In agriculture, soil type usually refers to the different sizes of mineral particles in a particular sample. Soil is made up in part of finely ground rock particles, grouped according to size as sand, silt, and clay. Each size plays a significantly different role. For example, the largest particles, sand, determine aeration and drainage characteristics, while the tiniest, sub-microscopic clay particles, are chemically active, binding with water and plant nutrients. The ratio of these sizes determines soil type: clay, loam, clay-loam, silt-loam, and so on.

However, ""soil type"" in the broader sense refers to a pedological classification of the natural (or human-influenced) soil. Then it is more correct to speak of "soil class".

There are many recognized soil classifications, both international and national.

See also

• soil structure
• soil survey
• FAO soil classification
• Canadian system of soil classification
• USA soil taxonomy
• International Committee on Anthropogenic Soils (ICOMANTH)

External links

• Soil classification systems
• A Compendium of On-Line Soil Survey Information Soil Classification for Soil Survey