The influence of parent materials, Pre-Cambrian rocks, and colluvial and alluvial sediments derived from them, as well as their topographical position in the soil genesis were studied in a toposequence representative of the Baixada Litorânea Fluminense landscape, at the Federal Rural University of Rio de Janeiro, Brazil. Six soil profiles, located on the shoulder position (P1 and P2), backslope (P3), footslope (P4 and P5), and foot slope position (P6) were analyzed. The pedogenic processes and soil properties were related to the geomorphologic and lithostratigraphic units described in the region. Profiles P1 and P2, formed in situ from the gneiss mantle, had high base saturation, medium clayey texture, and easily weathered primary minerals in the sand fraction (mica and feldspar). Profile P3, related to a thick colluvium mantle, differed from P1 and P2 due to a high aluminum saturation and absence of easily weathered primary minerals. Profiles P4 and P5, also formed from colluvial materials, had a sandier surface texture than P3, and showed an E horizon overlying a fragipan. Profile P6, formed from mixed colluvium and alluvium sediments, had gray colors, massive structure, clayey texture, and low base saturation. The soil profiles were classified as Argissol (P1, P2 and P3), Planossol (P4 and P5), and Gleissol (P6).
"Argissols"; "Planossols"; soil drainage