Reference soil Kenya 60: Solonetz

KE060

Solonetzes occur where a sodium source supplies the clay-rich subsoil with exchangeable Na, causing peptization of clay and organic substances and deterioration of the topsoil.

Characteristics

Soils having a natric horizon (a subsurface horizon with distinct higher clay content than the overlying horizon and more than 15% exchangeable sodium) within 100 cm from the soil surface.

Distribution of Solonetz (rough estimation supplied by soilgrids)

Reference soil KE060: Solonetz

Little soil fauna activity. Cracks from 39 to 80 cm. Slides: 10,195 - 10,196.

Classification

WRB 2006

WRB 1998

calcic horizon- Solonetz

Orthicalcic- Solonetz

30-110 cm	calcic horizon
5-70 cm	argic horizon
70-110 cm	natric horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Calcic Solonetz

Orthic Solonetz

0-16 cm	ochric A horizon
30-110 cm	calcic horizon
5-70 cm	argic B horizon
70-110 cm	natric B horizon
-	calcaric
-	sodic

0-16 cm	ochric A horizon
30-110 cm	calcic horizon
5-70 cm	argillic B horizon
70-110 cm	natric B horizon

Other classification

USDA-NRCS (1999)
USDA-SCS (1975)	Natrargid aridic 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
0-5	2	8.7	18.3	16.5	10.9	3.8	58.2	3.7	7.4	11.1	30.8
5-16	2	8.5	13.5	13.5	10.7	3.7	49.9	3.9	10.1	14	36.2
16-30	3	8.2	14.1	14.2	10.8	3.5	50.8	1.7	11.3	13	36.3
30-70	2	8.1	14.5	13.0	9.3	3.2	48.1	2.6	12.0	14.6	37.3
70-110	2	8.0	14.4	12.8	8.7	3.1	47	4.2	10.5	14.7	38.3

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-5	-	-	-	15.5	30.8
5-16	-	-	-	22.0	36.2
16-30	-	-	-	21.0	36.3
30-70	-	-	-	22.0	37.3
70-110	-	-	-	24.0	38.3

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
0-5	7.9	7.6	0.14	8.5	0.95	0.12	8	-	-	60.2	6.6	2.6	0.0	69.4
5-16	8.0	7.6	0.14	12.3	0.49	0.07	7	-	-	60.1	6.8	2.4	0.1	69.4
16-30	8.1	7.6	0.17	12.5	0.37	0.05	7	-	-	66.0	9.1	2.0	0.3	77.4
30-70	8.5	7.7	0.24	17.6	0.21	0.03	7	-	-	54.3	14.7	0.6	2.2	71.8
70-110	8.8	7.9	0.68	17.1	0.21	0.03	7	-	-	54.7	18.1	0.6	6.5	79.9

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 %
0-5	314	22.1	68	3.3	-	-	0
5-16	299	23.2	68	1.7	-	-	0
16-30	350	22.1	66	1.3	-	-	1
30-70	315	22.8	72	0.7	-	-	10
70-110	352	22.7	70	0.7	-	-	29

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
0-5	-	-	-	0.1	0.1	0.5	0.1	-	-	-	0.1
5-16	-	-	-	0.2	0.1	0.6	0.1	-	-	-	0.1
16-30	-	-	-	0.1	0.1	0.5	0.1	-	-	-	0.1
30-70	-	-	-	0.1	0.1	0.6	0.1	-	-	-	0.1
70-110	-	-	-	0.1	0.1	0.5	0.1	-	-	-	0.1

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-5	-	very weak to weak	-	-	-	-	very weak	-	weak	-	weak	-
5-16	-	very weak to weak	-	-	-	-	very weak	-	weak	-	weak	-
16-30	-	very weak to weak	-	-	-	-	weak	-	weak	-	weak	-
30-70	-	very weak to weak	-	-	-	-	weak	-	weak	-	medium	-
70-110	-	very weak to weak	-	-	-	-	weak	-	weak	-	medium	-

Profile description

Ak1 0-5 cm	brown (7.5YR 5/4, dry) (dark) brown (7.5YR 4/4, moist)sandy clay,weak very fine subangular blocky and weak very fine and fine granular,loose very friable sticky plastic,many very fine pores and few fine pores,many very fine and few fine roots,very few fine gravel fresh quartz fragments,moderately calcareous (2-10%),gradual smooth boundary to,
Ak2 5-16 cm	strong brown (7.5YR 5/6, dry) reddish brown (5YR 4/4, moist)clay,weak very fine subangular blocky and weak very fine and fine granular,loose very friable sticky plastic,many very fine pores and few medium pores,many very fine and few fine roots,very few fine gravel fresh quartz fragments,moderately calcareous (2-10%),gradual smooth boundary to,
Bk 16-30 cm	strong brown (7.5YR 5/6, dry) dark reddish brown (5YR 3/3, moist)clay,moderate fine and medium subangular blocky,slightly hard very friable sticky plastic,patchy thin clay cutans,many very fine pores and few fine pores,common very fine and few fine roots,few powdery calcareous soft segregations,very few fine gravel fresh quartz fragments,moderately calcareous (2-10%),abrupt smooth boundary to,
Btk1 30-70 cm	reddish brown (5YR 4/4, dry) dark reddish brown (5YR 3/3, moist)clay,strong coarse columnar,hard firm sticky plastic,broken thin clay cutans,many very fine few and very fine and medium pores,common very fine roots,few powdery calcareous soft segregations,very few fine gravel fresh quartz fragments,strongly calcareous (10-25%),gradual smooth boundary to,
Btk2 70-110 cm	dark reddish brown (5YR 3/4, dry) reddish brown (5YR 4/4, moist)clay,weak to moderate subangular blocky,hard firm sticky plastic,broken thin clay cutans,many very fine pores and few fine pores,few very fine roots,very few fine gravel fresh quartz fragments,strongly calcareous (10-25%),

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	marine sediments
Remarks on Parent Materials	Bay sediments, Marafa beds
Soil Depth	30cm
Texture of parent material	clayey
Texture of parent material (second entry)	clayey
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	partially or moderately

Occurrence of soil aggradation (McDonald et al., 1984)	not apparent
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	(semi-)natural vegetation
Remarks on Land Use / Vegetation	VEGETATION: Shrubbed woodland, browsed by camels and goat; 70% bare soil
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	cut over
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	deciduous woodland

Altitude	355m
Physiographic Unit	sedimentary 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

Lower limit of a slow permeable or stagnating layer in the profile	70cm
Drainage class ; FAO (2006) - Guidelines for soil description	imperfect
Dry From - To	0-110cm
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	slow
Estimated run off (class)	very slow
Upper limit of a slow permeable or stagnating layer in the profile	30cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	slightly alkaline
Surface cracking	no cracks observed
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	surface partly slaked, round smooth aggregates
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 60: Solonetz

Characteristics

Reference soil KE060: Solonetz

Classification