SOIL ERODIBILITY IN AREAS UNDER CITRUS (CITRUS SINENSIS L. OSBECK) AND FOREST IN RONDÔNIA, BRAZIL

Few studies have studied soil erodibility in areas that have undergone conversion processes from native forest to agricultural areas, especially in agricultural frontier regions. The present study aimed to evaluate soil erodibility in areas under citrus (Citrus sinensis L. Osbeck) and forest, using multivariate statistics and geostatistics in areas under different uses in Southern Rondônia, Brazil. A 42 × 30 m grid with regular spacing between sample points of 6 × 6 m was established for the studied native forest and citrus areas at depths of 0.00-0.20 m. At each sampling point, samples with preserved sod structure were collected at the evaluated depth for determination of soil texture and organic carbon, totaling 288 samples in the two studied areas. In the results it was observed that the area cultivated with citrus and under forest presented a greater predisposition of the soil to suffer erosion interril (Kiwepp), the citrus area also presented a greater susceptibility of the soil to suffer erosion in furrows (Krwepp), on the other hand, this area showed high values of critical shear stress, a fact that signals the resistance of the soil to the beginning of the erosive process. On the other hand, the forest area showed a greater predisposition to suffer erosion (K-factor), a fact possibly linked to the high values of silt and sand, which favored the present erodibility conditions.