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United States Department of Agriculture

Agricultural Research Service

Research Project: PEST BIOLOGY, ECOLOGY, AND INTEGRATED PEST MANAGEMENT FOR SUSTAINABLE AGRICULTURE Title: Crop Synergism can Improve Tolerance to Weeds

Author
item Anderson, Randal

Submitted to: Quarantine and Protection of Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 21, 2009
Publication Date: November 13, 2009
Citation: Anderson, R.L. 2009. Crop Synergism can Improve Tolerance to Weeds. Quarantine and Protection of Plants. 13:486-491.

Interpretive Summary: Producers worldwide are seeking to increase the diversity of crops in their rotations. An ancillary benefit of crop diversity is that weed management can be expanded to include cultural tactics related to weed population dynamics. A population-based approach reduces cost of weed management 50% compared to conventional management in the Great Plains. Additionally, we have found that crop diversity also affects crop tolerance to weeds. For example, yield loss in winter wheat due to a uniform infestation of wild rye was four times higher when winter wheat followed either spring wheat or soybean compared to dry pea. Another example is corn yield was two times higher following dry pea compared with soybean when a uniform infestation of foxtail millet was present. In some way, dry pea synergistically improves growth of winter wheat and corn to increase their tolerance to weeds. This synergism among crops is most prominent in rotations where no-till practices and crop diversity have been used for several years.

Technical Abstract: No-till systems have transformed crop production in the semiarid steppe of the United States. In a region where winter wheat (Triticum aestivum L.)-fallow was the standard rotation, no-till has enabled producers to add more crops to the rotation before fallow is needed again. Consequently, land productivity and net returns have more than doubled with these new rotations. Crop diversity and no-till have also changed the way producers manage weeds. Instead of relying just on herbicides, producers have broadened their approach to include cultural tactics that disrupt weed population growth. The population-based approach reduces cost of weed management 50% compared to conventional management. While testing cultural practices to improve crop competitiveness, we have found that the preceding crop can affect crop tolerance to weeds. For example, yield loss in winter wheat due to a uniform infestation of wild rye (Secale cereale L.) was four times higher when winter wheat followed either spring wheat or soybean [Glycine max (L.) Merr.] compared to dry pea (Pisum sativum L.). Corn (Zea mays L.) yield was two times higher following dry pea compared with soybean when a uniform infestation of foxtail millet [Setaria italica (L.) Beauv.] was present. In some way, dry pea synergistically improves growth of winter wheat and corn to increase tolerance to weeds. Synergism among crops is prominent in cropping systems studies where no-till practices and crop diversity have been used for several years.

Last Modified: 11/21/2014
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