_:b1217728 . _:b1217728 . _:b1217728 "Ferralsols represent the classical, deeply weathered, red or yellow soils of the humid tropics. These soils have diffuse horizon boundaries, a clay assemblage dominated by low-activity clays (mainly kaolinite) and a high content of sesquioxides."^^ . _:b1217728 . _:b1217728 "FAO:http://fao.org/ag/agl/agll/wrb/doc/wrb2006final.pdf"^^ .