Changes in land use and buffaloes trampling effects on soil health in environmentally vulnerable areas of an Atlantic Forest biome in southern São Paulo State, Brazil

This study was conducted to determine the impact of land use and livestock farming on riparian areas in the state of São Paulo, Brazil. A range of physical, hydraulic and chemical properties were measured in hydromorphic soils under four scenarios; namely: i) native vegetation (NV), ii) semi-extensive grazing (SEG, ∼21 animal units ha−1) with 30 years of established practice; iii) intensive grazing with 20 years of established practice (IG20, ∼24 animal units ha−1); and iv) intensive grazing after 1 year of being implemented (IG1, ∼21 animal units ha−1). The replacement of native vegetation with pastures, regardless of the duration and type of management, resulted in significant changes in soil structure and soil functioning, due to increased bulk density and penetration resistance, and concurrent reductions in macroporosity and saturated hydraulic conductivity. The soil under long-term intensive management (IG20) showed less structural degradation, closely resembling the conditions observed in the native vegetation area (NV). By contrast, the soil under semi-extensive grazing (SEG) management exhibited significant damage to the soil structure, which affected all measured soil physical and hydraulic properties. Despite these negative impacts on soil structure, SEG exhibited higher levels of total carbon, total nitrogen, and total sulfur. The results suggested that the intensive management system (IG20) tended to maintain higher soil quality in riparian areas than the condition observed under native vegetation, although these differences cannot be exclusively ascribed to grazing.