Black oat is an important winter cover crop in south Brazilian. However, it is a weed problem in cool season grain crops as well as ryegrass. Two trials in a randomized complete block design were conducted at Embrapa Trigo in Passo Fundo, Rio Grande do Sul state. This research aimed to study different oat management methods applied on black oat at anthesis and milk stage to avoid it becoming a weed plant in wheat cropped after soybean. The plot area was 60m². Nine treatments were tested, in both trials: spray herbicide; roll plus herbicide; hay harvest; silage harvest; mowing; grinding, silage; rolling; disking; and grain harvesting. The average total biomass at anthesis was 5,016kg DM ha-1 and at milk stage was 6,050kg DM ha-1. Soybean cropped in the summer season yield 2,080kg ha-1 and it was not affected by black oat treatments. During the second year, the wheat plots sprayed herbicide before planting yielded 2,472kg ha-1 and spike density of 355m-2, however plots without herbicide yielded 836kg ha-1 and had 225 spikes m-2. On black oat milk stage managements the yield average was 1,733kg ha-1 and 334 spikes m-2, on sprayed herbicide plots before planting. In opposite, the plots without herbicide, wheat plants were completely dominated by resurgent black oat plants, due to managements applied during previous winter. Mechanical management methods applied only in black oat development stages allowed seeds germination during winter crops cycle. This problem is avoided spraying herbicide before oat anthesis, because after that any management method tested was unsuccessful to control oat after the following winter crops, so is necessary to spray herbicide before seeding winter cash crops.
Avena strigosa; weed plant; mechanical management; rolling; disking
