Controle químico de Brachiaria decumbens em pastagem de Cynodon dactylon híbridos Coast-cross e Tifton 85

摘要

Aiming at the control of the Brachiaria decumbens in degraded pastures of the Coast-Cross and Tifton 85 hybrids (Cynodon dactylon), two experiments were carried out, each one for each forage, where increasing doses of the commercial mixture diuron/ MSMA and one dose of MSMA were applied. The randomized block experimental design was used with seven treatments and four replicates. The plots were 6m long and 4m wide. The treatments were applied on the total area and on mature weeds. The diuron / MSMA mixture at the dose of 1120 + 2880 g/ha, respectively, provided efficient control (90%) of B. decumbens at 42 DAA. MSMA at the dose of 2880 g/ha was not effective in controlling B. decumbens over the appraised period, since its control was lower than 70% from 14 to 42 DAA. Diuron / MSMA at the dose of 1120 + 2880 g/ha and MSMA at the dose of 2880 g/ha provided light injuries in C. dactylon hybrids from 7 to 14 DAA, that disappeared at 30 DAA and not affected the development of the forages, so making possible a fast reestablishment of the pasture.