Água residuária de suinocultura associada à adubação mineral em culturas de milho, aveia e soja

Abstract

This study aimed at evaluating the agronomic and environmental aspects as results from the continuing application of swine wastewater and mineral fertilizer in corn, black oats and soybeans. The experimental area has a history of swine wastewater application with trials that have been carried out since 2006, whose cycles under management are the seventh, eighth and ninth ones. Four doses of swine wastewater associated with the presence and absence of mineral fertilizer consisted on eight treatments applied to experimental plots. The agronomic and nutritional indices were determined in the three studied crops. The compounds of leachate collected at the beginning and end of each cycle were also recorded as well as soil characteristics at the beginning and end of each crop. The experimental design was in randomized blocks, under a 4x 2 factorial scheme with three replications. The results were submitted to ANOVA and means compared by Tukey test at 5% significance level. In maize crop, after a swine wastewater application, treated in digester, it could be observed that it could be partially used as an alternative fertilizer, since P and Mn+2 were supplemented with specific fertilization. A special management should be given to the accumulation of Fe+2, Cu+2 and Zn+2 in soil. Attention should be paid also to the levels of Cu+2, Fe+2, Mn+2, NO3-+NO2-, Na+ and Zn+2 in leachate material. In black oats crop, after two applications of swine wastewater treated in digester, it was concluded that swine wastewater can be partially used as an alternative fertilizer, since N, P and S could be supplied. Some attention should be taken with Cu+2 and Zn+2 accumulation in soil and some special care should also be given to the leaching of Cu+2, Fe+2, Mn+2, NO3-+NO2-, Na+ and Zn+2. In soybean crop, after three applications of wastewater treated in digester, the remaining wastewater could be partially used as an alternative fertilizer, since N, P, K+ and S were supplied by specific fertilization. There must have extra attention to the accumulation of Fe+2, Cu+2 and Zn+2 in soil as well as to percolation of Cu+2, Fe+2, Mn+2, NO3-+NO2-, Na+ and Zn+2 According to leachate.