Potencial produtivo e valor nutritivo do capim faixa branca submetido à adubação nitrogenada

Abstract

The difficulty in producing forage to meet the needs of grazing ruminants is due to weather problems, especially in regions where there is scarcity of rain. Allied to this, the little knowledge evaluating forage grasses adapted to drought conditions as in northeastern Brazil. Therefore this study was performed to evaluate the productive potential of the grass White Band (Digitaria eriantha Steud. Cv. Survenola) when subjected to nitrogen fertilization levels. The experimental period of 365 days beginning on August 1, 2014 and ending on July 31, 2015. The experiment was conducted in the laboratory of forage practices in the area of the Department of Animal Science of the Federal University of Sergipe. The treatments consisted of five nitrogen rates (0, 50, 100, 300 and 600 kg ha-1 yr-1) distributed in installments in the experimental units, using urea as nitrogen fertilizer. The experimental design was a randomized block design with four replications, totaling twenty experimental units. Nitrogenous fertilizers were divided in ten applications, performed after each cut forage. Overall, the increase in the amount of nitrogen applied resulted in increased foliage heights, light interception (LI) and leaf area index (LAI) arising from the increase in population density of total tillers (DPT) and basal (DPB). Nitrogen fertilization influenced positively the total dry matter production rate (MST), leaf (MSF) and stem (MSC) due to increase in pitch height, LAI, DPT and DPB. As for the qualitative aspects the accumulation of total dry matter (AT), dry matter leaf (AF) dry matter stem (AC), total volumetric density and stem the increase in crude protein, accumulated crude protein and total digestible nutrients (NDT) accumulated were influenced by nitrogen doses adjusting to a positive quadratic equation (P <0.05). the improvement in morphological, productive and qualitative characteristics of grass range White reach maximum values with nitrogen levels around 450 kg ha-1.