Dessecação acelerada de capim-marandu com a aplicação sequencial de glyphosate e amônio-glufosinate

: Background : Marandu grass can be an alternative forage in the crop-livestock integration system (CLI), although its burndown is slower than ruziziensis grass, and it is necessary to speed it up so that the sowing of early soybean cultivars occurs at the recommended time. Objective : Estimate times and doses of glyphosate and ammonium-glufosinate in sequential burndown of marandu grass with and without cutting for a shorter period of burndown. Methods : Four experiments in randomized blocks and three replications were carried out in a greenhouse with two combinations of glyphosate (g e.a. ha -1 ) and ammonium-glufosinate (g i.a. ha -1 ), respectively: (a) 1,625 and 600 and (b) 975 and 400, in plants with and without cutting. The treatments combined two times of first burndown (20 and 10 days before presumed soybean sowing – DBS) and four times of second burndown (7, 5, 3 and 0 DAS) and a control without herbicides. Results : At higher doses, there were control percentages between 75 and 98% with the 1 st. burndown at 10 DBS and the 2 nd. burndown between 7 to 0 DBS in plants with and without cutting at 7 days after application. In plants with cut and lower dose of herbicides, there was greater control with the 2 nd. burndown at 7 DBS (80%). Conclusions : The burndownn of marandu grass can be accelerated to 10 DAS when the highest dose of glyphosate and ammonium-glufosinate is applied in plants with and without cutting and with the lowest dose of herbicides in plants with cutting and 2 nd. burndown at 7 DBS.