Reference soil Kenya 64: Solonetz

KE064

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 KE064: Solonetz

Location: Garissa district, NE Province. Slides: 10,220 - 10,224.

Classification

WRB 2006

WRB 1998

calcic horizon- Solonetz (Albic Abruptic)

Albi-calcic horizon- Solonetz

10-20 cm	albic horizon
20-95 cm	natric horizon
-	abrupt textural change
-	secondary carbonates

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Abrupti-Calcic Solonetz

Solodic Planosol

0-10 cm	ochric A horizon
10-20 cm	albic E horizon
20-95 cm	natric B horizon
-	abrupt textural change
-	soft powdery lime

0-10 cm	ochric A horizon
10-20 cm	albic E horizon
20-95 cm	natric B horizon
-	abrupt textural change
-	soft powdery lime

Other classification

USDA-NRCS (1999)	Typic Natrargid
USDA-SCS (1975)	Typic Natrargid aridic 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
0-1	-	24.4	44.5	22.2	5.2	0.3	96.6	0.2	2.0	2.2	1.2
1-10	-	15.4	24.8	26.0	11.8	2.7	80.7	2.7	3.0	5.7	13.6
10-20	-	17.8	29.0	24.9	12.6	1.9	86.2	1.6	2.6	4.2	9.6
20-45	-	12.0	22.8	15.5	7.1	1.6	59	1.1	10.9	12	29.1
45-70	-	10.6	19.4	15.5	7.6	1.4	54.5	1.4	9.8	11.2	34.4
70-95	-	11.1	19.0	15.9	8.5	2.1	56.6	2.8	9.3	12.1	31.3

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-1	-	-	-	-	1.2
1-10	-	-	-	-	13.6
10-20	-	-	-	-	9.6
20-45	-	-	-	-	29.1
45-70	-	-	-	-	34.4
70-95	-	-	-	-	31.3

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
0-1	7.5	6.1	0.04	0.1	0.05	0.01	5	-	-	1.0	0.3	0.0	0.1	1.4
1-10	6.9	5.2	0.12	0.4	0.15	0.02	8	-	-	6.3	3.2	0.9	0.1	10.5
10-20	7.4	5.3	0.06	0.5	0.14	0.02	7	-	-	4.5	1.9	0.7	0.4	7.5
20-45	7.1	5.2	0.56	0.9	0.14	0.01	14	-	-	12.8	7.1	1.8	3.8	25.5
45-70	6.9	5.5	2.70	1.2	0.08	0.02	4	-	-	13.8	8.5	1.7	6.2	30.2
70-95	8.0	7.3	4.00	1.9	0.10	0.01	10	-	-	14.5	10.5	1.7	8.0	34.7
95-110	8.2	7.5	4.20	4.0	0.07	0.00	-	-	-	36.6	10.5	1.7	8.5	57.3
110-147	8.3	7.6	4.60	5.0	0.11	0.00	-	-	-	38.9	12.0	1.5	9.6	62
147-160	8.2	7.5	5.40	6.6	0.09	0.00	-	-	-	39.9	12.7	1.5	16.5	70.6

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 %
0-1	200	0.7	44	0.2	-	-	14
1-10	128	8.2	57	0.5	-	-	1
10-20	117	6.4	62	0.5	-	-	6
20-45	110	23.1	79	0.5	-	-	16
45-70	119	25.4	74	0.3	-	-	24
70-95	136	25.5	82	0.4	-	-	31
95-110	228	25.1	65	0.2	-	-	34
110-147	242	25.6	309	0.4	-	-	37
147-160	278	25.4	313	0.3	-	-	65

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-1	-	weak	-	-	-	-	weak	weak to medium	-	weak to medium	weak to medium	-
10-20	-	weak	-	-	-	-	weak	weak to medium	-	weak to medium	weak to medium	-
95-110	-	weak	-	-	-	-	weak	weak to medium	-	weak to medium	weak to medium	-
147-160	-	weak	-	-	-	-	weak	weak to medium	-	weak to medium	weak to medium	-

