Perdas de solo e nutrientes por eros?o num Argissolo com resíduos vegetais de cana-de-a?úcar

摘要

The objective of this study was to determine the losses of soil, organic matter (OM) and nutrients (P, K, Ca, and Mg) caused by erosion in an area cultivated with sugarcane containing controlled amount of crop residues in soil surface, in Catanduva city, S?o Paulo State, Brazil. The soil at the experimental site is an Alfisol. Test plots were 0 (CS0), 50 (CS50) and 100% (CS100) of crop residues cover, submitted to simulated rainfall simulated of 60 mm h-1, during 65 minutes. Analyses of the eroded sediment indicate an enrichment ratio of 2.7 - 1.9 (OM), 3.8 - 2.7 (P), 1.3 - 1.7 (K), 3.9 - 3.6 (Ca), and 2.9 - 2.6 (Mg) times in relation to the CS0 and CS50, respectively. The CS50 was more efficient for controlling the erosion processes in 69%, but not for the reduction of the OM and nutrients losses in the eroded sediment. On the other hand, CS100 was efficient for erosion control of 89% and in the reduction of OM (69%), P (88%), K (23%), Ca (74%) and Mg (75%) in the eroded sediment.