Sources and rates of nitrogen fertilizer used in Mombasa guineagrass in the Brazilian Cerrado region

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.