Reference soil Nigeria 24: Acrisol

NG024

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 NG024: Acrisols

BRIEF CHARACTERIZATION OF THE SOIL: Very deep, well drained dark grayish clay, derived from basic amphibolite, with strong angular blocky structure and some peripherally weathered amphobolite stones. Stoneline occurring between 160 and 170 cm depth.

Classification

WRB 2006

WRB 1998

Haplic- Acrisol (Profondic Clayic Rhodic)

Rhodi-Profondic- Acrisol

20-242 cm

argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Rhodi-Haplic Acrisol

Ferric Acrisol

0-20 cm	ochric A horizon
20-242 cm	argic B horizon

0-20 cm	ochric A horizon
20-242 cm	argillic B horizon
-	ferric

Local classification:	Itagunmodi Series

Other classification

USDA-SCS (1975)

Haplustalf ustic sandy over 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
0-10	0	1.2	5.6	21.8	32.8	10.3	71.7	7.2	5.7	12.9	15.5
20-50	0	1.0	4.1	13.8	20.0	6.5	45.4	6.7	4.5	11.2	43.5
50-90	0	1.2	3.5	11.2	17.1	6.0	39	5.9	4.9	10.8	50.3
90-130	0	1.4	3.7	10.4	15.9	5.7	37.1	2.8	6.1	8.9	54.0
13-180	0	2.3	3.5	9.2	13.9	5.4	34.3	3.0	6.4	9.4	56.2
190-242	0	1.4	3.3	8.8	14.5	6.2	34.2	3.5	10.6	14.1	51.7
242-277	0	1.2	3.3	10.5	16.9	6.8	38.7	6.2	11.5	17.7	43.6
277-310	0	1.0	3.1	10.4	17.8	6.7	39	5.5	13.5	19	42.0

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	-	-	-	7.0	15.5
20-50	-	-	-	3.3	43.5
50-90	-	-	-	1.0	50.3
90-130	-	-	-	0.5	54.0
13-180	-	-	-	0.5	56.2
190-242	-	-	-	1.0	51.7
242-277	-	-	-	0.0	43.6
277-310	-	-	-	0.4	42.0

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	6.1	5.4	0.08	-	1.13	0.10	11	0.1	0.0	4.1	1.0	0.2	0.0	5.3
20-50	5.3	4.5	0.03	-	0.42	0.04	11	0.2	0.0	1.8	1.0	0.1	0.0	2.9
50-90	5.2	4.4	0.02	-	0.33	0.04	8	0.4	0.0	1.6	0.7	0.0	0.0	2.3
90-130	5.3	4.4	0.01	-	0.25	0.03	8	0.4	0.2	1.4	0.7	0.1	0.0	2.2
13-180	5.4	4.4	0.01	-	0.27	0.03	9	0.6	0.0	1.3	0.4	0.0	0.0	1.7
190-242	5.4	4.3	0.01	-	0.13	0.02	7	0.8	0.2	0.8	0.3	0.1	0.0	1.2
242-277	5.1	4.2	0.02	-	0.14	0.01	14	0.7	0.2	0.6	0.3	0.0	0.0	0.9
277-310	5.3	4.3	0.01	-	0.16	0.01	16	0.7	0.5	0.8	0.3	0.0	0.0	1.1

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	71	7.5	48	4.0	-	0	0
20-50	49	5.9	14	1.5	-	0	0
50-90	9	24.7	49	1.2	-	0	0
90-130	33	6.6	12	0.9	-	3	0
13-180	25	6.7	12	0.9	-	0	0
190-242	18	6.5	13	0.5	-	3	0
242-277	12	7.5	17	0.5	-	3	0
277-310	12	9.4	22	0.6	-	5	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
0-10	-	-	-	0.05	0.00	1.95	0.12	-	-	-	0.10
20-50	-	-	-	0.10	0.00	4.52	0.39	-	-	-	0.23
50-90	-	-	-	0.10	0.00	5.08	0.49	-	-	-	0.23
90-130	-	-	-	0.12	0.00	5.47	0.52	-	-	-	0.22
13-180	-	-	-	0.11	0.00	5.85	0.55	-	-	-	0.22
190-242	-	-	-	0.10	0.02	5.96	3.85	-	-	-	0.17
242-277	-	-	-	0.08	0.00	6.55	0.49	-	-	-	0.15
277-310	-	-	-	0.08	0.00	6.41	0.48	-	-	-	0.15

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-10	-	-	-	weak to medium	-	-	strong	weak	weak	-	weak	-
20-50	-	-	-	weak to medium	-	-	strong to very strong	weak	weak	-	very weak to weak	-
50-90	-	-	-	weak to medium	-	-	strong to very strong	weak	weak	-	very weak to weak	-
90-130	-	-	-	weak to medium	-	-	medium	very weak to weak	very weak to weak	-	very weak	-
13-180	-	-	-	weak to medium	-	-	strong to very strong	very weak to weak	very weak to weak	-	very weak	-
190-242	-	-	-	weak to medium	-	-	strong to very strong	very weak to weak	very weak to weak	-	very weak	-
242-277	-	-	-	weak to medium	-	-	strong to very strong	very weak to weak	very weak to weak	-	very weak	-
277-310	-	-	-	weak to medium	-	-	strong to very strong	very weak to weak	very weak to weak	-	very weak	-

Profile description

Ap 0-20 cm	(2.5YR 3/3, moist)sandy loam,moderate medium subangular blocky,friable non sticky non plastic,many fine continuous exped and inped tubular oblique pores,many fine roots,non calcareous,gradual smooth boundary to,
Bt1 20-50 cm	dark red (2.5YR 3/6, moist)sandy clay,strong medium angular blocky,very firm slightly sticky slightly plastic,many micro discontinuous exped and inped tubular random pores,non calcareous,gradual smooth boundary to,
Bt2 50-90 cm	dark red (2.5YR 3/6, moist)clay,strong medium angular blocky,very firm slightly sticky plastic,many micro discontinuous exped tubular horizontal pores,non calcareous,clear smooth boundary to,
Bt3 90-130 cm	dark red (2.5YR 3/6, moist)clay,strong medium angular blocky,very firm sticky plastic,many micro continuous inped tubular vertical pores,non calcareous,diffuse wavy boundary to,
Bt4 130-180 cm	dark red (2.5YR 3/6, moist)clay,strong medium angular blocky,very firm sticky plastic,many micro continuous inped tubular vertical pores,non calcareous,

Depth1	190cm
Kind 1 (parent material) ; Parker (eds), 1984	metamorphic rock
Mode of accumulation or deposition of parent material	colluvial
Remarks on Parent Materials	basic amphibolite
Soil Depth	90cm
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	cocoa
Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	land clearing
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	arable farming
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	shifting - fallow bush
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	secondary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	semi-deciduous forest

Altitude	366m
Physiographic Unit	deeply dissected interfluve
Physiographic position of the site	middle slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	hill
Slope	7%
Form of the slope surrounding the site	straight
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	0-180cm

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

You are here

Reference soil Nigeria 24: Acrisol

Characteristics

Reference soil NG024: Acrisols

Classification