Desempenho agronômico e indicadores qualitativos da forragem de capim marandu sob estratégias de manejo e aporte de nitrogênio

Abstract

The objective of this study was to evaluate agronomic characteristics and the nutritive value of Urochloa brizantha cv. Marandu forage as affected by management strategies and nitrogen supply. The experiment was carried out in Sinop, Mato Grosso, Brazil, at Embrapa Agrosilvopastoral, from October 3, 2012 to May 16, 2013, in a randomized complete block design in a 2 x 4 factorial arrangement with three replications. The factors were two harvest strategies: 25 cm of canopy height and 28 days of rest period; 4 strategies of nitrogen supply: 0, 80 kg of N.ha-1, only 80 kg of inoculant and N.ha-1 inoculant. Pre-harvest samples were collected to characterize forage accumulation, morphologic composition and nutritive value. Data were analyzed using of SAS system. The 25 cm strategy had the higher rest period, which results in higher forage (2430 kg.ha-1) and leaf (1515 kg.ha-1) accumulation. While the 28 days strategy registered lower forage and leaf accumulation (1860 and 1230 kg.ha-1, respectively). Nitrogen supply associated to biological nitrogen fixation increases leaf proportion on the Marandu palisadegrass. Crude protein on the pre-harvest forage mass enhance when associated Azospirillum brasilense with mineral fertilizer.