Apply herbicide in-crop. Apply granules, zero incorporation. By applying different herbicides at different times of the growing season, no one group of weeds will be selected for or against. John O'Donovan with the Alberta Environmental Centre in Vegreville put forward a number of cultural practises that will give the advantage to the crop, making things rather uncomfortable for the weeds. His first suggestion is prevention.
Management is next.
He stresses that herbicides should be used wisely. Ditches and headlands should be mowed. Crops must be rotated. Crop competitiveness can be maximized by planting vigorous seed and seeding competitive crops when possible. He also suggested that biological control and intercropping might be additional components of the management strategy.