Reference soil Nigeria 09: Alisol

NG009

Alisols occur in the tropics and subtropics, and in the warm temperate regions of the world in relatively young landscapes. The high level of exchangeable aluminium in these soils is caused by rapid weathering of secondary high-activity clays such as vermiculite and smectite.

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 24 cmolc per kg clay or more, and which starts either 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 "alic" properties (high content of exchangeable aluminium) in the major part between 25 and 100 cm from the soil surface; moreover, only such diagnostic horizons as an ochric, albic, andic, ferric, nitic, plinthic, or vertic horizon are present.

Distribution of Alisols (rough estimation supplied by soilgrids)

Reference soil NG009: Alisols

Brief description on the profile: A deep reddish clayey soil with a thin blackish sandy surface horizon. Structure weak, fine subangular blocky down to 26 cm, strong fine subangular blocky below.From 50-145 cm clay cutans. Many (sub)rounded hard Fe/Mn nodules down to 145 cm, generally less than 1 cm across. Clay minerals are predominantly kaolinite. Location: Roadside cut, E of Ago-Are-Kishi road, 300 m S of MP 29 from Kishi. Physiographic unit: Part of a low ridge close to a subsidiary crest grading towards a U shaped valley. No recent shifting cultivation. Base saturation is >35% within critical depth. INRA classification: Sol ferrugineux tropical lessive a concretions Additional notes on the profile description: B1cn: Some ferruginized schist fragments. 2B2tcn(original designation): Prominent stress cutans around gravels and saprolithic in patches with yellowish streaks; few ferruginized schist fragments. 2B3: Yellowish and brownish mottles and streaks; soft saprolite without rock structure; pseudomorphs of feldspar. Climate data source: Agroclimatological data Africa 1, FAO. Rome 1987

Classification

WRB 2006

WRB 1998

Pisoplinthic-Cutanic- Alisol (Profondic Chromic)

Chromi-Profondic- Luvisol (Dystric)

26-145 cm

argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Haplic Alisol skeletic

Orthic Acrisol petric

0-26 cm	ochric A horizon
26-145 cm	argic B horizon

0-26 cm	ochric A horizon
26-145 cm	argillic B horizon
-	ferric

Local classification:	Sepeteri Series

Other classification

USDA-SCS (1975)

Paleustalf ustic loamy-skeletal over clayey mixed isohyperthermic

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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	24	6.7	6.6	15.3	25.3	20.7	74.6	10.1	5.7	15.8	9.6
15-26	66	10.8	9.2	19.5	22.3	16.1	77.9	7.5	4.8	12.3	9.8
26-46	69	14.1	11.6	18.2	16.7	14.0	74.6	7.5	4.9	12.4	12.9
46-100	61	18.1	11.1	12.0	11.3	9.1	61.6	8.2	3.5	11.7	26.7
100-125	39	23.5	11.3	9.4	9.8	6.7	60.7	7.5	4.6	12.1	27.2
125-145	39	17.7	9.0	8.8	10.6	8.3	54.4	10.1	4.9	15	30.7

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	-	-	-	-	9.6
15-26	-	-	-	-	9.8
26-46	-	-	-	-	12.9
46-100	-	-	-	-	26.7
100-125	-	-	-	-	27.2
125-145	-	-	-	-	30.7

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	6.3	5.5	0.11	-	1.49	0.09	17	-	-	7.5	2.4	0.2	0.7	10.8
15-26	6.1	5.2	0.04	-	0.53	0.05	11	-	-	1.2	0.3	0.1	0.0	1.6
26-46	5.5	4.3	0.02	-	0.25	0.03	8	-	-	1.8	0.7	0.1	0.6	3.2
46-100	5.7	4.3	0.01	-	0.26	0.03	9	-	-	1.5	0.7	0.1	0.0	2.3
100-125	5.6	4.5	0.01	-	0.29	0.04	7	-	-	1.9	1.0	0.1	0.0	3
125-145	5.6	4.5	0.01	-	0.24	0.04	6	-	-	2.1	7.3	0.1	0.4	9.9

