Reference soil Nigeria 22: Acrisol

NG022

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 NG022: Acrisols

BRIEF CHARACTERIZATION OF THE SOIL: Very deep, moderately well drained brown to red sandy clay loam derived from acidic schist; with moderate mottling in the subsoil.

Classification

WRB 2006

WRB 1998

Haplic- Acrisol (Alumic Hyperdystric Profondic Chromic)

Alumi-Profondic- Acrisol (Hyperdystric Chromic)

15-197 cm

argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Chromi-Haplic Acrisol

Ferric Acrisol

0-15 cm	ochric A horizon
15-197 cm	argic B horizon

0-15 cm	ochric A horizon
15-197 cm	argillic B horizon
-	ferric

Local classification:	Etionni Series

Other classification

USDA-SCS (1975)

Haplustult ustic sandy over loamy 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	12.6	17.4	15.9	13.9	5.0	64.8	3.8	8.7	12.5	22.7
15-50	0	16.5	14.5	9.5	8.8	4.0	53.3	1.6	7.3	8.9	37.9
50-114	0	12.4	14.4	10.6	9.4	4.3	51.1	2.8	7.8	10.6	38.3
114-176	0	14.6	14.3	10.2	9.4	4.4	52.9	2.5	6.4	8.9	38.2
176-197	12	16.1	14.6	9.4	9.1	4.5	53.7	3.6	6.8	10.4	36.0
197-263	0	18.4	14.3	9.0	8.4	4.4	54.5	4.1	10.8	14.9	30.6
263-294	18	17.6	14.3	9.1	9.3	4.8	55.1	5.4	11.2	16.6	28.4
294-332	10	19.8	16.0	9.6	9.3	4.1	58.8	5.0	9.0	14	28.2
332-372	0	16.0	16.9	10.2	8.5	3.7	55.3	4.8	8.4	13.2	31.5
372-412	0	18.8	17.4	10.7	8.8	3.9	59.6	4.4	7.3	11.7	28.8

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	-	-	-	7.0	22.7
15-50	-	-	-	27.4	37.9
50-114	-	-	-	1.0	38.3
114-176	-	-	-	1.0	38.2
176-197	-	-	-	1.8	36.0
197-263	-	-	-	0.9	30.6
263-294	-	-	-	1.4	28.4
294-332	-	-	-	0.5	28.2
332-372	-	-	-	0.0	31.5
372-412	-	-	-	0.0	28.8

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	4.4	3.9	0.11	-	1.34	0.12	11	2.2	1.8	0.4	0.1	0.1	0.1	0.7
15-50	4.6	3.9	0.04	-	0.56	0.06	9	2.9	2.3	0.6	0.3	0.1	0.0	1
50-114	4.6	4.0	0.02	-	0.35	0.04	9	2.7	2.3	0.2	0.1	0.1	0.1	0.5
114-176	4.7	4.0	0.02	-	0.23	0.03	8	3.2	1.6	0.2	0.1	0.1	0.0	0.4
176-197	4.7	4.0	0.02	-	0.22	0.03	7	2.0	1.6	0.2	0.3	0.0	0.0	0.5
197-263	4.8	4.1	0.01	-	0.15	0.02	8	1.6	1.1	0.2	0.3	0.0	0.0	0.5
263-294	4.9	4.2	0.01	-	0.09	0.02	5	1.3	0.9	0.0	0.3	0.0	0.0	0.3
294-332	4.9	4.2	0.01	-	0.07	0.01	7	1.6	0.9	0.0	0.3	0.0	0.0	0.3
332-372	4.9	4.1	0.01	-	0.13	0.01	13	2.0	1.6	0.0	0.3	0.0	0.0	0.3
372-412	4.9	4.1	0.01	-	0.08	0.01	8	2.0	1.6	0.0	0.0	0.0	0.0	-

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	11	6.3	28	4.7	-	29	2
15-50	16	6.3	17	2.0	-	37	0
50-114	10	4.9	13	1.2	-	47	2
114-176	10	4.0	10	0.8	-	40	0
176-197	17	3.0	8	0.8	-	53	0
197-263	22	2.3	8	0.5	-	48	0
263-294	14	2.1	7	0.3	-	43	0
294-332	12	2.6	9	0.2	-	35	0
332-372	9	3.2	10	0.5	-	50	0
372-412	-	3.0	10	0.3	-	53	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	-	-	-	0.12	0.00	1.30	0.27	-	-	-	0.10
15-50	-	-	-	0.12	0.00	2.31	0.46	-	-	-	0.12
50-114	-	-	-	0.12	0.00	2.11	0.40	-	-	-	0.10
114-176	-	-	-	0.10	0.00	1.84	0.33	-	-	-	0.10
176-197	-	-	-	0.08	0.00	1.65	0.27	-	-	-	0.08
197-263	-	-	-	0.10	0.00	2.60	0.36	-	-	-	0.10
263-294	-	-	-	0.08	0.00	2.40	0.33	-	-	-	0.05
294-332	-	-	-	0.07	0.00	2.84	0.31	-	-	-	0.07
332-372	-	-	-	0.07	0.00	2.14	0.24	-	-	-	0.02
372-412	-	-	-	0.08	0.00	1.53	0.18	-	-	-	0.03

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
294-332	-	very weak	-	weak	-	-	very strong	weak	weak	-	-	-
332-372	-	very weak to weak	-	weak to medium	-	-	very strong	weak	weak	-	-	-
372-412	-	very weak	-	weak	-	-	very strong	weak	weak	-	-	-

Profile description

Ap 0-15 cm	(dark) brown (7.5YR 4/4, dry)sandy loam,moderate medium crumb,soft friable non plastic,few fine continuous exped interstitial horizontal pores and few continuous exped vesicular horizontal pores,many medium roots,non calcareous,gradual smooth boundary to,
Bt1 15-50 cm	reddish brown (5YR 4/4, dry)sandy loam,weak medium crumb,slightly hard friable non plastic,few very fine continuous inped tubular vertical pores,many fine roots,very few small spherical soft manganiferous concretions,few fine gravel weathered quartz fragments,non calcareous,gradual wavy boundary to,
Bt2 50-114 cm	reddish brown (5YR 4/4, dry)sandy clay loam,weak medium crumb,slightly hard friable slightly sticky non plastic,few very fine discontinuous inped interstitial vertical pores,few fine roots,non calcareous,gradual smooth boundary to,
Bt3 114-176 cm	dark red (2.5YR 3/6, dry)sandy clay loam,weak medium subangular blocky,slightly hard firm slightly sticky,common (5-15%) medium distinct clear mottles 5.0Y8/0 (Invalid Code:),few very fine roots,very few fine gravel weathered quartz fragments,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	acidic schist
Kind 2 (parent material) (second entry); Parker (eds), 1984	quartzite
Mode of accumulation or deposition of parent material	slope wash
Mode of accumulation or deposition of parent material (second entry)	residual material
Soil Depth	176cm
Texture of parent material	loamy
Texture of parent material (second entry)	gravelly
Weathering Resistance	high
Weathering Resistance (second entry)	high
General characterization of the status of weathering of solid rock	partially or moderately
General characterization of the status of weathering of solid rock (second entry)	partially or moderately

Land use or vegetation in the immediate vicinity of the site	fallow
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	0m
Physiographic position of the site	lower slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	low hill
Slope	4%
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Dry From - To	0-176cm
Kind of ground water table (USDA, 1979)	no groundwater table observed

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 Nigeria 22: Acrisol

Characteristics

Reference soil NG022: Acrisols

Classification