Forage accumulation and morphogenetic and structural characteristics of Axonopus aureus in the Roraima´s savanna

Abstract

The effects of cutting plant age (21, 28, 35, 42, 49, 56, 63 and 70 days) on dry matter (DM) yield, and morphogenetic and structural characteristics of Axonopus aureus, during rainy season, were evaluated under natural field conditions. The experimental design was a completely randomized, with three replications. Evaluations were carried out during the period of June to August 2009. DM yield, absolute growth rate (AGR), number of tillers plant^-1, number of leafs plant^-1, leaf area, leaf senescence and elongation rates and blade length increased consistently with growth stage. The relations between DM yield and AGR with cutting plants age were described by the quadratic regression model. The maximum DM yield and forage production rate performance were estimated at 62.7 and 49.4 days of regrowth. The crop growth and relative growth rates, tiller and leaf appearance rates were inversely proportional to cutting plant age. These data suggest that cutting at 49 to 56 days were optimal for obtain maximum dry matter yields and improved the grass morphogenetic and structural characteristics.