EFEITOS DA INTERFERÊNCIA DE PLANTAS DANINHAS NA IMPLANTAÇÃO DE PASTAGEM DE BRACHIARIA BRIZANTHA

Abstract

The purpose of this study was to evaluate the effects of weed interference with Brachiaria brizantha pasture establishment and regrowth after cutting. Two experiments were conducted simultaneously in randomized complete blocks with four replications. In the first test, forage was grown together with weeds for 0; 7; 14; 21; 28; 35; 42; 49; 56, and 63 days after forage emergence (DAE) and in the second, the forage was maintained weed-free for the same periods. The weed population was evaluated during coexistence period between weeds and forage crop. The forage yield and leaf / stem ratio of B. brizantha were evaluated after forage cutting (63 DAE), and 119 and 289 DAE. Weed growth was strong in coexistence with B. brizantha during pasture formation, causing a reduction in forage yield. The period considered critical in the competition between the weed and forage community lasted from 9 to 26 DAE. However, there were also significant effects on the regrowth of B.brizantha after the second forage cut, in the dry season, showing that pasture recovery after cutting was prejudiced by the competing weeds during the pasture establishment. The competition did not affect the photoassimilate partitioning between leaves and stems in the forage plant.