather roads district boundary national park'boundary river
Fox LEGEND See APPENDIX
FERTILIZER USE RECOMMENDATION PROJECT (1987) Ministry of Agriculture National Agricultural Laboratories German Agricultural Team
10 15 20 25 km
_ District: Murang'a General Aspects 21.0
2. Location of the Trial Sites and Criteria for their Final Position
In Murang'a District, two first priority sites were selected as shown in Map 21.0.4.
Site selection in Murang'a District turned out to be rather time-consuming. Since farmers specialize in cash crop farming, it is uncommon to find a portion of land as large as two acres set aside for food crops only.
Trial Site 21.1 was scheduled to be in the area around Kangema, but lack of suitable sites made the team shift to Kandara Division. The District Crops Officer managed to lease two acres from the Kareti Secondary School. A rectangular plot was demarcated. Although the upper part has a steep slope of 14%, and the lower part is gently undulating (5%), extremely deep humic Nitisols were encountered over the entire trial plot.
Accessibility of this site is good if approached from the Nairobi-Murang'a main road, but poor if approached from the Kandara Divisional Office. The site has a very high demonstration effect. Farmers' fields are representative and within close range of the trial plot. The nearest suitable long-term rainfall station Thika, Kajuga Farm, is located 10 km SW of the Kareti Trial Site.
Trial Site 21.2 was established near Makuyu. A rectangular two acre plot was surveyed. Soils in both the trial site and farmers' fields are uniformly extremely deep eutric Nitisols. They are situated within walking distance from the main plot. The nearest long-term rainfall station: 09037143, Makuyu Divisional Office is just 1.3 km S of the Makuyu Trial Site.
The site has good accessibility and a very high demonstration effect. The site is situated close to a major dust road, and is close to Makuyu township. Unfortunately, the farmer does not live on the plot, which may imply a high risk of theft.
The criteria for the final position of the trial sites are listed in Table 21.0.3, which is self-explanatory. Criteria have been rated very good (1), good (2), moderate (3), poor (4) or non-relevant (nr).
- 0.13 - District: Murang'a General Aspects 21.0
Table 21.0.3: Ratings of Criteria Used for Trial Site Selection in Murang'a District
Criterion Site number
21.1 21.2
1. Representativeness of Agro-Ecological Zones 1 1 2. Representativeness of soils 1 1 3. Representativeness of topography 2 1
4. Adequacy of size and shape of the trial plot 3 2 5. Absence of trees and hedges 2 2 6. Absence of rocks and boulders 1 1 7. Absence of termite mounds 1 1 8. Uniformity of previous land use 2 2
9. Accessibility 2-3 2 10. Demonstration effect 1 1 11. Proximity to a long-term rainfall station 3 1
12. Availability of storage facilities 2 4 13. Availability of sturdy fences 4 4 14. Availability of housing facilities for T.A.s 1 1
15. Farmer's willingness to cooperate 1 2 16. Security - theft 2 4 17. Security - intruding animals 2 2
18. Proximity of on-farm trials 2 2 19. Representativeness of soils at on-farm trials 1 1
- 0,14 - District: Murang'a General Aspects 21.0
3. Names and Addresses of Government Officers Involved in FURP Activities in Murang'a District
The names and addresses of the agricultural staff members in the District are listed in Table 21.0.4.
Table 21.0.4: Names and Addresses of Government Officers in the District
OFFICER SITE NAME P.O. BOX TEL. NO.
DISTRICT D.C. Joel ole Waupari* 7-Murang'a 22606 D.A.O. J.K. Kanjagua 68-Murang'a 22604 D.C.O. John .K. Kamanu 68-Murang'a 22604 D.E.C. Miss A. Onyango* 68-Murang'a 22604
DIVISION Div. Ext. 21.1 Bernard Ondanyi 1-Kandara 13-Kandara Officer 21.2 Kithingi Inoti 28-Makuyu Soil Cons Officer 21.1 D.G. Kiritu 1-Kandara 13-Kandara
Loc. Ext. 21.1 not met Officer 21.2 not met
Technical 21.1 K. Wanyururu Assistant 21.2 not met
* not met during site selection
Period of site selection in the District: August 1986.
- 0.15 - District: Murang'a General Aspects 21.0
4. Trial Design and Execution Plan, Murang'a.
(Full details of the methodology for carrying out the trials are shown in Chapter IV of the main report).
Selection of crops for each of the three modules at the two Murang'a Trial Sites:
Site 21.1 Kandara- RAINY SEASONS Kareti. 1st, Long, March 2nd rains Aug-Oct
51 Standard Maize Hybrid 512 Hybrid 512 52 Maize & Peas H.512+ Beans GLP 2 H.512+ Beans GLP 2 53 Pot./Cabbages;Beans Anett/Copenhagen Beans, GLP 1004
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 first rains, and beans, GLP 1004 in the second rains.
Site 21.2 Makuyu. RAINY SEASONS 1st, Long, March 2nd, Short, Oct.
51 Standard Maize Hybrid 511 Katumani C.B. 52 Maize & Beans H.511+ GLP 92 Beans K.C.B.+GLP 92 53 Maize & Pigeon Peas Katumani P.P. K.C.B.+ K.P.P
The 1st sequence or module' is continuous, pure maize, twice/year. The 2nd is intercropped maize and beans in both rains. The 3rd is intercropped maize and pigeon peas in the October rains, with the pigeon peas remaining for the March 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. The standard design for Experiment 2 is a 2NP x 2K x 2L x 2 FYM factorial, also with 2 replications in each module. This is the design for the site at Makuyu, 21.2, but for the Kandara-Kareti Trial Site (21.1), the design will be modified by dropping lime, and will thus be: 2N x 2P x 2K x 2 FYM.
Each module thus consists of 64 plots, and the total for the 3 modules is 192 plots.
Fertilizers will be applied during both rains, except for FYM, which will be applied only to the crops during the first rains. The ratoon crop of pigeon peas will not receive fertilizer in its second season, namely the March rains. Where beans, peas or pigeon peas are intercropped with maize, the fertilizer will go on the maize. The intercropped beans, peas or pigeon peas 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.
- 0.16 - District: Murang'a General Aspects 21.0
5. Areas in Murang'a 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 21.0.5: Groupings of Soil Mapping Units), and in the second (Map 21.0.6) Agro-Ecological Units (AEUs) are shown in which, according to the information available, the soils and the climate can be considered homogeneous.
Map 21.0.5 shows the representativeness of FURP trial sites for the Murang'a District only as far as soils are concerned. The explanation for this Map shows 9 generalized "Groupings of Soil Mapping Units". These Groupings have the same or similar soil properties and, as such, they represent a specific soil environment, typified by one of the FURP trial sites. i."
The codes in the explanation to Map 21.0.5 refer to a specific trial site (21.1, 21.2, etc.) and to a specific degree of representativeness of soils (A, B+, B-). The combination of both forms a "Soil Representativeness Code". Unit 21.1.A, for instance, covers an area which is highly represented (A) by the Kareti Trial Site (21.1). Unit 22.1.B- covers an area which is moderately represented (B) by the Muirungi Trial Site in Nyeri District (22.1), although information on soil properties reveals slightly less favourable conditions in the represented area in the Murang'a District than at Muirungi itself (B-).
The explanation to Map 21.0.5 also lists those units of the Soil Map (Map 21.0.4) which are considered in the various groupings. A breakdown of soil properties referring to the Groupings of Soil Mapping Units is given as part of Table 21.0.5.
The soils of the Murang'a District are well represented by the FURP trial sites. This is testified by Map 21.0.5 which shows a very high A-cover (highly representative).
The different soils of the Aberdares-Mount Kenya Toposequence, discussed in Sub-Section 21.0.1, are represented in the following Groupings:
Volcanic Footridges: upper slopes : humic Andosols (Grouping 22.1.B-) and ando-humic Nitisols (Grouping 22.1.A); middle »lopes: humic Nitisols (Grouping 21.1.A); lower slopes: eutric Nitisols (Grouping 21.2.A);
Plateaus and High-Level Structural Plains:
Well drained, red, nito-rhodic Ferralsols (Grouping 24.2.A) and imperfectly drained, black, pellic Vertisols (Grouping (23.2).A). Trial Site 23.2 is put in brackets, as it has not yet been identified. It
- 0.17 - District: Murang'a General Aspects 21.0
is, however, advisable to have a site on the rather extensive Vertisol area occurring in Central Province and Embu District. As long as the site is not operational, the area should be considered as C (not represented by a trial site).
Areas which are not represented by any one trial site with respect to soils are coded C. This involves some hills and footslopes in the area bordering Machakos District and the highest parts of the Aberdares.
The second representativeness map, Map 21.0.6, shows the integrated representativeness of FURP trial sites involving both soils and climate. The map units are named "Agro-Ecological Units", and they represent a specific soil-climate environment, typified by FURP trial sites.
All combinations of the different soil-climate environments occurring in Murang'a District are shown in the Agro-Ecological Unit Map (Map 21.0.6) and are explained in Table 21.0.5. 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 21.0.5. In addition, Map 21.0.6 and Table 21.0.5 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 21.0.6 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 to which the code refers.
The map units marked with code "b" (e.g.: b++, b+- ,b+*) are only modera- tely represented by trial sites. In the AEU 21.1.A.b++, for instance, the soils are highly represented by the Kareti Trial Site (21.1.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 Kareti 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 - EXPLANATION TO MAP 21.0.5
Degree of representativeness Groupings of soil mapping units
A highly representative Soil Representativeness Soil Map Units Code (Map 21.0.5) 1» Included (Map 21.0.4) • B+ moderately representative (soils of map unit are slightly more favourable than soils at the trial site) 21.1.A RB2
B- moderately representative 21.2.A RB3 (soils of 'map unit are slightly less favourable than soils at the trial site) 21.2.B+ LB2
C non-representative 22.1.A RB1
22.1.B- MV2 I o Trial sites (23.2).A LB8 o 21.1 Kareti - Murang'a District 24.2.A LB1 21.2 Makuyu - Murang'a District 22.1 Muirungi - Nyeri District 24.2.B- UU1 (23.2) 2> Mwea-Tebere - Kirinyaga District 24.2 Gachoka - Embu District C others Legend see Appendix
1 ) Digits show trial site number; letters indicate degree of representativeness. For cartographic reasons, Soil Representativeness Code C is not indicated for the many scattered hills,_bottomlands, and flood plains. These areas should be considered inclusions of units with Representativeness Codes A, B , and B . 2) Site has not yet been identified. See Subsection 21.0.5 for explanation. MAP 21.0.5 GROUPINGS OF SOIL MAPPING UNITS REPRESENTED BY TRIAL SITES IN MURANG'A DISTRICT 37° E
• Site of first priority 21.1 Kareti 21.2 Makuyu soil groupings mapping code soil groupings boundary For EXPLANATION see PREVIOUS PAGF
Ö .30'
ABERDARE,/ NATIONAL/ PARK) ,'MVL
± S
SOURCE El Exploratory Soil Map of Kenya,1980 (scale 1:1,000,000) KEY LB1 soil mapping code — soil boundary 9# towns and major vi liages —. " tarmac road -^-"^ other all-weather roads district boundary national park boundary —---• river
For LEGEND See APPENDIX
FERTILIZER USE RECOMMENDATION PROJECT (1987) Ministry of Agriculture National Agricultural Laboratories German Agricultural Team
10 15 20 25 km Table 21.0.5: Hajor Soil Properties and Cliaatic Conditions of the Agro-Ecological Units in the Kurang'a District
Agro-Ecological Unit Soil properties Cliaatic Conditions Site Soil Cliaate drai- eff. nutr. top- aoist. classi- teap.l) teap. 1) rainfall Agro-Ec. Agro-Ec. Ho. Code Code nage depth avail, soil st.cap. fication aean ann. aean ain. 66X prob,2) Subtone Zone 3)
21.1. A v ed h Iah vh hu Hi a 18-21 11-14 560-680 a/1 i a/s UH 2 to ats/a b*t 18-21 11-14 560-740 f 1 i a to UH 1-2 a/1 i a/s b*x 18-21 11-14 740-800 f 1 i a UH 1 b c- a soil not representative 0 soil and/or cliaate are not representative ley: Effective toil depth Nutrient availabiliti 1) Teaperature (*C) (differentiated according to ABZ belts) ed eitreaely deep > 180 ca. h high vd very deep 120-180 ca. a aoderate 2) Rainfall 66X probability (in aa.) d deep 80-120 ca. 1 lov -referring to agro-huaid period of ad aoderately deep 50- 80 ca. vl very lov long rains only; sh shallov 25- 50 ca. Specification given •for definition of rainfall ranges see vsh very shallov < 25 ca. in Chapter IV.2 explanation to Hap 21.0.6; (aain report) -66X probability aeans that aaount of rainfall vill be exceeded in at least TOPSOLI properties Soil classification 20 out of 30 years. h huaic (base Ni Nitisols ao aollic ni-ch nito-chroaic 3) Agro-Ecological Subtone saturation >50 X) An Andosols hu huaic ni-rh nito-rhodic -approiiaalive indication only, since ah acid huaic (base Ca Caabisols or orthic an-hu ando-buaic suosones are not directlj related to saturation <50X| Lu Luvisols rh rhodic ve-eu verto-eutric aaount of rainfall; 2 thick (30-60 ca.) Ac Acrisols ch chroaic pe pellic -"--" in foraula aeans "folloved by"; 1 thin ((30 ca.) Fe Ferralsols eu eutric -for further explanation of subtones 0 noh-huaic Ve Vertisols see Chapter IV on aethodology; -Agro-ecological tones and subtones Drainale HoisUre storafe capaciti are shovn in Hap 21.0.3. se soaevhat eicessive vh very high > 160 aa. 4) Coaparable tiae: end of March-beginning of July. v veil h high 120-160 aa. a* aoderately veil a aoderate 80-120 aa. 5) Coaparable tiae: end of Harch-beginning of June. i iaperfect 1 lov < 80 aa. p poor 6) Hear the 350 aa-isobyete recoaaended. - 0.23 - EXPLANATION TO MAP 21.0.6 Soil Codes Climatic Codes = A = highly representative highly representative,i.e. same Agro-Ecol.Zones Belt and long rains (+/-10%) as at trial site moderately representative = B+ = moderately representative (soils of map unit are slightly more 1 AEZ Belt warmer, long rains 10-20% higher favourable than soils at the trial site) +• = 1 AEZ Belt warmer, long rains similar (+/-10%) 4— = 1 AEZ Belt warmer, long rains 10-20% lower = B- = moderately representative -+ = 1 AEZ Belt