Reference soil Kenya 36: Andosol

KE036

Andosols occur throughout the world where volcanic activity is common, especially in the circum-Pacific region and along the mid-Atlantic Ridge.

Characteristics

Soils with a vitric or andic horizon (slightly to moderately weathered horizons in pyroclastic deposits dominated by short-range-order minerals, notably allophane and imogolite) starting within 25 cm from the soil surface. In addition, they may have a histic, fulvic, melanic, mollic, umbric, ochric, duric, or cambic horizon. Other diagnostic horizons (unless buried deeper than 50 cm by volcanic deposits) are absent.

Distribution of Andosols (rough estimation supplied by soilgrids)

Reference soil KE036: Andosols

Andosol

Classification

WRB 2006

WRB 1998

Calcic-Mollic-Eutrosilic- Andosol (Fragic Sodic Hypereutric)

Molli-Eutrisilic- Andosol (Duric Calcaric)

28-70 cm	cambic horizon
70-180 cm	calcic horizon
90-180 cm	fragic horizon
-	andic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Fragi-Mollic Andosol

Mollic Andosol fragipan

0-28 cm	mollic A horizon
28-70 cm	cambic B horizon
-	andic
-	soft powdery lime

0-28 cm	mollic A horizon
28-70 cm	cambic B horizon
-	soft powdery lime

Other classification

USDA-NRCS (1999)	Mollic Ustivitrand
USDA-SCS (1975)	Mollic Vitrandept ustic fine-loamy mixed (calcareous) isohyperthermic

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
0-15	-	10.6	28.3	20.7	8.7	3.4	71.7	3.7	16.6	20.3	8.0
15-28	-	10.7	29.7	26.0	11.0	4.2	81.6	3.2	11.8	15	3.4
28-40	-	10.3	24.2	20.8	10.6	4.5	70.4	10.9	13.7	24.6	4.9
40-60	-	15.2	18.3	12.2	9.2	4.4	59.3	10.0	22.9	32.9	7.8
60-70	-	19.7	17.4	9.7	8.4	4.4	59.6	16.7	13.9	30.6	9.9
90-180	-	19.1	23.1	12.0	10.7	6.4	71.3	6.7	19.5	26.2	2.4

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-15	1.14	-	-	-	8.0
15-28	1.09	-	-	-	3.4
28-40	1.06	-	-	-	4.9
40-60	1.04	-	-	-	7.8
60-70	-	-	-	-	9.9
90-180	-	-	-	-	2.4

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
0-15	1.14	-	-	-	-	-	-	-	-
15-28	1.09	-	-	-	-	-	-	-	-
28-40	1.06	-	-	-	-	-	-	-	-
40-60	1.04	-	-	-	-	-	-	-	-

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
0-15	6.7	5.9	0.24	3.8	3.10	0.18	17	-	-	16.8	4.5	4.0	0.6	25.9
15-28	7.1	6.4	0.21	3.7	1.80	0.10	18	-	-	19.9	6.4	3.7	0.5	30.5
28-40	7.2	6.5	0.18	3.5	1.53	0.10	15	-	-	25.7	8.5	4.5	0.8	39.5
40-60	7.4	6.6	0.20	3.6	1.58	0.10	16	-	-	29.9	10.6	3.8	1.1	45.4
60-70	7.9	7.2	0.34	7.0	1.39	-	-	-	-	37.3	23.3	5.5	2.8	68.9
90-180	9.1	7.6	0.97	11.0	0.72	-	-	-	-	24.8	21.9	13.2	38.6	98.5

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 %
0-15	73	35.3	441	10.9	-	-	2
15-28	85	35.8	-	6.3	-	-	1
28-40	85	46.2	943	5.4	-	-	2
40-60	81	55.9	717	5.5	-	-	2
60-70	109	63.1	637	4.9	-	-	4
90-180	172	57.2	-	2.5	-	-	67

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
0-15	7.9	36	-	0.98	0.76	1.89	0.20	0.06	0.06	-	1.56
15-28	8.2	54	-	1.14	1.02	2.05	0.34	0.04	0.04	-	1.92
28-40	8.7	64	-	1.17	0.74	2.97	0.35	0.03	0.04	-	2.06
40-60	9.1	69	-	1.57	0.74	4.30	0.38	0.02	0.04	-	2.52
60-70	9.8	100	-	2.10	1.12	4.52	0.47	0.01	0.02	-	3.48
90-180	9.1	-	-	1.15	0.57	3.09	0.23	0.01	0.01	-	1.65

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	-	-	weak	-	-	-	-	-	-	-
40-60	-	-	-	-	weak	-	-	-	-	-	-	-

Profile description

Ah 0-15 cm	(10YR 4/2.5, dry) (10YR 2/1.5, moist)loam,weakly coherent porous massive,slightly hard very friable non sticky non plastic,many very fine pores and many fine pores,many fine roots,non calcareous,clear smooth boundary to,
15-28 cm	(10YR 3.5/3, dry) very dark brown (10YR 2/2, moist)sandy loam,weakly coherent porous massive,soft very friable non sticky non plastic,many very fine pores and many fine pores,many fine roots,non calcareous,gradual smooth boundary to,
Bw1 28-40 cm	yellowish brown (10YR 5/4, dry) very dark greyish brown (10YR 3/2, moist)sandy clay loam,porous massive to very weak granular,soft very friable non sticky non plastic,many very fine pores and many fine pores,common fine roots,non calcareous,gradual smooth boundary to,
Bw2 40-60 cm	yellowish brown (10YR 5/4, dry) very dark greyish brown (10YR 3/2, moist)sandy clay loam,porous massive to very weak fine subangular blocky,soft very friable non sticky non plastic,many very fine pores and many fine pores,common fine roots,non calcareous,clear smooth boundary to,
Bk 60-70 cm	(10YR 5.5/4, dry) dark brown (10YR 3/3, moist)gravelly sandy clay loam,porous massive to very weak fine subangular blocky,soft very friable non sticky non plastic,many very fine pores and many fine pores,common fine roots,thread-like calcareous soft segregations,strongly calcareous (10-25%),10% HCl,abrupt smooth boundary to,
Ck 70-90 cm	very pale brown (10YR 7/4, dry) dark yellowish brown (10YR 4/4, moist)very pale brown (10YR 7/4, dry) dark yellowish brown (10YR 4/4, moist),gravelly sandy clay loam,sandy clay loam,stratified structure and porous massive,porous massive,hard very firm,loose (dry and moist),many very fine pores and many fine pores,many very fine pores and many fine pores,few fine roots,few fine roots,thread-like calcareous soft segregations,thread-like calcareous soft segregations,broken strongly cemented fragipan pans,strongly calcareous (10-25%),10% HCl,strongly calcareous (10-25%),10% HCl,abrupt wavy boundary to,

Kind 1 (parent material) ; Parker (eds), 1984	pyroclastic, consolidated
Mode of accumulation or deposition of parent material	ejecta ash
Texture of parent material	loamy
Texture of parent material (second entry)	loamy
Weathering Resistance	poor
General characterization of the status of weathering of solid rock	partially or moderately

Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	VEGETATION: grassland of Digitaria macroblephara, Sporobolus fimbriatus and Chrysopogon aucheri
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	1170m
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plain
Slope	2%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-180cm
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	moderate
Estimated run off (class)	slow

Evidence of alkali ; Soil Survey Manual USDA, 1951	moderately alkaline
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 36: Andosol

Characteristics

Reference soil KE036: Andosols

Classification