Reference soil Cuba 19: Vertisol

CU019

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 CU019: Vertisols

Short field description: Deep, imperfectly drained, very dark brown clay. Large cracks when dry, prismatic angular structure, with presence of slickensides, moderately porous. Geology: Cauto Formation: clays, sandstones, limestones and silt. Geomorphology: fluvio-marine deltaic plain and terrace, plain and slightly undulating.

Classification

WRB 2006

WRB 1998

Mollic- Vertisol (Calcaric Humic Hyposodic)

Hyposodic- Vertisol

26-60 cm	vertic horizon
60-150 cm	calcic horizon
-	calcaric

0-60 cm	mollic horizon
26-60 cm	vertic horizon
60-150 cm	calcic horizon
-	calcaric

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Calcari-Eutric Vertisol sodic

Chromic Vertisol sodic

0-60 cm	mollic A horizon
60-150 cm	cambic B horizon
- cm	ochric A horizon
- cm	cambic B horizon
-	slickensides
-	sodic
-	vertic

0-60 cm	mollic A horizon
60-150 cm	cambic B horizon
-	slickensides
-	vertic

Local classification:	Oscuro plastico gleysoso

Other classification

USDA-NRCS (1999)	Typic Calciustert
USDA-SCS (1975)	Typic 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
0-26	-	0.1	0.2	0.3	2.3	6.8	9.7	14.2	23.6	37.8	52.4
26-60	-	0.1	0.3	0.5	2.5	6.2	9.6	11.6	17.8	29.4	61.0
60-100	-	0.0	0.1	0.3	5.0	10.2	15.6	12.4	22.5	34.9	49.4
100-150	-	0.0	0.1	0.2	7.3	12.3	19.9	18.5	22.8	41.3	38.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-20	1.220	-	-	-	-
0-26	-	-	-	23.9	52.4
26-60	1.3	-	-	34.1	61.0
20-40	1.370	-	-	-	-
40-60	1.300	-	-	-	-
60-100	-	-	-	19.3	49.4
100-150	-	-	-	14.7	38.7

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
0-20	1.220	48.7	48.4	48.6	45.5	43.6	42.7	39.5	31.8
26-60	1.3	49.4	49.4	49.4	49.0	48.0	47.4	46.1	38.4
20-40	1.370	47.6	47.6	47.7	47.1	46.0	45.4	44.2	39.4
40-60	1.300	51.2	51.2	51.2	50.9	50.0	49.4	48.0	37.5

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
0-26	6.3	4.9	0.16	2.0	1.52	0.14	11	-	-	21.1	14.6	0.4	1.2	37.3
26-60	6.6	5.1	0.18	2.6	0.94	0.08	12	-	-	22.4	22.1	0.3	2.2	47.0
60-100	8.6	7.2	0.29	10.8	0.24	0.03	8	-	-	56.3	21.0	0.4	2.8	80.5
100-150	8.7	7.1	0.30	4.8	0.07	0.02	4	-	-	61.1	19.7	0.2	2.9	83.9

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 %
0-26	95	39.1	68	5.3	-	-	3
26-60	96	49.0	78	3.3	-	-	4
60-100	207	38.9	87	0.8	-	-	7
100-150	242	34.6	93	0.2	-	-	6

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-26	-	weak	-	very weak	-	-	medium to strong	-	-	weak	very strong	-
26-60	-	weak	-	weak	-	-	strong	-	-	weak	very strong	-
60-100	-	weak	-	weak	-	-	strong	-	-	weak	very strong	-
100-150	-	weak	-	weak	-	-	medium to strong	-	-	weak	very strong	-

Profile description

Api 0-26 cm	very dark greyish brown (10YR 3/2, moist)clay,strong medium prismatic and strong coarse prismatic,very firm sticky plastic,patchy thin slickensides throughout cutans,few very fine pores and few pores moderately porous (40-60 vol%),very few medium spherical hard manganiferous concretions,no fragments,few channels,gradual irregular boundary to,
Ai 26-60 cm	very dark brown (10YR 2/2, moist)clay,very strong coarse angular blocky,firm very sticky very plastic,patchy moderately thick slickensides throughout cutans,few medium pores and few pores moderately porous (40-60 vol%),very few medium spherical hard manganiferous concretions,clear wavy boundary to,
Bw1 60-100 cm	dark greyish brown (10YR 4/2, moist)clay,moderate coarse subangular blocky,firm slightly sticky slightly plastic,common fine pores and common pores moderately porous (40-60 vol%),very few medium spherical hard manganiferous concretions,gradual irregular boundary to,
Bw2 100-150 cm	dark yellowish brown (10YR 4/4, moist)clay loam,moderate medium subangular blocky,friable slightly sticky slightly plastic,common fine pores and common pores moderately porous (40-60 vol%),very few medium spherical 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	Cauto Formation, clays sandstone, limestone and silt
Soil Depth	150cm
Texture of parent material	clayey

Major crops	sugar cane
Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	levelling
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)	secondary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	semi-deciduous shrub

Altitude	60m
Physiographic Unit	flat or almost flat
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.	peneplain
Slope	0%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Lower limit of a slow permeable or stagnating layer in the profile	60cm
Drainage class ; FAO (2006) - Guidelines for soil description	imperfect
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-150cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	slow
Upper limit of a slow permeable or stagnating layer in the profile	30cm

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)
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 Cuba 19: Vertisol

Characteristics

Reference soil CU019: Vertisols

Classification