Illinois farmers have spoken through the Illinois Soybean Association (ISA) Soybean Production Concerns Survey. Weed management—especially for herbicide-resistant species—along with conservation practices and pest management topped farmers’ research priorities. As vigorous weeds, especially waterhemp, adapt to current control methods, it’s time to start exploring other options to manage weeds and maintain cash crop productivity. 

When planted in the fall, overwintering cover crops such as cereal rye or winter barley can offer an alternative option for weed suppression. As they regrow in the spring, they can produce tons of biomass in addition to other benefits, such as nutrient and soil retention, that cover crops generally provide. 

Cereal rye or winter barley can serve as effective weed control tools by competing with weeds for space, water, nutrients and sunlight. Along with physical weed suppression, cereal rye also produces allelochemicals, which are chemical compounds that can prevent the germination and development of various weed species, enhancing its potential for weed control. 

However, it remains unclear how well cereal rye or winter barley control weeds when planted before soybeans in Illinois, which species is more effective, and how these cover crop species may affect soybean yields. 

To better understand the potential of cereal rye or winter barley to function as spring weed suppressants, ISA will conduct on-farm research trials across Illinois starting in the fall of 2025. To accomplish this, we are recruiting farmers from across the state who are currently operating minimal or no-till systems and who have previous cover crop experience to conduct these trials on their farms. 

Here is a brief overview of the protocol:  

• Three treatments:  

• • Cereal rye at 40-50 lb/A pure live seed (PLS) 

• • Winter barley at 40-50 lb/A PLS 

• • Untreated control (no cover crop) 

• Both species will be planted with a drill, 15” planter, or air seeder as soon as possible after harvest, but no later than November 15th. One or both species must reach 12” of growth in the spring prior to chemical termination. 

• A minimum of 40 acres is required to conduct the trial, but plot layout is flexible depending on equipment and field direction. A calibrated yield monitor is required, along with the capability to plant and terminate the cover crop. 

• The farmer will be responsible for planting and terminating the cover crop, as well as providing yield and management data. Other measurements, such as soil samples, cover crop biomass and weed counts will be conducted by an ISA staff member. Please refer to the complete version of the protocol for more information.  

This protocol was developed to help farmers answer crucial questions regarding cover crops as a technique for weed control. We would appreciate the opportunity to work directly with farmers and to learn from them. 

If you are interested in participating in this on-farm research study or want to learn more about other trials we are currently offering, please fill visit our On-Farm Trial Network page. If you have questions about participating in this study, contact Deanna Burkhart, Producer and Field Services Administrator, at deanna.burkhart@ilsoy.org or 309-307-9366. 

Qualified farmers participating in ISA’s On-Farm Trial Network may be eligible for cost-share and program payments. Eligibility requirements and payment amounts will vary based on specific program guidelines. The On-Farm Trial Network is funded by the Illinois Soybean checkoff program.