Tillage, Row Spacing And Corn Vs. Soybean Mike DeFelice, Chemical Technologies Specialist Summary Narrower rows help weed control when other control practices such as herbicides and tillage do not give adequate control alone.
Corn is generally more competitive against weeds than soybeans.
Conservation tillage systems that leave heavy residue on the soil surface can assist weed control programs by suppressing weed germination. The introduction of Pioneer soybean varieties resistant to Roundup herbicide, and the release of Pioneer corn hybrids resistant to Liberty herbicide next year will put greater demands on our ability to properly select and use weed management systems. Roundup and Liberty are expected to be successful and popular herbicides with their broad spectrum of weed control, wide window of application, and crop safety. Careful management will be needed to obtain successful weed control with these non-residual postemergence herbicides. There are a number of factors that influence effectiveness of postemergence herbicide programs.