Highlights:The best results for the rest period were found in the range of 280 to 333 kg ha -1 of N. The dose of 450 kg ha -1 of N provided the desired results when using a fixed rest period. The rest period alleviated the process of senescence, especially given application of higher nitrogen doses.
AbstractThe goal of this study was to evaluate the morphogenic and structural characteristics of Marandu grass cultivated under grazing management and nitrogen fertilization. The experimental design was a completely randomized 4 × 2 split-plot design with four blocks. The treatments consisted of combinations of two rest periods (28 days -RP Fixed -and height of 40 cm -RP Var ) and four nitrogen doses (0, 150, 300, and 450 kg N ha -1 year -1 ) applied as ammonium sulfate. The following variables were analyzed: leaf appearance rate (LAR), phyllochron, leaf elongation rate (LER), stem elongation rate (SER), leaf senescence rate (LSR), leaf life span (LLS), average length of leaf blade (ALLB), sheath length (SL), number of live and dead leaves (NLL and NDL), and tiller population density (TPD). The variables LAR, LER, SER, ALLB and SL presented positive linear relationships with RP Fixed and a quadratic relationship with RP Var , considering the application of the N doses. As for phyllochron and LLS, a negative linear relationship was observed with RP Fixed and a quadratic relationship with RP Var . The N doses caused an effect on LSR, following the quadratic model for both rest periods studied. NLL and NDL exhibited linear effects on RP Var . The best indexes for the rest period variable were obtained when nitrogen was applied in the range of 280 to 333 kg ha -1 , whereas the dose of 450 kg ha -1 of N provided desired results when using a fixed rest period. The rest period alleviated the process of senescence, especially given the application of higher nitrogen doses Objetivou-se avaliar as características morfogênicas e estruturais do capim Marandu submetido a estratégias de pastejo e adubação nitrogenada. Realizou-se o experimento em delineamento em blocos casualizados com parcelas subdivididas 4x2 com 4 blocos. Os tratamentos foram combinações entre dois períodos de descanso (28 dias -PD Fixo -e altura de 40 cm -PD Var ) e quatro doses de nitrogênio (0, 150, 300 e 450 kg N ha -1 ano -1 ), sendo o N aplicado na forma de sulfato de amônio. As variáveis analisadas foram: taxa de aparecimento foliar (TApF), filocrono, taxa de alongamento foliar (TAlF), taxa de alongamento de colmo (TAlC), taxa de senescência foliar (TSF), duração de vida foliar (DVF), comprimento médio de lâmina foliar (CMLF), comprimento de bainha (CB), número de folhas vivas e mortas (NFV e NFM) e densidade populacional de perfilhos (DPP). As variáveis TApF, TAlF, TAlC, CMLF e CB apresentaram comportamento linear positivo para PD Fixo e quadrático para PD Var com aplicação das doses de N. Filocrono e DVF apresentaram comportamento linear negativo para PD Fixo e quadrático para PD Var . A TSF apresentou efeito com as doses de N, enquadrando-se no modelo ...