Effect of nitrogen fertilizer sources on forage production and performance of cattle reared in marandu grass pasture

Abstract

Brazil has the largest commercial herd of cattle in the world, but poorly managed and degraded pastures result in low productivity, due to a drop in performance per animal and productivity. Nitrogen fertilization makes nitrogen available in different ways depending on the fertilizer source, which can change forage quality and, consequently, pasture productivity. This study aims to evaluate the productivity of a marandu grass pasture, evaluating the effects of different sources of nitrogen fertilizers on forage mass production and yields per animal and per area. The study will be conducted at FCAV/UNESP Campus of Jaboticabal-SP during the growing phase of animals kept in marandu grass pastures managed at heights between 25 to 30 cm, in a continuous stocking system and variable stocking rate. Forty-eight non-castrated male testers of the Nellore breed (Bos taurus indicus) with an average body weight of approximately 230 kg will be used. The study will consist of four treatments: 1 - no nitrogen fertilizer + agricultural gypsum; 2 - urea fertilization + agricultural gypsum; 3 - fertilization with ammonium sulfate; 4 - ammonium nitrate fertilization + agricultural gypsum, where 12 paddocks will be used, 3 repetitions (paddocks) per treatment. Forage mass, forage supply, morphological composition of pastures and animal performance will be measured. The hypothesis of this study is that ammonium sulfate and ammonium nitrate + agricultural gypsum nitrogen fertilizers will provide greater weight gains per area as a result of greater forage production.(AU)