cooler, long rains 10-20% higher (soils of map unit are slightly less — * r 1 AEZ Belt cooler, long rains similar (+/-10%) favourable than soils at the trial site) = 1 AEZ Belt cooler, long rains 10-20% lower •+ = AEZ Belt the same, long rains 10-20% higher *- = AEZ Belt the same, long rains 10-20% lower i XX = 2 AEZ Belts warmer, long rains 20-30% higher o Trial sites XX. = 2 AEZ Belts cooler, long rains 20-30% lower 30-50% h (M m = 1 21.1 Kariti (Muranga District) 21.2 Makuyu (Muranga District) 22.1 Muirungi (Nyeri District) (23.2) Mwea-Tebere (Kirinyaga District) 24.2 Gachoka (Embu District) Areas not represented = not represented by soils and/or climate For further explanation see Table 21.0.5 MAP 21.0.6 AGRO-ECOLOGICAL UNITS REPRESENTED BY TRIAL SITES IN MURANG'A DISTRICT 37° E • Site of first priority 21.1 Kareti 21.2 Makuyu agro-ecological units boundary For EXPLANATION see PREVIOUS PAGE and TABLE 21.0.5 0',30" 22 1 b ABERDAR NATIONAL/ PARK* 22.1 22 1 b THIKA SOURCE El Exploratory Soil Map of Kenya,1980 (sca±e 1 :1,000,000) KEY LB1 soil mapping code — soil boundary O# towns and major villages •-= tarmac road :===: other all-weather roads — district boundary national park boundary —-- river ., boundary of Forest Reserve For LEGEND See APPENDIX FERTILIZER USE RflCOMMENDATTON PROJECT (1987) Ministry of Agriculture National Agricultural Laboratories German Agricultural Team 10 15 20 25 Km District: Murang'a General Aspects 21.0 LEGEND TO THE SOIL MAP OF MURANG'A DISTRICT 1—Explanation of first character (physiography) H Mountains and Major Scarps H Hills and Minor Scarps L Plateaus and High-Level Structural Plains R Volcanic Footridges F Footslopes U Uplands, Upper, Middle and Lower Levels A Floodplains 2—Explanation of second character (lithology): À Alluvial Sediments fron Various Sources B Basic and Ultra-Basic Igneous Socks (basalts, nepheline phonolites; older basic tuffs included) U Undifferentiated Basement System Rocks (predominantly Gneisses) V Undifferentiated or Various Igneous Rocks 3—Soil descriptions MV1 Imperfectly drained, shallow to moderately deep, dark greyish brown, very friable, acid humic to peaty, loam to clay loam, with rock outcrops and ice in the highest parts dystric HISTOSOLS, lithic phase; with LITHOSOLS and Rock Outcrops MV2 ' Well drained, very deep, dark reddish brown to dark brown, very friable and smeary, clay loam to clay, with a thick acid humic topsoil; in places shallow to moderately deep and rocky humic AHDOSOLS, partly lithic phase HU1 Somewhat excessively drained, moderately deep, red, very friable, sandy clay loam to sandy clay; in places rocky ferralic CAMBISOLS; with rhodic or orthic FERRALSOLS and Rock Outcrops HUC 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 LB1 Well drained, very deep, dark red, very friable clay nito-rhodic FERRALSOLS LB2 Well drained, very deep, dark reddish brown to dark brown, friable to firm, clay; in places with a humic topsoil verto-eutric NITISOLS; with mollic NITISOLS LB8 Imperfectly drained, very deep, dark grey to black, firm to very firm, bouldery and stony, cracking clay; in places with a calcareous, slightly saline deeper subsoil pellic VERTISOLS, stony phase and partly saline phase - 0.27 - District: Murang'a General Aspects 21.0 LBC Complex of: noderately veil drained, shallow, yellowish red to dark yellowish brown, friable, gravelly clay over petroplinthite or rock (50-701) IROHSTOHE SOILS; vith LITHOSOLS and: poorly drained, deep to very deep, dark brown to very dark greyish brown, Bottled, firn to very firn, cracking clay; in places noderately deep to very deep over petroplinthite ©differentiated VERTISOLS and vertic GLEYSOLS RBI Hell drained, extrenely deep, dark reddish brown to dark brown, friable and slightly sneary clay, vith an acid hunic topsoil ando-hunic HITISOLS; vith hunic ANDOSOLS RB2 Hell drained, extrenely deep, dusky red to dark reddish brown, friable clay, vith an acid hunic topsoil hunic NITISOLS RB3 Hell drained, extrenely deep, dusky red to dark reddish brown, friable clay; vith inclusions of veil drained, noderately deep, dark red to dark reddish brown, friable clay over rock, pisoferric or petroferric material eutric NITISOLS; vith nito-chronic CAMBISOLS and chronic ACRISOLS and LDVISOLS, partly lithic, pisoferric or petroferric phase FDC Conplex of: sonevhat excessively drained to veil drained, deep to very deep, dark red to dark yellowish brown soils of varying consistence and texture; in places gravelly ferralic ARENOSOLS; vith ferralo-chronic/orthic LUVISOLS and ACRISOLS DD1 Hell drained, noderately deep to deep, dark red to yellowish red, friable, sandy clay loan to clay -r- rhodic and orthic FERRALSOLS; vith ferralo-chronic/orthic/ferric ACRISOLS AA1 Hell drained to imperfectly drained, very deep, brown to dark brown, friable, micaceous, slightly calcareous, sandy loan to clay loan; in places vith a saline-sodic deeper subsoil eutric FLOVISOLS HOTES: 1. nollic Nitisols and. chrono-luvic Phaeozens: soils are equally important 2. nollic Nitisols, with, chrono-luvic Phaeozens: Hitisols are prevalent 3. in places: in <30% of the area 4. in nany places: in 30-501 of the area 5. predominantly: in >50% of the area 6. deeper subsoil: below 80 en. - 0.28 - District: Murang'a Trial Site 21.1: Kandara-Kareti Contents of Chapter 21.1: Detailed Description of the Kandara-Kareti 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 1.5 Names and Addresses of Government Officers from the Division and Farmers Involved in FURP Activities 1.9 2. Climate 1.10 2.1 Prevailing Climatic Conditions 1.10 2.1.1 Agro-Climatic Classification of the Area Represented 1.10 2.1.2 Relevant Meteorological Data 1.11 2.1.3 Crop Suitability from the Climatic Point of View 1.16 2.2 Proposal for the Monitoring of Agro-Climatic Conditions in Phase II 1.20 3. Soils 1.21 3.1 Survey Data 1.21 3.1.1 Brief Soil Description and General Information on the Soil 1.21 3.1.2 Detailed Profile Description and Soil Classification 1.22 3.1.3 Soil Sampling 1.24 3.2 Laboratory Data 1.24 3.3 Evaluation of Soil Data 1.28 3.3.1 Literature References and Soil Correlation 1.28 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 1.30 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: Murang'a Trial Site 21.1: Kandara-Kareti List of Tables l) Page Table 21.1.1 Physiography of the Kandara-Kareti Trial Site 1.7 Table 21.1.2 .Vegetation, Past and Present Land Use 1.8 Table 21.1.3 Names and Addresses of the Divisional Staff Members and Farmers of the Kandara-Kareti Trial Site 1.9 Table 21.1.4a Data óf the Nearest Long-Term Rainfall Station 1.12 Table 21.1.4b Data of the Nearest Long-Term Rainfall Station 1.13 Table 21.1.5 Temperature 1.14 Table 21.1.6 Potential Evaporation (Eo) 1.14 Table 21.1.7 Agro-Climatological Crop List for Kandara-Kareti 1.16 Table 21.1.8 Crop Development Stages and Crop Coefficients 1.18 Table 21.1.9 Detailed Profile Description of the Kandara-Kareti Trial Plot 1.23 Table 21.1.10 Analytical Results (physical and chemical analyses) 1.25 Table 21.1.11 Analytical Results (chemical analyses, trial plot) 1.26 Table 21.1.12 Analytical Results (chemical analyses,farmers' (No Samples fields) Taken) Table 21.1.13 Soil Correlation with Respect to the Kandara-Kareti Trial Site 1.28 Table 21.1.14 Evaluation of Mehlich Analysis Data According to NAL Standards 1.32 1) See Footnote next page. - 1.2 - District: Murang'a Trial Site 21.1: Kandara-Kareti List of Figures x) Page Figure 21.1.1 Demarcation of the Kandara-Kareti Trial Site 1.4 Figure 21.1.2 Access Map of the Kandara-Kareti Trial Site 1.5 Figure 21.1.3 Map of the Kandara-Kareti Trial Plot 1.6 Figure 21.1.4 Location of Farmers' Fields for On-Farm Trials, Kandara-Kareti 1.7 Figure 21.1.5 Rainfall and Potential Evaporation 1.15 Figure 21.1.6 Water Requirement and Availability for Maize H 511, First Rains 1.19 Figure 21.1.7 Location of Composite Sampling Blocks and Profile Pit at the Kandara-Kareti Trial Plot 1.24 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. - 1.3 - District: Murang'a Trial Site 21.1: Kandara-Kareti 1. Geographical and Additional Technical Information 1.1 Final Position of the Trial Site The position of the site at Kandara-Kareti is shown in Figure 21.1.1, ex- tracted from Map No. 135/3 - Makuyu. Its UTM grid coordinates are E 79.7 and N 04.2. The elevation is 1640 m. Further details on the final position are shown in Figure 21.1.2 and the sketch map of the trial plot in Figure 21.1.3. »9Q7 9904 «03 "02 Figure 21.1.1: Demarcation of the Kandara-Kareti Trial Site on the 1:50,000 Topographic Map - 1.4 - District: Murang'a Trial Site 21.1: Kandara-Kareti 1.2 Sketch of the Trial Site. The location of and the access route to the Kandara -Kare ti site are shown in Figure 21.1.2 and the map of the trial plot in Figure 21.1.3. v Ngurueini Machengecha 3Km Figure 21.1.2: Access Map of the Trial Site, Kandara-Kareti - 1.5 - District: Murang'a Trial Site 21.1: Kandara-Kareti Coffee Plantation FURP pins. _j. + .,_ + Cultivation edge Tree, 4**4 10 20 30 40 50m. Figure 21.1.3: Map of the Trial Plot, Kandara-Kar'eti - 1.6 - District: Murang'a Trial Site 21.1: Kandara-Kareti The approximate location of the on-farm trials is indicated in Figure 21.1.4. Since the selection of farmers' fields has not yet been finalized, Figure 21.1.4 has not been drawn. Figure 21.1.4: Location of Farmers' Fields for On-Farm Trials, Kandara- Kareti 1.3 Physiography Information on the physiography of the trial site and its surroundings is summarized in Table 21.1.1 below. Table 21.1.1: Physiography of the Kandara-Kareti Trial Site Elevation 1640 m. Landform volcanic footridges Physiographic position of the site middle and lower slope Topography of surrounding country undulating to hilly (steepest slopes 16-30%) Slope on which trial plot is sited 5-15% Aspect S Microtopography convex-concave slope sequence - 1.7 - District: Murang'a Trial Site 21.1: Kandara-Kareti 1.4 Vegetation, Past and Present Land Use Information on vegetation and on past and present land use is summarized in Table 21.1.2 below: Table 21.1.2: Vegetation, Past and Present Land Use of the Kandara-Kareti Trial Site Vegetation Undifferentiated clearings and cultivations from lower moist intermediate forests Cropping system, (a) cleared since: more than 20 years (b) crops grown: maize, beans, potatoes (c) fallow periods: none (d) present land use: maize (2 crops a year) H 511, H 512 Inputs (a) mineral fertilizers: 20:20:0 or DAP (b) organic manure : not applied (c) means of land preparation: manual (d) means of weeding: manual (e) frequency of weeding: twice per crop stand (f) other capital inputs: dipterex (stalk borer) (g) level of know-how: moderate Produce (a) maize 12 bags/acre (90 kg bags) Livestock none Remarks - 1.8 - District: Murang'a Trial Site 21.1: Kandara-Kareti 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 21.1.3. The codes used for the additional "on-farm" farmers refer to the location of their farms as indicated in Figure 21.1.4. Table 21.1.3: Names and Addresses of Divisional Staff Members and of Farmers at the Kandara-Kareti Trial Site Divisional Name Address Staff D.E.O. Bernard Ondanyi Box 1 - Kandara L.E.O. not met T.A. Kimani Wanyururu Kareti Sec. School Farmers Name Address Trial plot P.N. Njoroge Box - Thika (Headmaster Kareti Sec. LOCATION: Gaichanjiru School) SUB-LOCATION: Kagumo-ini On-Farm trials Name Remarks 21.1.A P. Muiruri Muratha Kiheko 21.1.B Kenyoho Primary Sch. It 21.1.C Kinyanjui Kiguru Kagundu-ini 21.1.D Njoroge Kiragu 21.1.E Mûrio Wongwari Kareti 21.1.F Mwangi K. Muthuku Karuhiu 21.1.G Julia Mukuhi Macegecha 21.1.H Chege Kigotho Kareti Period of site selection: August 1986. - 1.9 - District: Murang'a Trial Site 21.1: Kandara-Kareti 2. Climate 2.1 Prevailing Climatic Conditions 2.1.1 Agro-Climatic Classification of the Area Represented by the Kandara-Kareti Trial Site The following brief climatic description refers to existing information: ACZ : 114 (H.M.H. BRAUN, 1982)1) AEZ : UM 2, m/1 i m/s (R. JÄTZOLD, 1983)2) Next long-term rainfall station: 09036220, Thika, Kajuga Farm. Agro-Climatic Zone (ACZ): Moisture availability Zone II (r/Eo): annual average precipitation is >65- 80% of the potential evaporation (Eo). Temperature Zone 4: mean annual temperature is 18-20°C Agro-Ecological Zone (AEZ): UM 2 = Main Coffee Zone UM = Upper Midland Zone: mean annual temperature is 18-21°C, mean minimum 11-14°C 2 = sub-humid; annual average precipitation is >65-80% of the potent- ial evaporation (Eo) Sub-zone according to growing periods for annual crops (calculated for a "normal" crop in 60% probability) m/1 i m/s = with a medium to long cropping season, intermediate rains, and a medium to short cropping season. 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. - 1.10 - District: Murang'a Trial Site 21.1: Kandara-Kareti Formula Cropping season Lengths of growing period (exceeded in 6 out of 10 years) m/1 medium to long 155 - 174 days m/s medium to short 115 - 134 days 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 Kandara-Kareti 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 recording stations: 09036052, Githumu Secondary School (elevation: 2130 m), 10 km NW, and 09037005, Gethumbwini Estate (elevation: 1520 m), located 10 km SE of the Kandara-Kareti Trial Site (elevation: 1640 m). The data are listed in Tables 21.1.4a and 21.1.4b. Data from the nearest suitable long-term rainfall station: 09036220, Thika Kajuga Farm, could not be made available, since the final selection of the Kandara-Kareti Site was not carried out in time to allow for the processing of data. At the trial site, rainfall amounts are lower than at Githumu and higher than at Gethumbwini. In 20 out of 30 years the precipitation at Kandara-Kareti is more than 620 mm during the agro-humid period of the first rains (see Map 21.0.1), and more than 360 mm during the second rains (see Map 21.0.2). 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 extrapolated from the Jacaranda Coffee Research Meteorological Station (elevation: 1610 m), 25 km NE of the trial site. The temperature gradient in this area is on average 0.6°C per 100 m. 