A soil classification that was devised in 1949, categorizing soils according to the climatic conditions in which they form. Soils were placed in three orders. Zonal soils are directly related to the climates in which they occur. Azonal soils are young soils and not related to climatic conditions. Intrazonal soils result from local conditions that are unrelated to climate; these include the soils of marshes and swamps, saline and alkaline soils, and littoral deposits. The soil orders are then divided into 9 suborders, and the suborders into great soil groups. See also pedalfer; pedocal. See illustration.
Great soil groups
Subjects: Ecology and Conservation.