Successive pig slurry application can increase the copper and phosphorus levels in the soil and the losses of these elements by surface runoff and percolation. The objective of this study is to evaluate the losses and the forms of both copper and phosphorus in the surface runoff and also in/on the percolation solution, on soils with successive pig slurry application under no tillage system. The experiment was installed in 2000, at Typic Hapludalf soil. The treatments consisted of successive applications of 0, 40 and 80m³ ha-1 of pig slurry applied on soil surface in no tillage system. Samples of surface runoff and percolated solutions were collected during the life cycle of oat (Avena strigosa) in the 2006 winter, when the soil had a history of 16 pig slurry applications. The following parameters have been evaluated: Cu, P, cation, anion and pH, dissolved organic carbon and electric conductivity. The Visual MINTEQ program version 2.15 was utilized to estimate the copper and phosphorus ionic speciation. The surface runoff is the most important form of copper and phosphorus loss of the soil. In addition, copper was found in the organic form (CuCOD) and phosphorus in the free forms (HPO4(2-) e H2PO4-) in the surface runoff solution. Thus, these elements could be an important source of water contamination in places where pig farming is widespread.
organic fertilizer; soil pollution; environmental contamination
