Forage production and morphogenesis of “Trachypogon vestitus” under different regrowth ages in the Roraima’s savannas

Abstract

The effects of plant age regrowth (21; 28; 35; 42; 49; 56; 63 and 70 days) on dry matter yield, and morphogenetic and structural characteristics of Trachypogon vestitus, submitted to burning, during rainy season, were evaluated under natural field conditions. Evaluations were carried out during the period of May to July 2009. The dry matter yield, absolute growth rate, number of tillers/plant, number of leafs/plant, leaf area, leaf senescence and elongation rates and blade length increased consistently with growth stage. The relations between dry matter yield and absolute growth rate, elongation leaf rate and medium leaf length with cutting plants age were described by the quadratic regression model. The maximum dry matter yield, absolute growth rate, leaf elongation rate and leaf blade length were estimated at 65.8, 50.1; 43.4 and 62.0 days of regrowth. The crop growth and relative growth rates, tiller and leaf appearance rates and nitrogen contents 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.