Volatilization nitrogen losses in organic and inorganic fertilizers during winter and spring applications: dry matter production of Tanzania Grass.

Abstract

Brazilian's grasslands stocking rates demonstrate low utilization of this resource once research and some producers have reached higher potential rates. Lower forage production during the winter time limits raises in the stocking rates because Brazilian cattle raisers keep these rates compatible to lower forage production seasons. The efficient use of fertilizers and soil fertility correctives can raise pasture productivity through increments in the forage production and it allows higher grazing efficiencies when it increases the animal stocking rate of the area. Nitrogen is the most important nutrient once it promotes quicker re-establishment of the leaf area index, due increases in the tiller production and in the leaf elongation rates. After grazing, nitrogen is mobilized to the first leaf formation and higher internal levels of this nutrient in the plant can promote quicker regrowth rates. The nitrogen fertilizer application in the end of the winter season to accelerate the growth in the beginning of the rainy season is not explored. The aim of this study will be evaluate nitrogen fertilization effects, during the winter and the beginning of spring, in the forage dry matter production and fertilizers nitrogen volatilization. Two inorganic nitrogen sources in three ways of application, one organic nitrogen source in one way of application and a control treatment without any nitrogen fertilization will be evaluated, totaling 5 treatments with 5 replicates each.