Alfisols are a soil order in USDA soil taxonomy. Alfisols form in semiarid to humid areas, typically under a hardwood forest cover. They have a clay and nutrient-enriched subsoil. "Alf" refers to aluminium (Al) and iron (Fe). Because of their productivity and abundance, the Alfisols represent one of the more important soil orders. They are widely used both in agriculture and forestry and are generally easier to keep fertile than other humid-climate soils, though those in Australia and Africa are… (More on Alfisols)