Fontes de nitrogênio na adubação do capim mombaça em sistema silvipastoril na amazônia oriental

Abstract

In a silvopastoral system, the light restriction imposed by shading compromises the production of fodder and changes its morphological components. The use of nitrogen in the fertilization of these forages can contribute to increase productivity. The use of protected fertilizers and sources less susceptible to volatilization and leaching can reduce nutrient losses. Therefore, the objective was to evaluate the use of nitrogen sources in the fertilization of mombaça grass (Megathyrsus maximus) in the silvopastoral system. The work was carried out in the experimental field of the School of Veterinary Medicine and Zootechny of the Federal University of Tocantins, Araguaína campus. The experiment was performed in randomized blocks in a 4x2 factorial scheme, with four repetitions, being three nitrogen sources (urea, ammonium sulfate and protected urea) plus treatment without nitrogen fertilization, both evaluated in two cultivation systems (single Mombasa and Mombasa in silvipastoril). The variables were evaluated: plant height, number of tillers, leaf area index, percentage of components (leaves, stems and dead material), leaf: stalk ratio and total dry mass. The evaluated systems provided changes in the characteristics of plant height, number of tillers, percentage of leaves, percentage of stalk and total dry mass of Mombasa grass. Of the variables mentioned, only the percentage of leaves did not vary the efficiency of the systems due to nitrogen fertilizer. Without nitrogen fertilization there is no difference in productivity between the systems. With application of nitrogen sources, the monoculture system provides greater productivity.