Reference soil Cuba 21: Vertisol

CU021

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 CU021: Vertisols

Short field description: Deep, imperfectly drained, yellowish brown clay. Large cracks when dry, moderately, (sub)angular blocky structure, presence of calcareous conglomerates. Third and fourth horizon are very hard. The inclusions in the first and second horizon are gravels. Geology: mid-lower Miocene, clays, sands, marls, limestones and conglomerate. Geomorphology: marine plain and terrace, abrasive, slightly undulating and plain.

Classification

WRB 2006

WRB 1998

Calcic-Stagnic-Sodic- Vertisol (Manganiferric)

Hyposodi-Calcic- Vertisol

27-95 cm	vertic horizon
27-95 cm	calcic horizon

0-27 cm	ochric horizon
27-95 cm	ferric horizon
27-95 cm	vertic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Sodi-Calcic Vertisol sodic

Chromic Vertisol sodic

0-27 cm	ochric A horizon
27-95 cm	calcic / cambic B horizon
- cm	ochric A horizon
- cm	cambic B horizon
-	slickensides
-	sodic
-	vertic

0-27 cm	ochric A horizon
27-95 cm	calcic / cambic B horizon
-	ferric
-	slickensides
-	vertic

Local classification:	Oscuro plastico gleysoso gris

Other classification

USDA-NRCS (1999)	Sodic Haplustert
USDA-SCS (1975)	Sodic Chromustert ustic clayey 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
0-27	-	5.3	5.2	4.6	5.3	3.7	24.1	7.0	15.9	22.9	53.0
27-75	-	3.6	4.4	4.2	5.1	3.0	20.3	3.1	16.2	19.3	60.3
75-95	-	1.1	1.8	2.4	3.8	2.6	11.7	1.7	21.9	23.6	64.8
95-150	-	0.1	0.1	0.2	0.5	1.1	2	3.0	27.3	30.3	67.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-27	-	-	-	42.2	53.0
15-20	1.220	-	-	-	-
27-75	-	-	-	41.8	60.3
25-40	1.340	-	-	-	-
65-70	1.35	-	-	-	-
75-95	-	-	-	38.4	64.8
95-150	-	-	-	37.5	67.7

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
15-20	1.220	52.1	51.8	50.7	49.9	48.5	47.8	39.0	31.8
25-40	1.340	50.6	50.4	48.2	46.8	45.6	45.0	42.7	33.2
65-70	1.35	50.6	50.4	49.2	48.2	46.8	46.1	42.9	33.3

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
0-27	8.1	7.2	0.29	7.0	1.60	0.21	8	-	-	60.9	7.5	1.0	0.6	70.0
27-75	8.7	7.2	0.36	15.0	0.32	0.04	8	-	-	56.0	11.0	0.4	4.7	72.1
75-95	9.0	7.3	0.72	18.4	0.19	0.03	6	-	-	53.9	12.8	0.4	11.2	78.3
95-150	8.8	7.2	1.20	13.0	0.06	0.03	2	-	-	47.9	12.6	0.4	19.0	79.9

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 %
0-27	141	49.7	93	5.6	-	-	1
27-75	159	45.3	87	1.1	-	-	10
75-95	178	44.1	83	0.7	-	-	25
95-150	174	45.9	78	0.2	-	-	41

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-27	-	-	-	weak	-	-	medium to strong	-	-	weak	very strong	-
27-75	-	-	-	weak	-	-	medium to strong	-	-	weak	very strong	-
75-95	-	-	-	weak	-	-	medium to strong	-	-	weak	very strong	-
95-150	-	-	-	weak	-	-	medium to strong	-	-	weak	very strong	-

Profile description

Ap 0-27 cm	brown (10YR 5/3, moist)clay,moderate fine subangular blocky,slightly sticky slightly plastic,no cutans,few fine pores and few pores slightly porous (<40 vol%),very frequent large irregular hard calcareous unspecified inclusions,no fragments,frequent channels,clear irregular boundary to,
Bi 27-75 cm	yellowish brown (10YR 5/4, moist)clay,moderate medium angular blocky and moderate medium prismatic,sticky plastic,common coarse distinct clear mottles (10YR 6/6),patchy distinct slickensides throughout cutans,few medium pores and few pores slightly porous (<40 vol%),very frequent large irregular hard manganiferous unspecified inclusions very frequent large irregular hard calcareous unspecified inclusions,no fragments,frequent channels,gradual wavy boundary to,
75-95 cm	brownish yellow (10YR 6/6, moist)clay,moderate coarse angular blocky and moderate coarse prismatic,sticky plastic,few coarse distinct clear mottles (10YR 5/8),continuous distinct slickensides throughout cutans,common fine pores and common pores moderately porous (40-60 vol%),few medium irregular soft calcareous nodules,no fragments,continuous weakly cemented petroferric pans,gradual irregular boundary to,
Ci 95-150 cm	brownish yellow (10YR 6/8, moist)clay,structureless massive,stony plastic,few distinct clear mottles (10YR 5/8),patchy moderately thick slickensides on pedfaces cutans,few common fine pores slightly porous (<40 vol%),frequent small irregular hard manganiferous concretions,

Kind 1 (parent material) ; Parker (eds), 1984	claystone
Mode of accumulation or deposition of parent material	marine sediments
Remarks on Parent Materials	Mid-early Miocene clays, sands, marl, limestone and conglomerate
Soil Depth	100cm
Texture of parent material	clayey

Intensity of the soil erosion type	slight
Soil erosion type	rill
Slope stability	stable

Major crops	sugar cane
Land use or vegetation in the immediate vicinity of the site	high level arable farming
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	degraded
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	shrub

Altitude	20m
Physiographic Unit	undulating
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.	low hill
Slope	2%
Form of the slope surrounding the site	undulating
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Lower limit of a slow permeable or stagnating layer in the profile	150cm
Drainage class ; FAO (2006) - Guidelines for soil description	imperfect
Flooding frequency (FAO, 1986)	never
Depth to groundwater table	300cm
Kind of ground water table (USDA, 1979)	groundwater table observed
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	medium
Upper limit of a slow permeable or stagnating layer in the profile	120cm
Wet From To	0-150cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	moderately alkaline
Average size of stone	4
Surface cracking	large cracks (width more than 1 cm, or depth more than 50 cm)
Evidence of salt; Soil Survey Manual USDA, 1951	slightly saline
Surface stoniness class (FAO (2006) - Guidelines for soil description)	very few stones

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Reference soil Cuba 21: Vertisol

Characteristics

Reference soil CU021: Vertisols

Classification