Reference soil Côte d'Ivoire 06: Acrisol

CI006

Acrisols occur dominantly in the wetter parts of the tropics and subtropics and the warm temperate regions in relatively young landscapes.

Characteristics

Soils having an argic horizon (a subsurface horizon with distinct higher clay content than the overlying horizon), which has a cation exchange capacity of less than 24 cmolc per kg in some part, either starting within 100 cm from the soil surface, or within 200 cm from the soil surface if the argic horizon is overlain by loamy sand or coarser textures throughout. They have a base saturation (total amount of Ca, Mg, K and Na with respect to the cation exchange capacity) of less than 50 percent in the major part between 25 and 100 cm from the soil surface

Distribution of Acrisols (rough estimation supplied by soilgrids)

Reference soil CI006: Acrisols

A gravelly, very deep soil (125-180 cm), derived from gneiss rich in biotite. Fragments of parent material can be found in CB horizon (30 % soil, 70 % parent material). The land is used for agriculture; the mesorelief shows yam mounds Ferric properties because of low CEC clay and the large amount of iron concretions MICRO RELIEF: Yam mounds: diameter 75 cm.

Classification

WRB 2006

WRB 1998

Pisoplinthic-Cutanic-Vetic- Acrisol (Chromic)

Veti-Pisoplinthic- Acrisol (Chromic)

0-100 cm	pisoplinthic horizon
50-160 cm	ferralic horizon
7-160 cm	argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Veti-Ferric Acrisol skeletic

Orthic Ferralsol petric

11-100 cm	argic / ferralic B horizon
1-11 cm	ochric A horizon

0-11 cm	ochric A horizon
11-100 cm	argillic / oxic B horizon
-	ferric

Local classification:	Sol ferrallitique, see remarks soil, 70 % parent material).

Other classification

USDA-NRCS (1999)	Typic Kandiudult
USDA-SCS (1975)	Typic Tropudult udic clayey oxidic 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
0-10	4	9.8	18.9	21.2	24.0	6.7	80.6	1.8	3.8	5.6	13.8
10-20	7	9.6	15.8	18.2	23.2	6.8	73.6	2.3	3.6	5.9	20.4
20-70	59	16.5	14.4	12.3	13.9	4.4	61.5	3.0	4.4	7.4	31.0
70-100	15	9.0	9.8	10.4	13.3	5.4	47.9	2.1	10.8	12.9	39.1
120-150	95	-	-	-	-	-	-	-	-	-	-

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-10	-	-	-	7.8	13.8
20-25	1.51	-	-	-	-
10-20	-	-	-	10.0	20.4
70-80	1.27	-	-	-	-
20-70	-	-	-	22.2	31.0
70-100	-	-	-	0.5	39.1
120-150	-	-	-	0.0	-

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
20-25	1.51	41.5	39.5	32.6	25.7	22.1	19.3	14.5	13.6
70-80	1.27	49.4	47.5	42.7	37.9	36.3	34.4	27.0	25.9

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
0-10	5.0	4.0	0.05	-	1.12	0.07	16	0.7	0.2	2.0	0.2	0.1	0.0	2.3
10-20	4.6	3.8	0.04	-	0.91	0.08	11	1.1	0.7	1.0	0.1	0.1	0.2	1.4
20-70	4.7	3.9	0.03	-	0.49	0.03	16	1.0	0.7	1.0	0.0	0.0	0.1	1.1
70-100	4.8	4.0	0.03	-	0.45	-	-	1.0	0.7	0.8	0.1	0.0	0.0	0.9
120-150	4.8	4.0	0.03	-	0.39	-	-	-	-	-	-	-	-	-

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 %
0-10	50	4.6	33	3.9	-	4	0
10-20	32	4.4	22	3.2	-	16	5
20-70	34	3.2	10	1.7	-	22	3
70-100	56	1.6	4	1.6	-	44	0
120-150	-	-	-	1.4	-	-	-

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
0-10	-	-	-	0.00	0.00	1.00	0.20	-	-	-	0.1
10-20	-	-	-	0.10	0.00	1.40	0.20	-	-	-	0.10
20-70	-	-	-	0.10	0.00	3.00	0.40	-	-	-	0.1
70-100	-	-	-	0.10	0.00	4.30	0.50	-	-	-	0.10
120-150	-	-	-	0.1	0	4.8	0.5	-	-	-	0.1

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
0-10	39.8	34.4	10.2	0.01	0.09	0.17	-	1.00
10-20	39.9	34.8	10.3	0.00	0.07	0.16	-	1.04
20-70	38.2	34.4	11.6	0.00	1.05	0.12	-	1.03
70-100	38.5	34.6	11.7	0.00	0.04	0.09	-	1.05
120-150	38.4	34.5	12.0	0.00	0.05	0.08	-	1.02

