Bromatological composition and nutrient concentrations of Brachiaria grass fertilized with nitrogen and phosphorus

Abstract

The experiment was conducted to evaluate the chemical composition of the leaf blade and stem + sheath of Brachiaria decumbens Stapf., fertilized with nitrogen and phosphorus. The completely randomized design was used, with three repetitions, in a 4 x 3 factorial scheme, with four doses of nitrogen (0; 100; 200 and 300kg/ha/year), and three doses of phosphorus (0; 50 and 100kg/ha/year). The potassium was applied 40kg/ha/year. The dry matter content decreased as nitrogen levels increased. The nitrogen content increased with increasing doses of nitrogen. The neutral detergent fiber (NDF) and acid detergent fiber (ADF) percentages of leaf and stem + sheath decreased with increasing of nitrogen doses. The phosphorus concentration in the leaf blade and stem + sheath decreased as increased nitrogen levels, with linear and quadratic effect. The calcium concentration in the leaf and stem + sheath showed a quadratic effect and the concentration of magnesium in the leaf blade increased with the nitrogen. The levels of nitrogen fertilization alters the chemical composition of Brachiaria decumbens grass, and the phosphorus did not influence the chemical composition. Increasing doses of N is a major factor in reducing the NDF and ADF levels in leaf blade and stem + sheath.