Behavior differences between soils of the South-American and Velhas geomorphic surfaces of the Cerrado region, all of them under native vegetation cover, were evaluated by physical, chemical, and mineralogical characterizations, and principal component analyses. According to their sub-region and geomorphic surfaces, the soils were separated in three groups: 1. clayey to very clayey texture, low- and mesoferric; 2. medium to sandy texture, lowferric; 3. clayey to very clayey texture, ferric. Water retention in the surface horizons of the studied soils was positively correlated with the clay and organic carbon contents. Soils of Group 3 showed the greatest amount of exchangeable bases in the surface horizons, which is mainly a consequence of the greater recycling efficiency imposed by the local forest formation when compared to the Cerrado formation (verified in 31 of the 33 soil profiles of Groups 1 and 2). Soils of Group 3, formed from mafic rocks, were the most homogeneous in mineralogical terms, since all profiles were hematitic. In averages, Groups 1 and 2 presented an overlapping mineralogical composition, though Group 1 is more gibbsitic than Group 2. In comparison to the US Soil Taxonomy, the efficacy of the Brazilian Soil Classification System at discriminating the studied soils is higher owing to the use of the ferric character in conjunction with the other attributes both systems have in common. The principal component analysis supported the understanding of the pedologic environment differences and similarities identified in the field.
Latosols; Oxisols; Quartzarenic Neosols; Entisols; geomorphic surfaces
