Agronomic and Bromatological Traits of Brachiaria brizantha cv. Piatã as Affected by Nitrogen Rates and Cutting Heights

Abstract

This study aimed to evaluate the bromatological traits of Brachiaria brizantha cv. Piatã submitted to different cutting heights and nitrogen (N) rates. A randomized complete block design with sixteen treatments and four replications was used. The treatments arranged in 4x4 factorial arrangement, comprised four cutting heights (8, 16, 24 and 32 cm) and nitrogen rates (0, 100, 200, 300 kg N ha-1). N rates were applied after a standardization cutting. Agronomic traits comprised number of tillers, dry mass, leaf blade pseudocolus ratio and amount of senescent material. Bromatological traits of morphological components leaf blade and pseudostem comprised crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and mineral matter (MM). In the first and second cuttings, maximum yields were obtained at 16 and 32 cm cutting heights combined with N rates of 180.5 and 230.5 kg ha-1, respectively. No interaction was observed between N rates and cutting heights. It was concluded that 16 and 24 cm cutting heights combined with N rates of 200 and 300 kg ha-1 improved agronomic and bromatological traits of Brachiaria with a better efficiency in pasture system.