Controle cultural de plantas daninhas em áreas de pastagem

Abstract

Weeds cultural control is a management technique that aims to increase crop competitiveness, turning into a relevant knowledge about the interaction between weeds and forage grasses. Therefore, forage species best choice and grazing intensity control are key alternatives on recovery of degraded pasture areas to enhance cattle production system. The objective of this research was to evaluate the effect of sowing densities and cutting intensity by grazing simulation in suppressing weeds, for this purpose, two experiments were conducted. The first experiment was arranged in a randomized block design with four replications and treatments consisting of five sowing densities (0, 25, 50, 75 and 100) expressed as the percentage of the recommendation to use Marandu grass. In the second one, plots referring to the sowing densities were subdivided and related to three levels of grazing intensity: super-grazing (15 cm), ideal grazing (30 cm) and sub-grazing (45 cm). In both experiments, the effect of treatments was determined by phytosociological survey of weeds community (identification, quantification and determination of dry mass), structural characteristics (stem diameter, tiller height and number of green leaves per tiller) and forage yield (dry matter and number of tillers). Results were submitted to analysis of variance and when significant, regression analysis was performed. It was observed that the increase in sowing density suppresses the weed community. Interspecific competition was established immediately after 7 days of coexistence between the plants and promotes a reduction the forage yield of Marandu grass. Under ideal grazing conditions over the sowing density of 75%, there was the lowest accumulation of dry matter and number of individuals from the weed regrowth at 49 DASG.