Reference soil Kenya 22: Solonetz

KE022

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 KE022: Solonetz

A salinic soil derived from quaternary sediments ("Hedad beds") with very light seasonal use (depressions devoid of vegetation), biological activities (krotowinas). There are few fine black primary mineral fragments throughout the profile. vegetation: accacia reficiens, indigofera Spinosa

Classification

WRB 2006

WRB 1998

Haplic- Solonetz (Abruptic)

Haplic- Solonetz

32-170 cm	argic horizon
55-90 cm	natric horizon
-	abrupt textural change

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Haplic Solonetz

Orthic Solonetz

0-8 cm	ochric A horizon
32-170 cm	argic B horizon
55-90 cm	natric B horizon
-	abrupt textural change

0-8 cm	ochric A horizon
32-170 cm	argillic B horizon
55-90 cm	natric B horizon
-	abrupt textural change

Other classification

USDA-NRCS (1999)	Haplic Natrargid
USDA-SCS (1975)	Haplic Natrargid aridic

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
0-8	-	2.8	18.1	29.4	25.8	7.7	83.8	5.4	1.8	7.2	9.1
8-32	-	5.0	21.0	28.5	24.4	7.6	86.5	4.1	1.5	5.6	7.8
32-55	-	5.0	18.4	23.6	17.8	5.3	70.1	4.9	5.3	10.2	19.7
90-130	-	5.1	14.5	16.9	13.2	4.4	54.1	5.9	4.8	10.7	35.3
55-90	-	4.4	13.7	17.0	11.9	3.8	50.8	5.1	10.7	15.8	33.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-8	-	-	-	5.8	9.1
8-32	1.72	-	-	5.2	7.8
32-55	1.54	-	-	9.5	19.7
90-130	-	-	-	17.5	35.3
55-90	1.53	-	-	17.2	33.7

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
8-32	1.72	30.4	28.2	21.5	13.6	11.0	9.1	5.8	5.5
32-55	1.54	38.4	36.7	33.0	26.9	24.3	21.6	14.9	14.8
55-90	1.53	45.0	44.3	42.7	37.5	34.3	31.2	27.3	25.1

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
0-8	8.1	6.9	0.09	0.9	0.29	0.02	14	-	-	3.6	-	0.8	0.1	6.6
8-32	7.9	6.1	0.06	0.7	0.13	0.01	13	-	-	2.6	-	0.6	0.0	4.9
32-55	7.9	5.6	0.16	1.1	0.14	0.01	14	-	-	5.9	-	1.4	0.4	12.3
90-130	8.9	7.2	0.68	2.1	0.12	0.01	12	-	-	11.6	-	2.1	2.9	24.8
55-90	8.8	7.2	0.82	2.1	0.16	0.01	16	-	-	11.9	-	1.9	4.7	27.6

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 %
0-8	87	7.6	73	1.0	-	-	1
8-32	75	6.5	78	0.5	-	-	0
32-55	82	15.0	75	0.5	-	-	3
90-130	100	24.9	71	0.4	-	-	12
55-90	96	28.9	86	0.6	-	-	16

Depth (cm)	CaSO4.2H2O %	P Bray mg/kg	P Olsen mg/kg	pH CaCl2	clay_noncarbonate % w/w	clay_carbonate % w/w	phosphorus4 mg/kg	phosphorus1 mg/kg	total_sulfur % w/w
0-8	-	-	8	-	-	-	-	-	-
8-32	-	-	6	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-8	-	very weak to weak	-	-	-	-	very weak to weak	medium to strong	-	-	medium to strong	-
32-55	-	very weak to weak	-	-	-	-	very weak to weak	medium to strong	-	very weak	medium to strong	-
90-130	-	very weak	-	-	-	-	very weak to weak	weak to medium	-	very weak	strong	-

