CARACTERÍSTICAS ESTRUTURAIS E PRODUTIVAS DE BRACHIARIAS, AO LONGO DAS ESTAÇÕES CLIMÁTICAS, FERTILIZADAS COM ADUBAÇÃO QUÍMICA

Abstract

This research aimed to evaluate the effect of nitrogen fertilization on the forage production of brachiaria cultivars, and how this management can interfere with the seasonality production between the wet and dry seasons. The experimental period comprised the dry and wet periods of the 2021/2022 harvest. The Marandu, Mavuno, Xaraés, G172, G153 and G156 cultivars were distributed in the plots, in a randomized block design, while in the subplots the cover fertilizations (0 to 80 kg ha-1 N) were allocated, in which it was divided in two doses of 40 kg ha-1 N, applied during the rainy season, between November and January, the highest rainfall, with four replications per treatment, totaling 48 experimental units. The Marandu cultivar was used as a marker for defoliation management, and cuts were made when it reached between 35 and 40 cm during the rainy season. There was no interaction between brachiaria cultivars and fertilization for the dry season variables. Cultivars G153 and G172 showed higher values in the rainy season for the variable percentage of mass per leaf blade. The Mavuno cultivar stood out in the number of live leaves per tiller with 2.35 leaves. For the tiller density variable, the cultivars G153, G156 and Marandu showed higher values than the other cultivars when there was no fertilization. On the other hand, when the cultivars received fertilization, the G153 presented a greater number of tillers. It was observed that the forages in the rainy season showed a higher production, with emphasis on the variables total dry mass, mass per leaf blade and percentage of leaf blade. Even with fertilization of 80 kg N ha-1, divided into two applications of 40 kg N ha-1, in the water, there was no residual effect during the dry period.