Soil great group

Argiustol

Of the Ustol suborder; it has a clay accumulation horizon (argillic): clay washed from the surface accumulated lower.

What the name says

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

Taxonomic orderMolisolSoil with a thick, dark surface horizon rich in organic matter (the mollic epipedon), with more than half of its exchange capacity occupied by calcium, magnesium, potassium and sodium. It forms under grassland.
SuborderUstolMolisol from subhumid to semi-arid climate (ustic moisture regime): water is enough in the growing season but there are long dry periods.
Great groupArgiustolWithin the Ustol suborder, it has a clay accumulation horizon (argillic): clay washed from the surface accumulated lower.

What it means for farming

They are the soils agricultural lands par excellence: the Pampas grassland formed them and most of Argentine agriculture is done on them. They retain water and nutrients; its limitation, when there is one, is below: clay, sodium, calcareous hardpan or drainage.

Most common surface texture
Loam
Most common drainage
Well drained
Typical effective depth
100 cm

Where it is found

According to the 1:500.000 national map, it covers about 6.240.035 ha, spread over 102 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
Salta1.804.549 ha
Santiago del Estero1.690.526 ha
Chaco749.177 ha
Córdoba714.139 ha
Buenos Aires691.464 ha
Jujuy226.753 ha
Río Negro142.162 ha
Tucumán95.097 ha
Catamarca58.237 ha
Santa Fe34.183 ha

Districts where it is most common

It also appears on the detailed maps of: Buenos Aires, 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 55 (Well); half of the units fall between 50 and 66.

Land capability

I
II
III

class I: 11% · class II: 36% · class III: 43% · class IV: 4% · class V: 1% · class VI: 5%

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

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.

Buenos Aires

Erize · Laguna Puan · Sauce Chico · Cura Malal · Saavedra · Fuerte Argentino

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