An acrisol is a type of soil as classified by the Food and Agriculture Organization. It is clay-rich, and is associated with humid, tropical climates, such as those found in Brazil, and often supports forested areas. It is one of the 30 major soil groups of the World Reference Base for Soil Resources. Acrisols correspond to the aquult, humults, udults and ustults sub-orders of ultisols in the USDA soil taxonomy and also to oxisols with a candic horizons and some alfisols. The acrisols low fertility and toxic amounts of aluminium pose limitations to its agricultural use, favouring in many places its use for silviculture, low intensity pasture and protected areas. Crops that can be successfully cultivated, if climate allows, include tea, rubber tree, oil palm, coffee and sugar cane.