Reference soil Botswana 07: Luvisol

BW007

Luvisols occur mainly in temperate regions, particularly in areas with a Mediterranean-type of climate.

Characteristics

Soils having an argic horizon (a subsurface horizon with a distinct higher clay content than the overlying horizon) with a cation exchange capacity equal to or more than 24 cmolc per kg clay throughout.

Distribution of Luvisols (rough estimation supplied by soilgrids)

Reference soil BW007: Luvisols

A moderately deep, moderately well drained reddish brown to yellowish red sandy loam with an apreciable amount of coarse fragments of a weak structural development and gradual horizonation, from 87 cm onwards underlain by a plinthite horizon in which coarse prominent red mottles occur from 87-100 cm.

Classification

WRB 2006

WRB 1998

Stagnic- Luvisol (Ferric Rhodic)

Rhodi-Endostagnic- Luvisol

55-87 cm	argic horizon
87-115 cm	plinthic horizon
87-115	stagnic colour pattern
87-115	reducing conditions

0-35 cm	ochric horizon
55-87 cm	argic horizon
87-115 cm	plinthic horizon
87-115 cm	ferric horizon
87-115	stagnic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Plinthi-Ferric Luvisol

Luvic Xerosol

0-35 cm	ochric A horizon
55-87 cm	argic B horizon
87-115	plinthite

0-35 cm	ochric A horizon
55-87 cm	argillic B horizon
87-115	plinthite

Other classification

USDA-NRCS (1999)	Aridic Haplustept ustic sandy siliceous hyperthermic
USDA-SCS (1975)	Aridic Ustochrept ustic sandy mixed hyperthermic

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
0-17	0	3.6	9.1	13.2	34.1	20.3	80.3	7.1	3.2	10.3	9.3
17-35	0	7.2	11.1	12.1	28.3	23.7	82.4	5.7	3.1	8.8	8.8
35-55	0	7.5	13.3	14.0	31.0	16.5	82.3	6.2	2.1	8.3	9.5
55-70	0	10.3	15.3	16.4	22.6	16.7	81.3	5.1	2.6	7.7	11.0
70-115	74	16.0	16.4	18.8	17.1	9.4	77.7	6.0	4.2	10.2	12.3

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-17	-	-	-	-	9.3
17-35	-	-	-	-	8.8
35-55	-	-	-	-	9.5
55-70	-	-	-	-	11.0
70-115	-	-	-	-	12.3

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
0-17	6.4	5.7	0.19	-	0.38	0.04	10	-	-	1.6	0.7	0.3	0.2	2.8
17-35	6.1	5.3	0.11	-	0.44	0.02	22	-	-	1.4	0.7	0.3	0.1	2.5
35-55	5.9	5.0	0.1	-	0.24	0.02	12	-	-	1.0	0.6	0.3	0.2	2.1
55-70	5.4	4.6	0.09	-	0.18	0.01	18	-	-	0.6	0.6	0.3	0.1	1.6
70-115	5.7	5.1	0.12	-	0.21	0.03	7	-	-	1.2	1.0	0.2	0.1	2.5

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 %
0-17	80	3.5	38	1.3	-	-	6
17-35	76	3.3	38	1.5	-	-	3
35-55	78	2.7	28	0.8	-	-	7
55-70	52	3.1	28	0.6	-	-	3
70-115	58	4.3	35	0.7	-	-	2

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
0-17	47.0	26.9	8.8	0.02	0.87	2.29	0.16	1.44
17-35	46.9	27.0	8.9	0.01	0.82	2.24	0.15	1.41
35-55	45.6	28.0	9.0	0.02	0.82	2.13	0.12	1.39
55-70	46.3	29.2	8.9	0.01	0.74	1.96	0.14	1.31
70-115	44.7	28.7	8.8	0.01	0.74	1.81	0.10	1.23

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
0-17	0.05	0.27	11.2	99	3	14.2	2.5	4.8
17-35	0.04	0.31	11.2	98.98	2.9	14	2.4	4.8
35-55	0.04	0.17	11.3	98.59	2.8	13.5	2.3	4.9
55-70	0.03	0.14	11.5	100.23	2.7	13.8	2.3	5.1
70-115	0.05	0.10	11.8	98.04	2.6	13.5	2.2	5.1

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
0-17	7.4	0.06	1.5	3.58	0.11	-	83.2	0.30
17-35	6.9	0.05	1.5	3.61	0.07	-	84.8	0.31
35-55	7.2	0.03	1.7	3.39	0.13	-	83.1	0.25
55-70	7.5	0.04	2.0	3.44	0.10	-	84.1	0.35
70-115	8.7	0.05	5.5	3.89	0.09	-	76.1	0.27

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
0-17	7.7	1.7	0.01	0.01	19.1	147.4	16.9
17-35	7.2	1.7	0.01	0.02	20.9	150.2	18.3
35-55	6.6	1.7	0.00	0.01	19.6	129.9	17
55-70	5.9	1.9	0.00	0.01	19	111.8	16.3
70-115	2.5	2.5	0.00	0.01	14.8	36.8	10.6

Profile description

Ah 0-17 cm	dark reddish brown (5YR 3/4, moist) (dark) brown (7.5YR 4/4, dry)sandy loam,fine subangular blocky,hard friable non sticky non plastic,common tubular pores,non calcareous,gradual smooth boundary to,
BA 17-35 cm	dark reddish brown (5YR 3/4, moist) (dark) brown (7.5YR 4/4, dry)sandy loam,structureless,hard friable non sticky non plastic,common fine tubular pores,non calcareous,gradual smooth boundary to,
Bw1 35-55 cm	reddish brown (5YR 4/4, moist) yellowish red (5YR 5/6, dry)sandy loam,structureless,slightly hard firm non sticky non plastic,common fine tubular pores,non calcareous,gradual smooth boundary to,
Bw2 55-70 cm	yellowish red (5YR 4/6, moist) yellowish red (5YR 5/6, dry)sandy loam,structureless,slightly hard friable non sticky non plastic,common fine tubular pores,non calcareous,gradual smooth boundary to,
70-87 cm	strong brown (7.5YR 4/6, moist) strong brown (7.5YR 5/6, dry)sandy loam slightly gravelly,structureless,slightly hard friable slightly sticky slightly plastic,few fine gravel quartz fragments,non calcareous,clear smooth boundary to,
Cv1 87-100 cm	yellowish brown (10YR 5/4, moist) light yellowish brown (10YR 6/4, dry)sandy loam gravelly,massive,hard firm non sticky non plastic,coarse prominent mottles (2.5YR 4/8),plinthite pan,non calcareous,clear smooth boundary to,
Cv2 100-115 cm	brown (10YR 5/3, moist) (10YR 6/5, dry)loamy sand gravelly,few (2-5%) fine prominent mottles (5YR 4/8) and few (2-5%) coarse mottles,plinthite,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	igneous rock
Remarks on Parent Materials	Granite from Basement Complex

Major crops	cereals (unspecified)
Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	land clearing
Land use or vegetation in the immediate vicinity of the site	low level arable farming
Remarks on Land Use / Vegetation	Savanna, Acacia Mixed Woodland
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	semi-deciduous woodland

Altitude	980m
Physiographic position of the site	upper slope
Slope	4%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

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)	levees (artificial)
Microrelief pattern	reticulate
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline

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Reference soil Botswana 07: Luvisol

Characteristics

Reference soil BW007: Luvisols

Classification