In spite of possessing good herbicidal action, some factors affect the effectiveness of the glyphosate and, in that context, studies were accomplished looking for more effective formulations. The experiment was installed in area of FCAV-UNESP Campus, in Jaboticabal, São Paulo State. The potassium glyphosate formulation was compared to CS and WG formulations, at the same rate (0.36 kg.ha-1 a.e), in five intervals (1, 2 ,4 6 and 48 hours) without rain after the application, compared to a control without herbicides. They were applied in post emergence on Brachiaria plantaginea, B. decumbens and Digitaria horizontalis. The herbicides were applied with costal sprayer, at a constant pressure (35 lbf/pol²), with four nozzles DG 11002. The equivalent spray volume was 200 L.ha-1. The weeds control by potassium glyphosate was the earliest, it needs only four hours without rainfall after application to have a control equivalent to that treatement without rain for 48 hours after the application. The other formulations need at least six hours of interval.
post emergence; absorption; formulations