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	85	12.7	132	5.2	-	-	6
15-26	23	7.0	71	1.9	-	-	0
26-46	35	9.2	71	0.9	-	-	7
46-100	26	8.9	33	0.9	-	-	0
100-125	29	10.5	39	1.0	-	-	0
125-145	97	10.2	33	0.8	-	-	4

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
0-15	41.4	30.3	11.1	0.25	0.43	0.87	-	1.31
15-26	40.2	31.0	11.6	0.05	0.40	0.85	-	1.42
26-46	39.6	31.5	11.2	0.04	0.40	0.82	-	1.35
46-100	39.8	33.4	11.2	0.01	0.38	0.66	-	1.13
100-125	39.5	34.0	10.6	0.04	0.30	0.58	-	0.99
125-145	40.4	34.4	10.4	0.03	0.29	0.56	-	0.98

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
0-15	0.12	0.28	13.0	99.06	2.3	9.9	1.9	4.3
15-26	0.10	0.19	12.4	98.21	2.2	9.2	1.8	4.2
26-46	0.05	0.18	12.5	97.64	2.1	9.4	1.7	4.4
46-100	0.04	0.16	13.1	99.88	2	9.4	1.7	4.7
100-125	0.03	0.11	13.4	99.55	2	9.9	1.6	5
125-145	0.03	0.10	13.2	100.39	2	10.3	1.7	5.2

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	6.2	0.20	6.6	0.44	0.08	-	82.4	0.84
15-26	7.0	0.06	7.5	0.41	0.01	-	82.5	0.83
26-46	20.1	0.04	18.9	0.26	0.16	-	50.7	0.75
46-100	21.1	0.04	17.5	0.33	0.01	-	51.4	0.82
100-125	20.6	0.04	19.1	0.33	0.02	-	49.6	0.78
125-145	21.0	0.04	17.2	0.33	0.12	-	51.0	0.80

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	1.5	4.7	0.07	0.05	22.6	33.2	13.4
15-26	1.5	3.5	0.06	0.03	20	29.3	11.9
26-46	1.7	9.2	0.04	0.05	4.3	7.1	2.7
46-100	1.9	9.2	0.04	0.04	4.1	7.8	2.7
100-125	1.7	9.5	0.04	0.05	4.1	6.9	2.6
125-145	1.9	9.3	0.04	0.04	4.1	7.9	2.7

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	very weak to weak	very weak to weak	-	-	strong	very weak to weak	very weak to weak	very weak to weak	-	-
15-26	-	-	very weak to weak	very weak to weak	-	-	strong	very weak to weak	very weak to weak	very weak to weak	-	-
26-46	-	-	very weak to weak	very weak to weak	-	-	strong	very weak to weak	very weak to weak	very weak to weak	-	-
46-100	-	-	very weak to weak	very weak to weak	-	-	very strong	weak	very weak to weak	very weak to weak	-	-
100-125	-	-	very weak to weak	very weak to weak	-	-	very strong	very weak to weak	very weak to weak	very weak to weak	-	-
125-145	-	-	very weak to weak	very weak to weak	-	-	very strong	very weak to weak	very weak to weak	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
0-15	3.8	-	96.2	72	2	98
15-26	5.6	-	94.4	86	-	100
46-100	14.8	-	85.2	87	-	100

Minerals

Depth (cm)	Anatase % w/w	Andalusite % w/w	Apatite % w/w	Augite % w/w	Biotite % w/w	Hornblende (basaltic) % w/w
0-15	-	2	-	-	-	3
15-26	-	2	-	-	-	1
46-100	-	-	-	-	-	1

Depth (cm)	Brookite % w/w	Chloritic % w/w	Disthene % w/w	Epidote % w/w	Garnet % w/w	Glaucophane % w/w
0-15	-	-	-	11	-	-
15-26	-	-	-	9	-	-
46-100	-	-	-	6	-	-

Depth (cm)	Grenate % w/w	Grossular % w/w	Muscovite % w/w	Rutile % w/w	Sillimanite % w/w	Spinel % w/w
0-15	-	-	-	-	1	-
15-26	-	-	-	1	1	-
46-100	-	-	-	1	6	-

