Soil subgroup

Paleargid petrocálcico xerólico

It is less dry than the typical one: it is close to the Xeroles, Molisoles Mediterranean climate.

What the name says

Soil Taxonomy names are built from parts, and each part says something about the soil. From general to specific:

Taxonomic orderAridisolSoil 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.
SuborderArgidAridisol with a clay accumulation horizon, inherited from a more humid past climate.
Great groupPaleargidWithin the Argid suborder, it is very old and evolved: very thick clay horizon, or a petrocalcic horizon (calcareous hardpan) indicating a long time of formation.
SubgrouppetrocálcicoIt has a petrocalcic horizon—the calcareous hardpan: cemented calcium carbonate—within the meter and a half. Limits the useful depth for roots and water.
SubgroupxerólicoIt is less dry than the typical one: it is close to the Xeroles, Molisoles Mediterranean 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).

Frequent on the Patagonian plateau: old clay horizon, often on calcareous hardpan or cemented boulders.

Most common surface texture
Sandy loam
Most common drainage
Well drained
Typical effective depth
21 cm

Where it is found

According to the 1:500.000 national map, it covers about 356.713 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.

ProvinceArea
Río Negro339.958 ha
Buenos Aires16.755 ha

Districts where it is most common

Other Paleargid 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