Estimates of soil losses in watershed under tropical of altitude climate in Brazil

Abstract

Water erosion is one of the main degradation processes of tropical soils. In steepest areas with coffee cultivation, the erosion rates are intensified and could reach levels above the Soil Loss Tolerance Limits (T). Thus, the objective of this work was to evaluate the susceptibility to water erosion in steepest areas under predominant coffee cultivation using the Revised Universal Soil Loss Equation (RUSLE) and compare the results to T limit. The research was carried out at the Ribeirão José Lúcio subbasin located in Conceição do Rio Verde Municipality and the Ribeirão São Bento subbasin located in Cambuquira Municipality, both in South of Minas Gerais State, Brazil. The parameters involved in the RUSLE and T calculations were determined from the physical and edaphoclimatic characteristics of the subbasins. The total soil loss of the Ribeirão São Bento subbasin was 1,032 Mg year-1, while the Ribeirão José Lúcio subbasin present an erosion rate of 5,014 Mg year-1 with 13.16% and 7.90% of the areas above the T limits, respectively. We found the highest losses in steepest and exposed soil areas, which should be prioritized in the adoption of conservation management practices, seeking to minimize water erosion, and ensuring the long-term sustainability of agricultural production. The RUSLE model is a fast, simple, and inexpensive tool that contributes to the assessment of soil conservation in hydrographic subbasins.