Variabilidade espacial da erodibilidade do solo em áreas de pastagens e floresta no município de Porto Velho, RO

Abstract

Erodibility is a characteristic of the soil that represents the susceptibility with which its particles of the most superficial layer are taken and transported to lower places by erosive agents, causing environmental and economic damages. The objective of the present work was to estimate soil erodibility in pasture and forest areas in the city of Porto Velho-Rondônia. In the field, three areas with different vegetation were selected, one with forest, one with brachiaria and one with mombaça grass. In the areas with pastures, 90 m x 60 m sampling meshes were delimited, and in the forested area a 90 m x 50 m mesh, with a regular spacing of 10 m between the sampling points for both areas. They were collected at the crossing points of the meshes, at a depth of 0 - 0.2 m, making 70 sample points in each area with pastures and 60 sample points in the forest area, totaling 200 values. These were collected with preserved structure (clods). Laboratory analyzes were analyzed to determine the texture followed by fractionation of the sand, and organic carbon followed by the estimation of the organic matter in the soil. The erodibility factors were calculated and then we applied univariate analysis, geostatistics and multivariate techniques to analyze the data. Indirect water erosion prediction models were used to estimate the K factor. The pasture environments differed from the forest environment. However, the mombaça area functions as an intermediate environment between the forest and the brachiaria, being closer to the forest environment.