KENYA AGRICULTURAL RESEARCH INSTITUTE NATIONAL AGRICULTURAL RESEARCH LABORATORIES KENYA SOIL SURVEY

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1 KENYA AGRICULTURAL RESEARCH INSTITUTE NATIONAL AGRICULTURAL RESEARCH LABORATORIES KENYA SOIL SURVEY SITE EVALUATION OF THE JAMHURI PARK DEMONSTRATION PLOTS (Kibera Division, Nairobi) by H.C.K. Kinyanjui ISIIC LIBRARY Site Evaluation Report No.P89. January, 996. KE Wageningen The Netherlands

2 SITE EVALUATION OF THE JAMHURI PARK DEMONSTRATION PLOTS ISRIC LIBRARY _k. 5^6>o^> Wagoningen, The Netherlands by H. C. K. Kinyanjui 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.isrioawur.nl indicating the item reference number concerned. Site evaluation report No. P89, January, 996. isisa

3 . INTRODUCTION The Ministry of Agriculture approached Kenya Soil Survey to carry out both topographical and soil survey of their demonstration plots at Jamhuri Park show ground. Topographical survey was carried out in November while the soil survey was carried out in December 989. The main aim of both exercises was to assist in the re-planning of the demonstration plots. The field work took 0 days. A total of 60 augerhole and 3 profile pit observations were made following transects running North to South. The topographical survey was carried out by B.G. Muriithi and S. Wataka. Soil Survey was carried out by the author, C.R.K. Njoroge, E. Kinyanjui, C.N. Kariuki and H. Onyono. 2. ENVIRONMENT 2. Location Jamhuri park is beyond the sprawling Kibera Estate, within Nairobi Province and it borders the Kenya Science Teachers College. The National Agricultural Shows are held in this ground towards the end of the year. Within the show ground the Ministry of Agriculture has demonstration plots. These plots are located on the northern end of the show ground next to the Kibera railway station. 2.2 Climate Climatic data used is from Dagoretti Corner Rainfall Station No which upto 972 had 7 years of rainfall recording. The station lies at an altitude of about 799 m above sea level and at latitude 8'S and longitude 36 45'E. This station is about 500 m east of the survey area Annual and seasonal rainfall averages The survey area has a mean annual rainfall (r) of 072 mm. It is characterized by two rainfall seasons. The long rains period is between March and May, the peak occurring in April. The short rains season starts in October and extends to January with the peak occurring in November. Dry months are February and June to September, the driest month being July. The average seasonal rainfall for the long rains is 53 mm (48%) and for the short rains 398 mm (37%) while the dry months contribute 6 mm (5%) Potential evaporation and évapotranspiration. The mean annual potential evaporation (Eo) is estimated to be 778 mm using the Woodhead's (968) equation Eo (mm) = h, where h is the station's altitude in

4 metres. The survey area is at the same altitude with the rainfall station. The mean annual potential évapotranspiration (Et) which is estimated as 2/3 Eo, is 85 mm (see table ). Et is considered as the crop water requirement Simple water balance The difference between the amount of precipitation and the loss by évapotranspiration (r - Et) is what is being considered as simple water balance. Only the months of April, May and November have surplus. All the other months have deficits. The months of April, May and November have more rainfall than potential evaporation (Table ). Table. Simple water balance of Jamhuri Park Mon. J F M A M r (mm) Eo (mm) Et (mm) r-et(mm) A S O N D Year AA Mean maximum and mean minimum temperatures The survey area falls in agro-climatic zone 5 which is Semi-humid (Sombroek et al 982). The zone has medium to high potential for plant growth and the risk of failure of an adopted crop is fairly low (5-0%). Mean maximum temperature is 23.3 C and mean minimum.7 C. Absolute minimum temperature is 2.5 C. The area can be classified as cool temperate. Chances of night frost are none to very rare Geology and physiography The demonstration plots are at the boundary of the Nairobi trachytes which occupy the valley bottom and the middle and upper Kerichwa Valley tuffs on the higher areas within the survey area (Saggerson, 97). Two physiographic units have been identified namely the uplands and the valley bottom. The valley bottom occurs in the northern portion of the demonstration plots. Within this unit a small stream flows from some ponds which have been constructed to store water for irrigating the plots. The uplands occur on the undulating to rolling areas which forms the southern portion of these plots. 2

