STUDIES ON THE INFLUENCE OF ANIMAL WASTE ON SOIL FERTILITY. CASE STUDY - PIG SLURRY.

The use of pig slurry as fertilizer has a clear impact on farm-level energy input requirements, being a correct and natural way of its decomposition and also contributing to the reducing of the amount of chemical fertilizers used, which, in addition to the high cost, may leads to the pollution of the areas where they are applied. Swine sludge could provide between 38 and 61% of the nitrogen, phosphorus and potassium in chemical fertilizer. The purpose of the work is to determine the changes that the application of pig sludge, as a fertilizing resource, has on some soil fertility indicators, such as: pH, organic carbon content, C/N ratio and the content of nitrate and ammonium ions. The experiments in the field were carried out on a soil with low fertility, in the pedoclimatic conditions of the western part of Romania. The sludge was applied in doses between 80 and 95 mc/ha, for 4 consecutive years, resulting in acidification of the soil, an increase in the organic carbon content, but also in the content of nitrate ions in the soil. Considering both its fertilizer value and the increasing cost of chemical fertilizers, the economic value of slurry is beyond doubt. [ABSTRACT FROM AUTHOR]