Forage dry matter production of native pastures in southern Brazil is usually low due to the restricted soil nutrient availability - a limitation that can be compensated by application of liquid swine manure. In an experiment carried out from November 1995 to November 1999, in an area near a swine farm in Paraíso do Sul County, Rio Grande do Sul State, the efficiency and frequency of liquid swine manure application in relation to dry matter production and nutrient uptake by native grass pasture were evaluated. Liquid swine manure (0, 20 and 40 m³ ha-1) was applied every 45 to 60 days. Before each manure application, the pasture dry matter was measured and the plots mowed. A dose of 20 m³ ha-1, applied at intervals of 45 to 60 days, was most efficient to supply nutrients for the native grass pasture. Phosphorus amounts introduced by the liquid swine manure were much greater than what was taken up by the pasture. Potassium and Mg contents in the liquid swine manure should be carefully considered, due to their high extraction rates by the native pasture. During the low temperature periods of fall and winter, when the dry matter production of the native pasture is restricted, a reduction in manure application rates becomes necessary.
pig slurry; animal residues; manure