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 09136084, Jacaranda Coffee Research Meteorological Station. Temperature and evaporation data for the Kandara-Kareti Trial Site are given in Tables 21.1.5 and 21.1.6, and the rainfall pattern and potential evaporation are shown in Figure 21.1.5. For more detailed information on the methodology of climatic description see Chapter IV.2.2 of the main report. - 1.11 - Table 21.1.4a : Data of the Nearest Long-Term Rainfall Station Station No.: 09036052 Total years for calculation: 18 Githumu Sec. School. First year included: 1955 Elevation: 1550 m Last year included: 1985 Average annual rainfall: 1798 mm Rainfall surpassed in 20 out of 30 years (-66% Probability): 1st rains: 850 mm 2nd rains: 480 mm (beg. of Mar. - beg. of Jul.) (end of Oct. - mid Jan.) Decades Arithmetic Average Number of Rainy -66% Probabi- Years and Mean Days with Rainfall lity of ex- anal- Month (mm) >= 1 mm > = 5 mm ceeding ... mm ized 1 JAN 14.5 1 .0 1 .0 2.0 17 2 16.4 1 .0 0.9 2. 1 17 3 40. 1 2.2 2.2 8.8 17 4 FEB 34.5 1 . 9 1.8 13.9 16 5 19.4 1 .2 1 .2 5.5 16 6 27.2 0.8 0.8 0.0 16 7 MAR 14.2 1 .4 1.4 5.9 17 8 60.3 2.5 2.5 19.9 17 9 63.7 4.0 4.0 39.3 17 10 APR 110.1 4.5 4.5 66.0 17 1 1 137.7 6.3 6.3 105.2 17 12 146.0 6.5 6.4 89. 1 17 13 MAY 136.8 6.8 6.7 95.6 18 14 119.2 5.9 5. 9 78.2 18 15 60. 4 4.5 4.5 38.5 18 16 JUN 20.7 2.6 2.5 11.5 18 17 17.6 2.5 2.5 8.6 18 18 29.7 3.3 3.0 13.7 18 19 JUL 22. 2 2.2 2.2 7.3 17 20 21 . 4 2.9 2.9 8.5 17 21 12.9 2. 1 2.0 7.4 17 22 AUG 15.0 2.6 2.5 7.2 1 7 23 21 .6 2.9 2.8 8.2 17 24 13.8 2.2 2.0 6.3 17 25 SEP 10.9 1 .8 1 .7 4. 7 16 26 10.1 1.8 • 1 .6 5.8 16 27 25.2 2. 1 1 .9 2.7 16 28 OCT 51 .3 2.6 2.6 31 .5 14 29 44.3 3.0 3.0 23.0 14 30 92.8 4. 1 4.0 58.5 1 4 31 NOV 89.0 4.6 4.6 66.2 16 32 87.5 5.0 5.0 49. 9 16 33 70.8 4.0 4.0 41 .5 16 34 DEC 44.0 3.0 2.9 30.7 1 1 35 46.0 2.2 2. 1 29.0 1 1 36 50.6 1 .7 1 .7 17. 5 1 1 - 1.12 - Table 21.1.4b : Data of the Nearest Long-Term Rainfall Station Station No.: 09037005 Total years for calculation: 56 Thika, Gethumbuini Est. First year included: 1926 Elevation: 1500 m Last year included: 1985 Average annual rainfall: 1016 mm Rainfall surpassed in 20 out of 30 years (^66% Probability): 1st rains: 460 mm 2nd rains: 270 mm (beg. of Mar. - beg.of Jul.) (end of Oct. - mid Jan.) Decades Arithmetic Average Number of Rainy =66% Probabi- Years and Mean Days with Rainfall lity of ex- anal- Month (mm) >= 1 mm > = 5 mm ceeding . . .mm ized 1 JAN 11.1 1 .1 1 .1 2.6 53 2 10.7 1 .1 1 .1 2.6 53 3 12.5 1 .0 1 .0 3.5 53 4 FEB 14.8 1.1 1 .1 2.8 54 5 13.0 1 .3 1 .2 3.5 54 6 17.5 1 .4 1 .3 4.0 54 7 MAR 29.9 2.2 2.2 12.1 54 8 28.4 2. 1 2.0 11.3 54 9 53.3 4.0 3.9 33.9 54 10 APR 59.8 4.7 4.5 40.5 54 11 92.0 5.9 5.8 63. 1 54 12 93.8 5.4 5.3 64.4 54 13 MAY 66.5 4.8 4.8 39.9 52 14 51 .5 4.0 3.9 28.5 52 15 28.6 2.6 2.6 11.2 52 16 JUN 16.2 1 .9 1 .8 6.3 53 17 10.1 1 .5 1 .4 3.6 53 18 8.7 1 .9 1 .8 4.4 53 19 JUL 5.3 1 .2 1 . 1 0.0 54 20 6.2 1 .5 1 .5 2.2 54 21 7.5 1 .5 1 .4 2.0 54 22 AUG 6.3 1 .5 1 .4 1 .8 53 23 7.9 1 .7 1 .6 -3.8 53 24 6.1 1 .8 1 .5 2.7 53 25 SEP 7.8 1 .4 1 .3 1 .9 55 26 4.9 1 .0 0.9 0.0 55 27 11.0 1 .4 1 .4 3.5 55 28 OCT 8.3 1 .4 1 .4 2.5 56 29 23.9 2.3 2.2 11.2 56 30 51 .9 4.4 4.3 31 .6 56 31 NOV 53.6 4.6 4.5 36.0 55 32 60.4 5.4 5.2 42.0 55 33 49.7 5.0 4.8 31 .6 55 34 DEC 39.8 3.8 3.7 21 .7 55 35 24. 1 2.6 2.5 12.5 55 36 22.5 2.0 1 .9 8.0 55 - 1 . 1.3 - District: Murang'a Trial Site 21.1: Kandara-Kareti Table 21.1.5: Temperature (c O JAN. FEB. MAR. APR. MAY JUN. Mean temp. 19.0 19.7 20.1 19.8 19.0 17.4 Mean max.temp. 25.9 27.4 26.9 25.1 23.9 22.9 Mean min.temp. 12.1 12.1 13.4 14.6 14.1 12.0 JUL. AUG. SEPT. OCT. NOV. DEC. Mean temp. 16.5 16.8 18.1 19.4 18.9 18.5 Mean max.temp. 22.1 22.3 24.6 25.8 24.0 24.1 Mean min.temp. 11.0 11.4 11.6 13.1 13.8 12.9 annual mean: 18.6 mean max. : 24.6 mean min. : 12.7 Table 21.1.6: Potential Evaporation (Eo) in mm per Decade : JAN. FEB. MAR. APR. MAY JUN. 1st decade 46 52 50 41 35 30 2nd decade 46 52 50 41 35 30 3rd decade J51 41 55 41 38 30 Total : 143 145 155 123 108 90 JUL. AUG. SEPT. OCT. NOV. DEC. 1st decade 28 31 40 45 39 41 2nd decade 28 31 40 45 39 41 3rd decade 31 34 4_0_ Jtl _3J? 45 Total : 87 96 120 139 117 127 average annual potential evaporation: 1450 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. - 1.14 - 200 (mm) 190 Rainfall Station: 09036052 Githumu Sec. School 180 170 Meteorological Station: 160 09136084 Ruiru, Jacaranda 150 140 130 120 110 100 66% Probability UI 90 I 80 70 Eo 60 50 40 30 20 10 0 1 2 3 4 5 6 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Figure 12.1.5: Rainfall and Potential Evaporation District: Murang'a Trial Site 21.1: Kandara-Kareti 2.1.3 Crop Suitability from the Climatic Point of View A summary of the agro-climatic suitability of the most important seasonal crops is given in Table 21.1.7 below. Additional information on other crops, considered suitable from the agro-climatic viewpoint is given in the Farm Management Handbook, Vol. II/B, Central Kenya *). Table 21.1.7: Agro-Climatological Crop List for Kandara-Kareti 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 4) m = medium (m.) grow.period a — 1st rains 1 - late (mm. ) b = 2nd rains Sunflowers/ 120-135 0 - 1800 350-650 a)good to HS 301 A very good Maize/m.mat. 130-160 1000-1700 500-750 a) good like H 511 b) fair Beans/e.mat. a) good like GLP 92 90-110 700-1800 300-500 =Mwitemania b) good Beans/e.mat a) good like GLP 2 80-100 700-1800 250-450 =Rosecoco b) good Potatoes/ 140-170 1800-2900 450-750 a) good m.mat. b) fair 1) R. JÄTZOLD and H. SCHMIDT, eds.(1983): Farm 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 - 40-60X and poor <40% of the expected yield under optimum water availability adapted from R. JÄTZOLD and H. SCHMIDT, eds. (1982): Farm Management Handbook of Kenya, Vol. II/A, West Kenya. - 1.16 - District: Murang'a Trial Site 21.1: Kandara-Kareti For the most important food crops in the area around the Kandara-Kareti Trial Site, the crop coefficients (kc) are shown in Table 21.1.8, 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 21.1.8. The crop coefficients for the climatic conditions at the Kandara-Kareti Trial Site were estimated on the basis of data obtained from DOORENBOS and PRUITT (1977)1) and DOORENBOS and KASSAM (1979)2). The data on the duration of each of the growing seasons and on the 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) evapotranspiration (ETm) under the prevailing climate, assuming that water is not a limiting factor for plant growth. For this calculation the following approximative formula was employed: ETm = kc * Eo whereby: ETm= maximum (potential) evapotranspiration kc = crop coefficient Eo = potential evaporation (climatic evaporative demand) In Figure 21.1.6, the ETm-values are used to indicate the estimated maximum water requirements of an important food crop for optimum growth. Furthermore, the rainfall data at 66% reliability are shown in Figure 21.1.6 to give an indication of the water availability. However, when reading these figures, it must be borne in mind that the actual availabi- lity 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 21.1.6 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 - 1.17 - Table 21.I.S : Crop development stages 1) and crop coefficients (Kc) 2) for approx. naxinun (potential) crop evapotranspiration of the most important seasonal crops grown at Kareti (site no. 21.1) Crop/ Number of decades from seeding resp. planting to (physiological) maturity Variety 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 19 20 21 22 23 24 HAIZE 0.6 0.7 0.8 0.83 0.89 0.96 1.02 1.05 1.05 1.05 1.05 1.05 0.9 0.79 0.63 H511 I I I II II II II III III III III III IV IV IV POTATOES 0.6 0.7 0.8 0.84 0.92 1.0 1.05 1.05 1.05 1.05 0.98 0.87 0.76 I I I II II II III III III III IV IV IV BEANS 0.6 0.7 0.77 0.88 0.99 1.05 1.05 1.05 1.05 0.82 0.49 Rose coco I I II II II III III III III IV IV 00 I BEANS 0.6 0.7 0.77 0.88 0.99 1.05 1.05 1.05 1.05 1.05 0.82 0.49 GLP 92 I I II II • II III III III III III IV IV SUNFLOWER 0.6 0.7 0.76 0.85 0.95 1.05 1.1 1.1 1.1 1.1 1.1 0.92 0.52 HS 301 A I I II II II II III III III III III IV IV 1) Crop development stages as defined in chapter IV 2.2 (main report) I : initial stage II : development stage III = mid season IV : late season 2) Kc : crop coefficient as defined in chapter IV 2.2 (main report) Figure 21.1.6: Water requirements Rainfall Station: 09036052 and availability for crop Githumu Sec. School Maize H 511, first rains 120i Trial Site 21.1 Kareti mm 100- Probability 80- 60- I 40- 20- Decade 8 10 11 12 13 14 15 16 17 18 19 20 21 22 MAR APR MAY JUN JUL AU G District: Murang'a Trial Site 21.1: Kandara-Kareti 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 raingauge has to be installed at the Kandara-Kareti Trial Site to measure the actual precipitation on the spot. Subsequently, data can be compared with both rainfall for a particular year and the interpolated long-term average from the two nearby rainfall recording stations of the Meteoro- logical Department: 09036052, Githumu Secondary School and 09037005, Thika Gethumbwini Estate. 2) Records on other relevant meteorological parameters : Data on temperature, windrun, sunshine hours and relative humidity can be obtained from 09136084, Jacaranda Coffee Research Meteorological Station (elevation: 1610 m) in order to calculate Eo (climatic evaporative demand). For this purpose, a computerized PENMAN formula, modified by MC CULL0CH (1965) is available on PC. 3) Phenological records : Dates of planting or sowing of each crop, emergence, start of tasselling (for maize crop), budding (for bean 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 the actual evapotranspiration 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. - 1.20 - District: Murang'a Trial Site 21.1: Kandara-Kareti 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 extremely deep, dark reddish brown in colour, and consist of friable clay, with an acid humic topsoil. Prevailing soil structure is weak to moderate, sub-angular to angular blocky, and bioporosity is very high throughout the profile. Rating of soil-related land factors - Parent rock 1 rich: basic igneous rocks 2 moderately rich 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 1 high 2 moderate 3 poor 4 very poor - Topsoil properties 0 non-humic 1 humic 2 thick humic la acid humic 2a thick acid humic - 1.21 - District: Murang'a Trial Site 21.1: Kandara-Kareti - Salinity 0 non-saline 1 slightly saline 2 saline - Södicity 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 21.1.9. The location of the profile near the trial plot is shown in Figure 21.1.7. 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): humic Nitisol. 2. USDA Soil Taxonomy (Soil Survey Staff, 1975): typic Palehumult. very fine-clavev family. - 1.22 - Table 21.1.9: Detailed Profile Description of the Kareti Trial Plot [Profile nuaber: 21.1 jDate of examination: 10-10-1986 Authors: Sialing/Doelger ! Saiple Horizon Colour Mottling Texture Cutans Structure Biopores Consistence f w Concretions Other ! j No. (Hoist) j5 Features Genetic j Depth | Boundary weak •any v.f. hard; I 1 21.1.1 Ahl 0-20 5 YR 3/3 clay — fine •any f. friable; n.d. ... dark redd, subangular •any i. sl.sticky- 1 clear browi blocky •any c. sl.plastic 1 wavy I 2.5 YR •oderate •any v.f. hard; cotpaction 1 21.1.2 Ah2 20-37 2.5/4 clay — aediua •any f. fir«; n.d. ... due to dark redd, subangular •any i. sticky- tractor gradual browi blocky coaaon c. plastic ploughing saooth weak •any v.f. sl.hard; ft, 1 1 21.1.3 AB 37-65 5 YR 3/4 ... clay patchy aediua •any f. friable; n.d. few, soft, dark redd, thin subangular •any a. sticky- stall, 1 clear brow clay blocky •any c. plastic rounded 1 CO saooth 1 broken weak •any v.f. sl.hard; ft, I } 21.1.4 Btl 65-90 5YR3/4 ... clay aoderately Kdiui •any f. friable; n.d. fen, soft dark redd, thick angular •any s. si.sticky- SMll, browi clay blocky coaaon c. si.plastic rounded 1 •oderate •any v.f. sl.hard; ft, 1 21.1.5 6t2 90-120 diffuse 5YR3/4 clay broken aediua •any f. friable; n.d. fen, soft, dark redd, thick angular •any a. si.sticky- small, 1 brow clay blocky coMon c. si.plastic rounded 1 1 21.1.6 Ahl (control saaple) Reaarks: Colour: dark redd. : dark reddish Biopores: v.f. - very fine; f : fine; • : aediua; c : coarse Consistence: si.: slightly Field pH: n.d. = not determined District: Murang'a Trial Site 21.1: Kandara-Kareti 3.1.3 Soil Sampling Soil samples (profile, composite, farmers' fields, pF rings) are listed in Sub-Section 3.2. Figure 21.1.7 shows the location of the composite sampling Blocks (I to IV) as well as the location of the profile pit. r 50 m Q.ree 35m I o 3 •z 55m II *pi F/it III sr D fD i IV / / / 1 > 1 1 65m 1 Figure 21.1.7: Location of Composite Sampling Blocks and Profile Pit at the Kandara-Kareti 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 21.1.10 to 21.1.12. The methodology applied for obtaining these results is described in detail in Chapter IV.2 of the main report. -1.24 - District: Kuranga Trial Site: 21.1 Kandara-Kareti Table 21.1.10 : Analytical Results (physical and chenical analysis, results on air dry soil basis) Profile Samples fron Trial Site Horizon Depth Field Lab. ) 2 n. Sand Silt Clay Texture pH PH Diff. Cond. en. No. No. X I X X Class KC1 H2O PH H20 1 Ahi 0-20 21.1.1 8767/86 9 18 73 C 4.9 5.3 0.4 0.12 2 Ah2 20-37 21.1.2 8768 11 24 65 C 5.0 5.4 0.4 0.10 3 AB 37-« 21.1.3 8769 13 26 61 C 5.3 5.8 0.5 0.11 4 Bti 65-90 21.1.4 8770 9 18 73 C 5.4 6.0 0.6 0.12 5 Bt2 90-120 21.1.5 8771 9 16 75 C 5.5 5.8 0.3 0.14 a 6 7 Ahi 0-20 21.1.6 8772 13 16 71 c 5.2 5.4 0.2 0.10 Saturation Extract Na K Kg Ca Hn ECK Bases Al AI H+Al X water pH El.Cond. ne./IOOgn. AgTU— X X ne. KC1 1 NA NA NA 0.06 0.29 2.45 5.80 1.60 15.7b 54.78 0.89 0.14 0.34 2 NA NA NA 0.08 0.38 2.75 9.00 1.82 13.00 93.92 0.77 0.10 0.20 3 NA NA NA 0.10 0.22 4 NA NA NA 0.10 0.22 5 NA NA NA 0.08 0.22 6 7 NA NA NA 0.10 0.24 105 deg.C Na K Ng Ca CEC pH8.2 Bases Bases+Al Al Org. C N C/N POlisen in rel.to R 5./100gn. Acetati X ne./100gi. X X X PI». air dry 1 0.14 0.49 2.40 4.35 21.80 33.85 7.52 1.86 2.28 0.19 12.0 0.94 2 0.14 0.35 2.56 3.95 19.00 36.84 7.10 1.41 2.04 0.17 12.0 0.93 3 0.40 0.35 1.95 4.69 19.50 37.90 7.49 1.34 1.97 0.14 14.1 0.93 6 0.12 0.39 2.80 3.22 23.30 28.03 6.63 1.51 1.26 0.12 10.5 0.93 5 0.17 0.15 2.40 2.88 24.50 22.86 5.68 1.41 1.18 0.09 13.1 0.93 D 7 0.13 0.60 2.48 4.14 22.30 32.96 7.45 1.34 2.17 0.19 11.4 0.94 8 Moisture Retention Capacity Horizon Depth Vol.X Moisture Avail. Moisture Bulk Dens CD. bar 0 1/10 1/3 5 15 Capacity gn./cc. pFO 2 2.5 3.7 4.2 nt./10cn. 105 deg.C 1 Ahi 15-20 56.6 40.1 38.6 31.3 29.8 10.3 1.08 2 Ah2/AB 35-40 56.9 39.7 37.3 34.8 33.6 6.1 1.01 3 4 NA : not applicable ne./IOOgi. : lilliequivalents per 100 gi. of soil AgTU : Silver Thio Urea Extraction Acetate : Bases by Annniun Acetate pH 7, CEC by Sodiun Acetate 8.2 pH pH and conductivity in suspension 1:2.5 v/v - 1 .25 - District: Huranga Trial Site:21.1 Kandara-Kareti Table 21.1.11 : Analytical Results (clwrical analysis, results on air dry soil basis) Trial Site Coqiosite Sanples Depth BJock nutter x S Hax. ! en. I II III IV V VI VII diff. ! ; , Lab. No. /86 20 8773 8775 8777 8779 I 2 50 8774 8776 8778 8780 ! 