Effects of increasing nitrogen levels in Mombasa grass on pasture characteristics, chemical composition, and beef cattle performance in the humid tropics of the Amazon

Improving beef cattle production in pasture-based systems without expanding agricultural land has been the focus of several studies over the last decades. Nitrogen fertilization is one of the available strategies with high potential to optimize cattle performance in tropical systems. This study aimed to evaluate the effects of increasing nitrogen levels (150, 300, and 450 kg ha −1 of N year −1 ) in Megathyrsus maximus cv. Mombasa in the humid tropics of the Amazon. The following parameters were evaluated: pasture agronomic characteristics, herbage chemical composition, and beef cattle performance. A total of 24 nine-month-old Nellore bulls with initial mean weight of 173 ± 1.95 kg were used for the performance test. The experimental design was a randomized block with three treatments. Herbage mass and leaf mass contents were increased by the highest nitrogen level ( P