Reference soil Kenya 48: Ferralsol

KE048

Ferralsols occur in tropical and subtropical regions of the world, mainly on old and stable land surfaces.

Characteristics

Soils having a ferralic horizon (strongly weathered horizon with low-activity clays and very low amounts of weatherable minerals) between 25 and 200 cm from the soil surface. They lack a nitic horizon (a horizon with strongly developed, nut-shaped structure) and do not have a layer which fulfils the requirements of an argic horizon and which has, in the upper 30 cm, 10 percent or more water-dispersible clay.

Distribution of Ferralsols (rough estimation supplied by soilgrids)

Reference soil KE048: Ferralsols

Small ridges with grass are grown along the paths and small terraces are made in the field (width 50cm,height 10 - 20cm) both to prevent erosion. Slides: 10,073 - 10,079.

Classification

WRB 2006

WRB 1998

Haplic- Ferralsol (Humic Dystric Clayic)

Hyperdystri-Humic- Ferralsol

11-50 cm	cambic horizon
50-130 cm	ferralic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Humi-Haplic Ferralsol

Orthic Ferralsol

0-11 cm	ochric A horizon
11-50 cm	cambic B horizon
50-130 cm	ferralic B horizon
-	strongly humic

0-11 cm	ochric A horizon
11-50 cm	cambic B horizon
50-130 cm	oxic B horizon

Other classification

USDA-NRCS (1999)	Inceptic Haplustox
USDA-SCS (1975)	Inceptic Haplustox ustic isothermic

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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
0-11	-	0.7	0.9	2.1	3.5	1.9	9.1	4.6	9.4	14	76.9
11-50	-	0.6	0.6	1.4	2.3	1.4	6.3	4.6	6.8	11.4	82.1
50-90	-	0.7	0.6	1.0	2.1	1.4	5.8	4.6	7.9	12.5	81.7
90-120	-	7.4	1.8	1.0	1.6	1.4	13.2	3.8	9.4	13.2	73.6

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-11	-	-	-	18.6	76.9
11-50	-	-	-	15.7	82.1
50-90	-	-	-	0.5	81.7
90-120	-	-	-	-	73.6

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
0-11	6.4	5.3	0.10	-	2.75	0.20	14	0.1	0.0	8.5	4.9	1.9	0.3	15.6
11-50	5.4	4.5	0.06	-	1.53	0.12	13	0.4	0.2	2.1	1.7	1.0	0.0	4.8
50-90	5.2	4.4	0.03	-	1.09	0.09	12	0.8	0.4	1.0	0.8	0.7	0.5	3
90-120	5.4	4.4	0.02	-	0.96	0.09	11	0.9	0.4	0.8	0.5	0.6	0.2	2.1

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 %
0-11	64	24.2	31	9.6	-	-	1
11-50	28	17.4	21	5.4	-	-	0
50-90	20	14.7	18	3.8	-	-	3
90-120	14	15.2	21	3.4	-	-	1

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
0-11	8.7	-	-	0.6	0.1	4.7	0.5	-	-	-	0.5
11-50	9.4	-	-	0.6	0.1	4.8	0.7	-	-	-	0.5
50-90	9.7	-	-	0.6	0.1	5.0	0.6	-	-	-	0.5
90-120	9.5	-	-	0.5	0.1	5.3	0.8	-	-	-	0.5

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-11	-	-	weak	weak	-	-	medium	-	weak	-	-	-
11-50	-	-	weak	weak	-	-	medium	-	-	-	-	-
50-90	-	-	weak	weak	-	-	medium	-	-	-	-	-
90-120	-	-	weak	weak	-	-	medium	-	-	-	-	-

Profile description

Ap 0-11 cm	dark reddish brown (5YR 3/2, dry) dark reddish brown (5YR 3/4, moist)silty clay,moderate medium and coarse subangular blocky parting to crumb,slightly hard very friable sticky slightly plastic,patchy thin clay cutans,many very fine few fine and medium pores,many very fine and few medium roots,very few medium spherical hard irregular concretions,non calcareous,abrupt smooth boundary to,
Bo1 11-90 cm	yellowish red (5YR 4/6, dry) yellowish red (5YR 4/6, moist)silty clay,moderate very coarse subangular blocky,slightly hard very friable sticky slightly plastic,broken thin clay cutans,many very fine few fine and medium pores,common very fine and few fine roots,very few medium spherical hard irregular concretions,non calcareous,clear wavy boundary to,
Bo2 90-130 cm	yellowish red (5YR 5/8, dry) yellowish red (5YR 4/6, moist)silty clay very gravelly,weak medium and coarse subangular blocky parting to single grain,slightly hard very friable sticky slightly plastic,patchy thin clay cutans,many very fine few fine pores,common very fine roots,frequent medium spherical hard irregular concretions,common medium gravel strongly weathered nepheline phonolite and few coarse gravel weathered nepheline phonolite fragments,few termite channels,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	basic volcanic breccia
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	phonolite
Soil Depth	100cm
Texture of parent material	clayey
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	highly

Occurrence of soil aggradation (McDonald et al., 1984)	absent
Slope stability	stable

Major crops	maize
Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	terracing
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	no irrigation
Land use or vegetation in the immediate vicinity of the site	low level arable farming
Remarks on Land Use / Vegetation	LAND USE: Fallow around the pit
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant

Altitude	1142m
Physiographic Unit	minor valley in plateau
Physiographic position of the site	middle slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plateau
Slope	7%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-130cm
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	small cracks (width less than 1 cm, or depth less than 50 cm)
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
Microrelief Height: variation in height	15
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	terracettes
Microrelief pattern	linear
Rock outcrop class (FAO (2006) - Guidelines for soil description)	little rocky
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 48: Ferralsol

Characteristics

Reference soil KE048: Ferralsols

Classification