4 Fine earth X 20 100 100 100 100 100 0.00 0.00 ! ! 5 50 100 100 100 100 100 0.00 0.00 ! ! 6 Vol.might gn./cc. 20 1.01 1.04 1.04 1.04 1.03 0.02 0.03 ! ! 7 50 0.99 1.00 0.99 0.98 0.99 0.01 0.02 ! ! 8 105 deg.C /air dry 20 0.94 0.94 0.93 0.93 0.94 0.01 0.01 ! : 9 50 0.94 0.93 0.93 0.93 0.93 0.00 0.01 : ! to ! il PHH20 1/1 20 5.7 5.8 5.6 5.6 5.68 0.10 0.20 ! 12 50 6.1 6.2 5.9 5.6 5.95 0.26 0.60 ! 1 i« pH H20 1/2.5 20 5.5 5.6 5.6 5.7 5.60 0.08 0.20 ! 14 50 5.4 5.3 5.3 5.4 5.35 0.06 0.10 ! 15 pH N KCI 1/2.5 20 4.6 4.7 4.8 4.7 4.70 0.08 0.20 ! 16 50 4.4 4.4 4.4 4.3 4.38 0.05 0.10 ! ! 17 ! 18 Corg. X 20 2.22 2.03 2.01 2.08 2.09 0.09 0.21 ; : 19 50 1.36 1.16 1.38 1.59 1.37 0.18 0.43 ! ! 20 N tot. X 20 0.28 0.26 0.18 0.26 0.25 0.04 0.10 ! ! 21 50 0.18 0.08 0.14 0.10 0.13 0.04 0.10! ! 22 C/N 20 8 8 11 8 8.73 1.63 3.36 ! ! 23 50 8 15 10 16 11.95 3.91 8.34 ! 24 ! 25 Nod.Olsen Abs. 260m 20 ! 26 (1/1000) 50 ! 28 S04 soluble ppi. 20 ! 29 50 ! 30 ! 31 P Heh.1/5 ppr. 20 7 11 7 11 9.00 2.31 4.00 ! 32 50 7 3 Trace 3 3.25 2.87 7.00 ! 33 P Olsen pp. 20 4.00 ! 34 50 8.00 ! 35 P nd.Olsen pp. 20 13.30 16.50 16.40 13.30 14.88 1.82 3.20 ! 36 50 8.00 6.80 5.30 5.40 6.38 1.28 2.70 ! 37 P Citric ac. ppr. 20 ! 38 50 1 «a ! 40 ECEC AgTU M./lOOp. 20 14.80 15.30 : 4i Bases X 20 70.54 70.20 : 42 AIX 20 NA NA : 43 ! 44 Hp BaC12 n./IOOgn. 20 not applicable ! 45 50 not applicable ! 46 Ht Al KCI n./IOOp 20 not applicable ! 47 50 not applicable ! 48 Al 3- KCI K./lOOgB. 20 not applicable ! 49 50 not applicable ; so AI 3- AgTU ne./100gn 20 not applicable : si ! 52 Sat.Ext. X H20 20 not applicable ! 53 50 not applicable ! 54 Sat.Ext. El.Cond. 20 not applicable ! 55 50 not applicable ! 56 Sat.Ext. pH 20 not applicable ! 57 50 not applicable 1 KO , 08 District: Kuranga Trial Site:21.1 Kandara-Kareti Table 21.1.11 : Analytical Results (chwical analysis, results on air dry soil basis) Trial Site Conosite Sanies Depth Block nunber X S Hax. ! en. I II III IV V VI VII diff. ! ; ! Lab. No. /86 20 8773« 8775 8777 8779 ! 2 50 8774 8776 8778 8780 ! 59 Na Heh.1/5 ne./IOOgn 20 0.07 0.07 0.07 0.07 0.07 0.05 0.00 ! 60 50 0.21 0.11 0.11 0.07 0.13 0.06 0.14 ! ! 61 Na Ag-TU ne./IOOgn. 20 0.08 0.08 ! 62 ! 63 K Ken. 1/5 ne./IOOgn. 20 0.25 0.11 0.07 0.07 0.13 0.09 0.18 ! 64 50 0.11 0.07 0.07 0.03 0.07 0.03 0.08 , ! 65 K nd.OI. ne./IOOgn. 20 0.58 0.23 0.13 0.08 0.26 0.23 0.50 ! I 66 50 0.13 0.18 0.08 0.10 0.12 0.04 0.10 ! 67 K Ag-TU ne./IOOgn. 20 0.76 0.36 1 CÛ 1 Do ; 69 Hg Heh.t/5 ne./IOOgn 20 1.20 1.20 1.70 1.30 1.35 0.24 0.50 ! 70 50 1.70 1.80 1.70 1.20 1.60 0.27 0.60 ! ! 71 Hg nod.Ol. ne./IOOgn 20 2.84 2.00 2.62 2.38 2.46 0.36 0.84 ! 72 50 3.44 3.42 3.05 2.75 3.17 0.33 0.69 ! 73 Hg Ag-TU ne./IOOgn. 20 2.60 2.70 ! 74 ! 75 CaKeh. 1/5 ne./IOOgn 20 2.80 2.80 2.80 2.30 2.68 0.25 0.50 ! 76 50 1.50 3.70 3.70 1.90 2.70 1.17 2.20! ! 77 Ca md.Ol. ne./IOOgn 20 10.00 10.00 9.90 7.60 9.38 1.18 2.40 I ! 78 50 6.70 11.60 7.20 7.20 • 8.18 2.30 4.90 ! 79 Ca Ag-TU re./IOOgn. 20 7.00 7.60 1 AA I flu ! 81 KnKeh. 1/5 ne./IOOgn 20 0.61 0.53 0.50. 0.65 0.57 0.07 0.15 ! 82 50 0.41 0.43 0.77 0.53 0.54 0.17 0.36 ! ! 83 Hn nd.OI. ne./IOOgn 20 0.65 0.46 0.51 0.60 0.56 0.09 0.19 ! ! 84 50 0.32 0.42 0.64 0.56 0.49 0.14 0.32 ! 85 Hn Ag-TU n./IOOp. 20 1.38 1.24 ! 86 ! 87 Zn HC1 ppn. 20 22.80 1 88 50 11.15 I 89 Zn nd. 01. ppn. 20 24.80 21.80 22.70 18.80 22.03 2.49 6.00 ! 90 50 11.50 21.30 18.60 10.00 15.35 5.46 11.30 ! ! 91 ! 92 Cu HC1 ppn. 20 7.80 ! 93 50 7.75 ! 94 Cu nd. 01. ppn. 20 27.40 27.00 24.30 21.70 26.10 2.65 5.70 ! 95 50 18.70 24.90 22.30 25.00 22.73 2.96 6.30 ! ! 96 ! 97 FeHCl ppn. 20 a9 ! 98 50 10 ! 99 Fe nd. 01. ppn. 20 100 109 104 109 105.50 4.36 9.00 : loo 50 87 95 136 107 106.25 21.47 49.00 ! M1 mlUI 1102 FeOxalate S 20 0.60 |103 50 0.67 !1O4 Al Oxalate 1 20 1.00 nos 50 1.00 NA : not applicable ne./IOOgn. : nilliequivalents per 100 gn. of soil Hen. : Kehl ich Analysis nd. 01. : Modified Olsen Extraction AgTU : Silver Thio Urea Extraction - 1.27 - District: Murang'a Trial Site 21.1: Kandara-Kareti 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 (main report). A report referring to the area in which the trial site is situated is 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. 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 21.1.13. Moreover, the FURP soil map unit (Map 21.0.4) and the classification of the soil of the profile at the trial plot are given. Table 21.1.13: Soil Correlation with Respect to the Kandara-Kareti Trial Site Reference Map unit Soil Classification El R2 humic Nitisols FURP RB2 humic Nitisols Trial plot profile humic NITISOL The only source for the area around Kareti is El. It indicates humic Nitisols for this area, which was confirmed at the trial site. 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). - 1.28 - District: Murang'a Trial Site 21.1: Kandara-Kareti 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 FURP trial sites are representative of the soils of Murang'a District is shown in Map 21.Q.5: "Groupings of Soil Mapping Units Represented by Trial Sites in Murang'a District". This map is discussed in Sub-Section 21.0.5. 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 are representative. Within Murang'a District, the Kandara-Kareti Trial Site has high represen- tativeness (Grouping 21.1.A) for the humic Nitisols of soil map unit RB2, which includes the Kandara, Kigumo and Kangema areas. The Kandara-Kareti Trial Site is also representative of large areas outside Murang'a District. Only in Nyeri District, however, is Grouping 21.1.A indicated, as Trial Sites 20.1 (Githunguri, Kiambu District), 23.1 (Keru- goya, Kirinyaga District), 24.3 (Embu A.R.S., Embu District), and 25.1 (Kaguru F.T.C., Meru District) also represent soil map unit RB2 in these respective districts. Grouping 21.1.A covers a large part of Central Nyeri District. It includes Karatina, Nyeri and Mweiga areas. 3.3.3 Variability of Soil Properties within the Trial Site The trial plot is situated on an irregular slope, convex and sloping in the upper part and concave to straight and very gentle in the lower part. The analytical data, however, showed a narrow range for pH and organic carbon content of the topsoils of the different composite blocks. pH-KCl: profile: 5.1 composite blocks: 4.6 - 4.8 organic carbon content: profile: 2.1% composite blocks: 2.0 - 2.2% A comprehensive breakdown of soil analytical data is given in Tables 21.1.10 to 21.1.12. 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. - 1.29 - District: Nurang'a Trial Site 21.1: Kandara-Kareti 3.3.4.1 Soil Profile The analytical data of the soil samples taken from the profile pit, situated on the side of the trial site between Block II and the road (see Figure 21.1.7), are presented in Table 21.1.10 and are interpreted in the following paragraphs. There is no presence of physical obstacles or extreme acidity in the subsoil which would limit the rooting depth of the soil. The capacity for plant available moisture in the upper 100 cm. of the profile may be roughly estimated from the pF analysis carried out for the Ahl horizon and the transition Ah2/AB: the figure is just below 80 mm. As plant roots may exploit a considerably deeper soil volume down to below 180 cm., this estimate is not apt to ratify the effective moisture storage capacity. The increase in micro-pores from the Ahl to the Ah2/AB reflects the reported compaction of the soil through tractor ploughing. The low available moisture capacity of the topsoil (10 mm. per 10 cm. depth) is further reduced (6.1 mm. per 10 cm. depth) in the compact horizons. The entire profile down to a depth of 120 cm. (maximum sampling depth) has a moderate CEC (pH 8.2) of 18 to 24 me./100 gm., decreasing somewhat from the Ahl to the Ah2, and increasing again with depth. The CEC appears closely related to the clay content with exceptionally little influence from the organic matter. The indicated base saturation is moderate down to 90 cm. and is low in the Bt2 horizon. With reference to the moderate CEC, exchangeable K is medium in the upper 90 cm. (Ah to Btl, 0.49 - 0.35 me./100 gm.) and decreases suddenly below the Btl to the low value of 0.15 me./100 gm. Mg is very high throughout (>2 me./100 gm.), showing a distinct minimum in the AB horizon. Ca is low in comparison to the other bases and in the low range (<5 me./100 gm.). The particularly low Ca by Ammonium-Acetate is neither confirmed by the Ca value obtained from the Silver-Thiourea extraction nor by the data from the trial site composite samples. Exchangeable bases are well balanced with respect to plant nutrition. The soil reaction increases with depth and is in the slightly acid range (pH KC1 5 - 5.5). The trial site composite samples show pH values of approximately 0.5 units lower (moderately acid), which appear more reasonable for the profile also. At this pH only negligible amounts of Al are exchangeable or soluble. The organic matter content of the three upper horizons down to a depth of 65 cm. is high (>2 % C) and decreases rather slowly with depth. The Bt2 below 90 cm. shows a medium humus" content of 1.2 % C. The N content of the soil covers the medium range and N decreases from 0.19 % in the Ahl to 0.09 % in the Bt2. The C/N ratios appear wide. 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 21.1.11. No samples were taken from the farmers' fields selected around this trial site and consequently Table 21.1.12 has been omitted. - 1.30 - District: Murang'a Trial Site 21.1: Kandara-Kareti 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. The very humic soil (2 - 2.2 % C in the topsoil composite samples) contains high amounts of total N (0.18-0.28 % N) in the topsoil and medium (0.08- 0.18 X N) amounts in the subsoil. The medium C/N ratios and other pre- vailing soil factors indicate that the N availability is probably moderate. According to the Mehlich analysis, "available" P is in the low range (<11 ppm.), the differences between the blocks being insignificant. In the subsoils Mehlich-P is extremely low in Blocks II to IV. In contrast, the modified Olsen method shows moderate to high P values (>13 ppm. in the topsoil). Block II in particular is very high in P. The subsoil has a low to moderate P status. The P availability, as indicated by the Mehlich analysis, is certainly inadequate to the N supplying capacity of the soil. The considerably higher modified Olsen-P might be slightly low in respect to the N availability in Blocks I, III and IV. This is indicated by the ratios of C/P (m.01.) and N/P (m.01.), which are on average 1500 and 100. This is approximately double the suggested level for optimum plant growth. The K status of the soil decreases considerably down slope, from Block I to Block IV. This change is much more pronounced in the topsoil than in the subsoil. "Available" K as determined by the Mehlich analysis is low to very low; in the topsoil it ranges from 0.25 me./100 gm. (Block I) to 0.07me./ 100 gm. (Blocks III and IV). These K values are in the same magnitude as the reported Na levels. This decrease from Block I to IV is even more pronounced in the results obtained by the modified Olsen method: While K is high in Block I (0.58 me./100 gm.), it is as low as Mehlich-K in Block IV (0.08 me./100 gm.). The analytical data provide no good reason for these changes in K, which are not observed with any other element analyzed. The "available" quantities of Mg are fairly constant over the entire trial site and high to very high throughout. The subsoil shows higher Mg levels than the topsoil. The Ca status of the soil as indicated by both methods (Mehlich analysis and modified Olsen method) is almost uniform in the topsoil and in the moderate to high range; the subsoil data are slightly more erratic. According to the Mehlich analysis, "available" Mn is well within the adequate range, the modified Olsen method shows almost identical data. - 1.31 - District: Murang'a Trial Site 21.1: Kandara-Kareti According to the modified Olsen method, Zn and Cu are available in very high amounts (Zn: 22 ppm., Cu: 25 ppm.) throughout. The HC1 extractable Zn and Cu determined in Block I are similarly high. The amount of Fe extracted by the modified Olsen method is high. The oxalate extraction for amorphous oxides and hydroxides yielded only low quantities of Fe and Al. The trial site composite samples are moderately to strongly acid (pH KC1 4.6 - 4.3). The soil pH is very uniform over the entire plot—pH (KC1) 4.6 - 4.8 in the topsoil and pH (KC1) 4.3 - 4.4 in the subsoil. In the moderately acid soils, the exchangeable acidity and especially exchangeable Al are too low to have any meaningful adverse effects on crop production. The evaluation of the Mehlich Analysis data according to NAL standards is given in Table "21.1.14. Table 21.1.14: Evaluation of the Mehlich Analysis Data According to NAL Standards Parameter Trial Site Farmers' Fields Soil reaction (pH) Moderately acid Acidity (Hp) Low Available nutrients Sodium Low Potassium Low Calcium Adequate Magnesium Adequate Manganese Adequate Phosphorus Very low Total Nitrogen Moderate Organic Carbon Moderate C / N Ratio Favourable Ca / Mg Ratio Favourable Ca / K Ratio Not favourable K / Mg Ratio Not favourable Remarks on Trial Site: Soil reaction is favourable. Positive yield responses to K, P, manure, and N applications are expected. Responses to lime applications are unlikely. - 1.32 - District: Murang'a Trial Site 21.1: Kandara-Kareti 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 February/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:P75 