Productive characteristics of Convert HD364 grass under low level of technology and different cutting heights during the rainy-dry season

For greater efficiency in pasture use, an efficient management is important, and for the most common cultivars grasses, there is a wide knowledge, but those that have recently been released, such as the Brachiaria hybrid cv. Mulato II (Convert HD364), many research are necessary. This study aimed to evaluate grass green mass, dried mass (Dmass), volumetric density (VD) and crude protein (CP) production of Convert HD364 grass managed with low fertilization and different cutting heights (30, 45, 60 and 75 cm) in the rainy-dry season (from April to June 2015). The experiment was carried out at the Federal University of Mato Grosso, and the design was completely randomized, with four treatments (cutting height) and six repetitions. When it reached the predetermined heights, forage was cut. It was utilized three squares (0.25 m?) and a 15 cm of residue was left. The collected samples were weighed to determine the green forage mass. Then the material was homogenized and a subsample, were dried in a forced-air oven during 72 hours at 55?C. Data were, submitted to analysis of variance and regression considering a significance level of up to 5% probability. Grass green mass (? = 39336.20-1010.73x+10.80x², R² = 0.75), Dmass (? = 14752.18-485.87x+5.30x², R² = 0.98), VD (? = 405.84-11.17x+0.10x², R² = 0.96) and CP production (? = 1056.89-28.56x+0.25x², R² = 0.80) adjusted for quadratic regression model (P < 0.05), with lower values at 46.79, 45.83, 57.12 and 55.85 cm, respectively. At 30 cm, more cutting frequency was obtained in relation to 45, 60 and 75 cm, implying in similar Dmass (5057.40 kg dry matter ha^-1) in relation to greater heights (5016.35 and 8029.32 kg dry matter ha^-1, respectively for 60 and 75 cm). Considering that in low fertilization management grasses growth at slow rates, lower height management allowed better characteristics, higher VD (160.74, 105.69, 95.64 and 130.29 kg ha^-1 cm^-1 respectively for 30, 45, 60 and 75 cm) and best CP production (443.52, 244.10, 303.00 and 332.82 kg ha^-1, in the same order). For Convert HD364 grass, with low fertilization, management at 30 cm allows the best productive characteristics during rainy-dry season.