Revisiting the contribution of cover crops to weed management in Conservation Agriculture

The evolution and spread of herbicide resistant weeds in conservation agriculture is a significant sustainability challenge. Currently, there is a critical need for advancing adoption of integrated weed management (IWM) strategies to improve weed management outcomes, slow herbicide-resistance evolution, and limit adverse environmental impacts associated with herbicide use. Winter annual cover crops have the potential to be a foundational component of IWM systems. In this chapter, the authors describe how cover crops can be managed to impose ecological stressors that reduce the fitness of annual weed species. They use this foundation to explain how ecological stressors imposed by cover crop management practices can be integrated with herbicide-based tactics to promote weed population decline in the context of proactive herbicide-resistance management. Finally, they review the range of cover crop management practices that influence weed control outcomes, and the agronomic tradeoffs associated with these practices.