Reference soil Kenya 19: Planosol

KE019

Planosols occur in level landscapes throughout the world often associated with broad river valleys.

Characteristics

Soils having an eluvial horizon, the lower boundary of which is marked. within 100 cm from the soil surface, by an abrupt textural change associated with stagnic properties above that boundary. The feature of albeluvic tonguing, however, is lacking.

Distribution of Planosols (rough estimation supplied by soilgrids)

Reference soil KE019: Planosols

LOCATION: KE 19 is located in a plain close to a termite mound, but out of its influence. KE 18 is located on the slope of the mound and KE 17 on its active part. MICRO RELIEF: termite mounds of 1-2 m high and a diameter of 3-6 m occur at distances of 30-50 m. VEGETATION/LAND USE: on the mounds shrubs, between the mounds grass, which is used for extensive grazing. SOIL PROCESSES: profiles KE 17, 18 and 19 are associated soils. Termites have throroughly mixed the different horizons as occuring in profile KE 19 which results in KE 17. KE 18 is a transition to KE 19. Additional notes on profile description: Ah, E1 and E2: mottles are dark yellowish brown; Bt2: few weak not intersecting slickensides; texture: gravelly and stony clay; stones are mainly quartzitic with a few jaspis and weathering granites; mottles are reddish yellow; BC: mottles are yellowish brown and white.

Classification

WRB 2006

WRB 1998

Alic- Planosol (Albic Hyposodic Clayic)

Ali-Hyposodic- Planosol (Albic)

12-50 cm	albic horizon
50-105 cm	argic horizon
-	abrupt textural change

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Ali-Dystric Planosol sodic

Solodic Planosol

0-12 cm	ochric A horizon
12-50 cm	albic E horizon
50-105 cm	argic B horizon
-	abrupt textural change
-	stagnic

0-12 cm	ochric A horizon
12-50 cm	albic E horizon
50-105 cm	argillic B horizon
-	abrupt textural change
-	hydromorphic

Other classification

USDA-NRCS (1999)	Typic Albaqualf
USDA-SCS (1975)	Typic Tropaqualf aquic very fine mixed isohyperthermic

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
10-20	-	1.0	4.4	14.0	13.1	6.4	38.9	42.0	0.0	42	19.1
30-40	-	2.1	11.7	19.2	15.9	6.2	55.1	21.3	0.0	21.3	23.3
60-90	7	3.8	7.8	3.5	2.8	0.4	18.3	6.2	0.0	6.2	75.5

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
10-20	-	-	-	4.8	19.1
30-40	-	-	-	7.0	23.3
60-90	-	-	-	26.2	75.5

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
10-20	5.8	3.7	0.05	-	0.85	0.09	9	1.7	1.1	3.9	0.2	0.1	0.4	4.6
30-40	5.9	3.8	0.04	-	0.73	0.12	6	1.9	1.3	3.2	0.1	0.1	0.5	3.9
60-90	6.0	3.7	0.03	-	1.19	0.17	7	7.7	7.1	13.3	0.3	0.3	3.6	17.5

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 %
10-20	51	9.1	48	3.0	-	12	4
30-40	49	7.9	34	2.6	-	16	6
60-90	46	37.8	50	4.2	-	19	10

Elemental composition of the clay

Depth (cm)	SiO2 % w/w	Al2O3 % w/w	Fe2O3 % w/w	CaO % w/w	MgO % w/w	K2O % w/w	Na2O % w/w	TiO2 % w/w
10-20	53.8	20.2	10.0	0.04	0.46	0.69	-	1.46
30-40	48.7	21.2	12.9	0.04	0.46	0.69	-	1.54
60-90	44.5	25.8	11.6	0.03	0.45	0.49	-	0.96

Depth (cm)	MnO2 % w/w	P2O5 % w/w	Ign.Loss clay % w/w	Total Clay % w/w	SiO2/Al2O3 mol/mol	SiO2/Fe2O3 mol/mol	SiO2 / R mol/mol	Al2O3/Fe2O3 mol/mol
10-20	0.04	0.24	10.5	97.43	4.5	14.3	3.4	3.2
30-40	0.02	0.26	10.9	96.71	3.9	10	2.8	2.6
60-90	0.01	0.12	12.6	96.56	2.9	10.2	2.3	3.5

