Como a adubação nitrogenada no inicio do diferimento modifica a produção de forragem e estrutura do capim cayana ?

Abstract

Pasture deferral is a relatively simple technique for providing forage during the dry season of the year, when food is scarce. However, the way this practice is conducted affects the quantity and quality of deferred forage. In this sense, nitrogen fertilization is a strategy that affects the results obtained with pasture deferral. Therefore, the objective of this study was to evaluate the effects of different doses of nitrogen (N) on forage production and canopy structure of deferred cayana grass (Urochloa spp. cv. Cayana). The experiment was conducted at the Capim Branco Experimental Farm in Uberlândia, Minas Gerais, using three paddocks of 2,800 m² each. The treatments were two fertilization conditions: without or with the application of 50 kg/ha of N at the beginning of the pasture deferral period. The start and end dates of the deferral period will be April 14, 2025, and June 21, 2025, totaling 68 days of deferral. At the beginning of deferral, the pastures were 34.5 cm tall. The initial forage mass was similar between the deferred pastures. The forage mass at the end of the deferral period and the forage production rate were higher when the cayana grass was fertilized with N, compared to the deferred pasture without nitrogen fertilization. Cayana grass deferred with 50 kg/ha of N presented higher masses of live leaves (3,905 kg/ha of DM) and live stalks (2,462 kg/ha of DM) when compared to unfertilized pasture (2,497 and 2,154 kg/ha of DM of live leaves and live stalks, respectively). Dead leaf and dead stalk masses were higher in unfertilized pasture (4,616 and 3,231 kg/ha DM, respectively) than in fertilized pasture (4,154 and 2,462 kg/ha DM, respectively).