Aggregate Stability in Two Soils Under Different Uses and Managements

This study was carried out in Jardim Novo Horizonte sub-basin river, in Ilha Solteira municipality, northwest São Paulo state, Brazil, a region with environmental issues such as soil erosion and river silting. The aim of the research was to assess the aggregates stability in the soils of the sub-basin river in order to verify the susceptibility to erosion. Soils in the sub-basin river are classified as Oxisol and Alfisol, both with medium texture. The analysis was carried out in samples from ten locations, six located in the Oxisol and four in the Alfisol and in each location five replications were made consisting of the following uses: one with mango cropping, four with pasture and one with an annual crop in the Oxisol and two with pasture, one with annual crop and one with forest fragment in the Alfisol. The different uses and managements influenced aggregate stability only in the Oxisol. The areas cropped with pasture presented the highest percentages of the largest aggregate classes in the two soils studied. The opposite effect was observed in the areas under annual crops, with greater percentages of the small aggregate classes. The greatest mean weighted diameter values were found for the pasture and the smallest for the annual crops, regardless of the soil. The areas cultivated with annual crops had a higher susceptibility to erosion.