5 3. WORKING METHODS A copy of the topographical map of the demonstration plots which had just been completed by another team within the Kenya Soil Survey was used as a base map. Transects fifteen metres apart were plotted on the base map. Augerhole observations were made along the transects at intervals of fifteen metres except where obstacles or other factors forced the observation to be made off the transect. The soil characteristics observed in the field were used in the delineation of the different soil boundaries. Soils with similar characteristics were grouped together to form a mapping unit. In every mapping unit, a representative profile pit was made. In all a total of 60 augerhole and 3 profile pit observations were made. In the field the soils were examined for depth, texture, mottling, consistence, calcareousness and ph. The examination follows "Guidelines for soil profile descriptions", (FAO, 977). These properties were recorded on the standard Kenya Soil Survey forms. The soil colour was determined using the "Munsell Soil Colour Charts" (Munsell, 97). The different horizons within the profile were sampled and the samples taken to the laboratory for both physical and chemical analysis. A composite sample for fertility analysis was collected in the area near the profile pits and also at selected augerhole observations. All samples taken to the laboratory were analyzed following the procedures described in Hinga SOUS 4.. General properties of the soils Three major mapping units have been delineated. One mapping unit falls in the uplands and the other two in the valley bottom. The unit falling in the uplands has soils which are well drained, red, friable clay. It was further divided according to depth classes as follows:- very deep, deep and moderately deep. The two units falling in the valley bottom were divided according to colour. The unit with brown soils was moderately well drained to imperfectly drained with a patched water table at 60 cm depth, dark reddish brown to dark greyish brown, friable to firm clay. It had Iron and Manganese concretions from 60 cm. The second mapping unit in the valley bottom has soils which are deep, very dark greyish brown to dark greyish brown, moderately drained to imperfectly drained, friable to firm clay. 3

6 4.2. Svstematics and nomenclature Each mapping unit is identified on the soil map by a symbol with the following codes:- Phvsiographv u V - Uplands Minor Valley. Bottom Geologv P Pyroclastic rocks (tuffs) Soil Characteristics r b g red colour brown colour greyish colour Depth classes P 0-50 cm-shallow p cm - moderately deep p cm - deep > 20 cm - very deep 4.3. Description of the soil mapping units Three mapping units were identified after comparing the data from the augerhole descriptions. Two of the mapping units were further subdivided according to depth classes. Three profile pits were described and sampled taking into consideration the dominant class in the units with subdivisions. Mapping Unit UPr Extent Parent material Relief Slope Land use Susceptibility to erosion Drainage 0.45 ha Pyroclastic rocks - tuff Gently undulating to rolling, 4-8% Cultivation Low to moderate well drained Soils, general : These are well drained, very deep (other subdivisions are 4

7 Colour Texture Structure consistence moderately deep to deep), red to dark red, friable clay soils which tend to be gravelly in the lower subsoil or nearer the surface where the top horizons have been removed during levelling. A-horizon: dark reddish brown (5YR 3/2 moist). B-horizon: red to dark red (2.5YR 4/8 to 2/5YR 3/6, moist). clay throughout the profile A-horizon: moderate, fine to medium subangular blocky B-horizon: weak, fine to medium subangular blocky friable, sticky and plastic throughout the profile the profile Chemical properties A-horizon - %organic carbon is 3.52, ph-h 2 0 is 6.3, ph-kci is 5.4, CEC is 23.5 me/00g soil, base saturation is over 00% B-horizon - %organic carbon ranges from 0.69 to.0, ph-h 2 0 ranges from 5.0 to 5.8 decreasing with depth, ph-kci ranges from 3.7 to 4.6 reducing with depth also, CEC ranges from 2.8 to 7.6 me/00g soil decreasing with depth, base saturation is over 00% Diagnostic horizons Classification cambic B chromic CAMBISOLS For detailed descriptions and analytical data see soil profile no. (Observation no. 48/4-). Mapping Unit VPbp Extent Parent material Relief Slopes Land use Susceptibility to erosion Drainage Soils, general Colour 0.24 ha Pyroclastic rocks (tuff) gently undulating to rolling 0-4% demonstration plots nil to very low moderately well drained to imperfectly drained. These are well drained, moderately deep to very deep, dark reddish brown to dark greyish brown, friable to very firm clay soils. There are few, 2-3 mm (diameter) iron and manganese concretions from 60cm, many, thick clay cutans and abundant, thick slickensides > 60 cm A-horizon: top 0-60 cm is dark reddish brown (5YR 3/4 5

