Utilizing Brassica Cover Crops for Weed Suppression in Annual Cropping Systems

Weed management is an essential component of successful crop production. Synthetic herbicides and cultivation are the primary means of managing weeds in modern agriculture. However, there are environmental hazards associated with herbicides, as well as an increase in herbicide-resistant weeds. Erosion and sustainability issues are also associated with cultivation. As a result, there is an increasing interest in developing alternative methods of weed control, including the use of weed-suppressive cover crops. Integrated weed management involves managing weeds through a series of mortality-and fitness-reducing events (Williams, Mortensen, and Doran, 1998). A cover crop is any living ground cover that is planted into or after a main crop and then commonly killed before the next crop is planted (Hartwig and Ammon, 2002) and that provides benefits such as decreased soil erosion, increased soil organic matter, or pest suppression (Sainju and Singh, 1997). Cover crops, as a component of weed management, reduce the fitness of weeds relative to the main crop. Nagabhushana, Worsham, and Yenish (2001) reviewed the use of allelopathic cover crops in cropping systems and concluded that herbicide use can be reduced and top soil conserved with the proper use of cover crops.