Profile description

Ah1 0-1 cm	dark yellowish brown (10YR 4/4, dry) dark brown (7.5YR 3/2, moist)Description sand,single grain,loose (dry and moist) non sticky non plastic,quartz fragments,slightly calcareous (0-2%),abrupt smooth boundary to,
Ah2 1-10 cm	dark yellowish brown (10YR 4/4, dry) dark brown (7.5YR 3/2, moist)sandy clay loam,moderately coherent massive parting to weak fine and medium subangular blocky,slightly hard friable slightly sticky slightly plastic,many very fine pores and few fine pores,very few fine gravel fresh quartz fragments,slightly calcareous (0-2%),clear smooth boundary to,
E 10-20 cm	light brownish grey (10YR 6/2, dry) very dark greyish brown (10YR 3/2, moist)loamy sand,weakly coherent massive parting to single grain,slightly hard very friable non sticky non plastic,many very fine pores and few medium pores,many very fine and few medium roots,very few fine gravel fresh quartz fragments,slightly calcareous (0-2%),abrupt irregular boundary to,
Btn1 20-45 cm	(dark) brown (7.5YR 4/4, dry) dark brown (7.5YR 3/4, moist)clay,strong coarse columnar parting to strong medium and coarse angular blocky,very hard very friable sticky plastic,patchy thin clay cutans,many very fine pores and few fine and medium pores,many very fine and few medium roots,very few fine gravel fresh quartz fragments,slightly calcareous (0-2%),gradual smooth boundary to,
Btn2 45-70 cm	(dark) brown (7.5YR 4/4, dry) dark brown (7.5YR 3/4, moist)clay,strong coarse prismatic parting to strong medium and coarse angular blocky,very hard friable sticky plastic,patchy thin clay cutans,many very fine pores and few fine and medium pores,many very fine roots,very few fine gravel fresh quartz fragments,slightly calcareous (0-2%),clear wavy boundary to,
Bt 70-95 cm	dark yellowish brown (10YR 3/4, dry) (dark) brown (10YR 4/3, moist)clay,weak medium and coarse angular blocky,hard friable sticky plastic,broken thin clay cutans,many very fine pores and few fine pores,many very fine roots,gradual wavy boundary to,
2Ck1 95-110 cm	light yellowish brown (10YR 6/4, dry) (dark) brown (10YR 4/3, moist)sandy clay loam,weakly coherent massive parting to weak medium angular blocky,slightly hard friable slightly sticky slightly plastic,many very fine pores and few fine and medium pores,common very fine roots,few powdery irregular soft calcareous crystals,moderately calcareous (2-10%),gradual wavy boundary to,
2Ck2 110-145 cm	brown (10YR 5/3, dry) dark greyish brown (10YR 4/2, moist)sandy clay loam,weakly coherent massive parting to weak fine and medium angular blocky,slightly hard friable slightly sticky slightly plastic,many very fine pores and few fine pores,common very fine roots,few powdery irregular soft calcareous crystals,moderately calcareous (2-10%),abrupt smooth boundary to,
2Ck3 145-160 cm	brown (10YR 5/3, dry) dark greyish brown (10YR 4/2, moist)sandy clay loam,moderately coherent massive parting to weak fine and medium angular blocky,slightly hard friable slightly sticky slightly plastic,common large irregular hard calcareous concretions,moderately calcareous (2-10%),

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	marine sediments
Remarks on Parent Materials	Plio-Pleistocene Bay sediments, Marafa beds
Soil Depth	80cm
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)	absent
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	shrubland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Wooded shrubland. LAND USE: Browsing by camels, cows and goats.
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	primary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	deciduous shrub

Altitude	220m
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	0-160cm
Flooding frequency (FAO, 1986)	irregular
Nature of flood water	fresh
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	20cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	slightly alkaline
Surface cracking	small cracks (width less than 1 cm, or depth less than 50 cm)
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	surface partly slaked, round smooth aggregates
Microrelief pattern	none
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 64: Solonetz

Characteristics

Reference soil KE064: Solonetz

Classification