one of the 30 soil groups in the classification system of the Food and Agriculture Organization (FAO) (soil). Regosols are characterized by shallow, medium- to fine-textured, unconsolidated parent material that may be of alluvial origin and by the lack of a significant soil horizon (layer) formation because of dry or cold climatic conditions. Regosols occur mainly in polar and desert regions, occupying about 2 percent of the continental land area on Earth, principally in northern China, Greenland, Antarctica, north-central Africa, the Middle East, and northwest Australia. They are usually found under their original natural vegetation or under limited dryland cropping.