Soil great group

Paleargid

Of 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.

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.

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
Imperfect
Typical effective depth
100 cm

Where it is found

According to the 1:500.000 national map, it covers about 10.168.276 ha, spread over 60 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
Santa Cruz3.414.007 ha
Río Negro2.067.068 ha
Catamarca1.399.769 ha
Chubut1.287.438 ha
Salta954.244 ha
Jujuy890.493 ha
Neuquén127.907 ha
Buenos Aires16.755 ha
Tucumán10.593 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 28 (low); half of the units fall between 28 and 28.

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.

Subgroups on the maps

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