Reference soil Kenya 58: Acrisol

KE058

Acrisols occur dominantly in the wetter parts of the tropics and subtropics and the warm temperate regions in relatively young landscapes.

Characteristics

Soils having an argic horizon (a subsurface horizon with distinct higher clay content than the overlying horizon), which has a cation exchange capacity of less than 24 cmolc per kg in some part, either starting within 100 cm from the soil surface, or within 200 cm from the soil surface if the argic horizon is overlain by loamy sand or coarser textures throughout. They have a base saturation (total amount of Ca, Mg, K and Na with respect to the cation exchange capacity) of less than 50 percent in the major part between 25 and 100 cm from the soil surface

Distribution of Acrisols (rough estimation supplied by soilgrids)

Reference soil KE058: Acrisols

Many termite channels and some crotovinas. Other landuse: small scale rainfed annual crops. Slides: 10,173 - 10,183.

Classification

WRB 2006

WRB 1998

Cutanic- Acrisol (Clayic Chromic)

Chromic- Acrisol

26-104 cm

argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Chromi-Haplic Acrisol

Ferric Acrisol

0-26 cm	ochric A horizon
26-104 cm	argic B horizon

0-26 cm	ochric A horizon
26-104 cm	argillic B horizon
-	ferric

Other classification

USDA-NRCS (1999)	Udic Rhodustalf
USDA-SCS (1975)	Udic Haplustox ustic fine-loamy over clayey isohyperthermic

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Physical characteristics

Particle size distribution

Depth (cm)	Gravel % v/v	very coarse sand % w/w	coarse sand % w/w	medium sand % w/w	fine sand % w/w	very fine sand % w/w	Total sand % w/w	coarse silt % w/w	fine silt % w/w	Total silt % w/w	Clay % w/w
0-14	-	8.9	23.0	22.3	16.6	4.8	75.6	2.1	7.0	9.1	15.3
14-26	-	8.3	16.4	20.2	16.9	4.0	65.8	7.6	6.1	13.7	20.4
26-56	-	5.1	12.3	15.0	13.7	4.5	50.6	5.2	5.4	10.6	38.3
56-78	-	6.9	12.4	14.1	12.4	2.7	48.5	5.9	5.9	11.8	39.5
78-104	-	6.9	11.5	12.8	11.6	4.0	46.8	5.9	6.7	12.6	40.6
104-138	-	11.7	11.0	12.2	12.6	3.4	50.9	7.1	8.8	15.9	33.1
138-	-	10.9	14.8	14.2	12.9	6.4	59.2	9.1	10.5	19.6	21.1

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-14	-	-	-	6.7	15.3
14-26	-	-	-	9.3	20.4
26-56	-	-	-	7.8	38.3
56-78	-	-	-	7.5	39.5
78-104	-	-	-	7.5	40.6
104-138	-	-	-	6.5	33.1
138-	-	-	-	5.2	21.1

Chemical data

Depth (cm)	pH H2O	pHKCl	EC 1: 2.5 dS/m	CaCO3 % w/w	C % w/w	N %	C / N	Exch. Acid cmol(c)/kg	Exch. Al cmol(c)/kg	Ca cmol(c)/kg	Mg cmol(c)/kg	K cmol(c)/kg	Na cmol(c)/kg	Sum Cations cmol(c)/kg
0-14	7.0	6.1	0.15	0.3	0.87	0.11	8	-	-	4.8	2.2	1.0	0.0	8
14-26	6.2	5.1	0.09	-	0.30	0.05	6	-	-	3.0	1.8	0.9	0.1	5.8
26-56	5.0	3.9	0.05	-	0.29	0.05	6	1.1	1.7	2.7	1.6	0.8	0.0	5.1
56-78	4.8	3.8	0.04	-	0.23	0.06	4	1.2	0.9	2.4	1.6	0.7	0.0	4.7
78-104	4.8	3.7	0.03	-	0.26	0.05	5	1.5	1.1	2.4	1.7	0.6	0.0	4.7
104-138	4.8	3.6	0.02	-	0.18	0.04	5	2.0	1.6	2.0	1.3	0.4	0.1	3.8
138-	4.9	3.7	0.02	-	0.04	0.02	2	1.9	1.6	1.8	1.2	0.5	0.0	3.5

