ARE SWINE WASTES A FERTILIZER OR A SOIL POLLUTANT?

Abstract

The widespread practice of growing swines in high density confined systems leads to large amounts of wastes that must be recycled. The most practical approach at farm level has shown to be the use as a soil fertilizer. Practicability and short-term records of crop yields are not sufficient criteria however, as far as the sustainability of such a system is concerned. As long as the unbalance between the swine wastes composition and the crop demand for nutrients remains, a warning persist about the sustainability of any agricultural system fertilized with such residues yet nutrients will accumulate in the soil where, if in surplus, may cause environmental damage. In this issue some critical points were presented to be thought carefully about regarding to the use of swine wastes as a soil fertilizer, some reasons for the delay in noticing the side effects of such a practice as well as some environmental damage already noticed in regions where these kind of wastes have been applied to the soil in a long-term basis.