Soil type characteristics:
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)
Description:
Reference soil US023: Vertisols
General information:
| Authors | Wilding LP |
| Location | Texas State, Falls County |
| Lat/Lon | 31.2883, -96.9495 |
Code:
US023
Classification
WRB 1998
| Vertisol |
FAO-UNESCO-ISRIC 1974
| Pellic Vertisol |
Local classification
| Classification information | Houston Black clay |
Other classification
| USDA-NRCS (1999) | Udic Calciustert ustic fine montmorillonitic thermic |
| USDA-SCS (1975) | Udic Pellustert ustic fine montmorillonitic thermic |
Chemical characteristics
| 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 | - | - | - | - | - |
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 |
Other physical data
| 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 |
Water retention characteristics
| 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 |
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 | - |