N0:P75 N75:P0 Trial II: 0 N+P FYM FYM+P FYM+N+P ' N+P+K 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:P75 N0:P75 N75:P0 Trial II: 0 N+P FYM FYM+P FYM+N+P N+P+K 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 H 511, first rains, at the Kandara-Kareti Trial Site, can be interpreted as follows : Figure 21.1.6 shows that the maximum water requirements (ETm) of the maize crop are not in line with the rainfall pattern at the 66% probability level, but on the prevailing deep soils, the surplus of water (peak in April/May) can be stored to a large extent. It must be borne in mind, however, that rainfall amounts at the trial site are 10- 15% lower than shown in the diagram (rainfall station: 09036052, Githumu Secondary School). - 1.33 - District: Murang'a Trial Site 21.1: Kandara-Kareti Run-off is considered to be high: the upper part of the trial site is located on considerably sloping land (13-14%) and the crop does not provide adequate ground cover at the time of maximum rainfall intensity in April and May. Deep percolation and lateral sub-surface flow could be estimated, but can be omitted, since they are generally very low, except during the period of high rainfall intensity in April/May. Since lateral sub- surface flow and run-off are mainly concentrated on the upper parts of the plot, the water "lost" from here flows mainly as additional water (as run-on and sub-surface flow) to the lower Block. For the Kandara-Kareti Trial Site, the moisture storage capacity is very high (i.e. >160 mm.). Therefore, the water surplus of April and May can, to a large extent, be stored and used to offset the rainfall deficits likely to occur from June onwards. Summarizing the evaluation of the climatic factors, the yield potential can, from the climatic point of view, generally be rated as good on a "20 out of 30 year" basis for the maize crop planted during the first rains. It must, however, be stressed again, that water availability conditions are less favourable in the upper block than in the lower block of the trial site. In the second rains, conditions are generally less favourable than in the first rains. 4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement The soil is characterized by a high humus content: probably the mineral- ization of the organic matter is slow and retarded. The natural N supply from the soil is probably moderate. P availability is very low according to the Mehlich analysis. In contrast, the modified Olsen method indicates a moderate to high P status. According to the latter method, Block II is particularly high in P. K decreases considerably from Block I to Block IV. The Mehlich analysis indicates low to very low K in the entire trial site, whereas K by the modified Olsen method ranges from high to very low. The moderately acid soil reaction is favourable for the growth of most crops. Fertilizer applications should first of all involve N and P, but in the lower parts of the trial site, K is equally important. P as TSP will probably be more efficient than SSP or rock phosphate in the first season. P from rock phosphate is less subject to fixation than P from TSP, and under the moderately acid soil conditions a reasonable avail- ability of P from soft, finely ground rock phosphate may be expected. The risks of P fixation into non-available forms are probably only low to moderate. The efficiency of P applications may be enhanced by the addition of small amounts of fresh FYM to stimulate soil biological activity. This treatment can also have a positive effect on the release of N and S from the soil. - 1.34 - District: Murang'a Trial Site 21.1: Kandara-Kareti Superphosphate contains about 12% S and therefore may act as a two-element fertilizer. Under farmers' conditions this might be very useful when limited S availability is suspected. The efficiency of mineral N applications will probably be enhanced when combined with adequate P supply. Top dressings may prove more efficient than broadcast applications at planting time. The N supply from the soil will probably be sufficient to make starter N unnecessary. High mineral N applications at planting time may lead to losses through denitrification, especially if high rainfall occurs and the aeration of the compact topsoil is (even slightly) restricted. During the high rainfall in April and May this may be expected in places with a weakly structured topsoil. For a more reliable estimate of the extent to which denitrifica- tion may occur, precise data on the soil air and moisture regime and its effects on N losses are required. K applications are probably not needed in the upper part (Block I) of the trial site and response to K may not be obtained there. However, in the lower parts, N and P applications will have to be supplemented with K. In Block IV response to K alone may also be obtained. The K fertilizer should at least replace the amounts of K removed with the harvests. The analytical data give no estimate of the reserves of K beyond the exchangeable pool, but its limitations are indicated by the rather low K levels found in the subsoil. As K fertilizer, K2S04 should generally be preferred to KC1 (both contain 50% K20) as the S04-ion enhances P availability. The form in which K is applied should also take into account crop requirements (e.g. KC1 to cabbages, but not to Irish potatoes). Under the present soil conditions liming is not needed and the acidifying effects of the applied mineral or organic fertilizers will be sufficiently buffered by the soil for the duration of the trials over five years. However, soil acidity and exchangeable Al should be closely monitored. Over longer periods of fertilizer use, the increasing soil acidity should be counterbalanced by liming. 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. CaCO3 per Kg. N or 0.2 Kg. lime per Kg. of CAN will be needed. TSP does not contribute sub- stantially to the Ca budget of the soil; soft rock phosphate (30% P205) contains about 2.7 Kg. CaCO3 equivalents per Kg. of P2O5. 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. In general, the topsoils of the humic Nitisols have good physical proper- ties. High porosity and stable structure maintain an environment in which no impeded gas exchange is to be expected. - 1.35 - District: Murang'a Trial Site 21.1: Kandara-Kareti b) Rootability. The extremely deep soils with their stable blocky structures and high porosity provide a very good environment for unhampered root development and tuber expansion. c) Resistance to erosion. The area has a moderate to high resistance to erosion. The negative influence of high rainfall intensity and the undulating to rolling topography is largely offset by the high structure stability (low erodibility) of the surface soil. d) Ease of cultivation and scope for agricultural implements. Although the soils impose no serious limitations to manual land preparation and oxen ploughing, areas with a rolling topography are less suitable for tractor ploughing. Moreover, tractor ploughing generally leads to the deterioration of physical properties of the topsoil (compaction). 5. Trial Design and Execution Plan, Kandara-Kareti (Full details of the methodology for carrying out the trials are shown in Chapter IV of the main report.) Selection of crops for each of the three modules at the Kandara site: Site 21.1 Kandara- RAINY SEASONS Kareti. 1st, Long, March 2nd rains Aug-Oct 51 Standard maize Hybrid 512 Hybrid 512 52 Maize & peas H.512+ Beans GLP 2 H.512+ Beans GLP 2 53 Pot./Cabbages;Beans Anett/Copenhagen Beans, GLP 1004 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 first rains, and Beans, GLP 1004 in the second rains. Each module contains 2 experiments, namely Experiment 1 and Experiment 2. Experiment 1 is a 4N x 4P factorial, with 2 replications in each module. Experiment 2 is a 2N x 2P x 2K x 2 FYM factorial, also with 2 replications in each module. Each module thus consists of 64 plots, and the total for the 3 modules is 192 plots. Fertilizer will be applied during both seasons. 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 peas 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: Murang'a Trial Site 21.2: Hakuyu Contents of Chapter 21.2: Detailed Description of the Makuyu 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 2.15 2.2 Proposal for the Monitoring of Agro-Climatic Conditions in Phase II . 2.19 3. Soils 2.20 3.1 Survey Data 2.20 3.1.1 Brief Soil Description and General Information on the Soil . 2.20 3.1.2 Detailed Profile Description and Soil Classification 2.21 3.1.3 Soil Sampling 2.23 3.2 Laboratory Data 2.23 3.3 Evaluation of Soil Data 2.28 3.3.1 Literature References and Soil Correlation 2.28 3.3.2 Representativeness 2.29 3.3.3 Variability of Soil Properties within the Trial Site 2.29 3.3.4 Fertility Status of the Soil 2.30 3.3.4.1 Soil Profile and Global Fertility Rating 2.30 3.3.4.2 Soil Fertility Assessment of Composite Samples 2.31 3.4 Sampling Programme for Laboratory Analysis 2.33 3.4.1 Soil Samples 2.33 3.4.2 Plant Samples 2.34 3.4.3 Other Samples 2.34 4. Conclusions from the Analyses of Climate and Soils 2.34 4.1 Moisture Availability 2.34 4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement 2.35 4.3 Other Relevant Land Qualities 2.36 5. Trial Design and Execution Plan 2.37 - 2.1 - District: Murang'a Trial Site 21.2: Makuyu List of Tables1) Page Table 21.2.1 Physiography of the Makuyu Trial Site 2.7 Table 21.2.2 Vegetation, Past and Present Land Use 2.8 Table 21.2.3 Names and Addresses of the Divisional Staff Members and Farmers of the Makuyu Trial Site 2.9 Table 21.2.4 Data of the Nearest Long-Term Rainfall Station 2.12 Table 21.2.5 Temperature 2.13 Table 21.2.6 Potential Evaporation (Eo) 2.13 Table 21.2.7 Agro-Climatological Crop List for Makuyu 2.15 Table 21.2.8 Crop Development Stages and Crop Coefficients 2.17 Table 21.2.9 Detailed Profile Description of the Makuyu Trial Plot 2.22 Table 21.2.10 Analytical Results (physical and chemical analyses) 2.24 Table 21.2.11 Analytical Results (chemical analyses, trial plot) 2.25 Table 21.2.12 Analytical Results (chemical analyses, farmers' fields) 2.27 Table 21.2.13 Soil Correlation with Respect to the Makuyu Trial Site 2.28 Table 21.2.14 Evaluation of Mehlich Analysis Data According to NAL Standards 2.33 1) See Footnote next page. : - 2.2 - District: Murang'a Trial Site 21.2: Makuyu List of Figures *) Page Figure 21.2.1 Demarcation of the Makuyu Trial Site 2.4 Figure 21.2.2 Access Map of the Makuyu Trial Site 2.5 Figure 21.2.3 Map of the Makuyu Trial Plot 2.6 Figure 21.2.4 Location of Farmers' Fields for On-Farm Trials, Makuyu 2.7 Figure 21.2.5 Rainfall and Potential Evaporation 2.14 Figure 21.2.6 Water Requirement and Availability for Maize Katumani C.B., First Rains 2.18 Figure 21.2.7 Location of Composite Sampling Blocks and Profile Pit at the Makuyu Trial Plot 2.23 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. - 2.3 - District: Murang'a Trial Site 21.2: Makuyu 1. Geographical and Additional Technical Information 1.1 Final Position of the Trial Site The position of the site at Makuyu is shown in Figure 21.2.1, extracted from Map No. 135/3 - Makuyu. Its UTM grid coordinates are E 98.4 and N 01.5. The elevation is 1430 m. Further details on the final position are shown in Figure 21.2.2 and the sketch map of the trial plot in Figure 21.2.3. Figure 21.2.1: Demarcation of the Makuyu Trial Site on the 1:50,000 Topographic Map - 2.4 - District: Murang'a Trial Site 21.2: Makuyu 1.2 Sketch of the Trial Site. The location of and the access route to the Makuyu site are shown in Figure 21.2.2 and the map of the trial plot in Figure 21.2.3. KamahuT.C. •'. Falls 3Km. Figure 21.2.2: Access Map of the Trial Site, Makuyu - 2.5 - District: Murang'a Trial Site 21.2: Makuyu Fence Trees '4 O 10 20 30 40 50m Figure 21.2.3: Map of the Trial Plot, Makuyu - 2.6 - District: Murang'a Trial Site 21.2: Makuyu The approximate location of the on-farm trials is indicated in Figure 21.2.4. major dust road vallevbotton major i dust j» ?.enark: funen' field K is situated close T to the Divisional Office. Figure 21.2.4: Location of Farmers' Fields for On~Farm Trials, Makuyu 1.3 Physiography Information on the physiography of the trial site and its surroundings is summarized in Table 21.2.1 below. Table 21.2.1: Physiography of the Makuyu Trial Site Elevation 1430 m. Landform volcanic sheets weakly dis- sected or peneplain-like 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 2-3% Aspect NE Microtopography forming gully crossing the eastern plot-boundary - 2.7 - District: Murang'a Trial Site 21.2: Makuyu 1.4 Vegetation, Past and Present Land Use Information on vegetation and on past and present land use is summarized in Table 21.2.2 below: Table 21.2.2: Vegetation, Past and Present Land Use of the Makuyu Trial Site Vegetation Undifferentiated Combretum types Cropping system (a) cleared since: more than 20 years (b) crops grown: maize, beans, potatoes (c) fallow periods: occasional (d) present land use: maize (2 crops a year) H 511 Inputs (a) mineral fertilizers: 20:20:0 (b) organic manure: applied (c) means of land preparation: manual (d) means of weeding: manual (e) frequency of weeding: twice per crop stand (f) other capital inputs: dipterex (stalk borer) (g) level of know-how: moderate Produce (a) maize 25 bags/acre (90 kg bags) Livestock none Remarks - 2.8 - District: Murang'a Trial Site 21.2: Makuyu 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 21.2.3. The codes used for the additional "on-farm" farmers refer to the location of their farms as indicated in Figure 21.2.4. Table 21.2.3: Names and Addresses of Divisional Staff Members and of Farmers at the Makuyu Trial Site Divisional Name Address Staff D.E.O. Francis Inoti Box 28 - Makuyu L.E.O. Peter Gathii n T.A. Bernard Kimani n Farmers Name Address Trial plot Charles Njonjo Box 28 - Makuyu LOCATION: Makuyu SUB-LOCATION: Gakungu On-Farm trials Name Remarks 21.2.A Esther Waithera manure applied 21.2.B Kabue Macharia 21.2.C Francis Chomba 21.2.D Mburu Njoroge 21.2.E James Mburu manure + 20:20:0 21.2.F Barnaba Mburu manure + 20:20:0 21.2.G Francis Thuo Vertisol 21.2.H Francis Mbau Vertisol Note: fields G and H are on Vertisols in the bottomlands. Period of site selection: August 1986. - 2.9 - District: Hurang'a