The objective of this work was to evaluate Brachiaria brizantha cv. MG5 growth under reduced rates of fluazifop-p-butyl to allow its intercropping with soybean. The effects of three doses of the herbicide (0, 18,75 and 37.50 g ha-1) on B. brizantha growth were evaluated in eight timings (14, 18, 28, 35, 42, 49, 56 and 70 days after emergence - DAE). The experiment was arranged in a completely randomized design, with four replications. At each timing, the plants were harvested and the biomass of the leaves, stem, roots and leaf area was obtained. Absolute growth rate, relative growth rate, net assimilation rate, leaf area ratio, specific leaf area, stem and leaf weight ratio were calculated using dry biomass and leaf area data. B. brizantha had suppressed the apical dominance by reduced rates of fluazifop-p-butyl inducing greater tillering. The stems presented greater total biomass and stem length was reduced in the plants treated with the herbicide. The plants treated with fluazifop-p-butyl had thinner leaves, reduced leaf area and absolute growth rate, showing that it is possible to use reduced doses of fluazifop-p-butyl only to reduce B. brizantha growth.
growth analysis; Brachiaria; herbicide; ACCase; crop-livestock integration
