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ARS Home » Midwest Area » St. Paul, Minnesota » Plant Science Research » Research » Publications at this Location » Publication #302974

Research Project: Enhanced Alfalfa Germplasm and Genomic Resources for Yield, Quality, and Environmental Protection

Location: Plant Science Research

Title: Controlling herbicide-resistant weeds: consider incorporating alfalfa in a corn/soybean rotation

item Gronwald, John
item Gunsolus, Jeffrey

Submitted to: Forage Focus
Publication Type: Trade Journal
Publication Acceptance Date: 3/12/2014
Publication Date: 3/18/2014
Citation: Gronwald, J.W., Gunsolus, J.L. 2014. Controlling herbicide-resistant weeds: consider incorporating alfalfa in a corn/soybean rotation. Forage Focus. p. 16-17.

Interpretive Summary:

Technical Abstract: Herbicide resistant weeds (HRW) are a serious problem in the U.S. In 1968, the first confirmed case of herbicide resistance in weeds was reported in Washington state. In the 46 years since, the number of HRW in the U.S. has increased dramatically. A major reason for the recent increase in HRW has been the development of glyphosate-resistant weeds. There are also increasing reports of weeds exhibiting multiple herbicide resistance. It's becoming apparent that in the long term, preventing and controlling HRW will require the development of a diversified, integrated weed management (IWM) program. An IWM program means using all the tools in the weed control toolbox; not just herbicides. It involves integration of chemical, mechanical and cultural weed control strategies. Crop rotations are one cultural weed control strategy that can help prevent or reduce HRW. Incorporating alfalfa in a corn/soybean rotation can be an effective way to control HRW. A dense stand of alfalfa will suppress growth of HRW. In addition, multiple cuttings made throughout the year will reduce production of herbicide-resistant seed. For many weed species, growing alfalfa for 2-3 years will significantly reduce the amount of HRW seed in the soil.