Determinação do potencial erosivo do solo nas bacias dos rios São Francisco Falso e São Francisco Verdadeiro, região oeste do estado do Paraná

Abstract

In environmental management, soil erosion is one of the recurring problems, which in turn makes it necessary to have a territorial physical planning that orders soil use according to its potentialities and limitations. The present study had as objective to determine the laminar erosion potential for the São Francisco Falso River Basin (SFFRB) and the São Francisco Verdadeiro River Basin (SFVRB), using the Universal Soil Loss Equation (USLE). First, the morphometric and geoenvironmental characterization of the watersheds were carried out, where the hydrography, hypsometry, slope, soil, rainfall and land use and cover maps were made. Based on this primary mapping, it was possible to compile the USLE (or factor A) factor maps, which were rainfall erosivity (R), soil erodibility (K), slope length (LS), land use and cover (C) and conservation practices (P). Also, it was made the Soil Loss Tolerance (T) map. The in loco verification of critical areas (where A>T) were performed using a drone aerial survey. From USLE map it was found that for both watersheds the average loss of soil is concentrated in the minimum range, from 0 to 2,50 t ha-1 year-1. The lowest values of A occurred in the regions of high slope, where the terrain is less dissected and the Neosols predominate. However, the highest values of A occurred in the medium and low slope regions, where there is the occurrence of Nitosols and greater terrain dissection. Fractions of 15,68% and 18,27% of SFVRB and SFFRB areas, respectively, presented higher soil loss than soil loss tolerance. It was verified the applicability of USLE to determine soil erosive potential in watersheds, a fact that could be validated from drone surveying. The maintenance of riparian forests deserves to be highlighted as it is insufficient in all areas mapped with drone surveying.