Reference soil Kenya 49: Phaeozem

KE049

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 KE049: Phaeozems

Small fields of 3 x 3m dissected by ditches for drainage, rainfed irrigation. Slides: 10,082 - 10,088.

Classification

WRB 2006

WRB 1998

Gleyic- Phaeozem (Pachic Clayic Novic)

Pachi-Endogleyic- Phaeozem

140-165 cm	cambic horizon
25-140 cm	mollic horizon
-	fluvic
-	gleyic colour pattern
-	reducing conditions

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Fluvi-Gleyic Phaeozem inundic

Gleyic Phaeozem

0-25 cm	ochric A horizon
25-55 cm	mollic A horizon
55-165 cm	cambic B horizon
-	fluvic
-	gleyic

0-25 cm	ochric A horizon
25-55 cm	mollic A horizon
55-165 cm	cambic B horizon
-	hydromorphic

Other classification

USDA-SCS (1975)

Ustropept ustic very fine 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
0-25	-	0.7	1.4	1.6	1.9	1.7	7.3	12.2	30.3	42.5	50.2
25-55	-	2.1	2.2	2.8	3.5	2.2	12.8	4.5	21.6	26.1	61.1
55-90	-	1.6	1.7	2.4	4.5	3.1	13.3	9.3	28.3	37.6	49.1
90-140	-	3.6	3.4	3.7	6.1	4.0	20.8	8.2	19.3	27.5	51.7
140-160	-	8.4	4.5	3.6	4.7	3.3	24.5	4.8	18.5	23.3	52.2

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-25	-	-	-	20.2	50.2
25-55	-	-	-	17.7	61.1
55-90	-	-	-	20.2	49.1
90-140	-	-	-	-	51.7
140-160	-	-	-	-	52.2

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
0-25	6.2	4.9	0.10	-	3.15	0.24	13	-	-	11.3	3.8	2.0	0.0	17.1
25-55	6.4	4.8	0.06	-	2.29	0.17	13	-	-	12.2	3.8	0.7	0.1	16.8
55-90	6.4	4.8	0.06	-	2.30	0.13	18	-	-	12.5	4.1	0.7	0.2	17.5
90-140	6.3	4.8	0.09	-	1.64	0.10	16	-	-	11.2	3.6	0.0	0.2	15
140-160	6.4	4.9	0.08	-	0.81	0.08	10	-	-	8.7	3.4	0.6	0.2	12.9

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 %
0-25	77	22.1	44	11.0	-	-	0
25-55	77	21.9	36	8.0	-	-	0
55-90	81	21.7	44	8.1	-	-	1
90-140	82	18.3	35	5.7	-	-	1
140-160	86	15.0	29	2.8	-	-	1

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
0-25	8.2	-	-	0.5	0.1	4.6	0.4	-	-	-	1.3
25-55	8.4	-	-	0.5	0.1	4.3	0.4	-	-	-	1.3
55-90	8.3	-	-	0.4	0.1	4.2	0.4	-	-	-	1.4
90-140	8.0	-	-	0.4	0.1	4.5	0.4	-	-	-	1.3
140-160	7.8	-	-	0.2	0.1	5.3	0.4	-	-	-	1.2

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-25	-	very weak	weak	weak	-	-	medium	very weak	-	-	-	-
25-55	-	weak	weak	weak	-	-	medium to strong	weak	-	-	-	-
55-90	-	weak	weak	weak	-	-	medium to strong	weak	-	-	-	-
90-140	-	very weak	weak	weak	-	-	medium	weak	-	-	-	-
140-160	-	weak	weak	weak	-	-	medium	weak	-	-	-	-