Profile description

Ah 0-10 cm	(dark) brown (7.5YR 4/2, dry) very dark brown (7.5YR 2/2, moist)slightly gravelly medium sandy loam,very weak fine subangular blocky parting to weak fine crumb,very friable non sticky non plastic,common fine interstitial pores and many fine inped tubular random pores,many fine roots,frequent small spherical ferruginous nodules and frequent small spherical manganiferous nodules,non calcareous,gradual wavy boundary to,
10-26 cm	reddish brown (5YR 4/3, dry) dark reddish brown (5YR 3/3, moist)very gravelly medium sandy loam,weak fine subangular blocky parting to weak fine crumb,slightly hard very friable non sticky non plastic,common fine interstitial pores and many fine inped tubular random pores,many fine and common medium roots,very frequent medium spherical hard ferruginous nodules and medium spherical hard manganiferous nodules,common gravel subrounded quartz and few medium gravel angular quartz fragments,non calcareous,gradual smooth boundary to,
Boc 26-46 cm	dark reddish brown (5YR 3/4, moist)very gravelly medium sandy loam,moderate fine subangular blocky,friable non sticky non plastic,broken thin cutans on pedfaces,common fine interstitial pores and many fine inped tubular random pores,common fine and few medium roots,very frequent medium spherical hard ferruginous nodules and medium spherical hard manganiferous nodules,few fine gravel subrounded quartz and very few medium gravel strongly weathered angular quartz fragments,non calcareous,gradual smooth boundary to,
Btoc1 46-125 cm	(2.5YR 3.5/6, moist)very gravelly clay loam,moderate to strong fine subangular blocky,firm slightly sticky plastic,broken moderately thick cutans on pedfaces,common fine inped tubular random pores and few medium inped tubular random pores,common fine and few medium roots,very frequent medium spherical hard ferruginous and manganiferous nodules,few fine gravel subrounded quartz and very few medium gravel strongly weathered angular quartz fragments,non calcareous,clear wavy boundary to,
2Btoc2 125-145 cm	(2.5YR 3.5/6, moist)(2.5YR 3.5/6, moist),very gravelly sandy clay,gravelly sandy clay loam,moderate fine angular blocky,moderate to strong fine subangular blocky,firm slightly sticky plastic,very firm slightly sticky slightly plastic,many (15-40%) fine distinct clear mottles and many medium distinct mottles,broken thin cutans,broken moderately thick cutans on pedfaces,common fine inped tubular random pores,common fine inped tubular random pores,few fine and medium roots,few fine roots,medium spherical hard ferruginous and manganiferous concretions,small ferruginous and manganiferous nodules nodules,few fine gravel quartz fragments and few ferruginized schist,fine gravel quartz fragments,few channels,non calcareous,non calcareous,gradual wavy boundary to,

Depth1	46cm
Kind 1 (parent material) ; Parker (eds), 1984	metamorphic rock
Kind 2 (parent material) (second entry); Parker (eds), 1984	metamorphic rock
Mode of accumulation or deposition of parent material	colluvial
Mode of accumulation or deposition of parent material (second entry)	residual material
Remarks on Parent Materials	probably schist
Texture of parent material	loamy
Texture of parent material (second entry)	sandy clay
Weathering Resistance	moderate
Weathering Resistance (second entry)	moderate
General characterization of the status of weathering of solid rock	highly
General characterization of the status of weathering of solid rock (second entry)	highly

Land use or vegetation in the immediate vicinity of the site	(semi-)natural vegetation
Remarks on Land Use / Vegetation	Southern Guinea Savanna grass and shrubs
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	primary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	woodland

Altitude	400m
Physiographic Unit	side slope
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.	low hill
Slope	2%
Slope Aspect	south-south-east
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	moderately well
Dry From - To	0-26cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	26-190cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	medium

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	level
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline

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Reference soil Nigeria 09: Alisol

Characteristics

Reference soil NG009: Alisols

Classification