The objective of this experiment was to evaluate the structural characteristics and agronomic traits of Brachiaria brizantha cv. Xaraés under different nitrogen levels (0, 125, 250, 375 and 500 kg.ha-1 of N) grown in Campus Rondonópolis, Mato Grosso, in the period 10/12/2006 to 08/23/2007. The treatments were arranged in a randomized design with four repetitions. The results were submitted to statistical analysis by grouping the data into two periods: rain and throughout the year. The N influenced the number of leaves appeared at the time rainy, and the number of green leaves. The number of leaves was influenced by N rates during the rain and throughout the year. There was an increase of 27% in the average length of the leaf blade to the dose of 343.9 kg ha-1 N for the rainy season. The density of tillers was influenced by N rates for both evaluation periods. Since the height of the plants was influenced by N rates for the two seasons evaluated. The increased availability of dry per hectare was 87.5% for the highest N in the water (333.3 kg ha-1 N) compared with the control treatment. Nitrogen fertilization positively influences all characteristics related to growth and production mass, especially during the rainy season, when the fertilization must be divided into four or five doses, with no need for fertilization in the dry season.
morphogenesis; nitrogen fertilization; pastures; tillering
