Soil great group

Paleustol

Of the Ustol 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 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 groupPaleustolWithin the Ustol 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

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
Loamy sand
Most common drainage
Moderate
Typical effective depth
140 cm

Where it is found

According to the 1:500.000 national map, it covers about 91.383 ha, spread over 18 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
Salta48.884 ha
Jujuy23.680 ha
Tucumán18.491 ha

Districts where it is most common

It also appears on the detailed maps of: Buenos Aires, Salta.

How productive it is

Where it is the main soil of the map unit, the productivity index has a median of 54 (average); half of the units fall between 54 and 54.

Land capability

II
III
IV

class II: 50% · class III: 13% · class IV: 38%

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

Dufaur · Estela · Monte La Plata · Molina

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