Reference soil Kenya 04: Phaeozem

KE004

Phaeozems occur all over the world, but especially on the more moist side of the steppe regions, bordering Chernozems.

Characteristics

Soils having a mollic horizon (deep, brownish or blackish surface horizon with a significant accumulation of organic matter and high base saturation); a base saturation of 50 percent or more between 25 and 100 cm from the soil surface; a calcium carbonate-free soil matrix at least to a depth of 100 cm from the soil surface, or to a contrasting layer between 25 and 100 cm; no diagnostic horizons other than an albic, argic, cambic or vertic horizon, or a petrocalcic horizon in the substratum.

Distribution of Phaeozems (rough estimation supplied by soilgrids)

Reference soil KE004: Phaeozems

Location: grit numbers: 21.6.9 E, 98.86.7 S / Classification: Eutric Regosol? Typic Ustorthent? / Additional notes on profile description: Ah: the lowest 2-5 cm pumiceous gravel; somewhat stratified at places; roots especially in the upper 10 cm; C: very dark greyish brown (2.5Y 3/2) in upper part to very dark grey (2.5Y 3/0) in lower part (moist); the lowest 20 cm with small volcanic glass fragments; upper part stratified; roots concentrated in cracks and above the layer with glass; C2: gravel layer of pumice.

Classification

WRB 2006

WRB 1998

Haplic- Phaeozem (Calcaric Tephric)

Calcari-Tephric- Phaeozem

0-40 cm	mollic horizon
-	tephric
-	calcaric

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Calcaric Phaeozem

Mollic Andosol

0-40 cm	mollic A horizon
-	calcareous
-	weatherable minerals

0-40 cm	mollic A horizon
-	exchange complex dominated by amorphous material

Other classification

USDA-SCS (1975)

Ustorthent ustic

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
0-24	-	0.1	0.5	9.0	41.3	25.3	76.2	12.3	7.2	19.5	4.4
24-44	-	0.3	0.8	9.4	39.4	24.7	74.6	13.0	9.0	22	3.4
44-52	-	0.6	1.7	4.6	22.5	20.1	49.5	21.4	24.3	45.7	4.9
52-75	-	0.3	0.9	6.0	22.3	15.9	45.4	47.0	4.3	51.3	3.3
75-104	-	0.5	1.8	10.2	32.8	19.6	64.9	15	18.4	33.4	1.8
104-123	29	13.9	12.3	15.0	18.8	9.3	69.3	7.5	17.9	25.4	5.4
123-130	-	6.2	12.5	20.9	23.4	12.2	75.2	10.9	11.6	22.5	2.3
145-160	-	1.9	2.9	6.5	17.2	8.9	37.4	8.0	39.8	47.8	14.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-24	-	-	-	0.9	4.4
27-32	1.32	-	-	-	-
53-58	1.26	-	-	-	-
24-44	-	-	-	0.9	3.4
44-52	-	-	-	1.5	4.9
78-83	1.31	-	-	-	-
52-75	-	-	-	1.9	3.3
103-108	1.08	-	-	-	-
75-104	-	-	-	0.5	1.8
148-153	1.03	-	-	-	-
104-123	-	-	-	0.0	5.4
123-130	-	-	-	0.0	2.3
145-160	-	-	-	0.0	14.7

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
27-32	1.32	47.0	46.7	45.0	38.6	34.2	27.4	-	-
53-58	1.26	50.3	49.3	47.6	44.3	39.3	20.6	-	-
78-83	1.31	47.2	45.6	43.5	36.9	28.0	20.5	-	-
103-108	1.08	47.3	45.1	42.5	32.7	24.7	15.6	-	-
148-153	1.03	59.1	58.7	55.2	49.7	48.2	41.9	-	-

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
0-24	6.6	5.3	0.09	0.5	0.77	0.11	7	-	-	3.6	0.6	0.9	0.0	5.1
24-44	6.9	5.5	0.09	0.5	0.66	0.10	7	-	-	3.4	0.7	1.1	0.0	5.2
44-52	7.1	5.6	0.08	0.4	0.37	0.08	5	-	-	2.4	0.5	1.4	0.0	4.3
52-75	7.2	5.7	0.07	0.3	0.27	0.04	7	-	-	2.4	0.3	1.4	0.0	4.1
75-104	7.4	5.7	0.06	0.4	0.10	0.05	2	-	-	1.2	0.1	0.7	0.0	2
104-123	7.7	6.1	0.23	0.3	0.20	0.05	4	-	-	3.6	0.2	3.2	2.7	9.7
123-130	7.9	5.9	0.06	-	0.03	0.04	1	-	-	1.0	0.1	0.8	0.1	2
145-160	9.7	7.9	0.77	-	0.66	0.11	6	-	-	0.4	3.1	0.1	4.2	7.8

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 %
0-24	96	5.3	59	2.7	-	-	0
24-44	84	6.2	115	2.3	-	-	0
44-52	96	4.5	68	1.3	-	-	0
52-75	114	3.6	81	0.9	-	-	0
75-104	182	1.1	42	0.4	-	-	0
104-123	117	8.3	142	0.7	-	-	33
123-130	200	1.0	39	0.1	-	-	10
145-160	144	5.4	21	2.3	-	-	78