Trial Site 21.2: Makuyu 2. Climate 2.1 Prevailing Climatic Conditions 2.1.1 Agro-Climatic Classification of the Area Represented by the Makuyu Trial Site The following brief climatic description refers to existing information: ACZ : IV4 (H.M.H. BRAUN, 1982)1) AEZ : UM 4, s/m + s (R. JÄTZOLD, 1983)2) Next long-term rainfall station: 09037143, Makuyu Divisional Office. Agro-Climatic Zone (ACZ): Moisture availability Zone IV (r/Eo): annual average precipitation is 40- 50% of the potential evaporation (Eo). Temperature Zone 4: mean annual temperature is 18-20°C Agro-Ecological Zone (AEZ): UM, 4 = Sunflower-Maize Zone UM = Upper Midland Zone: mean annual temperature is 18-21°C, mean minimum 11-14°C 4 = transitional; annual average precipitation is 40-50% of the potential evaporation (Eo) Sub-zone according to growing periods for annual crops (calculated for a "normal" crop in 60% probability) s/m + s = with a short to medium and a short cropping season. Formula Cropping season Lengths of growing period (exceeded in 6 out of 10 years) s/m short to medium 105 - 114 days s short 85 - 104 days + «= distinct arid period between growing periods 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: Murang'a Trial Site 21.2: Makuyu 2.1.2 Relevant Meteorological Data for the Makuyu Trial Site In this Section a breakdown is given of the following climatic parameters: rainfall, potential evaporation and temperature. Rainfall : Rainfall data are obtained from the nearest long-term rainfall station: 09037143, Makuyu Divisional Office (elevation: 1400 m), 1.3 km S of the Makuyu Trial Site (elevation: 1430 m). The data are listed in Table 21.2.4. At the trial site rainfall amounts are similar: in 20 out of 30 years the precipitation at the Makuyu Trial Site is more than 410 mm. during the agro-humid period of the first rains and more than 270 mm. in the agro- humid period of the second rains. The methods of rainfäll data analysis are described in Chapter IV.2.2 of the main report. Temperature and potential evaporation(Eo): Temperature data were obtained from 09037018: Punda Milia Estate temperature recording station (operating up to 1940, 8 recorded years), (elevation: 1370 m), 3 km NE of the trial site (elevation:•1430 m). Pote- . ntial 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: 09137048, Thika Agro-Mete- orological station (elevation: 1500 m), 18 km SW of the trial site. Temperature and evaporation data for the Makuyu Site are given in Tables 21.2.5 and 21.2.6, and the rainfall pattern and potential evaporation are shown in Figure 21.2.5. For more detailed information on the methodology of climatic description see Chapter IV.2.2 of the main report. - 2.11 - Table 21.2.4 Data of the Nearest Long-Term Rainfall Station Station No.: 09037143 Total years for calculation: 18 Makuyu D.O. First year included: 1967 Elevation: 1400 m Last year included: 1985 Average annual rainfall: 1009 mm Rainfall surpassed in 20 out of 30 years (=66% Probability): 1st rains: 410 mm 2nd rains: 270 mm (beg. of Mar. - end of June) (mid Oct. - end of Dec.) Decades Arithmetic Average Number of Rainy =66% Probabi- Years and Mean Days with Rainfall lity of ex- anal- Month (mm) >= 1 mm >= 5 mm ceeding . . .mm ized 1 JAN 8.9 0.9 0.9 1 .5 17 2 9.9 0.6 0.6 2.2 17 3 13.9 1 .2 1 .2 3.6 17 4 FEB 7.9 0.7 0.7 1 .2 18 5 15.5 1 .0 1 .0 1 .3 18 6 22.6 1 .2 1 . 1 2.5 18 7 MAR 24.0 1 .3 1 .3 7.9 17 8 31 . 1 1 .7 1 .7 12.5 17 9 53.6 3.3 3.3 35.6 17 10 APR 79.2 4.4 4.4 49.9 17 1 1 72.6 4.2 4. 1 54.2 17 12 108.2 4.2 4. 1 76.9 17 13 MAY 92. 1 3.6 3.6 52.6 18 14 38.0 2.2 2.2 13.9 18 15 27.1 1 .8 1 .8 11.5 18 16 JUN 8.8 0.7 0.7 2.9 17 17 7.9 0.7 0.6 2.7 17 18 12.4 0.9 0.9 2.7 17 19 JUL 5.7 0.6 0.5 1 .0 18 20 2.6 0.6 0.6 0.8 18 21 2.7 0.9 0.8 1 .1 18 22 AU6 1 .0 0.3 0.3 0.0 17 23 2.6 0.3 0.2 0.0 17 24 3.0 0.4 0.4 0.2 17 25 SEP 2.9 0.3 0.3 0.0 17 26 1.5 0.4 0.4 0.5 17 27 7.7 0.7 0.7 0.5 17 28 OCT 7.2 1 . 1 1 . 1 2. 1 18 29 25.2 1 .6 1 .6 6.9 18 30 75.2 3.9 3.9 42.5 18 31 NOV 62.8 3.5 3.4 40.4 16 32 70.5 4.1 4. 1 49.0 16 33 57.0 3.1 3. 1 36.6 16 34 DEC 27.7 1 .4 1 .3 7.8 14 35 13.3 1 .3 1 .3 6.5 14 36 6.4 0.9 0.8 1 .9 14 - 2.12 - District: Murang'a Trial Site 21.2: Makuyu Table 21.2.5: Temperature (°C) JAN. FEB. MAR. APR. MAY JUN. Mean temp, 20.2 21.5 22.4 21.5 20.6 18.8 Mean max.temp. 27.9 29.3 29.3 27 .3 25.9 24.4 Mean min.temp. 12.5 13.7 15.4 15.6 15.2 13.1 JUL. AUG. SEPT. OCT. NOV. DEC. Mean temp, 18.1 18.3 20.2 21.2 20.5 19.9 Mean max.temp, 24.0 24.0 27.3 27.6 26.0 25.8 Mean min.temp. 12.2 12.5 13.1 o 14.9 13.9 14.8 annual mean: 20.3 mean max. : 26.6 mean min. : 13.9 Table 21.2.6: Potential Evaporation (Eo) in mm per Decade : JAN. FEB. MAR. APR. MAY JUN. 1st decade 57 60 58 48 42 38 2nd decade 57 60 58 48 42 38 3rd decade 63 48 Je. 48 46 _3_8 Total : 177 168 170 144 130 114 JUL. AUG. SEPT OCT. NOV. DEC. 1st decade 33 39 53 58 51 52 2nd decade 33 39 53 58 51 52 3rd decade 37 Jil 53 Jtk 51 57 Total : 103 121 159 180 153 159 average annual potential evaporation: 1778 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. - 2.13 - Figure 21.2.5: Rainfall and Potential Evaporation (mm) Rainfall Station: 09037143 Makuyu D. 0. Meteorological Station: 09137048 Thika Agromet; St. 66% Probability 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC District: Murang'a Trial Site 21.2: Makuyu 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 21.2.7 below. Additional information on other crops, considered suitable from the agro-climatic viewpoint is given in the Farm Management Handbook, Vol. II/B, Central Kenya 1). Table 21.2.7: Agro-Climatological Crop List for Makuyu 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 4) m = medium (m.) grow.period a = 1st rains 1 = late ( mm. -) , b = 2nd rains Maize/e.mat. a) good/fair, Katumani C.B 85-110 700-1600 260-500 b) fair/poor Sorghum/ 85-110 0 - 1500 220-480 a) good e.mat.Serena b) fair Sunflowers/ a) good e. mat. 1 ike 80-100 0 - 1500 200-400 b) fair Issanka Beans/e.mat a) good/fair, like (GLP 2) 80-110 700-1800 250-450 b) fair/poor Rosecoco Beans/e.mat. 70-90 700-1600 230-420 a) good GLP 1004 b) fair 1) R. JÄTZOLD and H. SCHMIDT, eds. (1983): Farm 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. JÄTZOLD and H: SCHMIDT, eds. (1982): Farm Management Handbook of Kenya, Vol. II/A, West Kenya. - 2.15 - District: Murang'a Trial Site 21.2: Makuyu For the most important food crops in the area around the Makuyu Trial Site, the crop coefficients (kc) are shown in Table 21.2.8, differentiated according to decades (10 day periods) of the growing season which is the time between planting or sowing and physiological maturity. Furthermore, four crop development stages are distinguished in Table 21.2.8. The crop coefficients for the climatic conditions at the Makuyu Trial Site were estimated on the basis of data obtained from DOORENBOS and PRUITT (1977)1) and DOORENBOS and KASSAM (1979)2). The data on the duration of each of the growing seasons and on the 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) evapotranspiration (ETm) under the prevailing climate, assuming that water is not a limiting factor for plant growth. For this calculation the following approximative formula was employed: ETm = kc * Eo whereby: ETm= maximum (potential) evapotranspiration kc = crop coefficient Eo = potential evaporation (climatic evaporative demand) In Figure 21.2.6, 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 21.2.6 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 etc. The placement of the growing seasons of the various crops on the time axis as presented in Figure 21.2.6 was mainly based on the pattern of rainfall, whereby the peak water requirements of the plants should be met by high, reliable rainfall. Detailed information on the calculation procedures and references are 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 - 2.16 - Figure 21.2.6: Water requirements Rainfall Station: 09037143 and availability for crop Makuyu D. 0. Maize /Katumani, first rains Trial Site 21.2 Makuyu mm 00 I 14 15 16 17 18 MAR APR MAY JUN Table 21.2.8 : Crop development stages 1) and crop coefficients (Kc) 2) for approx. aaxiBua (potentiat) crop evapotranspiration of the aost important seasonal crops grovn at Hakuyu (site no. 21.2) Crop/ NuBber of decades froi seeding resp. planting to (physiological) laturity Variety 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 19 20 21 22 23 24 HAIZE 0.5 0.65 0.73 0.86 0.97 1.05 1.05 1.05 1.05 0.9 0.66 KATUKANI I I II II II III III III III IV IV S0R6HUH 0.5 0.65 0.73 0.86 0.97 1.0 1.0 1.0 1.0 0.89 0.63 SERENA I I II II II III III III III IV IV BEANS 0.5 0.65 0.73 0.86 0.97 1.05 1.05 1.05 0.82 0.49 Rose coco I I II II II III III III IV IV BEANS 0.5 0.65 0.73 0.97 1.05 1.05 1.05 0.82 0.49 6LP 1004 I I II II III III III IV IV SUNFLOVER 0.5 0.65 0.74 0.89 1.03 1.1 1.1 1.1 0.92 0.52 ISSANKA I I II II II III III III IV IV 1) Crop developaent stages as defined in chapter IV 2.2 (aain report) I : initial stage II : development stage III = aid season IV = late season 2) Kc : crop coefficient as defined in chapter IV 2.2 (aain report) District: Murang'a Trial Site 21.2: Makuyu 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 A rain gauge has to be installed at the Makuyu Trial Site to measure the actual precipitation on the spot. Subsequently, data can be compared with both rainfall for a particular year or season and the long-term average of the nearest long-term rainfall recording station of the Meteorological Department: 09037143, Makuyu Divisional Office. 2) Records on other relevant meteorological parameters: Data on temperature, windrun, sunshine hours and relative humidity can be obtained from: 09137048, Thika Agro-Meteorological Station (elevation: 1500 m), 18 km SW of the Makuyu Trial Site (elevation: 1430 m), in order to calculate Eo (climatic evaporative demand). For this purpose a computerized PENMAN formula, modified by MC CULLOCH (1965) is available on PC. 3) Phenological records : Dates of planting or sowing of each crop, emergence, start of tasselling (for maize crop), budding (for bean crop), flowering, ripeness or physiological maturity and harvest have to be recorded. Additionally the leaf area index (LAI) has to be determined (at least for the cereal crops) every week, 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 checks1) and observations on rooting depth at the above mentioned growing stages and run-off measurements would be needed to estimate the actual evapotranspiration 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. 1) Methods described in: P.J.M. COOPER and R. LAW, 1978: Enviro- nmental and Physiological Studies of Maize, Vol. 1.- Kenya Min. of Agr., and U.K. Min. of Overseas Dev., Maize Agronomy Res. Project, Final Report, Part III., N.A.R.S. Kitale and O.D.M. London - 2.19 - District: Murang'a Trial Site 21.2: Makuyu 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 extremely deep, dark reddish brown to dusky red in colour, and consist of friable clay. They have a predominantly moderate angular blocky structure and a very high bioporosity. General information on the soil - Parent rock 1 rich: basic igneous rocks 2 moderately rich 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 1 high to 2 moderate 3 poor 4 very poor - Topsoil properties 0 non-humic 1 humic 2 thick humic la acid humic 2a thick acid humic - 2.20 - District: Murang'a Trial Site 21.2: Makuyu - 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 21.2.9. The location of the profile near the trial plot is shown in Figure 21.2.7. 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): dystric 2. USDA Soil Taxonomy (Soil Survey Staff, 1975): "oxic" Paleustult. very fine-clavev family. - 2.21 - Table 21.2.9: Detailed Profile Description of the Kakuyu Trial Site '.Profile nurter: 21.2 Date of exanination: 2-10-1986 Author: Suai ing Saople Horizon Colour ! Mottling ! Texture ! Cutans ! Structure ! Biopores Insistence Field Concretions Other (Hoist) ' ' ' ' ' PH Features Ho. Genetic j Depth | Boundary many v.f, si.hard; 21.2.1 Ah 0- 12 5 YR 3/4 clay crumb many f. friable; n.d. dark redd, many m. si,sticky- clear brown many c. si.plastic wavy 2.5 YR moderate many v.f. si.hard; 21.2.2 BA 12-40 2.5/4 clay patçhy red i un many f. friable; n.d. Hn dark redd. thin subangular many m. si.sticky- very few gradual brown clay blocky common c. si.plastic snooth 2.5 YR moderate many v.f. si.hard; i 21.2.3 Bti 40-77 3/4 clay patçhy medium many f. friable; n.d. Hn. ru dark redd, thin angular many m. si.sticky- very few gradual brown clay blocky common c. si.plastic snooth broken moderate many v.f. si.hard; 21.2.4 Bt2 77 - 106 10 R 3/4 clay noderately medium many f. friable; n.d. Hn, dusky thick angular many m. si.sticky- very few diffuse red clay blocky common c. si.plastic weak many v.f. soft; 21.2.5 Bt3 106 - 125 2.5 YR 3/4 clay broken fine many f. friable; n.d. Hn dark redd. thin subangular many m. si.sticky- very few brown clay blocky common c. si.plastic 21.2.6 Ah (control sanple) Remarks: Colour: redd. : reddish Biopores: v.f. = verv fine; f. = fine; m. = medium; c. - coarse Consistence: si. - slightly Field pH: n.d. : not deternined District: Murang'a Trial Site 21.2: Makuyu 3.1.3 Soil Sampling Soil samples (profile, composite, farmers' fields, pF rings) are listed in Sub-Section 3.2. Figure 21.2.7 shows the location of the composite sampling Blocks (I to IV) as well as the location of the profile pit. major dust road -»Makuyu •profile nit Fig.StTht. II III IV Figure 21.2.7: Location of Composite Sampling Blocks and Profile Pit at the Makuyu 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 21.2.10 to 21.2.12. The methodology applied for obtaining these results is described in detail in Chapter IV.2 of the main report. - 2.23 - District: Nuranga Trial Site: 21.2 Hakuyu Table 21.2.10 : Analytical Results (physical and dmical analysis, results on air dry soil basis) Profile Sanies froi Trial Site Horizon Depth Field Lab. )2m. Sand Silt Clay Texture PH PH Oiff. Cond. a. to. No. * X X X Class KC1 H2O PH H2O 1 Ah 0-12 8666/86 _ 9 13 76 C 4.0 5.3 1.3 0.12 2 BA 12-40 8667 — 9 11 80 C 4.0 5.7 1.7 0.08 3 Btl 40-77 8668 — 9 11 84 C 4.2 5.6 1.4 0.05 4 Bt2 77-106 8669 — 7 9 80 C 4.7 5.2 0.5 0.02 5 Bt3 106-125 8670 — 9 11 80 C 5.0 5.1 0.1 0.03 0• 7 Ah Control 8671 — 9 15 78 C 3.9 5.2 1.3 0.09 8 Saturation Extract; Na K Mg Ca Mn ECK Bases Al Al H+Al PI frmH ..... luster PH CI.MMHI. B./IOOp. X X M./IOOp. KC1 1 NA NA NA 0.06 0.85 2.25 5.80 13.40 65.37 6.87 0.92 1.42 2 NA NA NA 0.06 0.40 1.80 5.80 13.00 62.00 10.15 1.32 2.20 3 NA NA NA 1.10 1.40 4 NA NA NA 0.24 0.46 5 NA NA NA 0.14 0.24 t o 7 NA NA NA 1.10 1.48 8 105deg.C Na K Ng Ca CEC pHB.2 Bases iÄS68+A1 Al Org. C N C/N P Olsen in rel.to •mt /MM« Irstatf X • ./100p. X X X PP. air dry 1 0.11 0.60 1.76 1.15 22.30 16.23 4.54 20.26 1.46 0.12 12.17 0.95 2 0.12 0.29 1.20 0.96 19.50 13.18 3.89 33.93 1.02 0.08 12.75 0.95 3 0.11 0.07 1.04 0.75 18.80 10.48 3.07 35.83 0.75 0.08 9.38 0.95 4 0.15 0.08 1.37 0.83 16.30 14.91 2.67 8.99 0.63 0.07 9.00 0.95 5 0.16 0.07 1.56 0.76 18.00 14.17 2.69 5.20 0.45 0.07 6.43 0.94 ft 0 7 0.12 0.53 1.92 1.02 22.00 16.32 4.69 23.45 1.65 0.10 16.50 0.95 8 Moisture Retention Capacity Horizon Depth Vol.X Moisture Avail. Moisture Bulk Dm Ci. bar 0 1/10 1/3 5 15 Capacity p./cc. PFO 2 2.5 3.7 4.2 •./10a. 105deg.C 1 Ah/BA 10-15 57.0 38.9 35.0 28.5 27.0 9.9 1.07 2 Btl 60-65 60.5 42.0 35.7 29.0 27.5 14.5 1.00 3 4 NA = not applicable B./100gi. : lilliequivalents per 100 p. of soil AgTU : Silver Thio Urea Extraction Acetate - Bases by Arnim Acetate pH 7, CEC by Sodim testate pH 8.2 pH and conductivity in suspension 1:2.5 v/v - 2.24 - District: Kuranga Trial Site: 21.2 Hakuyu Table 21.2.11 : Analytical Results (chenical analysis, results on air dry soil basis) Trial Site Conposite Samples Depth Block number X s Max. ; CD. I II Ill IV V VI VII diff. ] ; , Lab. No. /86 20 8672 8674 8676 8678 2 50 8673 8675 8677 8679 ! 