Reference soil Nigeria 27: Lixisol

NG027

Lixisols occur dominantly in the drier parts of the tropics and subtropics. Their high base status is partly due to less leaching, partly to admixture from airborne dust from adjacent desert regions.

Characteristics

Soils having an argic horizon (a subsurface horizon with a 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 either: 100 cm from the soil surface, or 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 50 percent or more in the major part between 25 and 100 cm from the soil surface.

Distribution of Lixisols (rough estimation supplied by soilgrids)

Reference soil NG027: Lixisols

Lixisol

Classification

WRB 2006

WRB 1998

Petroplinthic- Lixisol (Hypereutric Rhodic)

Rhodi-Endopetroplinthic- Lixisol

10-80 cm	argic horizon
80-97 cm	petroplinthic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Rhodi-Haplic Lixisol petroferric

Ferric Luvisol petric

0-10 cm	ochric A horizon
10-80 cm	argic B horizon
-	plinthite

0-10 cm	ochric A horizon
10-80 cm	argillic B horizon
-	ferric

Local classification:	Shepeteri Series

Other classification

USDA-SCS (1975)

Rhodustalf ustic sandy over clayey 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	-	5.6	6.1	11.6	17.7	12.2	53.2	8.1	13.9	22	25.0
10-25	-	16.7	10.7	10.4	12.4	6.5	56.7	7.1	5.4	12.5	30.9
25-55	-	18.0	11.8	9.9	10.7	7.3	57.7	7.5	3.5	11	31.4
55-80	-	16.9	10.5	9.6	11.3	6.1	54.4	4.9	4.9	9.8	36.0
80-97	-	15.5	12.9	10.8	11.2	7.3	57.7	6.1	5.1	11.2	31.1

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	-	-	-	14.3	25.0
10-25	-	-	-	15.5	30.9
25-55	-	-	-	2.0	31.4
55-80	-	-	-	16.9	36.0
80-97	-	-	-	7.4	31.1

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	7.4	7.2	0.40	3.1	1.77	0.12	15	-	-	36.6	4.5	0.8	0.4	42.3
10-25	5.4	4.6	0.13	-	0.82	0.07	12	0.1	0.0	3.3	2.0	0.3	0.0	5.6
25-55	5.0	4.2	0.04	-	0.43	-	-	0.7	0.5	2.0	0.7	0.1	0.2	3
55-80	5.1	4.3	0.04	-	0.44	-	-	0.4	0.2	2.9	1.0	0.1	0.0	4
80-97	5.2	4.7	0.02	-	0.19	-	-	0.3	0.0	2.3	0.7	0.1	0.1	3.2

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 %
0-10	196	21.6	86	6.2	-	-	2
10-25	72	7.8	25	2.9	-	0	0
25-55	50	6.0	19	1.5	-	8	3
55-80	56	7.1	20	1.5	-	3	0
80-97	52	6.1	20	0.7	-	0	2

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-10	-	-	-	weak	-	-	strong to very strong	weak to medium	very weak	-	-	-
10-25	-	-	-	weak	-	-	strong	weak	very weak to weak	-	-	-
25-55	-	-	-	weak	-	-	medium to strong	very weak to weak	very weak to weak	-	-	-
55-80	-	-	-	weak	-	-	medium to strong	very weak to weak	very weak to weak	-	-	-
80-97	-	-	-	weak	-	-	weak to medium	very weak to weak	weak	-	-	-

Profile description

Ap 0-10 cm	reddish black (10R 2.5/1, dry)sandy loam,moderate fine subangular blocky,friable slightly sticky non plastic,many medium discontinuous exped interstitial random pores,many fine roots,very few small spherical hard ferruginous concretions,moderately calcareous (2-10%),clear smooth boundary to,
Bt1 10-25 cm	dusky red (10R 3/4, dry)sandy clay loam,moderate medium subangular blocky,slightly sticky non plastic,many fine discontinuous exped interstitial horizontal pores,many fine roots,few small irregular hard ferruginous concretions,non calcareous,clear wavy boundary to,
Bt2 25-55 cm	dark red (10R 3/6, dry)sandy clay,moderate medium subangular blocky,slightly sticky slightly plastic,many fine discontinuous exped tubular horizontal pores,many fine roots,few small irregular hard ferruginous concretions,non calcareous,diffuse wavy boundary to,
Bt3 55-80 cm	dark red (10R 3/6, dry)sandy clay,moderate medium subangular blocky,slightly sticky slightly plastic,many fine discontinuous inped interstitial random pores,many fine roots,very few small spherical hard ferruginous concretions,non calcareous,diffuse smooth boundary to,
Btocm 80-97 cm	red (10R 4/6, dry)sandy clay,moderate medium subangular blocky,slightly sticky slightly plastic,few fine continuous inped tubular vertical pores,many fine roots,very few small spherical hard ferruginous concretions,continuous pisolitic indurated plinthite,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	coarse-grained igneous rock
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	parent rock: granite
Soil Depth	97cm
Texture of parent material	sandy clay
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	maize
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	low level arable farming
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	shifting - fallow grass
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)	deciduous woodland

Altitude	400m
Physiographic Unit	slope
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.	low hill
Slope	1%
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	well
Dry From - To	0-97cm
Flooding frequency (FAO, 1986)	never
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 27: Lixisol

Characteristics

Reference soil NG027: Lixisols

Classification