Organic Weed Management

weeds in soybeans

Weed management is one of the biggest challenges in the organic agroecosystem, and a barrier to conventional farmers who desire to transition. In response, researchers have invested heavily in the study of ecological weed management approaches for organic farms. 

Ecological weed management (EWM) is a suite of weed and crop management strategies that aim to reduce weed seed banks and control emerged weeds, while at the same time increasing biodiversity in the agroecosystem, and reducing the time and labor required to control weeds in the long-term. These approaches provide an alternative to herbicides for weed control, and can be used in organic farming systems or to reduce herbicide use in conventional or sustainable farms. See this page for more information.

Below are some EWM strategies. 

  • Control emerged/emerging weeds
    • tillage, flaming, weeding by hand, etc.
    • use of mulches, cover crops, nurse crops
  • Reduce weeds in the seed bank
    • create stale seedbeds
    • remove weeds before the go to seed
    • prevent introduction of weed seeds in seed or compost and on used equipment
  • Increase biodiversity in the agroecosystem
    • minimize bare ground time using cover crops, forages, etc.
    • use crop rotations that result in weeds germinating but not going to seed, eg. winter wheat following soybean
    • use practices that improve soil health by building tilth and improving soil aeration
    • support beneficial soil organisms by using tillage only when essential 
  • Increase a crop’s ability to compete with weeds
    • establish and maintain dense crop stands
    • consider using a cover crop between rows 
    • increase seeding rate
    • decrease row spacing
  • Reduce time, labor, and resources required to control weeds in the long term
    • Small weeds are easier to control.  Weed at the 'white thread' stage
    • All of the above will help, but reducing weed seed in the seedbank is most effective
For more information on non-chemical weed control, visit our Resources Page.

Current and Recent Weed Research Projects 

Quantifying and predicting the effects of ecological weed management strategies on the organic agroecosystem to inform farmer decision making 

Free Online Tool: Many EWM strategies require trade-offs. To help farmers examine these trade-offs in light of their specific farm conditions and priorities, we have developed an interactive online tool. The tool incorporates user responses with existing data on the performance of various EWM strategies over time. The software is free and available online: https://organicweedmanager.com/ 
Read more here. 

Field Study: The field component of this study began in spring 2017. We are studying the effects of intense tillage on soil health and on weeds present in the field and the seed bank. 

Soil Balancing

For most farmers and scientists, soil balancing refers to the theory and practice of attaining an optimum soil ratio of the plant nutrients calcium (Ca), magnesium (Mg), and potassium (K). Many row-crop and vegetable farmers have reported greater ease in managing weeds as the ‘balance’ of their soils improved. A cross-disciplinary team of Ohio State researchers is investigating the effect of soil balancing on weed populations, soil health, crop production, economics, and more. Read more here: offer.osu.edu/soil-balancing.

Additional Project Information Coming Soon.