Reference soil Kenya 39: Andosol

KE039

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 KE039: Andosols

In the profile is at 75cm a stoneline of weathered lapilli. Slides: 10.010 - 10.014 of profile, vegetation and site. The former crater appears as an "vlei" along the road a bit further on the track.

Classification

WRB 2006

WRB 1998

Silandic- Andosol (Hyperdystric Siltic Novic)

Hyperdystri-Silic- Andosol

8-113 cm	cambic horizon
-	andic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Humi-Haplic Andosol

Ochric Andosol

0-8 cm	ochric A horizon
8-113 cm	cambic B horizon
-	andic
-	strongly humic

0-8 cm	ochric A horizon
8-113 cm	cambic B horizon
-	exchange complex dominated by amorphous material

Other classification

USDA-SCS (1975)

Dystropept udic isothermic

More images

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	-	2.2	2.3	2.3	3.2	1.6	11.6	15.0	27.2	42.2	46.1
8-27	-	0.9	2.5	2.7	3.2	2.4	11.7	21.0	53.4	74.4	13.9
27-57	-	1.5	2.2	2.7	3.8	2.5	12.7	25.6	47.5	73.1	14.2
57-75	-	1.3	2.1	2.4	3.5	3.2	12.5	29.2	44.8	74	13.6
75-87	-	6.2	5.7	4.5	5.9	4.2	26.5	20.8	43.0	63.8	9.7
87-110	-	6.0	7.2	6.0	5.9	5.7	30.8	20.5	41.8	62.3	6.7
110-150	-	4.6	5.0	3.8	5.8	9.8	29	27.9	38.6	66.5	4.6

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	-	-	-	-	46.1
8-27	-	-	-	-	13.9
27-57	-	-	-	-	14.2
57-75	-	-	-	-	13.6
75-87	-	-	-	-	9.7
87-110	-	-	-	-	6.7
110-150	-	-	-	-	4.6

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	5.1	4.8	2.40	-	21.89	0.52	42	1.2	0.0	47.9	9.4	1.5	0.1	58.9
8-27	4.7	4.4	0.09	-	3.58	0.30	12	2.1	1.7	0.4	0.4	0.5	0.1	1.4
27-57	4.9	4.6	0.03	-	3.58	0.37	10	0.8	0.5	0.4	0.0	0.3	0.0	0.7
57-75	5.0	4.7	0.02	-	3.29	0.34	10	0.6	0.3	0.4	0.0	0.4	0.1	0.9
75-87	5.0	4.9	0.02	-	1.65	0.18	9	0.2	0.0	0.2	0.0	0.3	0.1	0.6
87-110	5.1	4.9	0.02	-	0.91	0.10	9	0.2	0.0	0.2	0.0	0.3	0.0	0.5
110-150	5.3	5.2	0.02	-	0.51	0.05	10	0.1	0.0	0.2	0.0	0.7	0.0	0.9

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	67	88.1	44	36.4	-	0	0
8-27	6	22.2	75	12.5	-	8	0
27-57	3	21.2	66	12.5	-	2	0
57-75	4	20.3	69	11.5	-	1	0
75-87	5	11.4	60	5.8	-	0	1
87-110	6	8.7	84	3.2	-	0	0
110-150	19	4.7	64	1.8	-	0	0

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
0-8	7.7	69	-	1.0	0.4	2.7	1.3	-	-	-	1.2
8-27	11.3	98	-	2.6	1.0	5.3	3.3	-	-	-	2.0
27-57	11.2	99	-	3.7	1.9	5.1	3.0	-	-	-	2.2
57-75	11.3	98	-	3.8	2.0	5.2	2.9	-	-	-	1.8
75-87	10.9	96	-	2.7	1.2	4.6	2.4	-	-	-	1.3
87-110	10.6	92	-	2.0	0.8	4.6	2.1	-	-	-	0.9
110-150	10.7	95	-	2.7	0.9	4.5	2.0	-	-	-	0.7

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-8	-	weak	medium	-	-	-	weak	weak	weak	weak	-	-
27-57	-	weak	weak	-	-	-	weak	weak	weak	weak	-	-
75-87	-	weak	medium	-	-	-	very weak	weak	weak	very weak	-	-
110-150	-	medium	medium	-	-	-	very weak	very weak	very weak	very weak	-	-

Profile description

Ah 0-8 cm	very dark grey (5YR 3/1, moist)clay,moderate very fine granular and moderate fine subangular blocky,loose (dry) friable slightly sticky slightly plastic (moist),Q wavy exped exped mottles (2.5 YR 7.8/6.6),many very fine and common medium roots,non calcareous,clear smooth boundary to,
Bw1 8-27 cm	(7.5YR 4/3, moist)clay,strong fine angular blocky,friable sticky plastic,continuous thin clay cutans,few very fine and few medium roots,non calcareous,clear smooth boundary to,
Bw2 27-87 cm	dark brown (7.5YR 3/2, moist)clay,strong fine angular blocky,friable sticky plastic,continuous thin clay cutans,few very fine and few medium roots,non calcareous,clear smooth boundary to,
2Bw3 87-113 cm	(dark) brown (7.5YR 4/4, moist)clay,moderate fine subangular blocky,friable sticky plastic,continuous thin clay cutans,few very fine and few medium roots,few medium and coarse gravel strongly weathered lapilli fragments,non calcareous,clear broken boundary to,
2C 113-150 cm	yellowish brown (10YR 5/6, moist)clay,moderate fine subangular blocky,friable slightly sticky slightly plastic,continuous thin clay cutans,few very fine and few medium roots,common medium and coarse gravel strongly weathered Lapilli fragments,non calcareous,

Depth1	113cm
Kind 1 (parent material) ; Parker (eds), 1984	tuff
Kind 2 (parent material) (second entry); Parker (eds), 1984	tuff
Mode of accumulation or deposition of parent material	ejecta ash
Mode of accumulation or deposition of parent material (second entry)	ejecta ash
Remarks on Parent Materials	Mt. Kenya Series
Soil Depth	150cm
Texture of parent material	silty
Texture of parent material (second entry)	stony
Weathering Resistance	poor
Weathering Resistance (second entry)	poor
General characterization of the status of weathering of solid rock	highly
General characterization of the status of weathering of solid rock (second entry)	partially or moderately

Major crops	crops (unspecified)
Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	no land improvement
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 vegetation
Remarks on Land Use / Vegetation	Podocarpus forest
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)	cut over
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	evergreen forest

Altitude	2310m
Physiographic Unit	crest on lower mountain slope
Physiographic position of the site	crest
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	volcano
Slope	0%
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	rolling

Lower limit of a slow permeable or stagnating layer in the profile	1cm
Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-10cm
Flooding frequency (FAO, 1986)	never
Depth to groundwater table	0cm
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	10-150cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	medium
Upper limit of a slow permeable or stagnating layer in the profile	0cm

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
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 39: Andosol

Characteristics

Reference soil KE039: Andosols

Classification