Lixiviação de nutrientes em solo após aplicação de biofertilizante

Abstract

The use of biofertilizer from the biodigestion of swine wastewater in the soil is notable for allying the wastewater treatment and final disposal from this activity with the water reuse in the production system and the complementation of the chemical fertilization of the crops, however, if performed indiscriminately, it presents high contaminant potential of groundwater due to the leaching of nutrients in the soil. The objective was to evaluate the effects of nutrient leaching after application of swine biofertilizer. The treatments consisted of 4 biofertilizer application doses 0 (control), 50, 150 and 250 m³ ha-1 , with 9 replications per treatment, submitted to irrigation film of 125% potential evapotranspiration applied during the italian zucchini crop cycle, in order to allow percolation and collection of the leached material by lysimeters. The lysimeters was filled with red-yellow Latosol and the biofertilizer was applied in a single dose. The samples were collected 10 times over time to analyze the proposed parameters. The experimental design was completely randomized with plots subdivided in time, being 4 treatments, 10 collections and 9 replications. It was evaluated Kjeldahl nitrogen, nitrate, phosphorus, pH and amount leachate. The biofertilizer application provided lower pH values, lower leachate phosphorus concentrations and higher Kjeldahl nitrogen and nitrate concentrations in the leachate. There was no effect of the biofertilizer doses on the leached volume.Nitrate concentrations in the leachate at the highest peaks of loss were higher than the limit proposed in the legislation, indicating groundwater contamination potential. The dose of 50 m³ ha-1 was recommended due to the lower impact in relation to groundwater contamination, considering nutrient leaching.