Soil series

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Arawak soil series. St. Croix, U.S. Virgin Islands
Arawak soil series. St. Croix, U.S. Virgin Islands

Soil series as established by the National Cooperative Soil Survey are soils that are grouped together because of their similar pedogenesis, soil chemistry, and physical properties. These result in soils which perform similarly for land use purposes. A soil series name generally is derived from a town or landmark in or near the area where the soil series was first recognized.

A soil series is a naturally occurring entity on the landscape. Therefore, a given series does not necessarily occur within the confines of only one county or state.

Each series consists of soils having soil horizons that are similar in soil color, soil texture, soil structure, soil pH, consistence, mineral and chemical composition, and arrangement in the soil profile. A soil profile is the sequence of natural layers, or horizons, in a soil. It extends from the surface downward to unconsolidated material. Most soils have three major horizons, called the surface horizon, the subsoil, and the substratum.

The surface layer (topsoil) has the maximum accumulation of organic matter and is the horizon of maximum leaching of clay minerals and of iron and aluminum oxides. Some soils have a subsurface layer below the surface layer.

The subsoil, which underlies the surface layer or subsurface layer, is the horizon of maximum accumulation of clay minerals, iron and aluminum oxides and other compounds. These compounds may have been leached from the surface layer and redeposited in the subsoil, or may have formed in place. Most likely, they occur as a result of a combination of both of these processes. The subsoil commonly has blocky or prismatic structure and generally is firmer and lighter in color than the surface layer.

The substratum is below the surface layer and subsoil. It consists of material that has been somewhat modified by weathering but is relatively unchanged by soil-forming processes. [1]

[edit] References

  1. ^ State Soils. USDA - NRCS. Retrieved on 2006-07-02.