Abstract

Soil, like any natural resource, needs to be classified in order to best utilize and conserve the resource. As long as humans have lived in communities, soils have been classified. In most cases, the classification approach is strongly influenced by the concept that the most important use of soils is for agriculture. Taxonomic classifications of the soil resource, however, can be applied to any number of use and management purposes when the classification is based on the physical, chemical, and morphological properties of the soils. As such, use and management assessment of soil resources are made through soil surveys based on taxonomic soil classifications. In this entry, I discuss the development and architecture of the soil taxonomic system used in the United States for the past 50 years—Soil Taxonomy. The discussion includes references and comparisons to other national classification systems, and the international soil classification system known as the World Reference Base. Recent advances in soil classification and current issues are also discussed.