System fertilization in the pasture phase enhances productivity in integrated crop-livestock systems

Abstract

Different fertilization strategies can be adopted to optimize the productive components of an integrated crop-livestock systems. The current research evaluated how the application of P and K to soybean (Glycine max (L.) Merr.) or Urochloa brizantha (Hochst. ex A. Rich.) R. D. Webster cv. BRS Piatã associated with nitrogen or without nitrogen in the pasture phase affects the accumulation and chemical composition of forage and animal productivity. The treatments were distributed in randomized blocks with three replications. Four fertilization strategies were tested: (1) conventional fertilization with P and K in the crop phase (CF-N); (2) conventional fertilization with nitrogen in the pasture phase (CF + N); (3) system fertilization with P and K in the pasture phase (SF-N); (4) system fertilization with nitrogen in the pasture phase (SF + N). System fertilization increased forage accumulation from 15 710 to 20 920 kg DM ha/year compared to conventional without nitrogen. Stocking rate (3.1 vs. 2.8 AU/ha; SEM = 0.12) and gain per area (458 vs. 413 kg BW/ha; SEM = 27.9) were higher in the SF-N than CF-N, although the average daily gain was lower (0.754 vs. 0.792 kg LW/day; SEM = 0.071). N application in the pasture phase, both, conventional and system fertilization resulted in higher crude protein, stocking rate and gain per area. Applying nitrogen and relocate P and K from crop to pasture phase increase animal productivity and improve forage chemical composition in integrated crop-livestock system.