Soluble sands

Depth (cm)	Ca mmol(c)/kg	Mg mmol(c)/kg	K mmol(c)/kg	Na mmol(c)/kg	sum cations mmol(c)/kg	CO3 mmol(c)/kg	HCO3 mmol(c)/kg	Cl mmol(c)/kg	NO3 mmol(c)/kg	SO4 mmol(c)/kg	sum anions mmol(c)/kg
0-8	0.0	0.0	0.1	0.1	0.2	0.0	0.1	0.0	0.0	0.0	0.1
8-32	0.0	0.0	0.0	0.1	0.1	0.0	0.1	0.0	0.0	0.0	0.1
32-55	0.0	0.0	0.0	0.4	0.4	0.0	0.1	0.0	0.0	0.0	0.1
90-130	0.0	0.0	0.1	1.5	1.6	0.0	0.7	0.8	0.0	0.1	1.6
55-90	0.0	0.0	0.0	2.0	2	0.0	0.6	1.2	0.0	0.1	1.9

Profile description

Ah 0-8 cm	strong brown (7.5YR 5/6, dry) reddish brown (5YR 4/4, moist)loamy sand,moderately coherent porous massive to weak fine and medium subangular blocky,slightly hard very friable non sticky non plastic,many very fine and fine discontinuous and many medium and coarse tubular pores,common roots,slightly calcareous (0-2%),clear smooth boundary to,
E 8-32 cm	yellowish red (5YR 5/8, dry) red (2.5YR 4/6, moist)loamy sand,porous massive,very hard very friable sticky plastic,many very fine and fine discontinuous and many medium and coarse continuous tubular pores,common roots,slightly calcareous (0-2%),abrupt boundary to,
Btn1 32-55 cm	dark red (2.5YR 3/6, dry) (2.5YR 3/5, moist)sandy clay,strong very coarse columnar to weak coarse and very coarse angular blocky,very hard very friable sticky plastic,continuous moderately thick clay and sesquioxide cutans,many very fine and fine and common medium and coarse pores,common roots,slightly calcareous (0-2%),gradual smooth boundary to,
Btn3 90-130 cm	red (2.5YR 4/6, dry) dark reddish brown (2.5YR 3/4, moist)sandy clay,strongly coherent prismatic to weak medium and coarse subangular blocky,hard very friable sticky plastic,continuous moderately thick clay and sesquioxide cutans,common very fine and fine pores and few medium and coarse pores,few roots,few small spherical soft calcareous concretions and few small spherical manganiferous concretions,moderately calcareous (2-10%),gradual smooth boundary to,
Btn4 130-170 cm	red (2.5YR 4/6, dry) dark reddish brown (2.5YR 3/4, moist)sandy clay,strongly coherent prismatic to weak medium and coarse subangular blocky,hard very friable sticky plastic,broken moderately thick clay and sesquioxide cutans,many very fine and fine pores,few roots,few small spherical soft calcareous concretions and few small spherical manganiferous concretions,
Btn2 55-90 cm	reddish brown (2.5YR 4/4, dry) (2.5YR 3/5, moist)sandy clay,moderate medium and coarse prismatic to coarse and very coarse subangular blocky,hard very friable sticky plastic,continuous thick clay and sesquioxide cutans,common very fine and fine few medium and coarse pores,common roots,very few small spherical soft calcareous concretions,moderately calcareous (2-10%),clear smooth boundary to,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	unconsolidated, unspecified
Remarks on Parent Materials	Quaternary sediments (Hedad beds)
Texture of parent material	sandy clay
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
Soil erosion type (second entry)	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	not used and not managed
Remarks on Land Use / Vegetation	VEGETATION: Acacia reficiens, Indigofera spinosa
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	dwarf shrub

Altitude	460m
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%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Dry From - To	0-170cm
Flooding frequency (FAO, 1986)	never
Depth to groundwater table	0cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	slow

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
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

You are here

Reference soil Kenya 22: Solonetz

Characteristics

Reference soil KE022: Solonetz

Classification