Soil subgroup

Natracualf típico

It is the central concept of the great group: it has its features and none that brings it closer to another group.

What the name says

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

Taxonomic orderAlfisolSoil with a clay accumulation horizon (argillic or natric) and good base saturation, but without the thick, dark surface of a Molisol.
SuborderAcualfAlfisol with excess water: saturated near the surface part of the year, with redox depletions.
Great groupNatracualfWithin the Acualf suborder, it has a natric horizon: accumulation of clay with a lot of exchangeable sodium, which disperses the clay and blocks the passage of water and roots.
SubgrouptípicoIt is the central concept of the great group: it has its features and none that brings it closer to another group.

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.

The sodic soil of the low-lying areas of the Pampa Deprimida and the plains of Salado: it floods in winter, hardens in summer, and sodium limits almost everything that is not natural grass.

Most common surface texture
Silt loam
Most common drainage
Poor
Typical effective depth
75 cm

Where it is found

According to the 1:500.000 national map, it covers about 9.799.168 ha, spread over 159 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 Fe2.522.237 ha
Buenos Aires1.826.882 ha
Salta1.529.347 ha
Santiago del Estero1.502.789 ha
Córdoba854.576 ha
Chaco627.663 ha
Formosa252.840 ha
Entre Ríos220.921 ha
Corrientes204.098 ha
Tucumán117.467 ha

Districts where it is most common

It also appears on the detailed maps of: Buenos Aires, Entre Ríos, Santiago del Estero.

How productive it is

Where it is the main soil of the map unit, the productivity index has a median of 10 (very low); half of the units fall between 3 and 13.

Land capability

IV
VI
VII

class IV: 15% · class VI: 39% · class VII: 45% · class VIII: 1%

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 Natracualf 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.

Buenos Aires

Gowland · Chelforo · Vedia · Los Mochos · Rancagua · Zapiola · La Libertad · Las Heras · Manantiales · Gelly · El Destino · Poblet · Amenabar · Tuyuti · Elena · La Saturna · La Guarida del Zorro · Estacion Doce de Octubre · La Limpia · Villa Rossi · Arroyo Juarez

Entre Ríos

Inocencio · Algarrobo · Arroyo Martínez I · Los Mosquitos · Arroyo Ormachea · Punta del Monte · Puntas del Monte

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