Reference soil Cuba 20: Vertisol

CU020

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 CU020: Vertisols

Short field description: Deep, imperfectly drained, black clay. Large cracks when dry, subangular to angular structure with presence of slickensides, slightly porous. Geology: Pleistocene. undifferentiated, marine-alluvial deposits. Cauto Formation: sands, clayey sands and guijarros-sands, with intercalation of silt, gravels and guijarros-gravels (colors: grey and greyish yellow). Geomorphology: marine plain and terrace, abrasive-erosive undulating.

Classification

WRB 2006

WRB 1998

Calcic- Vertisol (Albic Humic Hyposodic)

Pelli-Calcic- Vertisol (Hyposodic)

20-65 cm	albic horizon
20-90 cm	vertic horizon
90-150 cm	calcic horizon

0-20 cm	ochric horizon
20-65 cm	albic horizon
20-90 cm	vertic horizon
90-150 cm	calcic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Pelli-Calcic Vertisol sodic

Pellic Vertisol sodic

0-20 cm	ochric A horizon
20-90 cm	cambic B horizon
90-150 cm	calcic horizon
-	slickensides
-	sodic

0-20 cm	ochric A horizon
20-90 cm	cambic B horizon
90-150 cm	calcic horizon
-	slickensides
-	vertic

Local classification:	Oscuro plastico gleysoso negro

Other classification

USDA-NRCS (1999)	Typic Calciustert
USDA-SCS (1975)	Typic Pellustert ustic fine montmorillonitic isohyperthermic

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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
0-20	-	0.8	1.5	3.5	7.5	7.2	20.5	8.7	15.3	24.0	55.5
20-65	-	0.4	1.0	2.5	4.9	4.5	13.3	6.7	15.8	22.5	64.1
65-90	-	0.9	1.9	4.3	8.3	7.8	23.2	15.2	5.5	20.7	56.1
90-117	-	6.8	5.8	5.7	11.5	11.5	41.3	10.7	10.4	21.1	37.5
117-150	-	18.5	14.3	11.0	12.2	6.3	62.3	7.0	5.3	12.3	25.5

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	-	-	-	32.1	55.5
20-65	-	-	-	39.8	64.1
65-90	-	-	-	3.7	56.1
90-117	-	-	-	3.1	37.5
117-150	-	-	-	1.6	25.5

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
0-20	7.5	6.3	0.27	3.8	2.25	0.21	11	-	-	35.3	27.3	0.5	0.8	63.9
20-65	7.9	6.6	1.00	2.6	1.34	0.07	19	0	-	23.4	52.7	0.2	4.1	80.4
65-90	8.1	7.1	1.10	2.6	0.65	0.04	16	-	-	19.0	49.8	0.2	4.7	73.7
90-117	8.9	7.8	0.38	25.6	0.15	0.02	8	-	-	35.3	68.0	0.1	1.6	105.0
117-150	8.9	7.7	0.28	23.4	0.07	0.01	7	-	-	29.8	26.2	0.1	1.1	57.2

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 %
0-20	83	76.7	135	7.9	-	-	1
20-65	149	53.9	81	4.7	-	-	8
65-90	147	50.3	89	2.3	-	-	9
90-117	-	22.5	79	0.5	-	-	7
117-150	-	19.9	101	0.2	-	-	6

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-20	-	-	-	-	-	-	weak	-	weak	-	very strong	-
20-65	-	-	-	-	-	-	weak	-	weak	-	very strong	-
65-90	-	-	-	-	-	-	weak	-	weak	-	very strong	-
90-117	-	-	-	-	-	-	weak	-	weak	-	very strong	-
117-150	-	-	-	-	-	-	weak	-	weak	-	very strong	-

Rare clay minerals

Depth (cm)	Boehmite	Cristobalite	Jarosite	Nordstrandite	Palygorskite	Septechlorite
0-20	-	-	-	-	weak	-
20-65	-	-	-	-	medium to strong	-
65-90	-	-	-	-	medium to strong	-
90-117	-	-	-	-	medium to strong	-
117-150	-	-	-	-	medium to strong	-

Profile description

Ap 0-20 cm	(2.5Y 2/0, moist)clay,strong medium and coarse subangular blocky and strong medium and coarse angular blocky,friable slightly sticky plastic,no cutans,few medium pores and few pores slightly porous (<40 vol%),no inclusions,no fragments,frequent worm channels and pedotubules,gradual smooth boundary to,
Bi 20-65 cm	(2.5Y 5/1, moist)clay,strong coarse and very coarse prismatic,firm sticky very plastic,continuous moderately thick slickensides throughout cutans,few medium pores and few pores slightly porous (<40 vol%),no inclusions,no fragments,few worm channels,clear irregular boundary to,
CBi 65-90 cm	very dark grey (10YR 3/1, moist)sandy clay,weak medium prismatic and strong medium subangular blocky,friable slightly sticky slightly plastic,few fine faint diffuse mottles (2.5Y 5/4),patchy thin slickensides throughout cutans,many medium pores and few pores slightly porous (<40 vol%),no inclusions,no fragments,clear irregular boundary to,
Ck1 90-117 cm	light olive brown (2.5Y 5/4, moist)sandy clay,massive,friable slightly sticky slightly plastic,few fine faint diffuse mottles (10Y 5/2),no cutans,many medium pores and few pores slightly porous (<40 vol%),no inclusions,no fragments,clear irregular boundary to,

Kind 1 (parent material) ; Parker (eds), 1984	claystone
Mode of accumulation or deposition of parent material	marine sediments
Remarks on Parent Materials	Pleistocene marine-alluvial Cauto Formation, sands, clayey sands and guijarros-sands with intercalation of silt, gravel and guijarros-gravel
Soil Depth	120cm
Texture of parent material	sandy clay

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)	grassland

Altitude	106m
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.	low hill
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
(Estimated) maximum (lower) depth to groundwater table	150cm
Depth to groundwater table	150cm
Kind of ground water table (USDA, 1979)	groundwater table observed
(Estimated) minimum (upper) depth to groundwater table	100cm
Moist From - To	0-117cm
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	45cm
Wet From To	117-150cm

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	non-saline
Shape of stones (on average)	angular blocky
Surface stoniness class (FAO (2006) - Guidelines for soil description)	very few stones

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Reference soil Cuba 20: Vertisol

Characteristics

Reference soil CU020: Vertisols

Classification