Submitted to: Western Society of Weed Science Research Reports
Publication Type: Research Notes
Publication Acceptance Date: December 19, 2010
Publication Date: March 13, 2011
Citation: Anderson, R.L. 2011. Synergism among crops can help weed management. Western Society of Weed Science Research Reports. p. 106-107. Interpretive Summary: Producers are seeking to reduce the use and dependence on herbicides for managing weeds. We have observed in no-till systems that some crops can improve the following crop’s tolerance to weeds. For example, soybean yield loss to a uniform stand of foxtail millet was only 15% when corn preceded soybean, but yield loss due to weed interference was greater than 30% following either spring wheat or oat. Other crop sequences favorable for increasing tolerance to weeds have also been identified. Rotations that include these favorable sequences may reduce the impact of weeds on crop production, and thus, reduce the need for herbicides.
Technical Abstract: No-till practices have improved soil health by increasing soil organic matter levels and enhancing microbial community diversity. An ancillary consequence of this change in soil functioning is some crops can synergistically improve resource-use-efficiency of following crops. This improved growth efficiency also increases crop tolerance to weed interference. Our study showed that soybean is more tolerant of weed interference when following corn compared with spring wheat, oat, dry pea, or soybean as preceding crops. Foxtail millet was used as an indicator species to establish uniform weed interference. Yield loss was 50% when soybean followed soybean, but only 15% when soybean followed corn. In our research program, we have quantified several sequences where tolerance to weed interference can be improved. Designing rotations to include these sequences in a no-till system may help to minimize the need for herbicides to manage weeds.