Padrões de desfolhação e dinâmica de perfilhamento nos estádios vegetativo e reprodutivo do azevém

Abstract

The study was conducted with the objective to evaluate the intensity and frequency of defoliation and the tillering dynamics of ryegrass (Lolium multiflorum Lam.) of stages vegetative and reproductive, under rotational grazing. The interval between grazings was set by the thermal sum required for the appearing of 1.5 ryegrass leave (187.5 ºGD). The experimental design was completely randomized, with two phenological stages and six replicated areas for each stage. In the vegetative stage, the intensity defoliation (54%) it was similar in the different types of leaf blades. In the reproductive stage, the intensity of grazing was higher in leaves growing (78%) in relation to the expanded and senescent leaves (67%). Heifers explored 16.7% more grazing area in the reproductive stage compared to vegetative. The most removal intensity the leaves of expansion and the higher frequency defoliation are compensatory mechanisms used by animals when the ryegrass is located the reproductive stage. The first generation of tillers have greater longevity compared to other generations, contributing 58% of total tillers in the late vegetative stage of ryegrass and 36% of tillers in the last month of pasture utilization. The population of tillers in vegetative and reproductive stages of pasture is maintained stable when the ryegrass pasture is managed in a rotational system, considering the thermal sum of 187.5 ºGD and canopy height in the exit of the animals of the plots around 10 cm.