8 Texture Structure Consistence Chemical properties Diagnostic horizons Classification moist). B-horizon: Over 60 cm is dark greyish brown (0YR 4/2, moist). clay throughout the profile in all the observations cm the structure ranges between moderate very fine to médium, subangular blocky 0-60 cm - friable > 60 cm - very firm A-horizon - %organic carbon is 2.3, ph-h 2 0 is 6., ph-kci is 5., CEC is 23.6 me/00g soil. Basesaturation is over 00%. B-horizon - %organic carbon ranges from 0.84% to.5 % decreasing with depth. ph-h 2 0 ranges from 5.7 to 6.2, ph-kci ranges from 4.4 to 4.9. CEC ranges from 8.7 to 2.6 me/00g soil decreasing with depth. Base saturation is over 00%. ochric epipedon and cambic B gleyic CAMBISOLS For detailed descriptions and analytical data see soil profile no. 2 (Observation no. 48/4-2). Mapping Unit UPg Extent Parent material Relief Slope Land use Susceptibility to erosion Drainage Soils, general Colour Texture Structure 0.86 ha Pyroclastic rocks (tuffs) level to very gently undulating 0-4% demonstration plots, dam and farm houses slight rill along the stream moderately well drained to imperfectly drained. These are moderately well drained to imperfectly drained, very deep (other subdivisions are shallow to deep), very dark greyish brown to dark greyish brown, friable to firm clay soils. The deeper subsoil has few, moderate clay cutans and many, thick slickensides. A-horizon: yellowish red (5YR 4/6, moist) for most observations B-horizon: dark greyish brown (0YR 4/2, moist), clay throughout the profile in all observations. A-horizon: weak to moderate, very fine to fine subangular blocky B-horizon: moderate, very fine to fine subangular blocky 6

9 Consistence : A-horizon: friable B-horizon: firm Chemical properties : A-horizon: 0-0 cm, % organic carbon is 2. ph-h 2 0 ranges from 5.8 to 6.4 while ph-kci ranges from 4.8 to 5.3 in both cases decreasing with depth. CEC ranges from 5.2 to 20.0 me/00g soil. Base saturation is over 00%. B-horizon: %organic carbon ranges from 0.25 and 0.89 decreasing with depth, ph-h 2 0 ranges from 5.0 to 6.0 while ph-kci from 4.0 and 4.9. CEC varies from 9.2 to 23.8 me/00g soil. Base saturation is over 00%. Diagnostic horizons : ochric epipedon and argic B Classification : gleyic LUVISOLS For detailed descriptions and analytical data see soil profile no. 3 (Observation no. 48/4-3). 4.4 Soil fertility Table 2 gives the results of the soil fertility from the analysis of the composite samples taken from the area surrounding the representative profile pits at a depth of 0-30 cm. Table 2. Results of soil fertility analysis Mapping unit UPr VPbp VPg Observation No. 48/ / /3-72 Lab. No ph Na me/00g soil K Ca " Mg " Mn P ppm N% C% The results of the analysis show that the soils are moderately acid to slightly acid. Most of the plant nutrients are adequately supplied except nitrogen which is low in all the mapping units and phosphorus which is low in mapping unit VPg. Organic carbon is also low in all the mapping units. In view of the above deficiencies, application of fertilizers with phosphorus and nitrogen is 7