Depth (cm)	Base sat. %	CEC soil cmol(c)/kg	CEC clay cmol(c)/kg	CEC org cmol(c)/kg	ECEC cmol(c)/kg	Al sat. %	ESP %
0-14	49	16.3	88	3.0	-	-	0
14-26	50	11.6	52	1.1	-	-	1
26-56	32	15.8	38	1.0	-	4	0
56-78	54	8.7	20	0.8	-	10	0
78-104	42	11.1	25	0.9	-	10	0
104-138	50	7.6	21	0.6	-	21	1
138-	44	8.0	37	0.1	-	20	0

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-14	-	very weak	-	very weak	-	-	medium to strong	weak	-	-	weak to medium	-
26-56	-	-	-	very weak	-	-	strong	weak	-	-	weak	-
78-104	-	-	-	very weak	-	-	strong	weak	-	-	weak	-
138-	-	-	-	very weak	-	-	strong	weak	-	-	weak	-

Profile description

Ah 0-14 cm	dark reddish brown (2.5YR 3/4, dry) dark reddish brown (2.5YR 2.5/4, moist)sandy clay loam,weak fine and medium subangular blocky,slightly hard friable slightly sticky slightly plastic,many very fine and fine and few fine and medium pores,common very fine and few fine roots,few fine gravel fresh quartz fragments,frequent termite channels and few krotovinas,non calcareous,gradual smooth boundary to,
14-26 cm	red (2.5YR 4/6, dry) dark red (10R 3/6, moist)sandy clay loam,weak fine and medium subangular blocky,slightly hard very friable slightly sticky slightly plastic,many very fine and fine and few fine and medium pores,common very fine and few fine roots,few fine gravel fresh quartz fragments,frequent termite channels and few krotovinas,non calcareous,gradual smooth boundary to,
BA 26-56 cm	red (10R 4/6, dry) dark red (10R 3/6, moist)sandy clay loam,weak to moderate fine and medium subangular blocky and weak to moderate medium and coarse subangular blocky,slightly hard very friable slightly sticky slightly plastic,many very fine and fine and common fine pores,common very fine and few fine roots,very few fine gravel fresh quartz fragments,frequent termite channels and few krotovinas,non calcareous,gradual smooth boundary to,
Bt1 56-78 cm	red (10R 4/8, dry) dark red (10R 3/6, moist)clay,moderate fine and medium subangular blocky and moderate very fine angular blocky,hard very friable slightly sticky slightly plastic,patchy thin clay cutans,many very fine and fine and few fine pores,common very fine and few fine roots,very few fine gravel fresh quartz fragments,frequent termite channels and few krotovinas,non calcareous,diffuse smooth boundary to,
Bt2 78-104 cm	red (10R 4/8, dry) dark red (10R 3/6, moist)clay,moderate fine and medium subangular blocky,soft very friable slightly sticky slightly plastic,many very fine and fine and few fine pores,common very fine and few fine roots,very few fine gravel fresh quartz fragments,frequent termite channels and few krotovinas,non calcareous,clear smooth boundary to,
104-138 cm	red (2.5YR 5/8, dry) red (10R 4/6, moist)very gravelly sandy clay,weak to moderate fine and medium subangular blocky,soft very friable slightly sticky slightly plastic,many very fine and fine and few fine pores,common very fine and few fine roots,common medium gravel fresh quartz fragments,frequent termite channels and few krotovinas,non calcareous,clear smooth boundary to,
CB 138-138 cm	very gravelly sandy claycommon medium gravel fresh quartz fragments,non calcareous,

Depth1	140cm
Kind 1 (parent material) ; Parker (eds), 1984	gneiss
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	Basement system, biotite gneiss
Soil Depth	140cm
Texture of parent material	sandy clay
Weathering Resistance	high
General characterization of the status of weathering of solid rock	partially or moderately

Occurrence of soil aggradation (McDonald et al., 1984)	absent
Intensity of the soil erosion type	slight
Soil erosion type	sheet
Slope stability	stable

Land use or vegetation in the immediate vicinity of the site	shrubland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Wooded shrubland. LAND USE: Locally charcoal burning
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	degraded
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	deciduous shrub

Altitude	725m
Physiographic Unit	non dissected erosional plain
Physiographic position of the site	flat
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plain
Slope	0%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-140cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	medium

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Surface cracking	no cracks observed
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	surface partly slaked, round smooth aggregates
Microrelief Height: variation in height	60
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	animal tracks
Microrelief pattern	isolated
Rock outcrop class (FAO (2006) - Guidelines for soil description)	none
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Surface stoniness class (FAO (2006) - Guidelines for soil description)	none

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Reference soil Kenya 58: Acrisol

Characteristics

Reference soil KE058: Acrisols

Classification