Canopy structure and tillering of Piatã and Marandu grasses under two grazing intensities with sheep

Abstract

This study aimed to evaluate productive and structural parameters of Piatã and Marandu cultivars submitted to two grazing intensities. The experimental design was in randomized blocks with treatments in a 2 x 2 factorial arrangement (Marandu and Piatã palisadegrass x 25 and 30 cm residual heights). Intermittent stocking grazing method was used. Non-defined breed sheep were used as defoliation agents. Interaction between cultivars and height was not significant for any of the variables. In pastures managed at 25 cm post-grazing, a greater regrowth period was observed. Forage mass was on average 27% higher in Marandu palisadegrass in relation to Piatã palisadegrass, regardless of height. Dead material accumulation was higher in the Marandu cultivar. There was no difference in mass between the cultivars and heights for leaf blade or stem before and after grazing. The highest population density of tillers was observed in pastures lowered to 25 cm post-grazing height, with no difference between cultivars. In the third generation the appearance of tillers was higher in pastures managed at 25 cm. Post-grazing heights of 25 and 30 cm do not change pasture structure in Piatã and Marandu cultivars in pre-grazing; however, it is possible to obtain a shorter regrowth period if managed at 30 cm.