Submitted to: Western Society of Weed Science Research Reports
Publication Type: Research Notes
Publication Acceptance Date: December 1, 2007
Publication Date: March 11, 2008
Citation: Anderson, R.L. 2008. Crop diversity sequencing can improve crop tolerance to weeds. Western Society of Weed Science 2008 Research Progress Report. pp. 79-80. Interpretive Summary: Weed management is a major input cost for producers using the corn-soybean rotation in eastern South Dakota. Forty years of this rotation has led to a weed community comprised of species with similar life cycles to corn and soybean. We are exploring crop diversity in this rotation to determine if producers can reduce the need for herbicides for weed management. Crop diversity may help corn tolerate weeds because rotating crops usually improves crop growth. Our study showed that corn yielded the highest following pea, even when compared with soybean as a preceding crop. In contrast, corn following corn yielded much less. Also, corn yields more in weedy conditions when pea is the preceding crop. Producers may be able to develop new rotations that improve crop yields while reducing need for herbicides. A key to this approach is increasing crop diversity in their rotations.
Technical Abstract: The corn-soybean rotation in eastern South Dakota has led to a weed community comprised of species with similar life cycles to the crops; subsequently, weed management is a major input cost for producers. We are exploring crop diversity in this rotation to determine if producers can reduce the need for herbicides for weed management. Crop diversity may affect the interaction between corn and weeds because of its beneficial impact on crop growth. This study measured impact of crop sequence on corn tolerance to weed interference as well as corn response to preceding crops in weed-free conditions. All studies were established with no-till practices. Corn was more tolerant to weeds when corn followed pea; in contrast, tolerance to weeds was drastically reduced when corn followed corn. Even with weed-free conditions, preceding crop affected corn yield. Corn following pea yielded 10% more than following soybean whereas yield of corn following corn was 75% less compared with pea as the preceding crop. Our study shows that crop sequencing may be one tactic that helps weed management.