10 necessary to improve the yields. Application of manure is also recommended to improve soil conditions as well as providing plant nutrients. 5. LAND EVALUATION 5. Procedure The land evaluation approach as adopted by the Kenya Soil Survey closely follows the proposals of the "Framework of land evaluation" (FAO, 976). Kenya Soil Survey has also prepared proposals "Internal communication" No. 7 (Braun and van de Weg, 977) along the lines of the Framework. The following is a short summary of the basic concepts: -land evaluation is based on land qualities that can quantified and rated; -land qualities are usually combinations of single land characteristics ; -these land qualities are used to establish specifications for each land suitability class for a specific land utilization type (conversion table); -for each "tract" of land, a rating of all relevant land qualities is made for all land utilization types. 5.2 Land qualities and their rating scheme The suitability classification was done according to the framework for Land Evaluation (FAO 976) and KSS proposals for rating of land qualities (Braun and van de Weg, 977). Suitability was assessed for rainfed cultivation of field crops such as maize, potatoes, fruit trees and vegetables. In the process of assessment, the following assumptions were made. (i) (ii) Proper management and appropriate cultural practices for each crop will be followed i.e weeding, application of fertilizers, chemicals for pest and disease control, crop rotation, soil and water conservation among others. In addition it is assumed that labour is not a limiting factor. The land qualities considered in this evaluation are:-. Soil moisture storage capacity 2. Availability of oxygen. 3. Depth to the impermeable layer 4. Possibility of mechanization 5. Availability of nutrients 6. Resistance to erosion 8

11 5.3 Soil moisture storage capacity (smsc) The amount of water available to the plant is very important since all physiological processes in the plants take place with the help of water and as a result water deficiency affects the growth of the plants. The capacity of a soil to retain water available to plants has a direct influence on the type of crops that can be grown in a particular type of soil. Since no samples were taken for the determination of moisture storage capacity, the estimating method devised by the use of textural classes has been adopted (Braun and van de Weg, 977). Table 3. Estimates of soil moisture storage capacity Depth LS SL SCL SC C 80 cm (mod. deep) 20 cm (deep) 50 cm (v. deep) Rating Total productive available moisture (mm) very high high moderate low very low < Availability of oxygen (oxv) When rating this land quality, soil water drainage (soil drainage condition) is considered. Poor drainage affects soil aeration which retards proper root development. Consequently plant growth is affected leading to failure or poor performance in crop production. Table 4. Rating of availability of oxygen Rating Drainage condition well drained to somewhat excessively drained 2 moderately well drained 3 imperfectly drained 4 poorly drained 9

12 5.5 Depth to the impermeable layer (dp) The depth of the soil determines the type of the crops that can be grown in an area. Many qualities are determined by depth i.e availability of moisture, fertility, drainage and root holding (foothold) among others. Table 5. Rootable soil depth Rating Rootable depth depth class > 20 very deep cm moderately deep to deep 3 <50 cm very shallow to shallow 5.6. Possibility of mechanization (pm) This land quality considers land characteristics like steepness of the slope and shallowness of the soil due to stoniness and rockiness. Agricultural practices and operations are affected by these land characteristics. Possibilities for mechanization ratings Table 6a. Sub-rating steepness of the slope Slope class A-B-C (0-8%) D (8-6%) 2 E (6-30%) 3 F (30-70%) 4 G (<70%) 5 0

13 Table 6b. Sub-rating for stoniness/rockiness/shallowness of the soil. description rating non-stony, non to little rocky and not shallow fairly stony, fairly rocky and/or shallow 2 stony-rocky and/or shallow 3 very stony, very rocky and/or very shallow 4 exceedingly stony and/or very rocky or very shallow. 5 Table 6c. Final rating of possibilities of mechanization is arrived at by the sum of the sub-ratings 6a and 6b above sum of sub-ratings final rating 2. very high high 5 3. moderate low very low 5.7 Availability of nutrients (an) Availability and balance of the elements in the soil necessary for plant nutrition determines how fertile a soil is. This land quality was assessed using Cation Exchange Capacity (CEC) and the available cations. Availability of nutrients: Table 7a. Sub-rating CEC of the topsoil (0-30 cm) CEC (me/00g) rating >6. very high high moderate low <2 5. very low

