Soil texture and chemical characteristics along an elevation range in the coastal Atlantic Forest of Southeast Brazil

We analyzed soils under forest across an elevation range (100 m, Lowland Forest, 400 m, Submontane Forest, and 1000 m, Montane Forest) in the Atlantic Rainforest of São Paulo State, Brazil. We hypothesized that soil nutrient content would increase with elevation in the surface mineral soil as a result of higher organic matter stocks, and the observation that both above and below ground biomass increase with elevation in the Atlantic Forest. This hypothesis was partially confirmed. Percent silt, carbon (C) and nitrogen (N) increased with elevation. Base cation concentrations, pH (< 4), and extractable phosphorus (P) concentration were low across the sites and did not differ among elevations. Extractable aluminum (Al) was highest at 1000 m, but there was no trend with elevation. The sharp decrease in P and cation concentration with soil depth and the low concentration of these elements in the parent material, suggest that the vegetation of the Atlantic Forest is dependent on recycling of these nutrients or atmospheric deposition to maintain productivity.