Estimativa de perda de solos na Bacia Hidrográfica do Rio da Dona – BA

Abstract

The historical process of occupation of the Brazilian territory included the substitution of native vegetation cover for agricultural activities, constantly based on the excessive exploitation of natural resources. This process was responsible for several environmental problems, mainly the intensification of the erosion of the water. The objective of this work was to estimate the model of the Universal Soil Loss Equation (USLE) in the Dona River Basin – BA, to determine soil losses. Rainfall erosivity (R) was obtained by interpolation of precipitation data, soil erodibility (K) was determined by means of the soil map of the area under study, the topographic factor (LS) was generated from the equation proposed by Desmet & Govers (1996) e McCool et al. (1989) and the use and management factors and conservation practices (C and P) were obtained through the elaboration of the land use map of the Rio da Dona basin area. The factors R, K and LS were multiplied and generated the map of the Natural Potential of Erosion. In addition to the CP factor, we obtained the soil loss map expressed in t.ha-1. The erosivity and erodibility presented results of an average erosion susceptibility, the topographic factors inferred a low vulnerability to erosion and the CP factor presented a high susceptibility to erosion. The estimated soil losses for the basin under study have a mean of 21.19 t.ha-1 year-1 and when compared to the annual average PNE, 119.50 t.ha-1 year-1, one can conclude that the soil loss corresponds to 18% of the PNE, thus, the vegetation cover is an essential factor for the basin under study.