Soil subgroup
Ocracualf mólico
It has a dark surface rich in organic matter, almost like that of a Molisol.
Ocracualf 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 Epiacualf or Endoacualf.
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 | Acualf | Alfisol with excess water: saturated near the surface part of the year, with redox depletions. |
| Great group | Ocracualf | Within the Acualf suborder, it It has a clear surface and is poor in organic matter (ochric epipedon). |
| Subgroup | mólico | It has a dark surface rich in organic matter, almost like that of a Molisol. |
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
- Silt loam
- Most common drainage
- Very poor
- Typical effective depth
- 60 cm
Where it is found
According to the 1:500.000 national map, it covers about 540.270 ha, spread over 10 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 |
|---|---|
| Formosa | 396.128 ha |
| Chaco | 144.142 ha |
Districts where it is most common
- Bermejo · Formosa
- Patiño · Formosa
- San Fernando · Chaco
- Maipú · Chaco
- Pirané · Formosa
- General Donovan · Chaco
- 1° de Mayo · Chaco
- Bermejo · Chaco
- Presidencia de la Plaza · Chaco
- Libertador General San Martín · Chaco
It also appears on the detailed maps of: Entre Ríos.
How productive it is
Where it is the main soil of the map unit, the productivity index has a median of 20 (low); half of the units fall between 20 and 22.
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 Ocracualf subgroups
Soil series
Series are the specific soils, named after places, that detailed maps describe under this name. Two properties with the same series have the same soil.
Entre Ríos
Bovril · Viraró · Hernandarias · María Luisa
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)