USDA soil taxonomy

USDA Soil Taxonomy developed by United States Department of Agriculture and the National Cooperative Soil Survey provides an elaborate classification of soil types according to several parameters (most commonly their properties) and in several levels: Order, Suborder, Great Group, Subgroup, Family, and Series.

Example of classification of a soil type

Order: Entisols

Suborder: Fluvents

Great Group: Torrifluvents

Subgroup: Typic Torrifluvents

Family: Fine-loamy, mixed, superactive, calcareous, Typic Torrifluvents

Series: Jocity, Youngston.

Another Example

Suborder: Xeralfs

Great Group: Durixeralfs

Subgroup: Abruptic Durixeralfs

Family: Fine, Mixed, Active, thermic Abruptic Durixeralfs

Alfisols — moderately weathered, form under boreal or broadleaf forests, rich in Fe and Al
Andisols — form in volcanic ash and defined as containing high proportions of glass and amorphous colloidal materials, including allophane, imogolite and ferrihydrite
Aridisols — (from the Latin aridus, for “dry”) form in an arid or semiarid climate
Entisols — do not show any profile development other than an A horizon
Gelisols — soils of very cold climates which are defined as containing permafrost within two meters of the soil surface
Histosols — consist primarily of organic materials
Inceptisols — form quickly through alteration of parent material
Mollisols — form in semiarid to semihumid areas, typically under a grassland cover
Oxisols — best known for their occurrence in tropical rain forest
Spodosols — typical soils of coniferous or boreal forests
Ultisols — commonly known as red clay soils
Vertisols — high content of expansive clay