Beyond Herbicides: New Approaches to Managing Weeds

Herbicides are effective tools to control weeds yet there has been an over reliance on their use at the expense of other useful methods of weed management. This has led to ever increasing weed resistance around the world and environmental concerns in some situations. Effective, sustainable weed management systems should combine biological, chemical, cultural, and mechanical methods wherever possible. Herbicides should be thought of as one option, but not necessarily the option of first choice, when devising weed control programs. Successful long-term weed management requires a shift away from simply controlling problem weeds to systems that prevent weed reproduction, reduce weed emergence, and minimize weed competition with crops. Research has shown that use of diverse crop rotations, competitive crops, higher crop seed rates, specific timing and placement of fertilizer, crop mulches, and cover crops can effectively manage weed populations, especially when used in conjunction with limited but targeted use of herbicides. Research efforts are required to refine these integrated weed management principles for each cropping system and agro-ecological region. Extension efforts that demonstrate both the agronomic and economic merits of these new weed management and crop production systems are required to encourage acceptance and adoption by farmers.