Reference soil Kenya 10: Solonetz

KE010

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 KE010: Solonetz

A soil derived from brown sands and clays of pliocene/pleistocene bay sediments...

Classification

WRB 2006

WRB 1998

Haplic- Solonetz (Albic Magnesic)

Albi-Magnesic- Solonetz

12-45 cm	albic horizon
62-110 cm	natric horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Haplic Solonetz

Solodic Planosol

0-12 cm	ochric A horizon
12-45 cm	natric B horizon
62-110 cm	natric B horizon

0-12 cm	ochric A horizon
12-45 cm	albic E horizon
62-110 cm	natric B horizon
-	abrupt textural change

Other classification

USDA-NRCS (1999)	Typic Natrustalf
USDA-SCS (1975)	Typic Natrustalf ustic

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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
0-12	-	0.1	0.3	5.5	58.6	18.2	82.7	4.5	3.6	8.1	9.2
12-30	-	0.1	0.4	5.4	54.7	18.1	78.7	6.3	3.6	9.9	11.4
30-45	-	0.1	0.4	4.5	50.6	17.9	73.5	6.6	4.3	10.9	15.7
45-62	-	0.1	0.4	4.3	43.8	15.3	63.9	4.0	2.9	6.9	29.2
62-90	-	0.1	0.3	3.7	40.2	14.7	59	5.3	5.3	10.6	30.4
90-120	-	0.2	0.3	4.7	40.3	14.2	59.7	6.1	3.6	9.7	30.8

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-12	-	-	-	2.3	9.2
12-30	-	-	-	2.7	11.4
30-45	-	-	-	3.7	15.7
45-62	-	-	-	8.7	29.2
62-90	-	-	-	29.0	30.4
90-120	-	-	-	28.7	30.8

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
0-12	5.9	4.4	0.07	-	0.63	0.08	8	-	-	1.2	1.3	0.4	0.0	2.9
12-30	5.1	4.0	0.07	-	0.36	0.10	4	0.9	0.9	1.2	1.3	0.3	0.0	2.8
30-45	5.0	3.8	0.10	-	0.37	0.09	4	1.7	1.6	1.6	1.6	0.3	0.0	3.5
45-62	4.5	3.6	0.82	-	0.39	0.09	4	1.7	1.6	1.2	4.9	0.5	0.7	7.3
62-90	6.8	5.3	1.21	0.8	0.10	0.10	1	-	-	1.6	7.7	0.6	4.8	14.7
90-120	7.4	5.8	1.43	0.9	0.08	0.06	1	-	-	1.9	8.0	0.5	5.0	15.4

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 %
0-12	43	6.8	74	2.2	-	-	0
12-30	51	5.5	48	1.3	-	16	0
30-45	46	7.6	48	1.3	-	21	0
45-62	61	11.9	41	1.4	-	13	6
62-90	95	15.4	51	0.4	-	-	31
90-120	93	16.6	54	0.3	-	-	30

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
0-12	-	-	-	0.03	0.00	0.08	0.02	0.07	0.18	-	0.06
12-30	-	-	-	0.04	0.00	0.11	0.03	0.20	0.65	-	0.05
30-45	-	-	-	0.06	0.00	0.14	0.05	0.16	0.44	-	0.05
45-62	-	-	-	0.06	0.00	0.17	0.05	0.31	1.00	-	0.08
62-90	-	-	-	0.03	0.00	0.15	0.03	0.19	0.58	-	0.02
90-120	-	-	-	0.02	0.00	0.12	0.03	0.16	0.50	-	0.02

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
0-12	4.8	0.11	0.8	1.45	0.11	-	89.9	0.25
12-30	5.6	0.12	1.1	1.46	0.13	-	89.5	0.32
30-45	6.5	0.13	1.4	1.56	0.19	-	87.6	0.37
45-62	9.4	0.11	2.2	1.55	0.38	-	84.0	0.49
62-90	10.1	0.13	2.4	1.57	0.50	-	82.0	0.51
90-120	10.0	0.15	2.3	1.61	0.55	-	82.0	0.50

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
0-12	9.4	1.9	0.04	0.01	31.8	299.2	28.7
12-30	8.0	1.7	0.01	0.01	27.1	216.6	24.1
30-45	7.3	2.1	0.00	0.01	22.9	166.3	20.1
45-62	6.7	3.4	0.00	0.00	15.2	101.5	13.2
62-90	6.6	2.9	0.01	0.01	13.8	90.8	12
90-120	6.8	2.8	0.01	0.01	13.9	94.8	12.1

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-12	-	very weak to weak	-	-	weak to medium	-	-	-	-	weak to medium	weak to medium	-
12-30	-	very weak to weak	-	-	weak to medium	-	-	-	-	very weak to weak	weak to medium	-
30-45	-	very weak to weak	-	-	weak to medium	-	-	-	-	very weak to weak	weak to medium	-
45-62	-	-	-	-	medium to strong	-	-	-	-	-	strong to very strong	-
62-90	-	-	-	-	medium to strong	-	-	-	-	very weak to weak	strong to very strong	-
90-120	-	-	-	-	medium to strong	-	-	-	-	very weak to weak	strong to very strong	-

Profile description

Ah 0-12 cm	yellowish brown (10YR 5/4, dry) dark yellowish brown (10YR 3/4, moist)loamy sand,weak very fine angular blocky parting to granular,soft very friable non sticky non plastic,common very fine pores and few fine pores,non calcareous,clear smooth boundary to,
E 12-45 cm	light yellowish brown (10YR 6/4, dry) brown (10YR 5/3, moist)loamy sand,moderate medium angular blocky,hard very friable slightly sticky plastic,few (2-5%) fine faint mottles (10 YR 6/6),common very fine pores and few fine pores,non calcareous,gradual smooth boundary to,
Btg 45-62 cm	pale brown (10YR 6/3, dry) light brownish grey (10YR 6/2, moist)pale brown (10YR 6/3, dry) brown (10YR 5/3, moist),sandy loam,sandy clay loam,strong very coarse prismatic to massive,moderate medium angular blocky,hard friable slightly sticky plastic,very hard very firm sticky plastic,few (2-5%) fine faint mottles (10 YR 6/6),common (5-15%) fine prominent mottles (5 YR 5/8),common very fine pores and few fine pores,few very fine pores,slightly calcareous (0-2%),non calcareous,abrupt smooth boundary to,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	fluvio-glacial sediments
Remarks on Parent Materials	salty Pleistocene bay sediments
Texture of parent material	loamy
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	partially or moderately

Intensity of the soil erosion type	slight
Soil erosion type	wind

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	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Overgrazed grassland, 65 % bare ground; scattered bushes
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant
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)	grassland

Altitude	251m
Physiographic Unit	coastal plain
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.	coastal 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	poor
Dry From - To	0-110cm
Depth to groundwater table	0cm
Kind of ground water table (USDA, 1979)	no groundwater table observed
(Estimated) minimum (upper) depth to groundwater table	0cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	very slow
Drainage class - intergrade; FAO (2006) - Guidelines for soil description	imperfect

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	0
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 10: Solonetz

Characteristics

Reference soil KE010: Solonetz

Classification