DETERMINAÇÃO DOS PERÍODOS DE INTERFERÊNCIA DE PLANTAS DANINHAS EM PASTAGEM DE Panicum maximum

Abstract

Inadequate weed management is one of the main causes of the low productivity of Brazilian pastures. The objective of this research was to evaluate the effects of weed interference on Panicum maximum cv. Massai and its regrowth after cutting. Two trials were conducted in randomized blocks with four repetitions. In the first trial, the forage was kept in contact with weeds for the periods of 0, 7, 14, 21, 28, 35, 42, 49, 56 and 66 days after grazing emergence (DAE), and in the second trial , the forage was kept without weeds living for the same periods until the forage cut at 66 DAE. The plots were kept free of weeds living by hand weeding, according to treatment. With the increase of the weed community living periods with the forage greater the damages in the tillers production and the forage yield in the pasture implantation. The critical period of weed interference in the Panicum maximum cv. Massai was between 11 and 49 DAE. Weed interference also affected forage regrowth at 40 days after cutting, reducing tillering, plot cover and dry mass production, especially leaves.