ARS | Publication request: Can we reduce weed density with crop diversity?

Submitted to: Brookings Register
Publication Type: Popular Publication
Publication Acceptance Date: December 6, 2006
Publication Date: December 6, 2006
Citation: Anderson, R.L. 2006. Can we reduce weed density with crop diversity? Brookings Register, Brookings, South Dakota, December 6, 2006, p.B6.

Interpretive Summary: Weed scientists are seeking a broader approach to weed management, rather than rely mainly on herbicides. One approach is to add crops with different life cycles to the rotation. Our results suggest that adding cool-season crops such as winter wheat or canola may accelerate the death of weed seeds in the soil. This trend will reduce the number of weed seedlings that emerge in following crops, thus reducing the need for herbicides to control weeds in crops.

Technical Abstract: Weed management is evolving to include cultural tactics that reduce weed populations. This study evaluated impact of crop sequence and tillage on seedling emergence of common sunflower across years. In the third and fourth year of the study, seedling density was sevenfold greater after two years of soybean with tillage compared with a two-year sequence of canola and winter wheat with no-till. Apparently, canola and winter wheat enhanced the natural decline of common sunflower seed density in soil, leading to fewer seedlings in following years. Cool-season crops grown with no-till may affect weed seed survival in soil in the western Corn Belt.