Managing weeds with a dualistic approach of prevention and control. A review

Scientists have theorized that weed management would be more efficient if prevention tactics were integrated with control tactics. The goals of prevention are to reduce weed community density and improve crop tolerance to weeds. Here we describe the impact of this approach in the semiarid steppe of the United States. As a result, producers have reduced herbicide inputs and costs by 50% compared to conventional practices. Critical factors for success with this approach are rotation design and no-till practices. Rotations comprised of two cool-season crops followed by two warm-season crops are the most disruptive of weed population growth. The impact of rotation design on weed community density is enhanced by no-till. Crop tolerance to weeds is improved by systems of cultural tactics. The tolerance is greatest when three tactics are combined together. This dualistic approach of prevention and control effectively controls weeds with four-crop rotations such that herbicides are not needed in some crops of the rotation. Weed density is so low that crop yield is not affected by weed interference. With this approach, herbicides are a choice rather than a requirement for cropping success in the semiarid steppe of the United States.