Abstract

Brazilian Cerrado is constituted largely by extensive grazing. In this region, livestock production indices are low, because the producers do not perform a soil amendment. The aim of this work was to study a pasture with high production potential using sources and rates of nitrogen (N). Nitrogen sources used were: Ammonium nitrate, ammonium sulfate, ammonium sulphonitrate, sulfammo and urea applied on the basis of 100 kg ha^-1 per harvest, and N rates (0, 50, 100, 150 and 200 kg ha^-1 per harvest), using urea as source, in five harvests. The forage used was [Panicum maximum (syn. Megathirsus panicum) cv. Mombaça], and were evaluated:  Dry matter yield (DMY), crude protein (CP), neutral detergent fiber (NDF) and acid detergent fiber (ADF). Dry matter yield increased on the second harvest, as a function of N rates. Acid detergent fiber and NDF concentrations there were no significant to the sources, and no adjustment with increasing of N rates. Crude protein content showed no adjustment for the N rates, as well as the N sources were not significant. Because the N performance, we recommend the urea, as this is more affordable and the application of 50 kg ha^-1 of N for the maintenance of the Mombasa guineagrass.

Key words: Acid detergent fiber, crude protein, dry matter yield, neutral detergent fiber, Panicum maximum.