Reference soil United-States-of-America 23: Vertisol

US023

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 US023: Vertisols

Classification

WRB 1998

Vertisol

FAO-UNESCO-ISRIC 1974

Pellic Vertisol

Local classification:	Houston Black clay

Other classification

USDA-NRCS (1999)	Udic Calciustert ustic fine montmorillonitic thermic
USDA-SCS (1975)	Udic Pellustert ustic fine montmorillonitic thermic

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
0-14	-	0	0.5	2.1	3.6	5.3	11.5	15.2	20.2	35.4	53.1
14-38	-	0.2	0.5	1.5	2.5	3.6	8.3	13.4	21.9	35.3	56.4
38-60	-	0	0.6	1.5	2.5	3.5	8.1	12.2	23.5	35.7	56.2
60-86	-	0.3	0.5	1.5	2.4	3.4	8.1	11.2	23.2	34.4	57.5
86-108	-	0	0.5	1.5	2.4	3.4	7.8	11.9	23	34.8	57.4
108-130	-	0.2	0.5	1.6	2.4	3.2	7.9	10.2	23.6	33.8	58.3
130-172	-	0	0.5	1.8	2.7	3	8	10.7	23.3	34	58
172-193	-	0.1	0.4	0.7	1.7	2.6	5.5	8.4	34.7	43.1	51.4
193-259	-	0	0	0.4	1.8	2.5	4.7	6.7	35.1	41.8	53.5
259-280	-	0.1	0.1	0.5	3	3.8	7.5	6.8	34.4	41.2	51.3
280-320	-	0	0.1	0.5	3.1	3.9	7.6	6.7	32	38.7	53.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-14	1.68	-	0.131	-	53.1
14-38	1.74	-	0.148	-	56.4
38-60	1.77	-	0.145	-	56.2
60-86	1.76	-	0.149	-	57.5
86-108	1.72	-	0.147	-	57.4
108-130	1.73	-	0.139	-	58.3
130-172	1.75	-	0.137	-	58
172-193	1.74	-	0.111	-	51.4
193-259	-	-	-	-	53.5
259-280	-	-	-	-	51.3
280-320	-	-	-	-	53.7

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
0-14	1.68	-	-	-	-	-	-	-	26.4
14-38	1.74	-	-	-	-	-	-	-	25.6
38-60	1.77	-	-	-	-	-	-	-	25.7
60-86	1.76	-	-	-	-	-	-	-	26.3
86-108	1.72	-	-	-	-	-	-	-	25.5
108-130	1.73	-	-	-	-	-	-	-	25.8
130-172	1.75	-	-	-	-	-	-	-	25.2
172-193	1.74	-	-	-	-	-	-	-	19.6
193-259	-	-	-	-	-	-	-	-	19.6
259-280	-	-	-	-	-	-	-	-	17.9
280-320	-	-	-	-	-	-	-	-	18.3

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
0-14	7.5	-	-	13	2.68	0.217	12	-	-	-	1.4	1.5	0.1	3
14-38	7.8	-	-	15	1.51	0.108	14	-	-	-	1.1	1.0	0.2	2.3
38-60	7.8	-	-	17	1.36	0.094	14	-	-	-	1.1	1.1	0.2	2.4
60-86	7.9	-	-	18	1.26	-	-	-	-	-	1.0	1.1	0.2	2.3
86-108	7.9	-	-	18	1.10	-	-	-	-	-	1.1	1.0	0.3	2.4
108-130	8.0	-	-	19	1.01	-	-	-	-	-	1.1	1.0	0.3	2.4
130-172	7.9	-	-	18	0.96	-	-	-	-	-	1.3	1.0	0.4	2.7
172-193	7.8	-	-	43	0.33	-	-	-	-	-	1.2	0.6	0.3	2.1
193-259	8.0	-	-	55	0.17	-	-	-	-	-	1.1	0.4	0.3	1.8
259-280	7.9	-	-	64	0.12	-	-	-	-	-	0.9	0.4	0.2	1.5
280-320	7.7	-	-	64	0.15	-	-	-	-	-	1.0	0.3	0.2	1.5

