Reference soil Cuba 18: Vertisol

CU018

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 CU018: Vertisols

Short field description: Very deep, moderately well to well drained, dark yellowish brown clay derived from alluvium. Small slickensides are present in the subsoil. Geology: Holocene silty clay and alluvials sands. Geomorphology: alluvial plain and terrace, eroded and hilly.

Classification

WRB 2006

WRB 1998

Mollic- Vertisol (Calcaric Humic)

Eutric- Vertisol

25-45 cm	cambic horizon
45-115 cm	vertic horizon
-	calcaric

0-25 cm	mollic horizon
25-45 cm	cambic horizon
45-115 cm	vertic horizon
-	calcaric

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Molli-Eutric Vertisol

Chromic Vertisol

0-25 cm	mollic A horizon
25-150 cm	cambic B horizon
- cm	cambic B horizon
- cm	mollic A horizon
-	slickensides
-	vertic

0-25 cm	mollic A horizon
25-150 cm	cambic B horizon
-	slickensides
-	vertic

Local classification:	Aluvial diferenciado

Other classification

USDA-SCS (1975)

Haplustoll 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
0-25	-	0.5	0.5	1.6	12.3	10.0	24.9	12.8	21.8	34.6	40.6
25-45	-	0.0	0.2	0.8	9.5	9.2	19.7	16.5	16.5	33.0	47.3
45-80	-	0.0	0.1	0.4	6.6	10.2	17.3	14.3	20.8	35.1	47.6
80-115	-	0.1	0.2	1.1	13.5	12.6	27.5	15.8	23.3	39.1	33.6
115-150	-	0.0	0.5	2.2	6.8	6.8	16.3	11.4	24.6	36.0	47.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-25	-	-	-	10.3	40.6
0-20	1.450	-	-	-	-
20-40	1.430	-	-	-	-
25-45	-	-	-	18.9	47.3
45-80	1.520	-	-	28.2	47.6
80-115	1.570	-	-	13.9	33.6
115-150	-	-	-	26.4	47.7

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	1.450	44.9	44.5	43.3	41.3	40.3	39.1	34.2	26.3
20-40	1.430	45.3	45.1	44.2	43.0	42.6	41.7	34.1	29.5
45-80	1.520	46.9	46.9	46.4	44.8	44.3	43.2	35.8	28.6
80-115	1.570	43.9	43.9	43.1	41.2	40.1	38.5	33.9	27.6

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
0-25	7.7	6.8	0.22	4.0	1.53	0.03	51	-	-	41.5	5.6	0.7	0.4	48.2
25-45	6.7	5.2	0.10	2.4	0.86	0.11	8	-	-	26.1	6.0	0.5	0.6	33.2
45-80	6.7	5.3	0.14	3.6	0.35	0.06	6	-	-	33.2	7.5	0.4	1.1	42.2
80-115	8.4	6.0	0.21	3.0	0.17	0.04	4	-	-	33.5	7.4	0.4	1.6	42.9
115-150	8.2	6.1	0.21	4.6	0.07	0.04	2	-	-	33.6	9.6	0.6	2.3	46.1

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 %
0-25	149	32.4	72	5.4	-	-	1
25-45	104	31.8	63	3.0	-	-	2
45-80	108	38.9	83	1.2	-	-	3
80-115	116	37.0	112	0.6	-	-	4
115-150	115	40.2	88	0.2	-	-	6

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-25	-	weak	-	-	-	-	medium to strong	weak	-	very weak	very strong	-
25-45	-	very weak	-	-	-	-	medium to strong	weak	-	-	very strong	-
45-80	-	weak	-	-	-	-	medium to strong	weak	-	-	very strong	-
80-115	-	very weak	-	-	-	-	medium to strong	weak	-	-	very strong	-
115-150	-	very weak	-	-	-	-	medium to strong	weak	-	very weak	very strong	-

Profile description

Ap 0-25 cm	very dark greyish brown (10YR 3/2, moist)clay loam,strong medium subangular blocky,slightly hard slightly sticky non plastic,continuous thin humus throughout cutans,common fine pores and few pores highly porous (>60 vol%),no inclusions,no fragments,few worm channels and channels,gradual irregular boundary to,
25-45 cm	dark greyish brown (10YR 4/2, moist)clay loam,moderate medium and coarse subangular blocky,firm slightly sticky slightly plastic,patchy thin slickensides throughout cutans,common fine pores and few pores highly porous (>60 vol%),no inclusions,no fragments,few worm channels and channels,clear irregular boundary to,
Bi1 45-80 cm	dark yellowish brown (10YR 4/4, moist)clay loam,moderate medium wedge-shaped angular blocky to moderate fine and medium crumb,friable slightly sticky slightly plastic,patchy thin slickensides throughout cutans,common fine pores moderately porous (40-60 vol%),no inclusions,no fragments,gradual smooth boundary to,
Bi2 80-115 cm	dark yellowish brown (10YR 4/4, moist)loam,moderate medium subangular blocky,friable sticky plastic,continuous moderately thick slickensides throughout cutans,common medium pores and common pores moderately porous (40-60 vol%),no inclusions,no fragments,gradual smooth boundary to,
115-150 cm	dark yellowish brown (10YR 3/4, moist)clay,moderate fine and medium subangular blocky,firm sticky plastic,no cutans,few fine pores slightly porous (<40 vol%),no inclusions,no fragments,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	fluvial
Remarks on Parent Materials	Holocene silty clay and alluvial sands
Soil Depth	150cm
Texture of parent material	loamy

Major crops	sugar cane
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	seasonally irrigated
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	100m
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.	stagnant alluvial plain
Slope	0%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Dry From - To	0-25cm
Flooding frequency (FAO, 1986)	irregular
Nature of flood water	fresh
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	25-150cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	slow

Evidence of alkali ; Soil Survey Manual USDA, 1951	slightly alkaline
Surface cracking	small cracks (width less than 1 cm, or depth less 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 18: Vertisol

Characteristics

Reference soil CU018: Vertisols

Classification