Reference soil Nigeria 15: Acrisol

NG015

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 NG015: Acrisols

BRIEF CHARACTERIZATION OF THE SOIL: Very deep poorly to imperfectly drained, pale yellow sandy soil; derived from alluvium with a thick dark topsoil and strong mottling in the subsoil. PARENT MATERIAL: Derived from coastal plain sand.

Classification

WRB 2006

WRB 1998

Umbric-Gleyic- Acrisol (Albic Ferric Alumic Humic)

Umbri-Gleyic- Acrisol (Albic Humic)

25-55 cm	albic horizon
55-120 cm	argic horizon
55-165 cm	ferric horizon
-	gleyic colour pattern
-	reducing conditions

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Umbri-Gleyic Acrisol inundic

Gleyic Acrisol

0-25 cm	umbric A horizon
25-55 cm	albic E horizon
55-120 cm	argic B horizon
-	gleyic

0-25 cm	umbric A horizon
25-55 cm	albic E horizon
55-120 cm	argillic B horizon
-	hydromorphic

Local classification:	Obigwe Series

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
0-12	0	0.3	4.7	28.2	34.5	4.0	71.7	9.4	4.9	14.3	13.9
12-25	0	0.2	6.8	31.0	31.2	3.6	72.8	6.4	2.0	8.4	18.8
25-37	0	0.5	5.3	30.1	34.8	4.1	74.8	5.6	5.9	11.5	13.7
37-55	0	0.6	5.7	29.9	35.8	4.5	76.5	4.9	6.1	11	12.6
55-85	0	0.4	6.0	29.5	32.3	3.9	72.1	4.8	5.8	10.6	17.3
85-120	0	0.6	6.6	30.5	27.6	3.8	69.1	3.8	4.6	8.4	22.4
120-165	0	0.5	4.5	21.5	24.2	2.8	53.5	16.4	11.3	27.7	18.8
165-270	0	1.5	5.0	21.6	27.7	4.5	60.3	7.3	4.6	11.9	27.8
270-370	0	0.9	4.0	23.3	31.7	3.3	63.2	3.8	4.5	8.3	28.5
0-130	0	0.4	5.8	30.1	37.2	4.3	77.8	6.7	3.1	9.8	12.4

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-12	-	-	-	5.1	13.9
5-10	1.22	-	-	-	-
12-25	-	-	-	8.3	18.8
35-40	1.57	-	-	-	-
25-37	-	-	-	9.2	13.7
90-95	1.48	-	-	-	-
37-55	-	-	-	8.1	12.6
55-85	-	-	-	4.0	17.3
85-120	-	-	-	2.1	22.4
120-165	-	-	-	3.3	18.8
165-270	-	-	-	4.0	27.8
270-370	-	-	-	8.3	28.5
0-130	-	-	-	8.7	12.4

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
5-10	1.22	48.6	48.6	43.5	29.1	26.4	25.4	13.8	13.5
35-40	1.57	33.1	32.8	24.4	14.5	12.7	12.0	6.3	6.0
90-95	1.48	36.2	35.3	29.8	23.4	21.5	19.7	13.8	13.5

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
0-12	4.4	4.2	0.04	-	3.08	0.20	15	3.4	3.2	0.2	0.1	0.2	0.0	0.5
12-25	4.8	4.2	0.02	-	1.34	0.10	13	2.6	2.5	0.0	0.0	0.1	0.0	0.1
25-37	4.6	4.2	0.02	-	0.52	0.03	17	1.6	1.3	0.0	0.0	0.0	0.0	-
37-55	5.0	4.2	0.02	-	0.09	0.01	9	1.3	1.1	0.0	0.0	0.1	0.1	0.2
55-85	5.2	4.1	0.01	-	0.09	0.01	9	1.7	1.6	0.0	0.0	0.1	0.0	0.1
85-120	5.1	4.1	0.01	-	0.05	0.01	5	2.0	1.8	0.0	0.0	0.1	0.0	0.1
120-165	5.3	4.1	0.01	-	0.08	0.01	8	2.2	1.8	0.0	0.1	0.2	0.2	0.5
165-270	5.3	4.1	0.01	-	0.07	0.01	7	2.6	2.5	0.0	0.1	0.2	0.2	0.5
270-370	5.4	4.0	0.01	-	0.09	0.01	9	3.1	2.9	0.2	0.2	0.3	0.0	0.7
0-130	4.9	4.0	0.02	-	0.06	-	-	1.1	0.9	0.0	0.0	0.0	0.2	0.2

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 %
0-12	5	10.6	76	10.8	-	30	0
12-25	1	7.0	37	4.7	-	36	0
25-37	-	2.4	18	1.8	-	54	0
37-55	14	1.4	11	0.3	-	79	7
55-85	5	2.1	12	0.3	-	76	0
85-120	4	2.4	11	0.2	-	75	0
120-165	19	2.6	14	0.3	-	69	8
165-270	14	3.5	13	0.2	-	71	6
270-370	16	4.5	16	0.3	-	64	0
0-130	13	1.6	13	0.2	-	56	13