4 Fine earth X 20 100 100 100 100 100 0.00 0.00 ! ! 5 50 100 100 100 100 100 0.00 o.oo ! : 6 Vol.weight gn./cc. 20 0.93 0.98 0.95 0.97 0.96 0.02 0.05 I i 7 50 0.94 0.87 0.88 0.91 0.90 0.03 0.07 ! ! 8 105 deg.C / air dry 20 0.94 0.95 0.94 0.96 0.95 0.01 0.02 i ! 9 50 0.95 0.94 0.94 0.95 0.95 0.01 0.01 ! ! 10 ! H pH H2O 1/1 20 5.4 5.0 5.3 5.3 5.25 0.17 0.40 ! ! 12 50 5.1 4.7 4.9 5.0 4.93 0.17 0.40 ! ! 13 pH H20 1/2.5 20 5.0 4.7 4.9 4.8 4.85 0.13 0.30 ! ! 14 50 4.8 4.5 4.7 4.8 4.70. 0.14 0.30 ! ! 15 pH N KC1 1/2.5 20 4.2 3.9 4.0 4.0 4.03 0.13 0.30 ! ! 16 50 4.0 3.8 3.9 4.0 3.93 0.10 0.20 ! ! 18 C org. % 20 1.57 1.44 1.32 1.36 1.42 0.11 0.25 ! : 19 50 1.43 1.03 1.15 1.04 1.16 0.19 0.40 ; 1 20 N tot. X 20 0.09 0.13 0.09 0.16 0.12 0.03 0.07 ! ! 21 50 0.10 0.08 0.09 0.05 0.08 0.02 0.05 ! ! 22 C/N 20 17 11 15 9 12.92 3.94 8.94 ; ! 23 50 14 13 13 21 15.19 3.81 8.02 ! ! 24 . ! 25 Kod.Olsen Abs. 260nn 20 ! 26 (1/1000) 50 1 57 1 *' ! 28 S04 soluble ppn. 20 4 ! 29 50 4 ! 30 • ! 31 P Keh.1/5 ppm. 20 13 23 19 14 17.25 4.65 10.00 ! ! 32 50 15 23 19 19 19.00 3.27 8.00 : ! 33 P Olsen ppn. 20 4.00 ! 34 50 4.00 ! 35 P nod.Olsen ppn. 20 8.00 14.80 13.30 12.00 10.42 4.39 10.80 i 36 50 6.80 8.00 8.00 . 14.80 9.40 3.64 8.00 ! ! 37 P Citric ac. ppn. 20 ! 38 50 40 ECEC AgTU ne./100gn. 20 11.60 13.00 ! 41 Bases X 20 58.36 55.15 : 42 A1X 20 3.97 7.54 ! 43 !44 Hp BaC12 ne./100gn. 20 0.50 1.00 0.50 0.60 0.65 0.24 0.50 ! ! 45 50 1.20 2.00 1.10 0.90 1.30 0.48 1.10 i ! 46 H 4 Al KO ne./100gn 20 0.66 1.42 0.64 1.01 0.93 0.37 0.78 ! ! 47 50 1.60 2.40 1.86 1.48 1.84 0.41 0.92 ! ! 48 AI 3- KC1 ne./100gn. 20 0.46 0.98 0.48 0.78 0.68 0.25 0.52 ! ! 49 50 1.22 1.90 1.38 1.12 1.41 0.35 0.78 ! ! 50 Al 3- AgTU ne./100gn 20 ! 51 1 52 Sat.Ext. X H20 20 not applicable i 53 50 not applicable ! 54 Sat.Ext. El.Cond. 20 not applicable ! 55 50 not applicable ! 56 Sat.Ext. pH 20 not applicable ! 57 50 not applicable i en , 08 - 2.25 - District: Huranga Trial Site: 21.2 Kakuyu Table 21.2.11 : Analytical Results (chemical analysis, results on air dry soil basis) Trial Site Composite Samples Depth Block number X s Hax. ! en. I II III IV V VI VII diff. i ! i !Lab. No. /86 20 8672 8674 8676 6678 ! 2 ! 50 8673 8675 8677 8679 il s* \ 59 ! Na Heh.1/5ne./100gn 20 0.09 0.09 0.07 0.09 0.09 0.01 0.02 ! ! 60 [ 50 0.09 0.07 0.07 0.07 0.08 0.01 0.02 ! ! 61 [Ha Ag-TU ne ./lOOgn. 20 0.06 0.06 1 ! 62 1 I ! 63 IK Heh.1/5 se./100gn. 20 0.61 0.35 0.54 0.54 0.51 0.11 0.26 ! ! 64 i 50 0.39 0.13 0.20 0.23 . 0.24 0.11 0.26 ! ! 65 |K nod.01. oe./100gn. 20 0.66 0.46 0.69 0.64 0.61 0.10 0.23 ! ! 66 j 50 0.44 0.26 0.31 0.20 0.30 0.10 0.24 ! ! 67 |K Ag-TU me./lOOgn. 20 0.76 0.56 1 fiO i Do ! 69 Hg Heh.1/5 ne./100gn 20 2.10 1.90 1.90 1.90 1.95 0.10 0.20 I ! 70 j 50 1.80 1.30 1.50 1.60 1.55 0.21 0.50 1 ! 71 iHgnd.01. ne./100gn 20 2.50 1.75 2.42 2.00 2.17 0.35 0.75 I ! 72 50 1.75 1.25 1.42 1.40 1.46 0.21 0.50 I ! 73 !Hg Ag-TU M ./lOOgn. 20 1.95 2.15 1 ! 74 1 ! 75 ! Ca Heh.1/5ne./100gn 20 1.30 1.30 0.90 0.90 1.10 0.23 0.40 ; ! 76 50 0.90 Trace Trace Trace 0.23 0.45 0.90 ! ! 77 |Ca nod.01. me./IOOgn 20 5.00 5.50 6.30 5.00 5.45 0.61 1.30 ; ! 78 j 50 4.00 4.30 4.30 2.70 3.83 0.76 1.60 ! ! 79 iCa Ag-TU ffi!./100gn. 20 4.00 4.40 : ai !Hn Heh.1/5 ne./IOOgn 20 0.92 0.76 0.86 0.75 0.82 0.08 0.17 ! ! 82 50 0.83 0.75 0.67 0.80 0.76 0.07 0.16 i ! 83 |Kn nod.01. ne./IOOgn 20 1.72 1.67 1.03 1.71 1.53 0.34 0.69 ! ! 84 j 50 1.26 1.03 1.28 0.61 1.05 0.31 0.67 ! ! 85 |Hn Ag-TU n>!./100gn. 20 1.24 1.38 1 ! 86 1 j ! 87 !Zn KC1 ppn 20 11.70 ! 88 [ 50 2.70 I 89 !Zn nod. 01 ppn. 20 3.50 2.50 3.00 2.50 2.88 0.48 LOO ! ! 90 | 50 2.50 2.00 1.30 1.50 1.83 0.54 1.20 ! 1 ! 91 1 ! 92 |Cu HC1 ppn 20 2.45 ! 93 [ 50 1.80 ! 94 [Cu nod. 01 ppn. . 20 10.20 10.3 10.30 9.20 8.36 3.70 8.50 ! 95 | 50 9.20 9.00 11.40 10.20 9.98 0.80 2.40 ! i ! 96 i ! 97 !Fe HCI ppn 20 6.00 ! 98 50 5.00 ! 99 !Fe nod. 01 ppn. 20 132 134 200 141 151.63 32.50 68.50 |100 j 50 160 188 158 108 153.25 33.09 79.50 1 ; loi1 ! 102!Fe Oxalate X 20 ! 103 50 ; 104|A1 Oxalate X 20 50 ; los! ; NA : not applicable ne./IOOgn. = nilliequivalents per 100 gn. of soil Heh. : Hehl ich Analysis nod. 01. = Hodified Olsen Extraction AgTU : Silver Thio Urea Extraction - 2.26 - District: Huranga Trial Site: 21.2 Kakuyu Table 21.2.12 : Analytical Results (chemical'analysis, results on air dry soil basis) Farmers' Fields Composite Sanpies Depth Farmers1 fields (code) Trial site X S Hax. i cm. A B C D E F 6 H average diff. ! 1 Lab. No. /M 20 8680 8681 8682 8683 8684 8685 8686 8687 2 Fine earth X 20 too 100 100 100 too 100 100 100 100 100.00 0.00 0.00 i 3 Vol.weight gm./cc. 20 0.98 0.95 0.96 0.95 0.94 1.10 0.96 0.97 0.05 0.17 ! 4 105 deg. C / air dry 20 0.94 0.95 0.95 0.95 0.93 0.95 0.93 0.93 0.95 0.94 0.01 0.02 ! 0.95 0.94 6 pH H2O 1/1 20 5.60 5.20 5.10 5.80 5.90 5.30 5.40 5.50 5.25 5.45 0.27 0.80 ! 7 'pH H2O 1/2.5 20 5.10 4.80 4.70 5.50 5.40 5.30 5.20 5.20 4.85 5.12 0.28 0.80 ! 8 pH N KCI 1/2.5 20 4.20 3.90 3.90 4.60 4.80 4.50 4.30 4.40 4.03 4.29 0.31 0.90 ! 10 C org. X 20 1.68 1.36 1.29 1.76 1.92 1.50 1.95 1.80 1.42 1.63 0.25 0.66 ! 11 N tot. X 20 0.13 0.06 0.07 0.10 0.13 0.10 0.06 0.05 0.12 0.09 0.03 0.08 i 12 C/N 20 13 23 18 18 15 15 33 36 13 20.31 8.51 23.08 ! 14 Kod.Olsen Abs.260nn. 20 16 P Heh. 1/5 ppm. 20 23.00 31.00 23.00 25.00 13.00 19.00 13.00 11.00 17.25 19.47 6.61 20.00 ! 17 P mod.Olsen ppm. 20 4.00 6.80 9.30 6.80 10.60 12.00 13.30 8.00 10.42 9.02 2.91 9.30 ! 18 19 Na Heh.1/5 me./100gm. 20 0.09 0.07 0.07 0.09 0.13 0.33 0.25 0.15 0.09 0.14 0.09 0.26 ! 20 21 K Heh.1/5 me./100gm. 20 1.00 0.58 0.31 0.73 1.38 0.55 0.43 0.15 0.51 0.63 0.37 1.23 I 22 K mod.01. me./IOOgm. 20 0.93 0.55 0.33 0.68 1.33 0.73 0.61 0.74 0.32 1.00 Ï 23 24 Hg Heh.1/5 ne./100gm. 20 2.70 1.70 1.90 2.80 3.50 1.50 2.30 2.30 1.95 2.29 0.63 2.00 J 25 Hg mod.01. ne./100gm. 20 3.35 1.72 1.65 3.25 4.83 2.87 5.24 5.45 2.17 3.39 1.47 3.80 ! 26 27 Ca Heh.1/5 ne./IOOgm. 20 2.20 0.40 Trace 4.00 5.50 4.00 6.90 6.50 1.10 3.40 2.60 6.90 ! 28 Ca mod.01. ne./IOOgm. 20 6.00 3.80 3.60 10.30 12.90 5.80 13.30 12.60 5.45 8.19 4.04 9.70 ! 29 30 HnKeh. 1/5 ne./IOOgm. 20 0.80 0.73 0.88 0.97 0.83 0.38 0.31 0.15 0.82 0.65 0.29 0.82 ! 31 Kn mod.OI. ne./IOOgm. 20 0.65 0.96 0.95 0.78 0.88 0.92 0.85 0.40 1.53 0.88 0.30 1.13 ! 32 33 Zn mod.01. ppm. 20 4.90 3.70 2.80 4.30 5.60 3.70 4.10 1.80 2.88 3.75 1.15 3.80 |x 34 35 Cu mod.01. ppm. 20 12.10 97.60 12.50 10.30 11.00 11.60 11.70 6.00 8.36 20.13 29.13 91.60 ! 36 37 Fe mod.01. ppn. 20 115 94 107 77 61 62 128 197 152 110.29 44.31 136.00 : 38 39 Hp BaC12 me./IOOgm. 20 0.65 40 H 1 Al KCI ne./IOOgm. 20 0.34 1.32 1.72 0.22 0.26 0.42 0.32 0.28 0.93 0.65 0.55 1.50 ! 41 Al KCI ne./IOOgm. 20 0.22 0.86 1.24 11.12 0.18 0.28 0.20 0.16 0.68 0.44 0.40 1.12 i NA : not applicable me./tOOgm. : milliequivalents per 100 gm. of soil ppm. : parts per'miliion Heh. : Hehl ich Analysis Hod. 01. : Modified Olsen Extraction - 2.27 - District: Murang'a Trial Site 21.2: Makuyu 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. A report referring to the area in which the trial site is situated is 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. 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 21.2.13. Moreover, the FURP soil map unit (Map 21.0.4) and the classification of the soil of the profile at the trial plot are given. Table 21.2.13: Soil Correlation with Respect to the Makuyu Trial Site Reference Map unit Soil Classification eutric Nitisols; with nito- El R3 chromic Cambisols and chromic Acrisols, partly pisoferric or petroferric phase eutric Nitisols; with nito-chro- FURP RB3 mic Cambisols and chromic Acri- sols and Luvisols, partly lithic pisoferric or petroferric phase Trial plot profile dystric NITISOL Map unit R3 of the Exploratory Soil Map refers to a range of soil classification units. At the trial site, the soils key out as dystric Nitisols, although "eutric" is indicated by El as the prevailing classification unit. - 2.28 - District: Murang'a Trial Site 21.2: Makuyu 3.3.2 Repre s entât ivene s s 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 subsurface 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. The extent to which all FURP trial sites are representative of the soils of Murang'a District is shown in Map 21.0.5: "Groupings of Soil Mapping Units Represented by Trial Sites in Murang'a District". This map is discussed in Sub-Section 21.0.5. 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 are representative. Within Murang'a District, the Makuyu Trial Site has high representativeness (Grouping 21.2.A) for the lower slopes of the Aberdares including Murang'a, Saba Saba and Makuyu. It refers to soil map unit RB3. The Makuyu Trial Site is also representative of vast areas outside Murang'a District. It is highly representative (Grouping 21.2.A) of all eutric and dystric Nitisols around the Aberdares and Mount Kenya, which are the main soils in l«rge parts of Kiambv*,, Kirinyaga, Embu and particularly Meru Districts. " * The verto-eutric Nitisols of soil map unit LB2, which extends into Kirinyaga and Embu Districts, are moderately represented by the Makuyu Trial Site (Grouping 21.2.B+). 3.3.3 Variability of Soil Properties within the Trial Site The trial plot has a uniform appearance and has extremely deep soils throughout. A breakdown on the soil properties pH-KCl and organic carbon content of the topsoils is given in this section. pH-KCl: profile: 4.0 composite samples: 3.9-4.2 farmers' fields: 3.9 (fields B and C) - 4,8 (field E) - 2.29 - District: Hurang'a Trial Site 21.2: Makuyu organic carbon content : profile: 1.5% composite samples: 1:3% - 1.6% farmers' fields: 1.3% - 1.5% (B,C,F) 1.7% - 1.9% (A.D.E.G.H) The ranges appear to be narrow. A comprehensive listing of soil test values is to be found in Tables 21.2.10 to 21.2.12. 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 on the side of the trial site between Block I and the road (see Figure 21.2.7), are presented in Table 21.2.10 and are interpreted in the following paragraphs. There is no presence of physical obstacles or extreme acidity in the sub- soil which would limit the rooting depth of the soil.The capacity for plant available moisture in the upper 100 cm. of the profile may be roughly esti- mated from the pF analysis carried out for the transition Ah/BA and the Btl horizons; it attains approximately 120 mm. As plant roots may exploit a considerably .deeper soil volume down to below 180 cm., this estimate is not apt to ratify the effective moisture storage capacity, which should be very high. The portion of very coarse pores decreases from the top to the sub- soil, leading to a considerable increase of available moisture capacity from 9.6 mm. per 10 cm. depth in the Ah/BA to 14.5 mm. per 10 cm. depth in the Btl. The porosity of the topsoil facilitates rapid infiltration of heavy rains. The entire profile down to a depth of 125 cm. (maximum sampling depth) has a moderate CEC (pH 8.2) of 16 to 22 me./100 gm., decreasing with depth. The indicated base saturation is low (<16 %) and decreases with depth. However, exchangeable bases (particularly Ca) by Silver-Thiourea are considerably higher. Consequently, the base saturation calculated with these data appears moderate (40 %). The cations determined from the trial site composite samples support these higher values. With reference to the moderate CEC, exchangeable K is high to medium in the topsoil (Ah: 0.6 me./100 gm., BA: 0.3 me./100 gm.) and decreases sharply below the BA to very low values of 0.7 me./100 gm. Mg appears high throughout (1-2 me./100 gm.). It shows a distinct minimum in the Btl horizon. Ca is low in comparison to the other bases and in the medium to low range (<6 me./100 gm.). The extremely low Ca status by Ammonium-Acetate (<1.2 me./100 gm.) is neither confirmed by the Ca value obtained from the Silver-Thiourea extraction nor by the data from the trial site composite samples. Exchangeable bases are well balanced with respect to plant nutrition. - 2.30 - District: Murang'a Trial Site 21.2: Makuyu The soil reaction increases with depth and covers the strongly and moderately acid ranges (pH KC1 4-5). Despite the low pH of the topsoil, the amounts of exchangeable Al are still within the low range. The organic matter contents of the three upper horizons down to a depth of 77 cm. cover the moderate range (1.5 - 0.75 % C) and decrease continuously with depth. The Bt3 below 90 cm. shows a low humus content of 0.45 % C. Total N is low to moderate in the Ah and low in the underlying soil. The C/N ratios appear wide. 3.3.4.2 Soil Fertility Assessment of Composite Samples The analytical results for the composite samples from the triai site (depths 0-20 cm. and 20-50 cm.) are presented in Table 21.2.11. The data for the farmers' fields (depth 0-20 cm. only) selected around this trial site are given in Table 21.2.12. 