Reference soil Kenya 47: Nitisol

KE047

Nitisols occur mainly in the tropics and subtropics, as well as in areas with a Mediterranean type of climate. They are associated with basic rocks (e.g. basalts) or hard limestone or dolomite deposits.

Characteristics

Soils having a nitic horizon (a horizon with pronounced nut-shaped soil structure and significant amount of active iron) within 100 cm from the soil surface, and gradual to diffuse horizon boundaries between the surface and the underlying horizons. They do not have a ferric, plinthic or vertic horizon within 100 cm from the soil surface.

Distribution of Nitisols (rough estimation supplied by soilgrids)

Reference soil KE047: Nitisols

Brief soil description: Very deep, well drained soil derived from basic volcanic breccia; with a thin dark reddish brown, clay topsoil over a dark reddish brown clay subsoil with clay cutans. The soil is used for arable farming with crops as sweet potato and maize. Slides: 10,071 - 10,072.

Classification

WRB 2006

WRB 1998

Lixic-Ferralic- Nitisol (Humic Eutric)

Hyperferrali-Humic- Nitisol (Eutric)

18-150 cm

nitic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Chromi-Haplic Nitisol

Ferric Luvisol

0-18 cm	ochric A horizon
18-150 cm	argic B horizon
-	nitic

0-18 cm	ochric A horizon
18-150 cm	argillic B horizon
-	ferric

Other classification

USDA-NRCS (1999)

Udic Kandiustalf

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
0-15	-	0.3	0.5	1.0	2.0	1.4	5.2	18.0	34.4	52.4	42.5
18-35	-	0.1	0.3	1.0	1.8	1.3	4.5	10.6	22.3	32.9	62.7
35-85	-	0.1	0.2	0.8	1.7	1.1	3.9	19.5	28.1	47.6	48.3
85-115	-	0.1	0.2	0.7	2.1	1.8	4.9	21.9	22.8	44.7	50.3
115-150	-	0.1	0.2	0.5	1.3	1.1	3.2	17.0	20.4	37.4	59.4
85-150	-	0.1	0.1	0.6	1.6	1.2	3.6	19.7	23.9	43.6	52.9

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	-	-	-	18.4	42.5
23-28	1.016	-	-	-	-
63-68	0.976	-	-	-	-
18-35	-	-	-	20.1	62.7
98-103	1.003	-	-	-	-
35-85	-	-	-	9.8	48.3
85-115	-	-	-	0.9	50.3
115-150	-	-	-	-	59.4
85-150	-	-	-	-	52.9

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
23-28	1.016	58.4	56.4	51.1	40.5	35.4	32.5	28.7	27.5
63-68	0.976	60.2	57.8	52.9	41.7	35.1	31.6	27.7	26.4
98-103	1.003	58.5	56.0	51.6	41.9	35.4	31.9	28.1	27.1

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	6.1	4.9	0.11	-	1.99	0.14	14	-	-	6.6	2.9	1.2	0.0	10.7
18-35	5.9	4.8	0.06	-	1.65	0.12	14	-	-	4.8	2.4	0.6	0.0	7.8
35-85	5.7	5.0	0.07	-	1.28	0.09	14	-	-	2.9	2.1	0.1	0.0	5.1
85-115	5.9	5.4	0.03	-	0.83	0.07	12	-	-	2.5	1.6	0.1	0.0	4.2
115-150	6.0	5.5	0.03	-	0.72	0.06	12	-	-	2.1	2.0	0.0	0.0	4.1
85-150	5.7	5.4	0.04	-	0.74	0.07	11	-	-	2.3	1.9	0.1	0.0	4.3

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	87	12.3	29	7.0	-	-	0
18-35	71	11.0	18	5.8	-	-	0
35-85	61	8.3	17	4.5	-	-	0
85-115	65	6.5	13	2.9	-	-	0
115-150	71	5.8	10	2.5	-	-	0
85-150	61	7.1	13	2.6	-	-	-

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	8.4	-	-	0.4	0.1	5.5	0.4	-	-	-	0.5
18-35	8.4	-	-	0.5	0.1	5.2	0.5	-	-	-	0.5
35-85	9.2	-	-	0.5	0.1	5.8	0.5	-	-	-	0.5
85-115	9.5	-	-	0.5	0.1	5.9	0.5	-	-	-	0.6
115-150	9.5	-	-	0.4	0.1	5.9	0.5	-	-	-	0.6
85-150	-	-	-	0.4	0.1	5.8	0.5	-	-	-	0.6

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	medium	weak	-	-	medium	-	weak	-	-	-
18-35	-	-	medium	weak	-	-	medium	-	weak	-	-	-
35-85	-	-	medium	weak	-	-	medium	-	weak	-	-	-
85-115	-	-	medium	weak	-	-	medium to strong	-	weak	-	-	-
115-150	-	-	medium	weak	-	-	medium to strong	-	weak	-	-	-
85-150	-	-	weak to medium	weak	-	-	medium to strong	very weak to weak	-	-	-	-

Profile description

Ap 0-18 cm	dark reddish brown (5YR 3/4, dry) dark reddish brown (5YR 3/3, moist)clay,moderate very coarse prismatic parting to strong very coarse subangular blocky,hard very friable slightly sticky slightly plastic,patchy thin clay cutans,many very fine pores and few fine and medium pores,many very fine roots,non calcareous,gradual smooth boundary to,
18-35 cm	dark reddish brown (5YR 3/4, dry) dark reddish brown (5YR 3/3, moist)clay,moderate very coarse prismatic parting to strong very coarse subangular blocky,hard very friable slightly sticky slightly plastic,broken thin clay cutans,many very fine pores and few fine and medium pores,many very fine roots,non calcareous,gradual smooth boundary to,
Bt1 35-85 cm	yellowish red (5YR 4/6, dry) dark reddish brown (5YR 3/4, moist)clay,moderate very coarse prismatic parting to strong medium subangular blocky,hard very friable slightly sticky slightly plastic,broken thin clay cutans,many very fine pores and few medium pores,many very fine roots,non calcareous,diffuse smooth boundary to,
Bt2 85-150 cm	yellowish red (5YR 4/6, dry) dark red (2.5YR 3/6, moist)clay,strong very coarse prismatic parting to strong very coarse subangular blocky,hard very friable slightly sticky slightly plastic,patchy thin clay cutans,many very fine pores and few fine pores,many very fine roots,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	basic volcanic breccia
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	phonolite/lahar
Soil Depth	150cm
Texture of parent material	clayey
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	highly

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

Major crops	maize
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	low level arable farming
Remarks on Land Use / Vegetation	Mango, sweet potato, fertilizers used
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant

Altitude	1145m
Physiographic Unit	gently undulating plateau
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.	plateau
Slope	2%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-150cm
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)	medium

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
Microrelief pattern	none
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 47: Nitisol

Characteristics

Reference soil KE047: Nitisols

Classification