Morfogênese e estrutura de azevém anual submetido a três intensidades de pastejo

Abstract

Morphogenetic and structural characteristics of Italian ryegrass (Lolium multiflorum Lam) under grazing intensities were studied. The experimental design was completely randomized, with four repetitions (transects) and three treatments consisting of grazing intensities: 'High', 'Mean' and 'Low', corresponding to the disappearance of 61.0, 43.3 and 21.1% the value of initial forage mass, respectively. Intermittent grazing was used, with ewe lambs, and the interval among grazing corresponded to thermal sum of 313 degree-days. Grazing intensities affected the morphogenesis and structure of Italian ryegrass only in the first evaluation period; when Italian ryegrass in the 'Mean' intensity had the lowest leaf appearance rate and leaf elongation rate and it had the highest values of leaf life span. Pseudostem height, length of the intact and defoliated blades, number of intact and senescent leaves were higher in 'Low', and did not differ between 'Mean' and 'High'. Adoption of grazing intensities equivalent to 43.3 and 61.0% of the disappearance of the initial forage mass allows extending the Italian ryegrass vegetative stage. For management of Italian ryegrass, the use of 61.0% grazing intensity is recommended, which presents structural characteristics similar to those observed in intensity of 43.3% and provides stocking rate 24.1% higher.