ARS | Publication request: Corn tolerance to weed interference varies with preceding crop

Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 15, 2011
Publication Date: January 20, 2012
Citation: Anderson, R.L. 2012. Corn tolerance to weed interference varies with preceding crop. Weed Technology. 25:486-491.

Interpretive Summary: Producers are seeking to reduce the amount of herbicides they use because herbicide-resistant weeds are increasing. They also would like to reduce the possibilities of environmental damage that may occur with herbicide use. In our research program, we are seeking to increase the level of diversity in rotations, which will help manage weed dynamics and possibility reduce herbicide need. We have observed that some crops can improve the following crop’s tolerance to weed interference. Dry pea and corn are especially favorable in this aspect. For example, corn tolerance to weeds is twofold greater following dry pea compared with soybean or spring wheat as preceding crops. This unique interaction between some crops will lessen the impact of weeds on crop growth, and consequently, may help producers reduce herbicide use in crop production.

Technical Abstract: Crop diversity may improve tolerance to weed interference and reduce the need for herbicides. This experiment measured weed interference in corn as affected by the preceding crop in two studies. The first study, based on interference of the resident weed community, compared dry pea, soybean, canola, and spring wheat for effect on corn tolerance to weeds. Prominent weeds were green and yellow foxtail. The second study examined corn tolerance to a uniform infestation of foxtail millet as affected by dry pea, soybean, spring wheat, and corn as preceding crops. Each plot was split into weed-free and weed-infested subplots in both studies. Corn was most tolerant to weed interference following dry pea; compared to soybean, dry pea improved corn tolerance more than twofold. Corn also yielded the highest in weed-free conditions following dry pea; averaged across four years, corn yielded 13% more following dry pea than following either soybean or spring wheat. Crop diversity has helped producers reduce herbicide inputs in the Great Plains and may provide an additional benefit of reducing weed impact on crop yield.