14 Table 7b. Sub-rating available elements (cations) of the topsoil (0-30 cm) P (ppm) K(me/00g) Ca (me/00g) rating >200 >3.5 >20 very high high moderate < low <20 <0.3 <2 5 very low Table 7c. Final rating for available nutrients derived from the sum of the sub-ratings 7a and 7b Sum of sub-rating final rating 2. very high high 5-6 ~ 3. moderate low >9 5. very low 5.8 Resistance to erosion (rer) Soil erosion is the removal of topsoil by the agents of erosion which are water and wind. The major agent considered in the survey area is water. There are many characteristics that influence erosion i.e slope class, slope length, climate, susceptibility to sealing, silt/clay ratio and bulk density. Only the slope class characteristic will be considered. Table 8. Rating of slope classes Slope class rating A-AB-B (0-5%) C (5-8%) 2 D (8-6%) 3 E (6-30%) 4 2

15 5.9 Suitability classes and their criteria The suitability for land utilization types (LUT), was determined using the land qualities as shown by conversion tables below and expressed in the following classes: Class S: highly suitable - land having no significant limitations to sustainable use or productivity while using normal inputs. Class S2Y Class S3: Class NS: moderately suitable - land having limitations which are moderately severe for sustainable use and requires high inputs. marginally suitable - land having limitations which are severe for sustainable application and will require very high inputs to increase productivity. not suitable - land not suitable for sustainable production due to very severe limitations. The requirements of each LUT are defined as minimum ratings for a certain suitability class. The requirements are shown in conversion tables. Table 9. Conversion table for common garden crops e.g. vegetables, Irish potatoes, maize etc. Land qualities Suitability class smsc oxy dp pm an rer NS

16 Table 0. Conversion table for sweet potatoes and nappier grass Suitability class smsc oxy dp pm an rer S S2 S3. NS Table Rating of the land qualities for each mapping units Mapping unit smsc oxy dp pm AN rer UPrl VPbp VPgl Land suitability of the mapping units The ratings of each land quality for all mapping units with the requirements of the suitability classes have been matched using the tables above to arrive at the suitability of each mapping unit for the various LUTs. The result of the suitability classification are shown in table. Table 2. Land suitability classification mapping unit/slope class Garden crops (maize, potatoes vegetables)etc LUT Nappier + sweet potatoes UPrl VPbp VPgl S2 S2 S2 SUITABILITY CLASS S2 S2 S2 4

17 All the mapping units are low in soil fertility and this land quality down grades them to class S2. Mapping unit VPg has also been down graded by the drainage class; moderately well drained to imperfectly drained, which makes it have poor availability of oxygen. The other land qualities occur in the required levels. 5

18 6. REFERENCES Acland, J.D., 97 : East African crops, FAO-Longman, London. Braun, H. M. H. and R. F. Van de Weg, 977: Proposals for Rating of Land Qualities. Internal communication no. 7, Kenya Soil Survey,Nairobi. Braun, H. M. H. in prep : Evaporation in Kenya, Kenya Soil Survey, Nairobi. E. A. M. D., 952: Summary of rainfall in Kenya, E. A.M.D., Nairobi. E. A. M. D., 970 : Temperature data for stations in East Africa; part, Kenya. E. A. M. D., Nairobi. F. A. O., 976 : Framework for land evaluation, F. A. O., Rome. F. A. O., 977 : Guidelines for soil profile description, F. A. O., Rome. F.A.O.-U.N.E.S.C.O., 974: Soil map of the World, Rome. Hinga, C, F. N. Muchena and C. N. Njihia, 980 : Physical and chemical methods of soil analysis. Internal document, National Agricultural Laboratories, Nairobi. Munsell Color Co., 97 : Munsell soil colour charts, Baltimore, Maryland. Saggerson, E.P., 97 : Geological map of the Nairobi area, Mines and Geological Report No. 98, Nairobi. Sombroek W.G., H. M. H. Braun and B. J. A. Van de Pouw, 982 : The exploratory soil map and agro-climatic zone map of Kenya. Report no. E, Kenya Soil Survey, Nairobi. Woodhead, T., 968 : Studies of the potential evaporation in Kenya. EAAFRO, Nairobi. 6

