Cereal rye is a preferred fall-planted cover crop among soybean farmers in the Upper Midwest because of its ability to withstand cold winters and produce substantial biomass within a short growing season. It offers multiple benefits, including reducing soil erosion, storing carbon, and, most importantly, suppressing early-season weeds. However, the effectiveness of these benefits largely depends on achieving sufficient spring biomass. In Minnesota, the shorter growing season presents a significant challenge for cover crop biomass accumulation. One potential solution to this issue is “planting green,” where cash crops like soybeans are planted into living cover crops, allowing both to grow simultaneously for a limited time. Research conducted by Sarangi over four site-years in Minnesota (two years and two sites) showed that planting soybeans around May 15 and terminating cereal rye approximately a week later can provide good weed control without compromising crop yield. However, the results may vary with different weather, soil type, and other field management practices. A key concern with delaying cereal rye termination is the competition it poses to soybeans for critical resources like moisture, light, and nutrients. In particular, planting green can deplete soil moisture needed for soybean germination and growth. This issue is concerning given the increasingly frequent dry spring conditions in Minnesota, which have made farmers more hesitant to adopt cover crops. Limited data is available on the impact of planting green on soil moisture in this region, highlighting a need for further research.
Weeds not only compete with crops for nutrients and light but also reduce the soil moisture available for crop growth. Cereal rye’s ability to suppress weeds offers a dual advantage to farmers: reducing herbicide costs and conserving soil moisture. However, to optimize the benefits of cover cropping, it is crucial to study the system’s evapotranspiration and identify a balance between cover crop management and weed control. Despite recognizing the financial and environmental benefits of cover crops, many farmers in Minnesota remain hesitant to adopt them due to concerns about their potential impact on cash crop growth and yields. These uncertainties highlight the need for timely and relevant research to address these challenges. The primary objective of this research is to evaluate the effects of cereal rye termination timing including “planting green” and weed management strategies on soil moisture availability, evapotranspiration, and soybean yield under different soil types and water management. This work aims to provide valuable insights for soybean farmers in Minnesota, helping them integrate cover crops into their production systems more effectively.
In the fall of 2024, cereal rye was planted at UMN’s Rosemount Research and Outreach Center (RROC) in Rosemount, MN and Southern Research and Outreach Center (SROC) in Waseca, MN. Soil moisture access tubes will be installed in soybeans on the day of planting in 2025. This research will be part of the dissertation of a Ph.D. student, Sithin Mathew, and will be demonstrated at Field Days at SROC and RROC in 2025. The results will be disseminated through peer-reviewed and Extension articles anticipated to be published in early 2026. Additionally, the research data will be presented at the Minnesota Ag Expo, UMN Extension events, and the North Central Weed Science Society’s annual conference during 2025-2026.

The goal of this project is to provide critical insights into soil moisture availability when cereal rye cover crop is integrated into soybean production systems. This information will support soybean farmers in making informed decisions about cover crop termination timing to optimize both weed management and crop yield.
The specific objective of the project is to evaluate the impact of cereal rye termination timing and weed management strategies on soil moisture availability, evapotranspiration, and yield in Enlist E3® soybeans.

This team, consisting of Extension faculty and Educators Sarangi, Sharma, Cates, and Stahl, is deeply involved in soybean production, cover crops, irrigation management, and weed management research and outreach in Minnesota. Sarangi, Sharma, and Cates, as state Extension Specialists, frequently engage with soybean farmers, crop advisors, and other stakeholders to provide expert advice. The research plots and results will be showcased during summer Field Days at RROC, attracting over 40 attendees from industry, farming, academia, and Extension. Findings from this research will be incorporated into updated Cover Crop Recipe Guides published by the Midwest Cover Crop Council. To disseminate the research results, various online platforms will be utilized, including MN Crop News (with over 2,000 subscribers), regional Extension Crop Newsletters, radio spots, the Strategic Farming talk series, and Minneline articles. Social media channels such as X, LinkedIn, and YouTube will also be used to share updates and short videos. The results will be presented at several Extension events in 2025 and 2026, including the Crop Pest Management (CPM) Short Course, Research Update for Ag Professionals, Prairie Grain Research Update, Best of the Best Crop Management, and MN Ag-Expo. These events primarily attract agronomists, farmers, fertilizer/plant protection dealers, and independent crop consultants. Additionally, peer-reviewed journal articles will be published, and the research findings will be presented at the Agronomy Society of America’s and the North Central Weed Science Society’s Annual Meetings. A Ph.D. student will be mentored as part of this project, with the research contributing to their dissertation work.

Updated September 23, 2025:
The research project has been initiated at the University of Minnesota’s Rosemount Research and Outreach Center (RROC) in Rosemount, MN, and the Southern Research and Outreach Center (SROC) in Waseca, MN. A graduate student is actively involved in the project, which will contribute to his Ph.D. dissertation. The study was featured during the Weed Science Field Day at RROC and showcased as part of the CFANS New Career Faculty Orientation Tour at the same location.

With the increasing prevalence of herbicide-resistant weeds in Minnesota, farmers are seeking non-chemical management alternatives to complement herbicide applications and delay resistance evolution. Although farmers are interested in using cover crops as part of integrated weed management, the lack of localized information has slowed adoption in the state. Minnesota is often dry in the spring, raising concerns among soybean farmers about cover crop biomass in early termination and soil moisture depletion in late termination. Local research by Sarangi and Cates has shown that cereal rye cover crops are better suited before soybeans than corn, highlighting the need for the information proposed in this research.

"Planting green" is a method to improve cover crop biomass, and research by Sarangi, Cates, and Stahl has demonstrated its positive impact on weed and soil management. However, there is limited information on its effect on soil moisture. This research aims to inform soybean farmers about the appropriate timing for cereal rye termination under both irrigated and rainfed conditions. It will also provide insights into balancing cover cropping and preemergence herbicide application in terms of soil moisture availability, weed control, soybean canopy growth, and yield. This research will help soybean farmers make informed decisions about cover crops and weed management. We strongly believe that the results will not only aid in decision-making but also enhance soybean yield and marketability.