Reference soil Italy 13: Vertisol

IT013

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 IT013: Vertisols

A deep, dark reddish brown, clayey soil, developed in Holocene colluvial deposits covering Pleistocene colluvial deposits, both derived from weathering products of limestone, with some admixture of volcanic minerals. Common to many animal burrows and insect nests occur in the topsoil (0-50 cm). Below the surface layer (0-20 cm) an argillic horizon has been developed, showing clay-iron(-humus) cutans, abruptly overlying a strongly mottled subsoil with pronounced vertic properties (intersecting slickensides) and cutans on pedfaces. During the summer deep wide cracks occur down to a depth of 1.50 m. LANDFORM: slope of limestone hill towards undulating karts basin. MICRORELIEF: formerly some gilgai relief has been observed. HUMAN INFLUENCE: ploughing and levelling. References: See profile description IT009 (I9). Profile is comparable with prof. no. Sp/97 (Spaargaren, 1979). PROFILE DESCRIPTION: 2Bg1: also reddish yellow (7.5YR 6/6, moist) mottles; patchy moderately thick cly-iron cutans in some pedfaces, patchy thin iron-manganese cutans and common medium intersecting slickensides. 2Bg2: also yellow (10YR 7/6, moist) mottles; many large intersecting slickensides. 2Bg3: patchy thin iron-manganese cutans on some pedfaces and many medium intersecting slickensides. 2Bg4: many small intersecting slickensides. 3B(t): broken to continuous thin iron-manganese cutans on all pedfaces and few small intersecting slickensides.

Classification

WRB 2014

Vertisol

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Endostagni-Eutric Vertisol

Chromic Vertisol

- cm	cambic B horizon
- cm	ochric A horizon
-	stagnic
-	vertic

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

Local classification:	Vertisuolo

Other classification

USDA-NRCS (1999)	Albaquic Haploxerert
USDA-SCS (1975)	Albaquic Chromoxerert xeric very fine mixed thermic

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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
0-5	-	0.1	0.4	1	2.4	1.6	5.5	7.9	17.5	25.4	69.2
5-20	-	-	-	-	-	-	6	6.5	19	25.5	68.5
20-38	-	0.1	0.3	0.7	1.8	1.3	4.2	7.7	19.7	27.4	68.4
38-50	-	0.1	0.3	0.7	1.9	1.3	4.3	9.1	17.1	26.2	69.5
50-67	-	-	-	-	-	-	0.5	-	-	8	91.5
67-90	-	0	0	0	0.1	0.1	0.2	3.2	2.4	5.6	94.1
90-113	-	-	-	-	-	-	1.4	2	4.8	6.8	91.8
113-140	-	-	-	-	-	-	0.7	0.3	2.6	2.9	96.5
140-165	-	0	0	0	0	0	0.0	1	2.1	3.1	96.8

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-5	-	-	-	-	69.2
5-20	-	-	-	-	68.5
20-38	-	-	-	-	68.4
38-50	-	-	-	-	69.5
50-67	-	-	-	-	91.5
67-90	-	-	-	-	94.1
90-113	-	-	-	-	91.8
113-140	-	-	-	-	96.5
140-165	-	-	-	-	96.8

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
0-5	6.3	5.1	0.16	-	2.60	0	-	-	-	15.1	2.9	1.4	0.0	19.4
5-20	6.3	5.1	0.14	-	1.18	0.14	8	-	-	13.2	2.2	0.8	0.0	16.2
20-38	6.5	5.1	0.09	-	0.87	0.12	7	-	-	13.2	2.1	0.5	0.0	15.8
38-50	6.5	5.0	0.07	-	0.84	0.11	8	-	-	13.6	2.3	0.4	0.1	16.4
50-67	6.0	5.0	0.06	-	0.40	0.07	6	-	-	13.2	2.6	0.4	0.1	16.3
67-90	6.2	4.8	0.06	-	0.26	-	-	-	-	20.5	4.7	0.6	0.5	26.3
90-113	5.8	4.4	0.07	-	0.23	0.04	6	-	-	18.1	4.7	0.6	0.4	23.8
113-140	5.4	3.8	0.06	-	0.16	0.03	5	-	-	16.6	4.6	0.5	0.5	22.2
140-165	4.9	3.6	0.05	-	0.12	-	-	-	-	12.9	3.7	0.4	0.3	17.3

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 %
0-5	56	34.7	39	9.1	-	-	-
5-20	53	30.5	39	4.1	-	-	-
20-38	54	29	39	3.0	-	-	-
38-50	53	31	41	2.9	-	-	-
50-67	57	28.8	30	1.4	-	-	-
67-90	67	39	40	0.9	-	-	-
90-113	60	39.6	42	0.8	-	-	-
113-140	56	39.6	40	0.6	-	-	-
140-165	47	36.8	38	0.4	-	-	-

Depth (cm)	pH NaF	P Retention %	ODOE	Al o % w/w	Si o % w/w	Fe d % w/w	Al d % w/w	Fe p % w/w	Al p % w/w	C p % w/w	Fe o % w/w
0-5	-	-	-	0.28	0.14	4.11	0.43	-	-	-	0.4
5-20	-	-	-	0.31	0.16	4.34	0.47	-	-	-	0.42
20-38	-	-	-	0.31	0.16	4.5	0.49	-	-	-	0.46
38-50	-	-	-	0.3	0.14	4.49	0.51	-	-	-	0.47
50-67	-	-	-	-	-	4.32	0.41	-	-	-	-
67-90	-	-	-	0.29	0.16	3.92	0.4	-	-	-	0.32
90-113	-	-	-	0.26	0.19	4.03	0.34	-	-	-	0.39
113-140	-	-	-	0.24	0.17	3.25	0.28	-	-	-	0.4
140-165	-	-	-	0.25	0.16	3.91	0.28	-	-	-	0.5