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
0-12	-	-	-	0.22	-	0.04	0.20	-	-	-	0.02
12-25	-	-	-	0.18	-	0.03	0.10	-	-	-	0.00
25-37	-	-	-	0.05	-	0.10	0.06	-	-	-	0.02
37-55	-	-	-	0.02	-	0.45	0.09	-	-	-	0.02
55-85	-	-	-	0.02	-	0.77	0.12	-	-	-	0.02
85-120	-	-	-	0.02	-	1.01	0.12	-	-	-	0.05
120-165	-	-	-	0.05	-	1.19	0.12	-	-	-	0.05
165-270	-	-	-	0.05	-	2.18	0.18	-	-	-	0.07
270-370	-	-	-	0.05	-	1.40	0.15	-	-	-	0.03
0-130	-	-	-	0.02	-	0.17	0.03	-	-	-	0.00

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-12	-	-	-	-	-	-	very strong	-	weak to medium	weak	-	-
12-25	-	-	-	-	-	-	strong to very strong	-	weak	weak	-	-
25-37	-	-	-	-	-	-	strong to very strong	-	very weak to weak	weak	-	-
37-55	-	-	-	very weak to weak	-	-	very strong	very weak to weak	weak	weak	-	-
55-85	-	-	-	very weak to weak	-	-	very strong	weak	weak	weak	-	-
85-120	-	-	-	very weak to weak	-	-	very strong	weak	weak	very weak to weak	-	-
120-165	-	-	-	weak	-	-	very strong	weak	weak	very weak to weak	-	-
165-270	-	-	-	weak	-	-	very strong	weak	weak	very weak to weak	-	-
270-370	-	-	-	very weak to weak	-	-	very strong	weak	weak	very weak	-	-

Profile description

Ah1 0-12 cm	black (10YR 2/1, moist)loamy sand herbaceous fragments highly,moderate fine crumb,very friable,many medium tubular pores,many fine roots,non calcareous,clear smooth boundary to,
Ah2 12-25 cm	very dark grey (10YR 3/1, moist)Description sand,weak medium crumb,very friable,many fine tubular pores and many fine interstitial pores,many fine roots,non calcareous,clear smooth boundary to,
A/E 25-37 cm	pale brown (10YR 6/3, moist)medium sand,weakly coherent porous massive,very friable non sticky non plastic,many fine interstitial pores,common fine roots,non calcareous,clear smooth boundary to,
E 37-55 cm	pale yellow (2.5Y 7/4, moist)medium sand,weak medium subangular blocky,very friable non sticky non plastic,many (15-40%) coarse prominent mottles 2.5YR4/6 (red),many fine and medium tubular pores,few fine roots,very few small soft ferruginous nodules,non calcareous,clear wavy boundary to,
Btg1 55-80 cm	pale yellow (2.5Y 7/4, moist)sandy loam,weak medium subangular blocky,friable slightly sticky slightly plastic,many (15-40%) coarse prominent mottles 2.5YR6/4 (light reddish brown),many fine tubular pores and few tubular pores,few fine roots,very few small soft ferruginous nodules,non calcareous,gradual smooth boundary to,
Btg2 80-120 cm	very pale brown (10YR 7/3, moist)sandy clay loam,moderate medium subangular blocky,friable slightly sticky slightly plastic,many (15-40%) coarse prominent mottles 2.5YR4/6 (red),many fine tubular pores and common medium tubular pores,non calcareous,diffuse smooth boundary to,
Btg3 120-165 cm	light grey (10YR 7/2, moist)sandy clay loam,moderate medium subangular blocky,friable slightly sticky slightly plastic,many (15-40%) coarse prominent mottles 2.5YR4/8 (red),many fine tubular pores and common medium tubular pores,non calcareous,
Auger 165-440 cm	light grey (10YR 7/2, moist)sandy clay loam,many (15-40%) coarse prominent mottles 2.5YR4/8 (red),non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	fluvial
Remarks on Parent Materials	Sombreiri Warri
Soil Depth	80cm
Texture of parent material	sandy
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	partially or moderately

Occurrence of soil aggradation (McDonald et al., 1984)	not apparent
Slope stability	stable

Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Savanna
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	2m
Physiographic Unit	depression
Physiographic position of the site	depression
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	delta
Slope	0%
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	poor
Flooding frequency (FAO, 1986)	yearly
(Estimated) maximum (lower) depth to groundwater table	500cm
Depth to groundwater table	220cm
Kind of ground water table (USDA, 1979)	groundwater table observed
(Estimated) minimum (upper) depth to groundwater table	45cm
Moist From - To	0-180cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	ponded
Drainage class - intergrade; FAO (2006) - Guidelines for soil description	imperfect
Wet From To	180-440cm

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 15: Acrisol

Characteristics

Reference soil NG015: Acrisols

Classification