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 %
0-14	-	52.1	98	9.4	-	-	-
14-38	-	54.9	97	5.3	-	-	-
38-60	-	54.6	97	4.8	-	-	-
60-86	-	54.5	95	4.4	-	-	-
86-108	-	53.5	93	3.9	-	-	-
108-130	-	52.7	90	3.5	-	-	-
130-172	-	52.4	90	3.4	-	-	-
172-193	-	39.7	77	1.2	-	-	-
193-259	-	28.6	53	0.6	-	-	-
259-280	-	20.5	40	0.4	-	-	-
280-320	-	19	35	0.5	-	-	-

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
0-14	-	-	-	-	-	0.3	0.1	-	-	-	-
14-38	-	-	-	-	-	0.3	0.1	-	-	-	-
38-60	-	-	-	-	-	0.3	0.1	-	-	-	-
60-86	-	-	-	-	-	0.3	0.1	-	-	-	-
86-108	-	-	-	-	-	0.2	0.1	-	-	-	-
108-130	-	-	-	-	-	0.2	0.1	-	-	-	-
130-172	-	-	-	-	-	0.2	0.1	-	-	-	-
172-193	-	-	-	-	-	0.4	0.1	-	-	-	-
193-259	-	-	-	-	-	0.5	0	-	-	-	-
259-280	-	-	-	-	-	0.7	0	-	-	-	-
280-320	-	-	-	-	-	0.4	0	-	-	-	-

Depth (cm)	CaSO4.2H2O %	P Bray mg/kg	P Olsen mg/kg	pH CaCl2	clay_noncarbonate % w/w	clay_carbonate % w/w	phosphorus4 mg/kg	phosphorus1 mg/kg	total_sulfur % w/w
0-14	-	-	-	7.4	-	-	-	-	-
14-38	-	-	-	7.6	-	-	-	-	-
38-60	-	-	-	7.6	-	-	-	-	-
60-86	-	-	-	7.6	-	-	-	-	-
86-108	-	-	-	7.6	-	-	-	-	-
108-130	-	-	-	7.6	-	-	-	-	-
130-172	-	-	-	7.7	-	-	-	-	-
172-193	-	-	-	7.7	-	-	-	-	-
193-259	-	-	-	7.7	-	-	-	-	-
259-280	-	-	-	7.6	-	-	-	-	-
280-320	-	-	-	7.6	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
38-60	-	-	-	-	-	-	very weak to weak	very weak to weak	-	-	weak to medium	-
86-108	-	-	-	-	-	-	very weak to weak	very weak to weak	-	very weak	strong	-
172-193	-	-	-	-	-	-	very weak to weak	very weak to weak	-	very weak	strong	-

Soluble sands

Depth (cm)	Ca mmol(c)/kg	Mg mmol(c)/kg	K mmol(c)/kg	Na mmol(c)/kg	sum cations mmol(c)/kg	CO3 mmol(c)/kg	HCO3 mmol(c)/kg	Cl mmol(c)/kg	NO3 mmol(c)/kg	SO4 mmol(c)/kg	sum anions mmol(c)/kg
0-14	11.3	0.4	0.3	0.3	12.3	0	10.3	1.1	0	1.9	13.3
14-38	7.8	0.2	0.1	0.3	8.4	0	5.5	0.4	0	0.6	6.5
38-60	6.7	0.2	0.1	0.3	7.3	0	5.4	0.3	0.2	0.6	6.5
60-86	6.4	0.1	0.1	0.4	7	0	5.4	0.2	0	0.5	6.1
86-108	5.9	0.1	0.1	0.5	6.6	0	4.6	0.3	0	0.5	5.4
108-130	5	0.1	0.1	0.6	5.8	0	4	0.2	0	0.6	4.8
130-172	5.5	0.2	0.1	0.8	6.6	0	4.5	0.2	0	0.9	5.6
193-259	4.3	0.2	0.1	1.1	5.7	0	3	0.5	0	1.7	5.2

Depth (cm)	Sodium ads. ratio	pH e	EC e dS/m	EC 1 : 5 dS/m
0-14	-	6.9	1.15	-
14-38	-	7.2	0.64	-
38-60	-	7.1	0.63	-
60-86	-	7.1	0.59	-
86-108	-	7.2	0.58	-
108-130	-	7.2	0.5	-
130-172	-	7.2	0.57	-
172-193	-	-	0.22	-
193-259	-	7.5	0.56	-
259-280	-	-	0.21	-
280-320	-	-	0.22	-

You are here

Reference soil United-States-of-America 23: Vertisol

Characteristics

Reference soil US023: Vertisols

Classification