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
0-10	0.02	0.26	14.1	100.05	2	10.4	1.7	5.3
10-20	0.01	0.22	13.8	100.3	1.9	10.3	1.6	5.3
20-70	0.01	0.21	14.0	100.62	1.9	8.8	1.6	4.6
70-100	0.01	0.20	13.9	100.09	1.9	8.7	1.6	4.6
120-150	0.02	0.22	14.3	100.59	1.9	8.5	1.5	4.5

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
0-10	5.2	0.00	2.1	0.04	0.04	-	88.1	0.27
10-20	7.0	0.00	2.6	0.04	0.05	-	86.7	0.34
20-70	12.1	0.00	5.4	0.05	0.04	-	75.8	0.52
70-100	19.8	0.00	7.5	0.07	0.04	-	63.1	0.77
120-150	20.6	0.00	7.5	0.05	0.03	-	60.6	0.78

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
0-10	3.9	3.9	0.00	0.02	28.7	111.5	22.9
10-20	4.2	4.4	0.00	0.03	21	88.6	17
20-70	3.5	5.9	0.00	0.03	10.6	37.3	8.3
70-100	4.1	8.7	0.00	0.04	5.4	22.4	4.4
120-150	4.3	9.0	0.00	0.04	5	21.5	4.1

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-10	very weak to weak	-	weak	weak to medium	-	-	very strong	-	-	-	-	very weak
10-20	very weak to weak	-	weak	weak to medium	-	-	very strong	-	-	-	-	very weak
20-70	very weak to weak	-	weak	weak to medium	-	-	very strong	-	-	-	-	very weak
70-100	very weak to weak	-	weak	weak to medium	-	-	very strong	-	-	-	-	very weak to weak
120-150	very weak to weak	-	weak	weak to medium	-	-	very strong	-	-	-	-	very weak to weak

Profile description

Ap 0-11 cm	(7.5YR 4/3, moist)slightly gravelly sandy loam,moderate very fine and fine subangular blocky,very friable slightly sticky non plastic,many micro medium exped and inped tubular pores and many medium exped and inped interstitial pores,many very fine and many medium roots,few small spherical hard ferruginous concretions,non calcareous,gradual smooth boundary to,
11-20 cm	strong brown (7.5YR 4/6, moist)slightly gravelly sandy loam,moderate fine subangular blocky,very friable slightly sticky slightly plastic,many micro to fine tubular and many micro to fine interstitial pores,common very fine and common medium roots,few small spherical hard ferruginous concretions,few charcoal fragments,non calcareous,gradual smooth boundary to,
Bo 20-70 cm	(5YR 5/7, moist)very gravelly sandy clay loam,moderate very fine angular blocky to subangular blocky,friable sticky plastic,clay on rock fragments,many micro to fine exped and inped tubular pores and many micro to fine exped and inped interstitial pores,few very fine and fine roots,very frequent medium spherical hard ferruginous concretions,very few medium gravel weathered quartz very few coarse gravel strongly weathered schists fragments,non calcareous,gradual smooth boundary to,
70-110 cm	yellowish red (5YR 5/8, moist)slightly gravelly clay,moderate very fine and fine subangular blocky to angular blocky,friable sticky plastic,clay on rock fragments,many micro and very fine exped and inped tubular pores and many micro and very fine exped and inped interstitial pores,few very fine and fine roots,few medium gravel weathered quartz, mica and iron fragments and few medium gravel strongly weathered schists,non calcareous,diffuse irregular boundary to,
CB 110-150 cm	yellowish red (5YR 5/8, moist)gravel,weak fine subangular blocky and rock,friable sticky plastic,many micro to fine exped and inped tubular pores and many micro to fine exped and inped interstitial pores,many very fine to coarse roots,many very fine and fine roots,very few medium gravel weathered quar.,mica,iron fragments,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	gneiss
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	Precambrian
Texture of parent material	loamy
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	highly

Intensity of the soil erosion type	slight
Soil erosion type	rill

Major crops	yam
Land use or vegetation in the immediate vicinity of the site	arable farming
Remarks on Land Use / Vegetation	LAND USE: Xonstructed yam mounds, 75cm in diameter

Altitude	170m
Physiographic Unit	slope of low hill in dissected peneplain
Physiographic position of the site	upper slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	peneplain
Slope	8%
Slope Aspect	north-north-east
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	rolling

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	0-150cm
Estimated permeability (class) of least permeable part of the profile	high
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)	surface partly slaked, round smooth aggregates
Microrelief Height: variation in height	50
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	artificial terracing/mounds
Microrelief pattern	isolated
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 Côte d'Ivoire 06: Acrisol

Characteristics

Reference soil CI006: Acrisols

Classification