Reference soil Cameroon 01: Nitisol

CM001

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 CM001: Nitisols

Dystri- Haplic Nitisol

Classification

WRB 2006

WRB 1998

Acric-Ferralic- Nitisol

Dystri-Ferralic- Nitisol

15-210 cm	argic horizon
15-210 cm	nitic horizon
-	ferralic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

DystriHaplic Nitisol

Ferric Acrisol

0-38 cm	ochric A horizon
15-210 cm	argic B horizon
-	nitic

0-38 cm	ochric A horizon
15-210 cm	argillic B horizon
-	ferric

Other classification

USDA-NRCS (1999)	Typic Kandiudult
USDA-SCS (1975)	Typic Paleudult udic clayey kaolinitic isohyperthermic

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	-	0.8	3.0	5.3	5.8	3.2	18.1	8.0	20.3	28.3	53.6
15-38	-	0.7	1.7	2.6	2.9	1.8	9.7	3.9	11.4	15.3	75.1
38-55	-	0.8	1.6	2.2	2.5	1.7	8.8	3.8	10.5	14.3	76.9
55-83	-	0.7	1.3	1.7	2.0	1.5	7.2	4.3	9.8	14.1	78.6
83-137	-	0.5	1.2	1.7	1.8	1.4	6.6	1.8	9.9	11.7	81.7
137-165	-	0.7	1.1	1.2	1.7	1.2	5.9	3.3	10.1	13.4	80.6
165-210	-	1.0	1.2	1.3	1.5	1.3	6.3	3.2	11.7	14.9	78.9

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	-	-	-	36.4	53.6
15-38	-	-	-	2.0	75.1
38-55	-	-	-	1.0	76.9
55-83	-	97	-	0.0	78.6
83-137	-	-	-	1.5	81.7
137-165	-	98	-	4.0	80.6
165-210	-	-	-	0.0	78.9

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
0-15	6.4	5.8	0.14	-	3.00	0.29	10	0.0	0.1	9.3	4.0	0.4	0.1	13.8
15-38	6.1	5.4	0.05	-	0.80	0.09	9	0.0	0.1	2.9	1.1	0.3	0.0	4.3
38-55	5.9	5.4	0.03	-	0.54	0.06	9	0.0	0.1	2.3	1.1	0.2	0.0	3.6
55-83	5.8	5.4	0.03	-	0.44	-	-	0.0	0.1	2.3	1.3	0.2	0.0	3.8
83-137	5.7	5.4	0.02	-	0.35	-	-	0.0	0.1	2.3	1.6	0.2	0.0	4.1
137-165	5.7	5.4	0.02	-	0.32	-	-	0.0	0.1	1.9	1.5	0.2	0.0	3.6
165-210	5.7	5.4	0.02	-	0.22	-	-	0.0	0.1	1.9	1.6	0.1	0.0	3.6

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	61	22.7	42	10.5	-	0	0
15-38	33	13.2	18	2.8	-	1	0
38-55	29	12.4	16	1.9	-	1	0
55-83	31	12.1	15	1.5	-	1	0
83-137	36	11.4	14	1.2	-	1	0
137-165	32	11.4	14	1.1	-	1	0
165-210	32	11.1	14	0.8	-	1	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
0-15	-	-	-	0.17	0.03	6.61	1.11	0.28	0.15	-	0.41
15-38	-	-	-	0.15	0.03	7.25	1.32	0.04	0.07	-	0.37
38-55	-	-	-	0.15	0.04	7.31	1.36	0.02	0.07	-	0.33
55-83	-	-	-	0.14	0.03	7.42	1.40	0.01	0.07	-	0.24
83-137	-	-	-	0.14	0.02	7.32	1.42	0.01	0.06	-	0.21
137-165	-	-	-	0.14	0.04	7.53	1.38	0.01	0.06	-	0.18
165-210	-	-	-	0.15	0.04	7.69	1.36	0.01	0.06	-	0.15

Elemental composition of the clay

Depth (cm)	SiO2 % w/w	Al2O3 % w/w	Fe2O3 % w/w	CaO % w/w	MgO % w/w	K2O % w/w	Na2O % w/w	TiO2 % w/w
55-83	33.4	30.0	17.6	0.05	0.11	0.15	0.93	4.0
137-165	32.9	30.2	17.3	0.04	0.12	0.16	1.47	4.00

Depth (cm)	MnO2 % w/w	P2O5 % w/w	Ign.Loss clay % w/w	Total Clay % w/w	SiO2/Al2O3 mol/mol	SiO2/Fe2O3 mol/mol	SiO2 / R mol/mol	Al2O3/Fe2O3 mol/mol
55-83	0.15	0.5	13.4	100.29	1.9	5	1.4	2.7
137-165	0.10	0.45	13.4	100.14	1.8	5.1	1.4	2.7

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
0-15	19.0	0.38	16.9	0.14	0.30	-	40.0	5.6
15-38	23.1	0.13	17.6	0.15	0.25	-	37.8	5.27
38-55	23.0	0.09	17.1	0.14	0.25	-	36.2	5.05
55-83	24.1	0.09	17.5	0.15	0.22	-	35.7	5.07
83-137	25.0	0.08	17.6	0.16	0.22	-	36.8	5.11
137-165	25.4	0.08	17.5	0.15	0.20	-	36.1	4.95
165-210	25.4	0.08	17.5	0.15	0.19	-	36.1	4.89