19 Appendix. Description of soil profiles Description No. - Observation No. 48/3-74 mapping unit UPr Description No. 2 - Observation No. 48/3-73 mapping unit VPbp Description No. 3 - Observation No. 48/3-72 mapping unit VPg Appendix 2. Preliminary soil map of the Jamhuri Park demonstration plots (in folder) 7

20 Profile description No. General Site Information Mapping unit Soil Classification Observation no./date Location Parent material Physiography Relief, macro micro Slope gradient Land use Erosion Surface stoniness/rockiness Ground water Drainage class UPr chromic CAMBISOLS 48/74-, 8/2/90 Jamhuri park, Nairobi Tuff Uplands gently undulating to rolling local levelling 6-8% Demonstration plots nil nil nil well drained Profile description Ap 0-2 4cm dark reddish brown (5YR3/2, moist); clay; moderate, fine to medium subangular blocky; friable when moist, sticky and plastic when wet; many, very fine and fine, common medium pores; many, very fine, fine and medium roots; clear and smooth transition to: Bt, 24-60cm dark red (2.5YR 3/6, moist); clay; moderate, fine to medium subangular blocky, friable when moist, sticky and plastic when wet; many, strong clay cutans; many, very fine and fine, common medium pores; many very fine to medium roots; clear and smooth transition to: Bt 2 Bcs, 60-80cm 80-00cm red (2.5YR4/8, moist); clay; weak, medium to coarse subangular blocky; friable when moist, sticky and plastic when wet; common, moderate clay cutans; many very fine and fine, common medium pores; many very fine and fine, common, medium and coarse roots; gradual and smooth transition to: red (2.5YR 4/8, moist); clay; weak, very fine and fine subangular blocky; friable when moist, sticky and plastic when wet; few, weak, clay cutans; frequent, 3-5mm large, iron and manganese concretions; many, very fine and fine, common medium pores; many, very fine and fine, common, medium and coarse roots; clear and smooth transition to: Bcs, 00cm + Petrophinthrite (weak in places) 8

21 LABORATORY DATA OF PROFILE DESCRIPTION NO. Observation no:48/3-74 Mapping unit:upr Soil classification: chromic CAMBISOLS Laboratory no / Horizon Ap Bt, Bt 2 Bcs, Depth (cm) ph-h 2 0 (:26 suspension) ph-kcl (:2tt suspension) EC (mmhos/cm) C (%) N (%) C/N CEC (me/00g), ph ECe (mmhos/cm) Exch. Ca (me/00g) " Mg " " K " Na " sum of cations Base sat. %, ph 8.2 >00 >00 >00 >00 Qualitative CaC ESP at ph 8.2 Texture (limited pretreatment) Gravel % (>2.0 mm) Sand % ( mm) Silt % (O.5-O.O02mm) Clay % ( mm) Texture class C C C C Fertility aspects 0-30cm Laboratory no General Available nutrients ph-h 2 0(: VW) 5.7 Na(me/00g) 0.80 Mn (me/00g) 0.50 Exch. acidity (me/00g) - K 0.50 P (ppm) 4 C% 2.6 Ca 5.9 P-Olsen (ppm) N% 0.6 Mg 3.8 Remarks: 9

