Erosion is the main cause of soil degradation, and it leads to adverse effects to agriculture and environment, with social and economic implications. The objective of this study was to evaluate soil and nutrient losses in different soil tillage systems in a typic Acric Red-Yellow Latosol (Oxisol). On five plots with the following soil tillage treatments were evaluated: conventional tillage and down-slope tillage (CMA); conventional tillage and contour seeding (CEN); tillage with one passage of heavy disk harrow and one passage of leveling harrow and contour seeding (CNiv); tillage with two passages of leveling harrow and contour seeding (NA) and no tillage and contour seeding (CMN). The soil losses were determined by the direct method during the cotton crop cycle, from December 2005 to June 2006. Along each runoff sampling, soil samples were withdrawn to quantify the losses of N, P, K and organic carbon (C-org) in the sediments. Decreasing soil tillage lessened the losses of sediments, nutrients and organic carbon, indicating that the CMN treatment was the most efficient. The trends for N, P, K and C-org losses in the sediments were similar to the soil losses. N, P and K varied according to the fertilizers used. The constituent with the highest concentration in the sediment was C in organic compounds. The basic infiltration rate differed among the treatments in the following order: CMA < CEN <img src="/img/revistas/rbcs/v33n3/a21apro.gif" align="absmiddle"> CNiv <img src="/img/revistas/rbcs/v33n3/a21apro.gif" align="absmiddle"> NA < CMN, indicating that tillage systems that reduced soil revolving and increased organic C, increased the basic infiltration rate and decreased soil erosion.
erosion; organic carbon loss; basic infiltration rate