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
0-15	1.8	17.0	0.37	0.46	3.6	6.3	2.3
15-38	2.1	14.5	0.28	0.42	2.8	5.7	1.9
38-55	2.1	16.7	0.22	0.41	2.7	5.6	1.8
55-83	2.2	14.0	0.18	0.42	2.5	5.4	1.7
83-137	2.2	13.7	0.16	0.43	2.5	5.6	1.7
137-165	2.3	14.2	0.10	0.41	2.4	5.5	1.7
165-210	2.3	14.0	0.07	0.39	2.4	5.5	1.7

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	-	strong	-	-	strong	-	very weak to weak	-	-	-
15-38	-	-	-	strong	-	-	strong	-	very weak to weak	-	-	-
38-55	-	-	-	strong	-	-	strong	-	very weak to weak	-	-	-
55-83	-	-	-	strong	-	-	strong	-	very weak to weak	-	-	-
83-137	-	-	-	strong	-	-	strong	-	very weak to weak	-	-	-
137-165	-	-	-	strong	-	-	strong	-	very weak to weak	-	-	-
165-210	-	-	-	strong	-	-	very strong	-	very weak to weak	-	-	-

Sand mineralogy

Depth (cm)	Heavy Frac. sand % w/w	K-Feldspar % w/w	Light Fra. sand % w/w	Opaque % w/w	Plagioclase % w/w	Quartz % w/w
83-137	6.9	1	93.1	95	-	99

Minerals

Depth (cm)	Anatase % w/w	Andalusite % w/w	Apatite % w/w	Augite % w/w	Biotite % w/w	Hornblende (basaltic) % w/w
83-137	-	-	-	-	-	1

Depth (cm)	Brookite % w/w	Chloritic % w/w	Disthene % w/w	Epidote % w/w	Garnet % w/w	Glaucophane % w/w
83-137	-	-	1	-	-	-

Depth (cm)	Grenate % w/w	Grossular % w/w	Muscovite % w/w	Rutile % w/w	Sillimanite % w/w	Spinel % w/w
83-137	-	-	-	3	3	6

Profile description

Ah 0-15 cm	dark yellowish brown (10YR 4/4, moist) dark greyish brown (10YR 4/2, dry)clay,moderate medium subangular blocky to granular,friable sticky slightly plastic,many very fine pores,common fine roots,non calcareous,clear smooth boundary to,
ABh 15-38 cm	yellowish brown (10YR 5/4, moist) yellowish brown (10YR 5/6, dry)clay,moderate fine and medium subangular blocky,friable sticky plastic,patchy thin humus cutans in root channels and pores,many fine pores and common medium pores,common fine and medium roots,non calcareous,gradual smooth boundary to,
Bt1 38-55 cm	yellowish brown (10YR 5/6, moist)clay,weak coarse prismatic parting to moderate medium and coarse angular blocky,slightly hard friable sticky plastic,patchy thin clay and sesquioxide cutans on pedfaces,many fine common medium pores,few very fine and fine roots,very few fine gravel weathered basalt,non calcareous,gradual smooth boundary to,
Bt2 55-83 cm	yellowish brown (10YR 5/6, moist)clay,moderate medium and coarse prismatic parting to moderate medium and coarse angular blocky,friable sticky plastic,patchy thin clay cutans on pedfaces,many very fine and fine pores,few very fine and fine roots,very few fine gravel weathered basalt,non calcareous,gradual smooth boundary to,
Bt3 83-137 cm	yellowish brown (10YR 5/6, moist)clay,moderate medium and coarse prismatic parting to moderate medium and coarse angular blocky,friable sticky plastic,patchy thin clay cutans on pedfaces,many very fine and fine pores,very few fine gravel weathered basalt,non calcareous,gradual smooth boundary to,
Bt4 137-165 cm	brownish yellow (10YR 6/6, moist)clay,moderate coarse angular blocky,friable sticky plastic,patchy thin clay cutans,many very fine and fine pores,few very fine and fine roots,very few fine gravel weathered basalt,non calcareous,gradual smooth boundary to,
Bt5 165-210 cm	brownish yellow (10YR 6/6, moist)clay,weak to moderate coarse angular blocky,friable sticky plastic,many very fine and fine pores,few very fine and fine roots,very few fine gravel weathered basalt,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	fine-grained basic igneous rock
Remarks on Parent Materials	basalt
Soil Depth	210cm

Intensity of the soil erosion type	slight
Intensity of the soil erosion type (second entry)	moderate
Soil erosion type	sheet

Major crops	coffee
Land use or vegetation in the immediate vicinity of the site	arable farming
Remarks on Land Use / Vegetation	experimental fields

Altitude	1200m
Physiographic Unit	dissected lava plateau
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	pediplain
Slope	3%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	well
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-210cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	slow

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 Cameroon 01: Nitisol

Characteristics

Reference soil CM001: Nitisols

Classification