Profile description

Ap 0-25 cm	reddish brown (5YR 4/4, dry) dark brown (7.5YR 3/2, moist)gravelly clay,weak very coarse subangular blocky parting to moderate fine and medium crumb,hard friable slightly sticky slightly plastic,patchy thin clay cutans,many very fine pores and few fine and medium pores,many very fine and few fine roots,frequent small spherical hard manganiferous concretions frequent medium spherical hard manganiferous concretions,non calcareous,clear wavy boundary to,
2Ah 25-55 cm	dark brown (7.5YR 3/2, dry) dark reddish brown (5YR 2.5/2, moist)gravelly clay,moderate very coarse subangular blocky parting to moderate fine and medium crumb,hard friable slightly sticky slightly plastic,common (5-15%) medium distinct sharp mottles (7.5 YR 3/0),continuous cutans,many very fine and fine and few medium and coarse pores,many very fine and few very fine roots,non calcareous,clear smooth boundary to,
2Bg1 55-90 cm	dark reddish brown (5YR 3/2, dry) dark reddish brown (5YR 2.5/2, moist)gravelly clay,moderate very coarse subangular blocky parting to moderate medium subangular blocky,hard friable slightly sticky slightly plastic,many (15-40%) medium distinct sharp mottles 5YR2.5/1 (black),broken thin clay and sesquioxide cutans,many very fine and fine pores,many very fine and few fine roots,few small spherical hard manganiferous concretions and few medium spherical hard manganiferous concretions,non calcareous,gradual smooth boundary to,
2Bg2 90-140 cm	dark reddish brown (5YR 2.5/2, moist)slightly gravelly clay,moderate very coarse subangular blocky parting to moderate medium subangular blocky,hard friable slightly sticky slightly plastic,many (15-40%) medium distinct sharp mottles 5YR2.5/1 (black),continuous thin clay and sesquioxide cutans,many very fine and fine and few medium pores,many very fine roots,few small spherical hard manganiferous concretions and few medium spherical hard manganiferous concretions,non calcareous,gradual smooth boundary to,
2Bg3 140-160 cm	dark greyish brown (10YR 4/2, moist)slightly gravelly clay,moderate very coarse angular blocky,firm slightly sticky slightly plastic,many (15-40%) medium distinct sharp mottles 10YR2/1 (black),continuous thin clay and sesquioxide cutans,many very fine and fine and few medium pores,few small spherical hard manganiferous concretions and few medium spherical hard manganiferous concretions,non calcareous,clear smooth boundary to,
2Bg4 160-165 cm	(dark) brown (7.5YR 4/2, moist)slightly gravelly clay,slightly sticky slightly plastic,common (5-15%) fine distinct sharp mottles (7.5 YR 2/0),continuous thin clay cutans,few small spherical hard manganiferous concretions and few medium spherical hard manganiferous distinct,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	basic volcanic breccia
Kind 2 (parent material) (second entry); Parker (eds), 1984	basic volcanic breccia
Mode of accumulation or deposition of parent material	colluvial
Mode of accumulation or deposition of parent material (second entry)	fluvial
Remarks on Parent Materials	phonolite/lahar/ash
Soil Depth	100cm
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	highly

Occurrence of soil aggradation (McDonald et al., 1984)	present
Slope stability	stable

Major crops	banana
Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	draining
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	seasonally irrigated
Land use or vegetation in the immediate vicinity of the site	low level arable farming
Remarks on Land Use / Vegetation	LAND USE: Also cassava, sugarcane, vegetables

Altitude	1139m
Physiographic Unit	minor valley bottom in plateau
Physiographic position of the site	open depression
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plateau
Slope	1%
Form of the slope surrounding the site	concave
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Dry From - To	0-50cm
Flooding frequency (FAO, 1986)	yearly
Nature of flood water	fresh
(Estimated) maximum (lower) depth to groundwater table	150cm
Depth to groundwater table	0cm
Kind of ground water table (USDA, 1979)	flooded
(Estimated) minimum (upper) depth to groundwater table	0cm
Moist From - To	50-135cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	medium
Wet From To	135-160cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-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)	no surface slaking/crusting observed
Microrelief Height: variation in height	30
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	terracettes
Microrelief pattern	linear
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

You are here

Reference soil Kenya 49: Phaeozem

Characteristics

Reference soil KE049: Phaeozems

Classification