Elemental composition of the soil

Depth (cm)	Al2O3 % w/w	CaO % w/w	Fe2O3 % w/w	K2O % w/w	MgO % w/w	Na2O % w/w	SiO2 % w/w	TiO2 % w/w
10-20	5.6	0.20	2.9	0.56	0.10	-	86.1	0.60
30-40	5.3	0.14	3.5	0.46	0.08	-	86.1	0.54
60-90	19.8	0.43	9.8	0.44	0.33	-	57.3	0.80

Depth (cm)	Al2O3/Fe2O3 mol/mol	LOI % w/w	MnO2 % w/w	P2O5 % w/w	SiO2 / Al2O3 mol/mol	SiO2/Fe2O3 mol/mol	SiO2 / R mol/mol
10-20	3	4.7	0.02	0.03	26.1	78.9	19.6
30-40	2.4	4.5	0.01	0.02	27.6	65.5	19.4
60-90	3.2	11.2	0.01	0.04	4.9	15.5	3.7

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
10-20	-	-	-	-	-	-	weak	-	strong	weak to medium	-	-
30-40	-	-	-	-	-	-	weak	-	strong	weak to medium	-	-
60-90	-	-	-	-	-	-	weak	-	very strong	-	-	-

Profile description

Ah 0-12 cm	dark grey (10YR 4/1, dry) (10YR 3.5/2, moist)loam,weak to moderate very fine subangular blocky,very friable slightly sticky slightly plastic,common (5-15%) faint mottles,few very fine pores and few pores,non calcareous,clear smooth boundary to,
E1 12-42 cm	grey (10YR 5/1, dry) dark greyish brown (10YR 4/2, moist)sandy clay loam,weak very fine subangular blocky,very friable slightly sticky slightly plastic,common (5-15%) fine faint mottles,few very fine pores and few pores,non calcareous,clear wavy boundary to,
E2 42-50 cm	grey (10YR 5/1, dry) dark greyish brown (10YR 4/2, moist)coarse sandy loam gravelly,weak very fine subangular blocky,very friable slightly sticky slightly plastic,common (5-15%) fine faint mottles,few very fine pores and few pores,few weathered granite stones,non calcareous,abrupt broken boundary to,
Bt1 50-60 cm	very dark brown (10YR 2/2, moist)clay,strong fine angular blocky,firm sticky slightly plastic,many (15-40%) medium prominent mottles (2.5YR 5/8),continuous thick clay cutans,few very fine pores,non calcareous,clear wavy boundary to,
Bt2 60-105 cm	very dark brown (10YR 2/2, moist)clay gravelly,strong fine angular blocky,sticky slightly plastic,many (15-40%) fine distinct mottles,continuous thick clay cutans,no pores,common stones weathered quartz, jaspis, weathered rock fragments,non calcareous,clear wavy boundary to,
105-105 cm	dark grey (10YR 4/1, moist)clay,weak coarse angular blocky,firm sticky slightly plastic,common (5-15%) fine distinct mottles,no pores,abundant weathered rock stones,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	ejecta ash
Kind 2 (parent material) (second entry); Parker (eds), 1984	granite
Mode of accumulation or deposition of parent material	fluvial
Mode of accumulation or deposition of parent material (second entry)	residual material
Remarks on Parent Materials	underlain by granite
Soil Depth	105cm
Texture of parent material	loamy
Texture of parent material (second entry)	gravelly
Weathering Resistance	poor
Weathering Resistance (second entry)	moderate
General characterization of the status of weathering of solid rock	highly
General characterization of the status of weathering of solid rock (second entry)	partially or moderately

Land use or vegetation in the immediate vicinity of the site	extensive grazing
Remarks on Land Use / Vegetation	see remarks
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	1340m
Physiographic Unit	plain adjacent to termite moun
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%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Lower limit of a slow permeable or stagnating layer in the profile	105cm
Drainage class ; FAO (2006) - Guidelines for soil description	poor
Dry From - To	0-50cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	perched
Moist From - To	50-105cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	ponded
Upper limit of a slow permeable or stagnating layer in the profile	50cm

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)	no surface slaking/crusting observed
Microrelief Height: variation in height	200
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	termite/ant mounds
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 19: Planosol

Characteristics

Reference soil KE019: Planosols

Classification