Cycling of winter forage nutrients under integrated crop-livestock systems

This study aimed to evaluate the decomposition and release of nutrients from the remaining straw of two annual forage species conducted in an integrated crop-livestock system (ICLS). The experimental design used was randomized blocks, in split plots, with three replicates. The managements were allocated in the plots (52 m(2)): without grazing, one grazing, and two grazings. Subplots were defined by material collection times after the forage's desiccation (0, 30, 60, 90, and 120 days after desiccation). Dry matter yield, amounts of carbon, nitrogen, phosphorus, and potassium, and half-life time were evaluated. Oat cultivar IPR Esmeralda had the highest initial dry matter yield (6,099 kg ha(-1)) when not grazed, while triticale cultivar IPR 111 showed the highest average values when subjected to grazing (8,088 kg ha(-1)). The amounts of N, P, and K released from the remaining dry matter, regardless of the management adopted, decreased over time. Potassium was the nutrient that presented the most accelerated release, with an average half-life of 14 days. When subjected to grazing, triticale is more efficient in nutrient cycling, providing 197, 38, and 231 kg ha(-1) of N, P, and K, respectively, with a half-life time of 10, 37, and 25 days, respectively. Forage species can improve the cycling of nutrients and make them available to crops in succession in the ICLS.