MINERAL NITROGEN IN SOIL LEACHATE AFTER PIG SLURRY APPLICATION

Pig slurry is used as a fertilizer in agricultural soil. The intensification of swine breeding, along with high concentration of animals in small properties, generates great volumes of manure. Pig slurry has high nitrate content, which may contaminate surface and subsurface waters. This study aims to evaluate the environmental impact of pig slurry application in Ultisol and Alfisol samples. For this purpose, pig slurry doses obtained from distinct production systems (farrowing and finishing units) were applied in the following amounts: 0 m(3).ha(-1) (Control Treatment), 75 m(3).ha(-1) (T2), 150 m(3).ha(-1) (T3) and 300 m(3).ha(-1) (T4). Results showed presence of N-NO3-+N-NO2- in Alfisol and Ultisol leachates, and the pig slurry originated from farrowing units showed lower concentration of N-NO3-+N-NO2- for both soil leachates. The higher concentration of N-NO3-+N-NO2- in the leachate for both soils was at 19 days after the pig slurry application. Before using pig slurry as a fertilizer it is mandatory to establish criteria for the elaboration of management and provision strategies, in order to reduce environmental and health impacts.