Desempenho produtivo, composição química e morfogênese de Megathyrsus maximus cv. Tamani sob períodos de descanso

Abstract

The effects of pasture rest period (14, 21, 28, 35 and 42 days) on green dry matter (GDM) yield, chemical composition and morphogenetic and structural characteristics of Megathyrsus maximus cv. Tamani were evaluated under natural field conditions at the Roraima´s savannas. The decrease of rest period resulted in higher GDM yields, however implied significant decreases in the levels of nitrogen, phosphorus, calcium, magnesium and potassium. The leaf appearance rate and tiller populational density are inversely proportional to rest period, occurring the inverse for leaf senescence rate. Maximum GDM yields, number of live leaves tiller-1, average leaf length, leaf expansion rate and leaf area index were obtained with rest periods of 38.4; 30.4; 33.8; 15.2 and 36.2 days, respectively. These data suggest that pasture grass grazing at 35 days of rest period were optimal for obtain maximum yields and regrowth of rich forage.