Alterações e transferências de fósforo do solo para o meio aquático com o uso de dejeto líquido de suínos

Abstract

The pig slurry may work as nutrients source, however when is used is an improper way can cause accumulation of phosphorus in the soil, that later can be transferred to the aquatic environment causing eutrophication. Objective of this study was to evaluate alterations in soil phosphorus content and in sorption isotherms and his transfer for the aquatic environment by runoff and percolation flow with continue use of pig slurry. The experimental work was developed in the Federal University of Santa Maria, in a Typic Hapludalf under not tillage with superficial application of 0, 40 and 80m3 ha-1 of pig slurry for a period of five years. The phosphorus content was measured in the whole soil profile and the sorption isotherms in the 0-2,5cm and 30-60cm layers. In the runoff water and percolated water, it was determined the volume of transferred water and the forms of soluble, particulate, particulate bioavailable, particulate potentially bioavailable and total phosphorus. The increase in applied rate of pig slurry increased the content of extracted phosphorus by Mehlich-1 in the whole profile, consequently it reduced the maximum capacity of sorption and the constant of related energy to bound phosphorus, increasing the equilibrium phosphorus concentration in the soil. The applied of pig slurry potentially increased the phosphorus transfers by runoff and percolation flow reaching concentrations higher than the legislation established representing a potential of environmental contamination for eutrophication.