Nitrogen return in an integrated crop-livestock system with irrigation and forage legume

Expanding the use of different practices in integrated crop livestock system (ICLS) is essential to understanding the dynamics of nitrogen (N) return. This study evaluated the influence of legume and irrigation on nitrogen return in ICLS. The four treatments were: irrigated and non-irrigated x intercropped and not intercropped with legume, in a 2x2 factorial scheme in randomized blocks experimental design with three replications. The ICLS area was cultivated, in winter, with pasture of black oat (Avena strigosa) and ryegrass (Lolium multiflorium) overseeded in african star (Cynodon sp.), and vetch (Vicia sativa) in the intercropped paddocks, with rotational grazing method. And, in summer, with corn (Zea mays). Data were subjected to analysis of variance (F test, p<0.05). There were no significant effects of irrigation and legumes on the return of N through feces, urine, and pasture residues. Grain yield, straw, extraction, export, and return of N by corn were similar among treatments. The average total N return was 335.61 kg ha-1. Irrigation and intercropping with legumes did not influence N return in ICLS, after one-year evaluation.