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 presentee 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. The moderately to very humic soils (1.3 - 2 % C in the topsoil composite samples) contain only low to moderate amounts of total N, and the reported values are very erratic. In the topsoil of the trial site N ranges from 0.09 % to 0.16 %; in the farmers' fields N ranges from 0.05 % to 0.13 % (low to moderate). The wide to very wide C/N ratios indicate a very low N supplying capacity and a hampered mineralization of organic matter in the soil. However, on the basis of the humus content and other prevailing soil and climatic factors, a moderate N supply from the soil should be assumed. The solubility of S04 was only tested in Block I of the trial site and appeared very low (4 ppm.), which supports the low estimate of the natural N supply from the soil. According to both the Mehlich analysis and modified Olsen method , "available" P is in the low to moderate range (13-23 ppm. and 7-15 ppm. respectively) in the trial site. Block I appears lowest and Block II highest in P. In the farmers' fields the results of the two methods are not always consistent. While the Mehlich analysis indicates a medium to high P availability for fields A to D, the values obtained by the modified Olsen method are low to moderate. For the fields G and E the results are inverse. P is moderate in field F and low in field H. The K status of the trial site composite samples varies widely. In the topsoil K is medium to high (0.35 - 0.61 me./100 gm. by the Mehlich analysis, and 0.46 - 0.66 me./100 gm. by modified Olsen method), and the - 2.31 - District: Murang'a Trial Site 21.2: Makuyu subsoil shows considerably lower K values (0.13 - 0.39 me./100 gm., and 0.20 - 0.44 me./100 gm.). Block II shows a slightly lower K status than the other blocks. In the farmers' fields the K values are very erratic, but almost always in the high range. Only field E shows a moderate K level by modified Olsen method, and Mehlich analysis indicates low K in field H. The "available" quantities of Mg are fairly constant over the entire trial site, and high to very high in all samples. The Ca status of the soils, as indicated by both methods (Mehlich analysis and modified Olsen method), varies considerably from place to place. On average the Ca levels are low to moderate. The trial site shows very uniform Ca values. The topsoil is at the borderline to low (0.9 - 1.3 me./100 gm. by the Mehlich analysis, and 5 - 6.3 me./100 gm. by the modified Olsen method) and the subsoil data are in the low range. The farmers' fields B and C show very low Ca levels while fields D, E, G and H are high in Ca. In fields A and F Ca is moderate. According to both the Mehlich analysis and the modified Olsen method, available Mn is well within the adequate range. According to the modified Olsen method, Zn is available only in low to moderate amounts (1.8 - 5.6 ppm.). The trial site and particularly farmer's field H show low Zn levels (<4 ppm.). Cu is available in very high amounts (6-12 ppm.) throughout. The HC1 extractable Zn and Cu determined in Block I of the trial site are high in the topsoil and below the critical levels in the subsoil. The amount of Fe extracted by the modified Olsen method is moderate to high. The trial site composite samples are strongly to very strongly acid (pH KC1 3.8 - 4.2). The pH in^the farmers' fields ranges from 3.9 to 4.8 (moderately acid). While in the moderately acid soils, the exchangeable acidity and especially the exchangeable Al are too low to have any important adverse effects on crop production, this may be the major limiting factor in the very strongly acid soils. The evaluation of the Mehlich Analysis data according to NAL standards is given in Table 21.2.14. - 2.32 - District: Murang'a Trial Site 21.2: Makuyu Table 21.2.14: Evaluation of the Mehlich Analysis Data According to NAL Standards Parameter Trial Site Farmers' Fields Soil reaction (pH) Moderately acid Moderately acid Acidity (Hp ) High Moderate to high Available nutrients Sodium Low Low Potassium Adequate Adequate Calcium Low Adequate Magnesium Adequate Adequate Manganese Adequate Adequate Phosphorus Low Low to adequate Total Nitrogen Low Low Organic Carbon Moderate Moderate C / N Ratio Favourable Favourable Ca / Mg Ratio Not favourable Favourable Ca / K Ratio Not favourable Not favourable K / Mg Ratio Favourable Favourable Remarks on Trial Site: Soil reaction is not very favourable. Positive yield responses to lime, manure, N and P applications are expected. Responses to K application may be absent initially but are likely to occur later. Remarks on Farmers' Fields : Soil reaction is generally favourable. Positive yield responses to manure, N and P applications are expected. Responses to K and lime 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 February/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:P75 N0:P75 N75:P0 Trial II: 0 FYM FYM+NP NP+K FYM+lime FYM+NP+lime NP+K+lime - 2.33 - District: Murang'a Trial Site 21.2: Makuyu 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:P75 N0:P75 N75:P0 Trial II: 0 FYM FYM+NP NP+K FYM+lime FYM+NP+lime NP+K+lime 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/Katumani planted during the first rains at the Makuyu Trial Site can be interpreted as follows: Figure 21.2.6 shows that the maximum water requirements (ETm) of the maize crop are only in line with the rainfall pattern at the 66% probability level up to beginning of May. The variability of rainfall, especially in May, is tremendously high, as shown in Figure 21.2.5 (see also Table 21.2.4). The following distinct arid period leads to serious yield reductions, since the crop is still at the stage of peak water requirements. Run-off is considered to be moderate to low - the trial site is located on almost flat land (slope 2-3%). The soil has a stable structure (preventing crusting and surface-sealing), but the crop does not provide adequate ground cover at the time of high rainfall intensity in April/May. Deep percolation and lateral sub-surface flow could be estimated, but can be omitted, since they are generally very low. Run-on is not relevant for Makuyu Trial Site. For the Makuyu Trial Site, the moisture storage capacity is very high (i.e. >160 mm.). Therefore, the possible water surplus of April and May could be stored to a large extent, but on the 66% probability level - 2.34 - District: Murang'a Trial Site 21.2: Makuyu there is only little surplus in April/May. Hence, the distinct water deficits for the whole month of June cannot be compensated. Summarizing the evaluation of the climatic factors, the yield potential from the climatic point of view can, for the maize crop, first rains, be rated good/fair on a "20 out of 30 year" basis. In the second rains, water availability conditions are even less favourable. Crop failures often occur and only very early maturing, drought-tolerant crops such as sorghum, tepary beans, cowpeas or pigeon peas can be cultivated successfully on a long-term basis. 4.2 Nutrient Availability in Relation to Possible Fertilizer Requirement The N supplying capacity of the soils was only estimated globally and appears low to moderate. In most samples, available P is low to moderate and probably slightly inadequate to the expected N supply from the soil. K appears medium to high in the upper part of the soil, but the deeper subsoil of the profile shows very low K values. All soils analyzed are very rich in Mg. Ca was extracted in very erratic amounts covering the whole range from low to high. In the very strongly acid soils exchangeable Al, might be the major limiting factor for successful crop production. The micro-element Zn appeared low in some instances. Fertilizer applications should first of all consider the most relevant plant nutrients which include N and P. For sustained high yields regular N fertilization will be necessary, either from FYM or green manure or in mineral form. When mineral N is applied regularly, it should be supplemented with mulch and other organic amendments. This is to protect the topsoil, particularly during the heavy rains in April/May, and to maintain its high humus content. Humus plays an essential role in stabilizing the structure of the topsoil and in prevent- ing applied nutrients from leaching too quickly. N applications in whatever form will have to be supplemented with P. The trials will have to show whether a reasonable response to N can be obtained without P. P may be applied as TSP, SSP or finely ground soft rock phosphate (e.g. Hyperphos or from Minjingu). Under the prevailing acid soil conditions rock phosphate will be readily available to plants and almost as efficient as TSP in the year of application. P from rock phosphate is less subject to fixation than P from water soluble fertilizers such as TSP. P fixation by the soil is probably moderate. The efficiency of P application may be enhanced by the addition of small amounts of fresh FYM to stimulate the soil biological activity. Superphosphate contains about 12% S and therefore may act as a two-element fertilizer. Under farmers' conditions this might be very useful, since a limited S availability is likely in some fields. Liberal applications of N and P may induce or intensify deficiencies of micro-elements, notably Zn in this trial site. - 2.35 - District: Hurang'a Trial Site 21.2: tiakuyu K applications are not needed at the present stage and response to K may be only erratic or not be obtained at all, at least in the first years. Considerable differences are expected within short distances. The analytical data provide no information on the reserves of K beyond the exchangeable pool, but the low K status of the subsoil indicates that the K reserves are probably very limited. Permanent high applications of mineral N and P will, in the long run, need to be supplemented with K. FYM is normally a good source of K. If K fertilizer is to be applied, K2SO4 should generally be preferred to KC1 (both contain 50% K20), since the S04-ion enhances P availability. The form in which K is applied should also take into account crop requirements (e.g. KC1 to cabbage, but not to Irish potatoes). Under the present soil conditions, liming is not required immediately in the trial site although it is advisable in farmers' fields B and C. The amount of lime needed to neutralize excessive acidity may be roughly estimated from the exchangeable Al. In general 2 t./ha. of agricultural lime should be applied for every milliequivalent (me./lOO gm.) of Al in the topsoil. However, not more than 2 t./ha. should be used at any one time; if the lime requirement appears higher, the amount'needed should be split into yearly applications of 2 t./ha. Soils should not be limed over pH (KC1) 5. Liming enhances mineralization of organic matter in the soil. Care should, therefore, be taken to maintain the humus content at a high level for the above-mentioned reasons. In the trial site and the farmers' fields where immediate liming is not needed, the acidifying effects of the applied mineral or organic ferti- lizers should be counterbalanced," i.e. .approximately 1.8 Kg. of CaC03 per Kg. of. applied N: In.the caae of CAN, which contains Ca, only about 0.8 Kg. CaCOj per Kg.N, i.e. 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 phosphates (30% P2O5) contain about 2.7 Kg. CaCO3 equivalents per Kg. of P2O5. If lime is applied in excessive amounts, the availability of P and some micro-nutrients may become critical. This applies mainly for Zn, but Cu availability and plant uptake should also be monitored, at least for demanding crops. 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. The topsoils of the eutric Nitisols have reasonable physical properties. High porosity and permeability are prevalent. b) Rootability. The extremely deep soils with their high porosity provide a very good environment for unhampered root development and tuber expansion. - 2.36 - District: Murang'a Trial Site 21.2: Makuyu c) Resistance to erosion. The area has a moderate resistance to erosion. The negative influences of high rainfall intensity and of the undulating to rolling topography can not always be offset by the moderately high structure stability of the surface soil. d) Ease of cultivation and scope for agricultural implements. Although the soils impose no serious limitations to manual land preparation and oxen ploughing, areas with a rolling topography are less suitable for tractor ploughing. Moreover, tractor ploughing generally leads to deteri- oration of the physical properties of the topsoil (compaction). 5. Trial Design and Execution Plan, Makuyu (Full details of the methodology for carrying out the trials are shown in Chapter IV of the main report). Selection of crops for each of the three modules at the Makuyu site: Site 21.2 Makuyu. RAINY SEASONS 1st, Long, March 2nd, Short, Oct. 51 Standard Maize Hybrid 511 Katumani C.B. 52 Maize & Beans. H.511+ GLP 92, Beans K.C.B.+GLP 92 53 Maize & Pigeon Peas Katumani P.P. K.C.B.+ K.P.P The 1st sequence or module is continuous, pure maize, twice/year. The 2nd is intercropped maize and beans in both rains. The 3rd is intercropped maize and pigeon peas in the October rains, with the pigeon peas remaining for the March 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. Each module thus consists of 64 plots, and the total for the 3 modules is 192 plots. Fertilizer will be applied in both rains, except for FYM, which will be applied only to crops during the first rains. The ratoon crop of pigeon peas will not receive fertilizer in its second season, namely the March rains. Where maize and beans or pigeon peas are intercropped, the fertilizer will go on the maize. The intercropped beans or pigeon peas 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. - 2.37 - MURANG'A DISTRICT MAIZE, FIRST RAINS: MEAN GROSS MAR6IN EXPECTATION (KSh/ha) AT TREATMENT N50 P22) (BASED ON 1992 PRICES) -1,000 999 KSh 1,000 2,999 KSh EU 3,000 4,999 KSh 5,000 £,999 KSh 7,000 8,999 KSh 9,000 10,999 KSh 11,000 12,939 KSh 13,000 14,999 KSh 10 15 20 25 km I I Not suitable for maize cultivation by R.Rötter St C.Dreiser, 1992