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
0-24	7.8	11	-	0.07	0.00	0.66	0.04	0.02	0.02	-	0.21
24-44	7.8	10	-	0.07	0.00	0.65	0.06	0.02	0.02	-	0.21
44-52	7.7	6	-	0.05	0.00	0.48	0.03	0.01	0.01	-	0.08
52-75	7.7	4	-	0.04	0.00	0.39	0.03	0.01	0.01	-	0.05
75-104	7.7	4	-	0.02	0.00	0.19	0.01	0.00	0.00	-	0.03
104-123	7.7	5	-	0.05	0.00	0.44	0.03	0.01	0.00	-	0.05
123-130	7.7	3	-	0.02	0.00	0.11	0.00	0.00	0.00	-	0.02
145-160	8.1	15	-	0.24	0.02	1.86	0.11	0.00	0.00	-	0.16

Elemental composition of the soil

Depth (cm)	Al2O3 % w/w	CaO % w/w	Fe2O3 % w/w	K2O % w/w	MgO % w/w	Na2O % w/w	SiO2 % w/w	TiO2 % w/w
0-24	13.1	1.06	8.0	4.20	0.21	6.66	56.5	0.60
24-44	13.9	1.12	8.6	4.52	0.21	6.81	60.9	0.62
44-52	13.6	1.10	8.7	4.72	0.20	7.07	61.4	0.60
52-75	13.5	1.11	8.7	4.64	0.18	7.02	61.9	0.59
75-104	12.8	1.05	9.2	4.60	0.15	7.65	61.3	0.57
104-123	12.8	1.08	8.9	4.52	0.11	6.65	62.7	0.58
123-130	13.2	1.02	9.5	4.63	0.11	7.71	63.3	0.58
145-160	14.8	0.99	7.9	3.47	0.20	4.75	62.1	0.63

Depth (cm)	Al2O3/Fe2O3 mol/mol	LOI % w/w	MnO2 % w/w	P2O5 % w/w	SiO2 / Al2O3 mol/mol	SiO2/Fe2O3 mol/mol	SiO2 / R mol/mol
0-24	2.6	8.5	0.26	0.07	7.3	18.8	5.3
24-44	2.5	2.1	0.28	0.07	7.4	18.9	5.3
44-52	2.4	1.3	0.26	0.06	7.7	18.8	5.4
52-75	2.4	1.2	0.27	0.06	7.8	18.9	5.5
75-104	2.2	0.8	0.31	0.06	8.1	17.7	5.6
104-123	2.3	2.0	0.34	0.06	8.3	18.8	5.8
123-130	2.2	0.5	0.33	0.05	8.1	17.7	5.6
145-160	2.9	4.6	0.29	0.06	7.1	20.9	5.3

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-24	-	weak	-	-	-	-	-	-	very weak to weak	weak to medium	-	-
24-44	-	weak	-	-	-	-	-	-	weak	-	-	-
44-52	-	strong	-	-	-	-	-	-	very weak to weak	-	-	-
52-75	-	strong	-	-	-	-	-	-	very weak	-	-	-
75-104	-	strong	-	-	-	-	-	-	very weak	-	-	-
104-123	-	weak to medium	-	-	-	-	-	-	very weak	-	-	-
123-130	-	strong	-	-	-	-	-	-	very weak	-	-	-
145-160	-	weak to medium	-	-	-	-	-	-	very weak	-	-	-

Profile description

Ah 0-40 cm	dark greyish brown (2.5Y 4/2, dry) very dark greyish brown (2.5Y 3/2, moist)sandy loam,porous massive to weak subangular blocky,soft very friable non sticky non plastic,many very fine and fine pores,many very fine and fine roots,non calcareous,abrupt wavy boundary to,
C1 40-110 cm	(2.5Y 3/2, moist)sandy loam,porous massive,hard very firm non sticky non plastic,many very fine and fine pores, highly porous (>60 vol%),few very fine roots,few pumice gravel fragments and few volcanic glass fine gravel,slightly calcareous (0-2%),abrupt wavy boundary to,
C2 110-120 cm	gravelmassive,dominant pumice gravel,slightly calcareous (0-2%),abrupt wavy boundary to,
2Ahb 120-145 cm	(dark) brown (7.5YR 4/4, moist)sandy loam,moderate medium crumb,common very fine and common fine pores,many very fine and fine roots,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	ejecta ash
Mode of accumulation or deposition of parent material	ejecta ash
Remarks on Parent Materials	recent volcanic ash from eruption point in Mtlongonot region
Texture of parent material	loamy
Weathering Resistance	poor
General characterization of the status of weathering of solid rock	slightly

Intensity of the soil erosion type	slight
Intensity of the soil erosion type (second entry)	slight
Soil erosion type	rill
Soil erosion type (second entry)	wind

Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Grasses, herbs, thornbushes
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)	primary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	2020m
Physiographic Unit	Rift Valley floor
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	1%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	somewhat excessive
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	high
Estimated run off (class)	slow

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Surface cracking	no cracks observed
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline

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Reference soil Kenya 04: Phaeozem

Characteristics

Reference soil KE004: Phaeozems

Classification