Reference soil Kenya 17: Phaeozem

KE017

Distribution of Phaeozems

KE 17 is located on the active part of a termite mound and KE 18 is on the slope of the mound. KE 19 is on the plain, where no influence of the mound is noticeable. MICRO RELIEF: termite mounds of 1-2 m high and a diameter of 3-6 m occur at distances 30-50 m. VEGETATION/LAND USE: on the mounds shrubs, between the mounds grass, which is used for extensive grazing. Processes: profiles KE 17, 18 and 19 are associated soils. Termites have throroughly mixed the different horizons as occuring in KE 19, which results in profile KE 17. KE 18 is a transition to KE 19. Additional notes on profile description: - the first horizon from 0 - 160 cm consists of fresh building material; - the third horizon from 300 - 355 cm has mixed colours: 10YR 4/2 and 10YR 8/1 (dry); many gravel; - C: mixed colours: 10YR 5/2 and 5YR 6/4 (moist).

WRB 2006:

WRB 1998:

Vermic Phaeozem(Calcaric Pachic)

Calcari- Pachic Phaeozem(Vermic)

0-160 cm	mollic horizon
	calcaric material

FAO-UNESCO-ISRIC 1988:

FAO-UNESCO 1974:

Vermi-

Calcaric Phaeozem

0-160 cm

mollic A horizon

0-160 cm

mollic A horizon

Other classification

USDA-SCS (1975)

Ustochrept

fine

mixed

isohyperthermic

Location:

Nyanza Province, South Nyanza District, 10 km WSW of Rongo at Opapo

Parent material

The main parent rock/ material over which the soil has been formed (1st entry)	ejecta ash
Mode of Accumulation or deposition of parent material (1st entry)	fluvial
Texture of parent material (1st entry)	clayey
Weathering status of solid rock (1st entry)	highly
Resistance against weathering (solid rock) (1st entry)	poor
Depth1 of lithological boundary	300 cm
The main parent rock/ material over which the soil has been formed (2nd entry)	granite
Mode of Accumulation or deposition of parent material (2nd entry)	residual material
Texture of parent material (2nd entry)	gravelly
Weathering status of solid rock (2nd entry)	partially or moderately
Resistance against weathering (solid rock) (2nd entry)	moderate
Soil Depth; depth to which roots can easily penetrate throughout the year	200 cm
Remarks on Parent Materials	termite mound underlain by granite

Physical

Particle size distribution:

Depth (cm)		Gravel (%)	Very Coarse Sand (%)	Coarse Sand (%)	Medium Sand (%)	Fine Sand (%)	Very Fine Sand (%)	Total Sand (%)	Coarse Silt (%)	Fine Silt (%)	Total Silt (%)	Clay (%)
0-10	:	-	-	-	-	-	-	-	-	-	-	-
10-20	:	-	2.3	5.3	4.6	6.9	0.9	20	30.1	0.0	30.1	50.0
60-70	:	-	2.2	3.3	4.7	6.2	4.2	20.6	33.3	0.0	33.3	46.2
110-120	:	-	9.6	7.0	5.1	4.5	2.5	28.7	39.9	0.0	39.9	31.5
140-150	:	-	1.7	4.5	7.7	8.8	5.0	27.7	8.2	0.0	8.2	64.2

Other physical data

Depth (cm)		Bulk Density (kg/dm³)	Spec. Surf. Area (m2/g)	COLE (cm/cm)	Water Disp. Clay (%)	Clay (%)
0-10	:	-	-	-	-	-
10-20	:	-	-	-	15.7	50.0
60-70	:	-	-	-	14.5	46.2
110-120	:	-	-	-	-	31.5
140-150	:	-	-	-	-	64.2

Chemical characteristics:

Depth (cm)		pH H2O	pH KCl	EC 1 : 2.5 (mS/cm)	CaCO3 (%)	Org. C (%)	Org. N (%)	C / N	Exch. Acid (cmol/kg)	Exch. Al (cmol/kg)	Ca (cmol/kg)	Mg (cmol/kg)	K (cmol/kg)	Na (cmol/kg)	Sum Cations (cmol/kg)
0-10	:	6.5	5.4	-	-	5.12	0.38	13	-	-	30.5	5.4	0.5	0.8	37.2
10-20	:	6.7	5.7	0.92	1.6	1.43	0.18	8	-	-	24.8	4.6	0.4	0.6	30.4
60-70	:	7.6	6.1	1.33	1.6	1.05	0.14	8	-	-	25.0	3.5	0.4	0.6	29.5
110-120	:	7.1	6.2	0.40	0.5	0.09	0.06	2	-	-	26.5	3.9	0.3	1.1	31.8
140-150	:	5.3	4.7	0.12	-	1.68	0.18	9	0.2	0.0	17.0	5.1	0.4	0.2	22.7

Depth (cm)		CEC Soil (cmol/kg)	CEC Clay (cmol/kg)	CEC Org (cmol/kg)	ECEC (cmol/kg)	Base sat. (%)	Al sat. (%)	ESP (%)
0-10	:	35.8	-	17.9	-	104	-	2
10-20	:	30.1	-	5.0	-	101	-	2
60-70	:	31.7	-	3.7	-	93	-	2
110-120	:	30.3	-	0.3	-	105	-	4
140-150	:	28.0	-	5.9	-	81	-	1

Elemental composition of the clay:

Depth (cm)		SiO2 (wt%)	Al2O3 (wt%)	Fe2O3 (wt%)	CaO (wt%)	MgO (wt%)	K2O (wt%)	Na2O (wt%)	TiO2 (wt%)
0-10	:	51.8	18.2	10.2	0.94	0.49	0.44	-	0.77
10-20	:	51.2	19.9	11.1	0.21	0.54	0.51	-	0.90
60-70	:	53.4	18.9	10.5	0.29	0.60	0.52	-	0.89
110-120	:	51.2	20.9	10.8	0.18	0.74	0.55	-	0.80
140-150	:	50.2	20.5	11.6	0.07	0.53	0.54	-	0.94

Depth (cm)		MnO2 (wt%)	P2O5 (wt%)	Ign.Loss clay (wt%)	Total clay (%)	SiO2 / Al2O3 (mol/mol)	SiO2 / Fe2O3 (mol/mol)	SiO2 / R (mol/mol)	Al2O3 / Fe2O3 (mol/mol)
0-10	:	0.19	0.20	12.8	96.03	4.8	13.5	3.6	2.8
10-20	:	0.15	0.19	11.1	95.8	4.4	12.3	3.2	2.8
60-70	:	0.19	0.17	10.4	95.86	4.8	13.5	3.5	2.8
110-120	:	0.03	0.18	10.3	95.68	4.2	12.6	3.1	3
140-150	:	0.12	0.20	11.2	95.9	4.2	11.5	3.1	2.8

Elemental composition of the soil:

Depth (cm)		SiO2 (wt%)	Al2O3 (wt%)	Fe2O3 (wt%)	CaO (wt%)	MgO (wt%)	K2O (wt%)	Na2O (wt%)	TiO2 (wt%)
0-10	:	66.8	10.5	6.2	1.32	0.37	0.45	-	0.58
10-20	:	69.7	11.5	6.6	0.92	0.40	0.56	-	0.69
60-70	:	72.5	11.2	6.1	1.05	0.40	0.62	-	0.69
110-120	:	68.3	16.8	5.8	1.12	0.47	1.15	-	0.65
140-150	:	72.3	11.4	6.5	0.66	0.36	0.62	-	0.70

Depth (cm)		MnO2 (wt%)	P2O5 (wt%)	LOI (wt%)	SiO2 / Al2O3 (mol/mol)	SiO2 / Fe2O3 (mol/mol)	SiO2 / R (mol/mol)	Al2O3 / Fe2O3 (mol/mol)
0-10	:	0.21	0.10	14.7	10.8	28.7	7.8	2.7
10-20	:	0.12	0.09	8.8	10.3	28.1	7.5	2.7
60-70	:	0.17	0.11	8.0	11	31.6	8.1	2.9
110-120	:	0.02	0.09	6.0	6.9	31.4	5.7	4.5
140-150	:	0.11	0.07	8.8	10.8	29.6	7.9	2.7

Profile description:

Ah 0-160 cm	dark brown (7.5YR 3/2, dry), clay, strong very fine angular blocky, very hard slightly sticky slightly plastic, many (15-40%) medium faint mottles (7.5YR 4/4), very frequent termite channels, slightly calcareous (0-2%), gradual smooth boundary to,
Bg 160-300 cm	very dark grey (10YR 3/1, dry), clay, strong medium and coarse angular blocky, hard slightly sticky non plastic, common (5-15%) medium distinct mottles (10YR 4/2), frequent termite channels, non calcareous, clear wavy boundary to,
C1 300-355 cm	dark greyish brown (10YR 4/2, dry), gravelly clay, massive, common fine and medium gravel rounded stones, few termite channels, non calcareous, clear wavy boundary to,
C2 355->355 cm	greyish brown (10YR 5/2, dry), gravelly clay, massive, common coarse gravel angular quartz fragments, non calcareous,

Current land use at the site	(semi-)natural vegetation
Major crops
Main type of irrigation
Rotation scheme
Vegetation Type;The natural vegetation at the site	shrub
Status of vegetation
Remarks on Land Use / Vegetation	see remarks

The altitude of the soil profile relative to mean sea level, specified in meters	1340 m asl
Regional landform	plain
Topography of the surrounding country	flat or almost flat
Physiographic Unit in the immediate surrounding of the site	summit of termite mound
The slope refers to the inclination of the land immediately surrounding the site. The measured or estimated slope angle is specified to the nearest per cent	0 %
The physiographic position of the site where the profile is located	crest
Form of the slope surrounding the site
Slope Aspect of the site

Depth of groundwater table	cm
Groundwater Top	cm
Groundwater Bottom	cm
Kind of groundwater table	no groundwater table observed
Top Stagnating Layer	cm
Bottom Stagnating Layer	cm
Runoff	very rapid
Flooding frequency	never
Estimated permeablity (class) of least permeable part of the profile	high
Drainage Class	well
To Drainage Class
Moisture conditions of the profile: dry from -to	0-350 cm
Moisture conditions of the profile: moist from -to	cm
Wet From - To	cm

Microrelief type: small-scale differences in relief in the direct vicinity of the site	termite/ant mounds
Microrelief Pattern	isolated
Microrelief Height	200
Rockiness	none
Stoniness	none
Average size of stones
Shape of stones (on average)
Cracks	no cracks observed
Slaking of aggregates by tillage, rainfall or frost	no surface slaking/crusting observed
Evidence of salt	non-saline
Evidence of alkali	non-alkaline

Soil erosion type (1st entry)
Occurrence of soil aggradation
Slope Stability

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Reference soil Kenya 17: Phaeozem