Doses de fósforo e nitrogênio na produção de Brachiaria hibrida cv. Mulato II

The nutritional deficiency of Brazilian soils is one of the main factors limiting the production of fodder, and nitrogen and phosphorus nutrients that influence more biomass production. The objective was to evaluate the vegetative growth of Brachiaria hibrida cv. Mulato II under different phosphorus levels with and without nitrogen in northern Mato Grosso. The experimental design was a randomized complete block in a factorial 5 x 2 x 3 with three replications. The treatments consisted of application of five doses of phosphorus (0, 45, 90, 135 and 180 kg ha-1 P2O5), presence and absence of nitrogen (0 and 100 kg ha-1 of N) and three times with 30 intervals days. Shoot cuts were made at a height of 20 cm from the ground to determine the dry mass of leaves, dry weight of stem and total dry mass. For dry mass production leaves significant difference for phosphorus levels in isolation and interaction of nitrogen and cuts. In total dry mass were no significant differences for the double interactions of nitrogen and cuts, phosphorus and nitrogen, and phosphorus and cuts. As for the production of dry mass of stems, significant triple interaction for levels of phosphorus, nitrogen and cuts. The dry mass of leaves, stem and all responded positively to the application of 180 kg ha-1 match with the presence of nitrogen.