Reference soil India 12: Vertisol

IN012

Vertisols occur dominantly in level landscapes under climates with a pronounced dry season. Vast areas are found in Australia, India, northeastern Africa (Sudan, Ethiopia), southern Latin America and the USA.

Characteristics

Soils having a vertic horizon (a clayey subsurface horizon with polished and grooved ped surfaces ("slickensides") or wedge-shaped or parallelepiped structural aggregates) within 100 cm from the soil surface. They have 30 percent or more clay in all horizons to a depth of 100 cm or more, or to a contrasting layer (lithic or paralithic contact, petrocalcic, petroduric or petrogypsic horizons, sedimentary discontinuity, etc.) between 50 and 100 cm, after the upper 20 cm have been mixed. In addition, Vertisols exhibit wide cracks, which open and close periodically.

Distribution of Vertisols (rough estimation supplied by soilgrids)

Reference soil IN012: Vertisols

Deep, imperfectly drained, very dark grayish brown clayey soil derived from basalt with deep, wide cracks during the dry season, gilgai surface features, prominent slickensides and accumulation of calcium carbonates. The profile is located on level land with gradual slope (0-1%) towards the east.

Classification

WRB 2014

Vertisol

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Calcic Vertisol gilgai

Chromic Vertisol

- cm	calcic horizon
- cm	cambic B horizon
- cm	ochric A horizon
-	slickensides

- cm	calcic horizon
- cm	cambic B horizon
- cm	ochric A horizon
-	gilgai microrelief
-	slickensides

Local classification:	Medium black soil

Other classification

USDA-NRCS (1999)	Udic Calciustert
USDA-SCS (1975)	Udic Chromustert ustic fine montmorillonitic 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
0-32	-	0.2	0.5	0.7	1.7	1.8	4.9	12.4	32.7	45.1	50
32-48	-	0.2	0.7	0.4	1.2	2.3	4.8	13.1	48.3	61.4	33.8
48-60	-	3.4	7.8	3	1.9	2.4	18.5	17.6	37.3	54.9	26.6
60-135	-	1.1	5.4	2.9	3.7	4.1	17.2	14.5	39.7	54.2	28.6

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-32	-	-	-	-	50
32-48	-	-	-	-	33.8
48-60	-	-	-	-	26.6
60-135	-	-	-	-	28.6

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
0-32	7.8	6.6	0.44	0.6	-	-	-	-	-	65.2	10.6	0.5	0.1	76.4
32-48	8.0	6.7	0.34	30.1	-	-	-	-	-	52.8	15.0	0.3	0.3	68.4
48-60	8.2	6.9	0.32	28.1	-	-	-	-	-	43.3	15.7	0.3	0.3	59.6
60-135	8.1	6.9	0.35	28.5	-	-	-	-	-	39.3	18.3	0.3	0.8	58.7

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 %
0-32	119	64.4	129	-	-	-	-
32-48	112	60.9	180	-	-	-	-
48-60	111	53.9	203	-	-	-	-
60-135	109	53.9	188	-	-	-	-

Profile description

Ah 0-32 cm	very dark greyish brown (10YR 3/2, dry)silty clay,moderate coarse angular blocky,very hard very firm sticky plastic,moderately porous (40-60 vol%),
Bkci1 32-48 cm	dark brown (10YR 3/3, dry) very dark greyish brown (10YR 3/2, moist)clay,moderate medium angular blocky,very hard very firm sticky plastic,continuous slickensides on pedfaces cutans,slightly porous (<40 vol%),frequent medium irregular hard calcareous concretions,
Bkci2 48-60 cm	very dark greyish brown (10YR 3/2, dry) very dark greyish brown (10YR 3/2, moist)clay,moderate medium subangular blocky,very hard firm sticky plastic,continuous slickensides cutans,slightly porous (<40 vol%),frequent irregular hard calcareous concretions,wavy boundary to,
BCkci 60-135 cm	dark brown (10YR 3/3, dry)clay loam,massive to weak coarse subangular blocky,hard firm sticky plastic,continuous slickensides on pedfaces cutans,slightly porous (<40 vol%),frequent irregular hard calcareous concretions,few strongly weathered basalt fragments,

Kind 1 (parent material) ; Parker (eds), 1984	fine-grained basic igneous rock
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	basalt
Soil Depth	120cm
General characterization of the status of weathering of solid rock	highly

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

Land use or vegetation in the immediate vicinity of the site	cultivated pasture
Remarks on Land Use / Vegetation	Acacia catechu, Acacia arabica

Altitude	300m
Physiographic Unit	gentle slope
Physiographic position of the site	flat
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plateau
Slope	1%
Slope Aspect	east
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	imperfect
Dry From - To	0-135cm
Flooding frequency (FAO, 1986)	never
(Estimated) maximum (lower) depth to groundwater table	700cm
Depth to groundwater table	600cm
Kind of ground water table (USDA, 1979)	groundwater table observed
(Estimated) minimum (upper) depth to groundwater table	600cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	medium

Evidence of alkali ; Soil Survey Manual USDA, 1951	slightly alkaline
Surface cracking	large cracks (width more than 1 cm, or depth more than 50 cm)
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	gilgai
Microrelief pattern	reticulate
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 India 12: Vertisol

Characteristics

Reference soil IN012: Vertisols

Classification