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

Order: Alfisols

Suborder: Xeralfs

Great Group: Durixeralfs

Subgroup: Abruptic Durixeralfs

Family: Fine, Mixed, Active, thermic Abruptic Durixeralfs

Series: San Joaquin (soil)

Link to Official Series Description: ftp://ftp-fc.sc.egov.usda.gov/NSSC/StateSoil_Profiles/ca_soil.pdf

Orders

Global distribution of soil types of the USDA soil taxonomy system. A much larger version of the map is also available.

• 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

See also

• FAO soil classification
• International Committee on Anthropogenic Soils (ICOMANTH)
• Soil classification
• 1938 USDA soil taxonomy
• Soil

External links

• USDA / NRCS soil taxonomy webpage
• Soil taxonomy document
• A Compendium of On-Line Soil Survey Information: Soil Classification Systems
• USDA-NRCS Web Soil Survey