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-5	-	-	-	very weak to weak	-	-	medium to strong	weak to medium	weak	weak	-	-
5-20	-	-	-	very weak to weak	-	-	medium to strong	weak to medium	weak	weak	very weak to weak	-
20-38	-	-	-	very weak to weak	-	-	medium to strong	weak to medium	weak	weak	very weak to weak	-
38-50	-	-	-	very weak to weak	-	-	medium to strong	weak to medium	weak	weak	very weak to weak	-
50-67	-	-	-	very weak to weak	-	-	medium to strong	weak to medium	weak	very weak to weak	very weak to weak	-
67-90	-	-	-	very weak to weak	-	-	weak to medium	medium to strong	weak	-	very weak to weak	-
90-113	-	-	-	very weak to weak	-	-	weak to medium	medium to strong	very weak to weak	-	very weak	-
113-140	-	-	-	very weak to weak	-	-	weak to medium	-	weak	-	very weak to weak	-
140-165	-	-	-	very weak to weak	-	-	medium to strong	weak to medium	weak	-	very weak to weak	-

Profile description

Ap1 0-5 cm	dark reddish brown (5YR 3/3, moist)clay,weak coarse subangular blocky parting to moderate fine and medium subangular blocky,firm sticky plastic,many very fine coarse exped and inped tubular random pores,few small spherical soft manganiferous nodules,few pottery fragm. fragments,frequent pedotubules,clear smooth boundary to,
Ap2 5-20 cm	dark reddish brown (5YR 3/3, moist)clay,weak coarse subangular blocky parting to moderate fine subangular blocky,friable sticky plastic,patchy thin clay and sesquioxide on pedfaces cutans,many very fine coarse exped and inped tubular random pores,few small spherical soft manganiferous nodules,few pott./charcoal fragments,frequent pedotubules,clear smooth boundary to,
Bt1 20-38 cm	dark reddish brown (5YR 3/4, moist)clay,weak fine and medium prismatic parting to moderate fine and medium subangular blocky,friable sticky plastic,broken moderately thick clay and sesquioxide on pedfaces cutans,many fine discontinuous inped tubular random pores and common discontinuous vesicular horizontal pores,few small spherical soft manganiferous nodules,few pott./charc. fragments,very frequent pedotubules,clear smooth boundary to,
Bt2 38-50 cm	dark reddish brown (5YR 3/4, moist)clay,weak medium prismatic parting to moderate fine and medium subangular blocky,friable sticky plastic,few medium prominent clear mottles (7.5YR 4/4) and few coarse prominent mottles (10R 3/4),broken thick clay and sesquioxide on pedfaces cutans,many very fine fine discontinuous inped tubular random pores and few discontinuous exped vesicular horizontal pores,few small spherical soft manganiferous nodules,few pott./charc. fragments,few pedotubules,abrupt wavy boundary to,
2Bg1 50-67 cm	reddish brown (5YR 4/4, moist)clay,strong medium and coarse prismatic,firm sticky plastic,common coarse prominent clear mottles (5Y 7/2) and common medium faint mottles (10R 4/4),patchy thick clay and humus on vertical pedfaces cutans,common very fine fine discontinuous inped tubular random pores and few very coarse discontinuous exped vesicular horizontal pores,gradual smooth boundary to,
2Bg2 67-113 cm	reddish brown (5YR 4/4, moist)clay,strong coarse and very coarse wedge-shaped angular blocky,firm sticky plastic,many coarse prominent sharp mottles (5Y 7/2) and common medium distinct mottles (10R 4/4),patchy thick clay and sesquioxide in root channels and pores cutans,few very fine fine discontinuous inped tubular random pores,gradual smooth boundary to,
2Bg3 113-140 cm	reddish brown (5YR 4/4, moist)clay,strong coarse wedge-shaped angular blocky,firm sticky plastic,many medium distinct clear mottles (2.5Y 5/2) and many medium distinct mottles (10YR 6/6),patchy thick clay and sesquioxide in root channels and pores cutans,few very fine fine discontinuous inped tubular random pores,abrupt smooth boundary to,
2Bgi 140-165 cm	dark reddish brown (2.5YR 3/4, moist)dark reddish brown (5YR 3/3, moist),clay,clay,moderate fine and medium angular blocky,strong fine and medium wedge-shaped angular blocky,firm sticky plastic,firm sticky plastic,common coarse prominent diffuse mottles (5Y 7/2) and few fine distinct mottles (7.5YR 6/6),few medium prominent sharp mottles (2.5YR 5/8),patchy thin clay and sesquioxide on vertical pedfaces cutans,slickensides cutans,few fine discontinuous inped tubular random pores,few very fine discontinuous inped tubular random pores,clear wavy boundary to,

Kind 1 (parent material) ; Parker (eds), 1984	igneous rock
Mode of accumulation or deposition of parent material	colluvial
Remarks on Parent Materials	admix. volcanic min.
Texture of parent material (second entry)	clayey

Occurrence of soil aggradation (McDonald et al., 1984)	absent
Intensity of the soil erosion type	slight
Soil erosion type	rill
Slope stability	stable

Land use or vegetation in the immediate vicinity of the site	cultivated pasture
Remarks on Land Use / Vegetation	new grass, formerly wheat (3 years)
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	300m
Physiographic Unit	slope at foot limestone hill
Physiographic position of the site	slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	hill
Slope	10%
Form of the slope surrounding the site	concave
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

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	0-200cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	medium

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-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)	level
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 Italy 13: Vertisol

Characteristics

Reference soil IT013: Vertisols

Classification