22 Profile description No. 2 General Site Information Mapping unit Soil Classification Observation no./date Location Parent material Physiography Relief, macro micro Slope gradient Land use Erosion Surface stoniness/rockiness Ground water Drainage class VPbp gleyic CAMBISOLS 48/3-73, 8/2/90 Jamhuri park, Nairobi Tuff Uplands gently undulating rolling local levelling 0-4% Demonstration plots nil nil nil moderately well drained to imperfectly drained Profile description Ap 0-20cm : dark reddish brown (5YR 3/4, moist); clay; moderate, very fine and fine subangular blocky; friable when moist, sticky and plastic when wet; many, very fine, fine and medium pores; many very fine, fine and medium roots; gradual and smooth transition to: Bu, 20-45cm dark reddish brown (5YR 3/4, moist); clay; moderate, fine and medium subangular blocky; friable when moist, sticky and plastic when wet; few, fine, clay cutans; many, very fine, fine and medium pores; many, very fine, fine and medium roots; clear and smooth transition to: Bu, 45-60cm dark brown (7.5YR 3/2, moist); clay; moderate, very fine and fine subangular blocky; friable when moist, sticky and plastic when wet; many, very fine, fine and medium pores; many, very fine and fine roots; clear and wavy transition to: Bg 60-49cm+ dark greyish brown (0YR 4/2, moist); clay; strong, very fine and fine angular blocky and subangular blocky; very firm when moist, sticky and plastic when wet; many, thick clay cutans; abundant, thick slickensides; frequent, 2-5mm large iron and manganese concretions; few, very fine pores: 20

23 LABORATORY DATA OF PROFILE DESCRIPTION NO. 2 Observation no:48/3-73 Mapping unit: VPbp Soil classification: gleyic CAMBISOLS Laboratory no / Horizon Depth (cm) ph-h,0 (:2M suspension) G.l ph-kcl (l:2h suspension) EC (mmhos/cm) C (V) N (V) C/N :-; ' CEC (me/l00g), ph ECe (mmhos/cm) Exch. Ca (me/00g) Mg " K Na sum of cations Base sat. V, ph 8.2 >00 >00 >00 >00 Qualitative CaCO, ESP at ph B.2 Texture (limited pretreatment) Gravel * (>2.0 mm) Sand V ( mm) Silt V ( mm) Clay V ( mm) Texture class C C C C Fertility aspects 0-30cm Laboratory no. General Available nutrients ph-h,0 (: V/V) 6. Na (me/loog) 0.88 Mn (me/00g) 0.65 Exch. acidity (me/00g) _ K ".09 P (ppm) 36 C* 2.89 Ca " 7.4 P-Olsen (ppm) NV 0.24 Mg ". : 3.7 Remarks: 2

24 Profile description No. 3 General Site Information Mapping unit Soil Classification Observation novdate Location Parent material Physiography Relief, macro micro Slope gradient Land use Erosion Surface stoniness/rockiness Ground water Surface sealing Surface cracking Drainage class VPg gleyic LUVISOLS 48/4-3,8/2/90 Jamhuri park, Nairobi Tuff,.. Minor Valley bottom Very gently to gently undulating levelling and tracks 0-2% demonstration plots along the stream nil very deep nil nil moderate to imperfectly drained Profile description Ap AB Bw' Bw 2 0-0cm 0-40cm 40-60cm 60-90cm yellowish red (5YR4/6, moist); clay; moderate, very fine and fine subangular blocky; friable when moist, sticky and plastic when wet; many very fine and fine, few medium pores; many very fine, fine and medium roots; clear and wavy transition to: dark yellowish brown (0YR4/4, moist); gravelling sandy clay/clay loam; moderate, very fine arid fine subangular blocky; friable when moist, sticky and plastic when wet; common very fine and fine, few medium pores; common very fine and fine, few medium roots; gradual and smooth transition to: very dark greyish brown (0YR 3/2, moist); clay; weak, very fine and fine subangular blocky; friable when moist, sticky and plastic when wet; common, very fine and fine roots; gradual and smooth transition to: dark brown (0YR 3/3, moist); clay; moderate, very fine and fine subangular blocky; friable when moist, sticky and plastic when wet; common very fine and fine pores; few very fine and fine roots; clear and smooth transition to: Bg 90-4cm + dark greyish brown (2.5YR 4/2, moist); clay; moderate, very fine and fine subangular blocky; firm when moist, sticky and plastic when wet; many, thick slickensides; few, moderate clay cutans; few very fine and fine pores; few very fine and fine roots: 22

