Efficacy of glyphosate in the burndown of Urochloa species

Abstract

In Burndown cover plants in areas under no-till the glyphosate herbicide is the most widely used. With the aims to determine the lower dose to burndown the cover crop species adopted the Urochloa ruziziensis cv. Kennedy, U. decumbens cv. Basilisk e U. brizantha cv. BRS Piatã, in four doses (0, 0,72, 1,44 and 2,16 kg ha^-1 of acid equivalent). The experimental design was of randomized blocks with four replications, in a plot scheme subdivided (3 x 4), in which the plots were set up by the species of Urochloa and subplots by doses of glyphosate.  The U. ruziziensis was efficiently controlled the 14 DAA of glyphosate at 1.44 kg ha^-1, or up to 28 DAA with 0.72 kg ha^-1. Glyphosate applied at the rate of 2.16 kg ha^-1 was not sufficient to control the U. decumbens until 14 DAA, and until 28 DAA for U. Brizantha. The speed control of vegetation formed by U. ruziziensis with glyphosate was greater than U. decumbens and U. Brizantha