Reference soil Kenya 21: Solonchak

KE021

Solonchaks occur where saline groundwater comes near to the surface, or where through evapo(transpi)ration salts from the soil water accumulate in the soil, e.g. in desert regions

Characteristics

Soils having a salic horizon (horizon with accumulation of salts more soluble than gypsum) within 50 cm of the soil surface. They have no diagnostic horizons other than a histic, mollic, ochric, takyric, yermic, calcic, cambic, duric, gypsic or vertic horizon.

Distribution of Solonchaks (rough estimation supplied by soilgrids)

Reference soil KE021: Solonchaks

A salt-affected soil, dominated by quartz and clay minerals, derived from quaternary lacustrine sediments ("Chalbi beds") with cracks (extending to 1-2 cm width) to 20 cm depth and a very hard saline crust in dry season (many crystal needles).

Classification

WRB 2006

WRB 1998

Gypsic-Puffic- Solonchak (Sodic Chloridic Takyric)

Gypsi-Sodic- Solonchak (Takyric Chloridic)

0-100 cm	salic horizon
35-100 cm	gypsic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Takyri-Sodic Solonchak

Takyric Solonchak

0-20 cm	ochric A horizon
-	salic
-	sodic

0-20 cm	ochric A horizon
-	high salinity
-	takyric features

Other classification

USDA-SCS (1975)

Salorthid 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
0-20	-	0.4	0.9	1.9	4.0	6.3	13.5	12.9	12.3	25.2	61.2
20-35	-	0.0	0.2	0.2	4.0	12.9	17.3	17.8	19.7	37.5	45.3
35-50	-	0.0	0.3	0.6	5.0	23.9	29.8	13.5	23.8	37.3	33.0
60-75	-	0.2	0.7	1.3	5.6	20.5	28.3	16.5	24.5	41	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
0-20	1.11	-	-	60.7	61.2
20-35	1.29	-	-	44.9	45.3
35-50	1.30	-	-	31.4	33.0
60-75	-	-	-	29.6	30.8

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
0-20	1.11	58.5	56.3	53.1	47.2	38.5	37.0	33.2	33.0
20-35	1.29	59.0	57.4	56.2	55.1	54.0	52.1	39.3	36.5
35-50	1.30	58.3	56.8	55.4	54.2	53.1	51.4	29.6	27.0

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
0-20	10.4	10.0	28.00	7.8	0.24	0.02	12	-	-	20.6	1.6	1.3	182.6	206.1
20-35	10.5	10.2	30.00	5.8	0.31	0.01	31	-	-	0.2	0.3	0.9	200	201.4
35-50	10.5	10.3	30.00	5.5	0.26	-	-	-	-	0.2	0.3	0.7	194.8	196
60-75	10.6	10.3	29.00	8.5	0.27	-	-	-	-	-	-	-	-	-

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 %
0-20	451	45.7	75	0.9	-	-	400
20-35	456	44.2	98	0.8	-	-	452
35-50	566	34.6	105	1.3	-	-	563
60-75	-	34.6	112	0.8	-	-	-

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
0-20	0.0	0.0	0.7	1696	1696.7	170.0	53.8	841.8	0.0	600.3	1665.9
20-35	0.0	0.0	0.9	2044	2044.9	253	31.8	1160	0.0	621.0	2065.8
35-50	0.0	0.0	0.9	2239	2239.9	312.0	14.3	1426	0.0	591.0	2343.3
60-75	0.0	0.0	1.2	2478	2479.2	316.0	31.8	1616	0.0	640.0	2603.8

Depth (cm)	Sodium ads. ratio	pH e	EC e dS/m	EC 1 : 5 dS/m
0-20	-	10.0	176.0	-
20-35	-	10.0	-	-
35-50	-	10.1	220.0	-
60-75	-	10.0	230.0	-

Profile description

ABkz 0-20 cm	reddish brown (5YR 4/3, dry) reddish brown (5YR 4/4, moist)clay,strong very coarse prismatic and strong fine and medium subangular blocky,hard very friable sticky plastic,patchy thick clay cutans,many fine medium discontinuous exped and inped vesicular pores,strongly calcareous (10-25%),abrupt smooth boundary to,
2Ckz 20-35 cm	greyish brown (2.5Y 5/2, moist)sandy clay,massive and weak medium and coarse angular blocky,slightly hard friable sticky plastic,patchy moderately thick clay cutans in cracks,no pores,very few small soft calcareous concretions,strongly calcareous (10-25%),abrupt smooth boundary to,
2Cyz1 35-50 cm	greyish brown (2.5Y 5/2, moist)clay,massive and weak medium and coarse angular blocky,slightly hard friable sticky plastic,patchy clay cutans in cracks,no pores,few small soft calcareous concretions and few large spherical hard gypsiferous concretions,strongly calcareous (10-25%),abrupt smooth boundary to,
3Cyz2 50-100 cm	greyish brown (2.5Y 5/2, moist)sandy loam,massive weak medium and coarse angular blocky,slightly hard friable slightly sticky non plastic,no pores,frequent large spherical hard gypsiferous concretions,strongly calcareous (10-25%),

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Kind 2 (parent material) (second entry); Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	lacustrine sediments
Mode of accumulation or deposition of parent material (second entry)	lacustrine sediments
Remarks on Parent Materials	Chalbi beds
Texture of parent material	clayey
Texture of parent material (second entry)	loamy
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	slightly

Occurrence of soil aggradation (McDonald et al., 1984)	not apparent
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	not used and not managed
Remarks on Land Use / Vegetation	VEGETATION: Bare land with no vegetation
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant

Altitude	425m
Physiographic Unit	lacustrine 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	very poor
Flooding frequency (FAO, 1986)	yearly
Nature of flood water	saline
Depth to groundwater table	0cm
(Estimated) minimum (upper) depth to groundwater table	0cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	ponded

Evidence of alkali ; Soil Survey Manual USDA, 1951	strongly alkaline
Surface cracking	large cracks (width more than 1 cm, or depth more than 50 cm)
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	surface capped, crust on drying
Microrelief Height: variation in height	0
Rock outcrop class (FAO (2006) - Guidelines for soil description)	little rocky
Evidence of salt; Soil Survey Manual USDA, 1951	strongly saline
Surface stoniness class (FAO (2006) - Guidelines for soil description)	very few stones

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Reference soil Kenya 21: Solonchak

Characteristics

Reference soil KE021: Solonchaks

Classification