25 LABORATORY DATA OF PROFILE DESCRIPTION NO. 3 Observation no:48/3-72 Mapping unit: VPg Soil classification: gleyic LUVISOLS Laboratory no / Horizon Depth (cm) ph-hjo (:2'/2 suspension) ph-kcl (:2Vi suspension) EC (mmhos/cm) C (%) N (%) C/N CEC (me/00g), ph ECe (mmhos/cm) Exch. Ca (me/00g) " Mg " " K " Na " sum of cations 3, Base sat. %, ph 8.2 >00 >00 >00 >00 >00 Qualitative CaC0 3 ESP at ph 8.2 Texture (limited pretreatment) Gravel % (>2.0 mm) Sand % ( mm) Silt % (0.5-O.002mm) Clay % ( mm) Texture class SC/CL C C C Fertility aspects 0-30cm Laboratory no. General ph-h 2 0 (: VA/) 6. Na (me/00g) Available nutrients 0.76 Mn (me/00g) 0.37 Exch. acidity (me/00g) - K " 0.92 P (ppm) 3 C% 2.09 Ca 3.8 P-Olsen (ppm) N% 0.6 Mg 2.6 Remarks: 23

26 msi ou ÎSRC LIBRARY ^ O ^ W«o«nW9»n, Th» N«therl»n<l» PRELIMINARY SOIL MAP OF THE MINISTRY OF AGRICULTURE, JAMHURl PARK DEMONSTRATION FIELD, KIBERA DIVISION, NAIROBI Appendix 2 to report No. P89 LEGEND UPLANDS {slopes 4-B%) Soils developed on pyroclastic rocks (tuff) well drained, very deep, red to dark red, friable clay (chromic CAMBISOLS) as in UPrl, but deep as in UPrï, but moderately deep V MINOR VALLEYS (slopes 0-4%) VP Soils developed on pyroclastic rocks (tuff) VPbpj J moderately well drained to imperfectly drained, moderately deep to deep, dark reddish brown to dark greyish brown, friable to firm clay (gfeyfc CAMBISOIS) VPRII )moderately well drained to imperfectly drain ed, very deep;dark greyish brpwn to very dark greyish brown, friable to firm, clay (gleyk UVISOLS) vp g 2 PCHD as in vp 8 ' but-deep * VPg3pr""? ~"~as in VPg, but moderately deep las 'm VPgl, but shallow KEY.TO sippe CLASSES. riarhé óf ffiacrorelief Sl0pfr^;symhorj^ mmmmmmm A B C i flat to very gently undulating j gently undulating t undulating thickness soil in cm KEY TO DEPTH CLASSES symbol + over rock name 0-50 P shallow SO more than 20»!;*:! moderately deep deep very deep + it a complex or depth classes occurs within one unit, only the symbol and code of the shallowest depth class are indicated soil; mapping code depth class code slopeùclass code sodjagtmdar ä *$ «e«^ê,^f*-*f*%t!*"'**?s.f, '»,:«JW^«^;:^^#«g»^P*f?^f x X x X x x x» prcffde pit ot>sefvatlon wfisf refefèhèë number - ro fl farm building O.O025ha. river dam contours V.l. 60cm survey area boundary fence SOIL SURVEY AND MAP PREPARATION (995) Survey H. C. K. Kinyanjul. C R.K. Njoroge, É.K Kinyanjuv C.H. Kariukl and H. N. Onyono Map eompifatton Map correlation H.C.K. Kinyanjui S R. Rachilo and jp.jt. Gicheru Topographical mapping S Wataka and B. G. Muriithi Cartography, ).l. Osiemo Drawing No

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