Reference soil Kenya 31: Lixisol

KE031

Lixisols occur dominantly in the drier parts of the tropics and subtropics. Their high base status is partly due to less leaching, partly to admixture from airborne dust from adjacent desert regions.

Characteristics

Soils having an argic horizon (a subsurface horizon with a 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 either: 100 cm from the soil surface, or 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 50 percent or more in the major part between 25 and 100 cm from the soil surface.

Distribution of Lixisols (rough estimation supplied by soilgrids)

Reference soil KE031: Lixisols

A dark reddish brown (2,5 YR 3/4) to red soil (2,5 YR 4/8) with some surface sealing, derived from coarse grained sandstones (Mazeras formation), with a high porosity (many very fine and fine, few to common medium and large pores). In the Ap horizon some charcoal particles (<2cm) appear. There are termite burrows (2-15 cm) filled with material from higher horizons below 15 cm of depth. The land is used as arable land with cultivated and fallow fields.

Classification

WRB 2006

WRB 1998

Cutanic- Lixisol (Profondic Clayic Chromic)

Chromi-Profondic- Lixisol

15-150 cm

argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Chromi-Haplic Luvisol

Ferric Luvisol

0-15 cm	ochric A horizon
15-150 cm	argic B horizon

0-15 cm	ochric A horizon
15-150 cm	argillic B horizon
-	ferric

Other classification

USDA-NRCS (1999)	Rhodic Kandiustalf
USDA-SCS (1975)	Rhodic Paleustalf ustic

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
0-15	-	4.9	20.0	27.0	15.3	3.9	71.1	0.5	3.5	4	24.8
15-55	-	4.8	16.4	20.0	11.6	3.0	55.8	0.9	2.1	3	41.1
55-105	-	4.5	12.2	16.5	10.4	2.9	46.5	0.7	2.5	3.2	50.3
105-150	-	6.7	13.6	16.4	10.1	2.7	49.5	0.9	1.9	2.8	47.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-15	-	-	-	12.9	24.8
5-10	1.47	-	-	-	-
25-30	1.59	-	-	-	-
15-55	-	-	-	25.2	41.1
55-105	-	-	-	20.9	50.3
70-75	1.64	-	-	-	-
120-125	1.62	-	-	-	-
105-150	-	-	-	-	47.7

Other physical data

Depth (cm)	Bulk density kg/dm³	pF 0 % v/v	pF 1.0 % v/v	pF 1.5 % v/v	pF 2.0 % v/v	pF 2.3 % v/v	pF 2.7 % v/v	pF 3.4 % v/v	pF 4.2 % v/v
5-10	1.47	39.9	32.1	28.9	23.5	21.6	20.3	12.0	11.7
25-30	1.59	35.7	31.8	29.8	25.9	24.4	23.3	19.3	18.2
70-75	1.64	36.4	34.1	32.9	29.7	28.3	27.1	24.5	23.1
120-125	1.62	35.9	33.4	32.2	28.1	26.0	24.6	21.6	20.9

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
0-15	6.7	5.8	0.09	-	0.93	0.08	12	-	-	2.4	0.9	0.4	0.1	3.8
15-55	6.6	5.5	0.07	-	0.47	0.05	9	-	-	2.6	1.4	0.4	0.2	4.6
55-105	6.6	5.5	0.07	-	0.36	-	-	-	-	2.4	1.5	0.3	0.2	4.4
105-150	6.5	5.1	0.05	-	0.25	-	-	-	-	1.6	2.0	0.2	0.1	3.9

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 %
0-15	57	6.7	27	3.3	-	-	1
15-55	71	6.5	16	1.6	-	-	3
55-105	58	7.6	15	1.3	-	-	3
105-150	61	6.4	13	0.9	-	-	2

Depth (cm)	pH NaF	P Retention %	ODOE	Al o % w/w	Si o % w/w	Fe d % w/w	Al d % w/w	Fe p % w/w	Al p % w/w	C p % w/w	Fe o % w/w
0-15	-	-	-	0.07	0.01	0.89	0.09	0.08	0.04	-	0.03
15-55	-	-	-	0.08	0.01	1.51	0.14	0.11	0.05	-	0.04
55-105	-	-	-	0.06	0.01	1.85	0.17	0.05	0.04	-	0.04
105-150	-	-	-	0.07	0.02	1.75	0.16	0.03	0.04	-	0.04

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	-	weak	-	-	very strong	-	weak	-	-	-
15-55	-	-	-	weak	-	-	very strong	-	weak	-	-	-
55-105	-	-	-	weak	-	-	very strong	-	weak	-	-	-
105-150	-	-	-	weak	-	-	very strong	-	weak	-	-	-

Profile description

Ap 0-15 cm	dark reddish brown (2.5YR 3/4, moist)sandy clay loam,weak medium granular parting to weak medium angular blocky,hard friable slightly sticky slightly plastic,many very fine and fine and common medium pores,many very fine and few fine roots,small charcoal fragments,non calcareous,clear smooth boundary to,
BA 15-55 cm	dark red (2.5YR 3/6, moist)sandy clay loam,moderate medium and coarse prismatic parting to moderate medium and coarse angular blocky,hard firm slightly sticky plastic,patchy thin clay cutans in root channels and pores,many very fine and fine and few common to medium and coarse pores,common very fine and few fine roots,few termite channels,non calcareous,gradual smooth boundary to,
Bt1 55-105 cm	(2.5YR 4/7, moist)sandy clay,moderate medium and coarse prismatic parting to moderate medium and coarse angular blocky,hard firm slightly sticky plastic,patchy thin clay cutans in root channels and pores,many fine and very fine pores and few medium and coarse pores,common very fine and few fine roots,few krotovinas,non calcareous,diffuse smooth boundary to,
Bt2 105-150 cm	red (2.5YR 4/8, moist)sandy clay loam,moderate medium and coarse prismatic parting to moderate medium and coarse angular blocky,hard firm slightly sticky plastic,common to many very fine and fine pores and few medium and coarse pores,few krotovinas,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	non calcareous sandstone
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	poorly sorted coarse-grained Mazeras sandstone
Texture of parent material	loamy
Weathering Resistance	high
General characterization of the status of weathering of solid rock	highly

Intensity of the soil erosion type	slight
Intensity of the soil erosion type (second entry)	moderate
Soil erosion type	sheet

Land use or vegetation in the immediate vicinity of the site	arable farming
Remarks on Land Use / Vegetation	LAND USE: Maize, sorghum, coconuts

Altitude	270m
Physiographic Unit	plateau
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plateau
Slope	1%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	rolling

Lower limit of a slow permeable or stagnating layer in the profile	1cm
Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-5cm
Flooding frequency (FAO, 1986)	never
Depth to groundwater table	0cm
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	5-150cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	slow
Upper limit of a slow permeable or stagnating layer in the profile	0cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	surface partly slaked, round smooth aggregates
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 31: Lixisol

Characteristics

Reference soil KE031: Lixisols

Classification