From geology, a soil type that forms in areas where the average rainfall is less than 25 inches. Pedocals vary from the black earths, rich in organic material, to gray desert soils.
Because of limited rainfall, soluble minerals are not leached out of the soil to any great extent and therefore pedocal soils are very fertile. Pedocals occur through much of the western United States and, because no fertilizer is needed, farming in these areas can be profitable despite limited water supply. The great grain areas of the world are usually in areas right on the border of 25 inches rainfall, and are covered with black earths. Natural vegetation in pedocal areas is usually grasses and scrub.
The name pedocal derives from the Latin: ped, ground, + cal, calcium, referring to the fact that these soils are often rich in highly-soluble calcium minerals such as lime. (For more fun, see pedalfer.)