DIRECT DETERMINATION OF ERODIBILITYIN DIFFERENT FORMS OF SLOPES IN THE BELMONT STREAM BASIN IN PORTO VELHO - RONDÔNIA – BRAZIL

Abstract

This study aimed to quantify the surface erodibility (0-10cm) of oxisol in three slope morphologies in the Belmont basin Stream in Porto Velho, Rondônia – Brazil; through direct analysis using the Modified Inderbitzen equipment. The erodibility evaluation method was that of Heidemann, which considers a soil to be erodible when it obtains percentages greater than 5% of its mass disaggregation. The samples were exposed to showering in the Inderbitzen for 90 minutes at flow intensities of 3.00L/min. The erodible potential presented different values for each soil sample. The foothills of the Convex Slope - CX showed to be the most erodible of this, with a value of 14.51% of breakdown. The RectilinearSlope - RT presented the top and bottom as more erodible (12.43% and 7.8% respectively). The Concave slope - CV proved to be the most erodible slope of all analyzed, with the percentage of its surface above 20% of disaggregation. It was observed in the sample thirds that the different formats and slopes spatially influence the intensity of soil erosion in each slope third, influencing the variability of the erodible potential along the slopes.