Soil subgroup
Paleortid ustólico
It is less dry than the typical one: it is close to Ustoles, Molisoles subhumid climate.
Paleortid is a name from the 1975 taxonomy, which many INTA soil survey maps were made with. The current edition no longer has this group: today it would be classified as Petrocalcid.
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 | Aridisol | Soil arid climate: water is lacking most of the year and the profile accumulates what the rain cannot wash away (carbonates, gypsum, salts) or clay from more humid times. |
|---|---|---|
| Suborder | Ortid | Aridisol without clay horizon. |
| Great group | Paleortid | Within the Ortid suborder, it is very old and evolved: very thick clay horizon, or a petrocalcic horizon (calcareous hardpan) indicating a long time of formation. |
| Subgroup | ustólico | It is less dry than the typical one: it is close to Ustoles, Molisoles subhumid climate. |
What it means for farming
Without irrigation there is no agriculture: they are soils of native woodland, extensive grazing or, with water, irrigated oases (Mendoza, San Juan, the valleys of the NOA).
- Most common surface texture
- Sandy loam
- Most common drainage
- Something Excessive
- Typical effective depth
- 100 cm
Where it is found
According to the 1:500.000 national map, it covers about 587.971 ha, spread over 6 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 |
|---|---|
| La Pampa | 483.688 ha |
| Río Negro | 94.463 ha |
| Chubut | 9.820 ha |
Districts where it is most common
How productive it is
Where it is the main soil of the map unit, the productivity index has a median of 13 (very low); half of the units fall between 13 and 20.
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 Paleortid 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)