Biochar, farmyard manure and poultry litter on chemical attributes of a Distrophic Cambissol and soybean crop

Abstract

The use of organic wastes, as an alternative to inorganic fertilizer, can be an important strategy for Brazilian agriculture. The objective was to evaluate the residual effects and the agronomic efficiency of organic amendments use on chemical attributes of a Haplic Cambisol and to soybean crop. A field experiment was carried out in a completely randomized split-plot design with three replications in Minas Gerais, Brazil, 2008/09. In the plots, the sources of organic amendments were evaluated (poultry litter, farmyard manure, and biochar) using three application rates (3, 6 and 9 Mg ha -1) into the subplots, and control treatment without amendments. Agronomic efficiency of the wastes linearly increased with the doses, independent of the organic source. Poultry litter, a nutrient-rich organic amendment, increased the soybean grain yield. The biochar use boosted the availability of calcium and magnesium levels in the soil, and a consequent increase in the sum of bases, base saturation, pH and effective cation exchange capacity of the soil. The poultry litter utilization enhances the soil acidity and availability of potassium, sulfur and zinc, over the time. The use of organic amendments increases the levels of phosphorus, potassium and zinc in the soil, after soybean cropping.