Fatores determinantes e níveis de propensão á perda de solos e seus efeitos socioeconômicos e ambientais na bacia do Rio Serra Branca - PB.

Abstract

The Serra Branca River basin, located in the Brazilian Semiarid, is configured as a space environmentally diverse, due to the climate, the conformation of topography, soils, various features of the vegetation, but mainly for the use that is destined, which it is often in disagreement with the potential of each site. This fact has caused a lot of problems in the topsoil and vegetation in specific modifications, accelerating the already intense soil loss. Given the context described, this work aimed to analyze the factors that trigger to soil loss as geoenvironmental units in Serra Branca river basin, located in the western Cariri of Paraiba, and establish their level of propensity factors due to the natural order and anthropogenic, that occur in association. The methodology, based only on visual interpretation of satellite imagery has been adapted to suit the purpose of the study, incorporating aspects such as the extent of the topography, the occurrence of predominant soils and the various features of the vegetation. It was also made use of data from maps, reports, and field work. With these procedures it was possible to define three geoenvironmental units with traits homologous. The results showed that the units go through a slow downgrade of vegetation process, changes in soil properties, a fact that contributes to expose it to erosion processes, being more pronounced in the first geoenvironmental unit and best preserved in the third geoenvironmental unit. It was observed that the effect of cattle activity on soil properties was more evident in the Vertisol and consorted areas, and that the average level of soil loss within the basin is moderately susceptible.