Revista Brasileira De Herbicidas 2014; 13(2): 143-155
Paraquat doses and spray volumes in desiccation Brachiaria ruziziensis before planting off-season maize
Brachiaria ruziziensis can contribute to the consolidation of the no-tillage system due to high production of biomass that can be used in integrated management of weeds. However, there is little information regarding the desiccation of this forage, particularly with the use of contact action herbicides. The present work aimed to evaluate the different management methods of desiccation of B. ruziziensis, and the effect in second season maize crop and weed suppression. The experimental design was a randomized complete block design with four replications. The treatments were arranged in a factorial 4 x 6 + 1, corresponding to evaluation of four doses of paraquat (100, 200, 400, and 800 g ha-1), six spraying volumes (69, 138, 204, 273, 342, and 411 L ha-1), and an untreated control. To study the population dynamics of weeds a control was also used in fallow condition and another with only the crop, without the presence of straw (weeded). The spray nozzle used was Turbo TeeJet simple plan jet with angulation of 90°. The paraquat was efficient in desiccation B. ruziziensis up to 14 days after application. After this period there was regrowth of forage plants interfered negatively on maize yiled. The weed infestation was reduced in areas with B. ruziziensis in crop rotation with maize in relation to fallowing areas.
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