Soil subgroup
Haplustalf vértico
It has expansive clays: dry cracks or slickensides in the subsoil. When wet it becomes sticky and difficult to work with; when dry it cracks.
What the name says
Soil Taxonomy names are built from parts, and each part says something about the soil. From general to specific:
| Taxonomic order | Alfisol | Soil with a clay accumulation horizon (argillic or natric) and good base saturation, but without the thick, dark surface of a Molisol. |
|---|---|---|
| Suborder | Ustalf | Alfisol from subhumid to semi-arid climate (ustic moisture regime). |
| Great group | Haplustalf | Within the Ustalf suborder, it It is the simplest of the suborder: it does not have a clay horizon or any other feature that places it in a more specific group.. |
| Subgroup | vértico | It has expansive clays: dry cracks or slickensides in the subsoil. When wet it becomes sticky and difficult to work with; when dry it cracks. |
What it means for farming
Acceptable fertility, but the surface layer is thinner and poor in organic matter. In the Pampas region many Alfisoles are sodic or floodable (Natracualfes) and are left for livestock.
- Most common surface texture
- Clay loam
- Most common drainage
- Imperfect
- Typical effective depth
- 110 cm
Where it is found
According to the 1:500.000 national map, it covers about 2.035.531 ha, spread over 16 districts.
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National map units that list it. The scale is 1:500.000: good for seeing the region, not a single property.
| Province | Area |
|---|---|
| Salta | 1.057.585 ha |
| Santiago del Estero | 900.363 ha |
| Chaco | 34.218 ha |
| Formosa | 32.857 ha |
| Jujuy | 7.254 ha |
| Tucumán | 3.253 ha |
Districts where it is most common
- Rivadavia · Salta
- Moreno · Santiago del Estero
- Anta · Salta
- Copo · Santiago del Estero
- Pellegrini · Santiago del Estero
- General José de San Martín · Salta
- Jiménez · Santiago del Estero
- Orán · Salta
- Matacos · Formosa
- Almirante Brown · Chaco
- Metán · Salta
- General Güemes · Chaco
- Santa Bárbara · Jujuy
- Río Hondo · Santiago del Estero
- Ramón Lista · Formosa
- Burruyacú · Tucumán
It also appears on the detailed maps of: Salta, Santiago del Estero.
How productive it is
Where it is the main soil of the map unit, the productivity index has a median of 29 (low); half of the units fall between 29 and 29.
Land capability
class II: 78% · class III: 7% · class IV: 7% · class VI: 3% · class VII: 4%
Taken from the maps that include this data. A map unit with several soils has a single index, and it is only attributed to the dominant soil.
Other Haplustalf subgroups
Soils it shares map units with
Several soils share each map unit. These are the ones most often found alongside this one: on a property, you will likely find them in the nearby low ground or on the next rise.
The definitions are a plain-language summary of the USDA Keys to Soil Taxonomy. The formal definition includes thickness, color and percentage thresholds that are left out here.
Sources
- Soil Survey Staff. (2014). Claves para la Taxonomía de Suelos, 12.ª edición. USDA - Natural Resources Conservation Service. · Dominio público (USDA)
- INTA · Dominio público (carta 1:500.000)