Progress report for ONC24-144
Project Information
Cover crop adoption is increasing in the North Central Region (NCR), but many cover crop benefits depend on successful plant growth, or biomass. Preliminary data from a community science project conducted in partnership with 100 NCR farmers from 2022-2023 show that cover crop biomass is highly variable across working farms. This is because a range of environmental and management factors influence cover crop growth, and thus their contributions to nutrient cycling, soil health, and weed suppression. We are expanding upon this community science project, with the goal of equipping farmers with the knowledge and resources to improve cover crop management. Specifically, we will collaborate with NCR farmers from six Great Lakes states (MI, OH, IN, IL, WI, MN) to: 1) understand variation in cover crop biomass across different farming conditions using a brief field assessment paired with a short management survey; 2) develop practical recommendations for optimizing cover crop outcomes based on those findings; and 3) facilitate network building and knowledge sharing through field days, webinars, and an interactive online database map. These activities are being guided by an advisory committee of farmers from across the region, whose expertise will enhance the design, implementation, and application of this work.
Our proposal uses an integrated approach, combining community science, outreach, and education in partnership with farmers across the NCR to meet the following objectives:
- Partner with the NCR farming community to identify key drivers of variation in cover crop performance across the region.
- Develop practical and context-specific recommendations for optimizing cover crop performance in different growing conditions.
- Facilitate learning, network building, and data sharing within the agricultural community through field days, webinars, an interactive database map, and infographics portraying innovative practices used on participating farms.
Cooperators
- (Educator and Researcher)
- (Researcher)
Research
Building on a community science study piloted on 253 fields across six NCR states in Spring 2022-2023, this project pairs a management survey and field survey to identify key factors driving cover crop performance across different farming conditions. Cover crop biomass is the main response variable because it is a key determinant of ecosystem service delivery. Using a brief field survey developed during the pilot study, partnering farmers collect cover crop height measurements and ground cover photos before termination each spring, which can then be used to quantify cover crop biomass for cereal rye and multi-species mixtures. The management survey asks questions about cover crop management (e.g., species, seeding rates, planting strategy), as well as general field management (e.g., tillage practices, nutrient management).When paired together, the field survey and management survey data can be analyzed using regression trees (a machine learning technique) to determine context-specific strategies for improving cover crop performance.
Since beginning our Partnership Grant in September 2024, we have completed several new activities. In fall 2024, we updated the management survey in collaboration with our farmer advisory committee to improve the clarity and specificity of questions, and add new questions on topics of interest to the farming community, including cover crop grazing, interseeding, and planting green. We then began recruiting farmers to participate for the 2024-2025 cover crop season through emails, phone calls, and sharing presentations and handouts at farmer-focused events. To participate, farmers must have at least one field of overwintering cover crops. If they met the criteria, farmers were then invited to complete a management survey online using Qualtrics for each overwintering cover crop field they wished to include in the study. Because farmers enrolled cover crop types beyond cereal rye and mixtures this year, we collected additional ground truth data in spring 2025 (i.e., visiting fields to destructively sample cover crop biomass with a quadrat in conjunction with the field survey, and then correlating the two methods). Our field survey is now calibrated for the following cover crop types: grasses (R2=0.93, N=134), mixtures (R2=0.77, N=47), clovers (R2=0.84, N=42), and peas (R2=0.65, N=33).
Following the 2024-2025 cover crop data collection season, we analyzed results for all participating fields and compiled personalized reports that were distributed to farmers summarizing cover crop performance in their fields. We also analyzed the entire regional dataset using mixed models and regression trees to identify relationships between management, environment, and cover crop outcomes.
We are now in the process of repeating the procedures described above for the 2025-2026 cover crop season.
For the 2024-2025 season, farmers reported good weed control from their cover crops, with an average score of 1.5 on a scale of 1 to 5 (1 = very low weed pressure; 5 = very strong weed pressure). Cover crops provided an average of 43% ground cover, a small increase from previous years. However, cover crop biomass continues to be highly variable across fields, ranging from 0-9,173 lbs ac-1 in spring 2025, with estimated nitrogen content showing similar trends. To date, only 42% of fields in the study have reached 1000 lbs ac-1 of biomass, and only 26% have reached 2000 lbs ac-1, which are key thresholds for reducing nutrient losses and building soil carbon, respectively.
To provide management recommendations to farmers for improving cover crop outcomes, we analyzed the multi-year, regional dataset using mixed models, specifically for cereal rye and mixtures, which are best represented in the dataset so far. For cereal rye, growing degree days (GDD) was the most important factor constraining performance, indicating that farmers would benefit from finding ways to extend the rye growing season to fully reap its benefits. The second most important factor was planting method. We have consistently found that aerial seeding performs worse than other planting methods, except in cases where fields receive sufficient fall precipitation or have a relatively long history of organic amendment applications (e.g., compost and manure), which helps build soil organic matter and contribute to better soil moisture retention and structure over time. Soil texture also had a small, significant effect on cereal rye performance, with silt loam soils having the highest biomass, and sandy loam soils the lowest. Unsurprisingly, fields in which farmers had applied synthetic nitrogen or phosphorus fertilizer to their cereal rye cover crop tended to have higher biomass, on average, relative to those that hadn’t received fertilizer. Cereal rye biomass also increased with precipitation, as expected, and there was a small, yet positive effect of increasing seeding rate on rye biomass. Finally, farmers with greater cover crop experience tended to have slightly better cereal rye performance, but this effect was small relative to the other variables noted above.
For cover crop mixtures, precipitation was the primary factor limiting performance. However, we also found that organic amendment applications (e.g., compost and manure) and higher species richness in mixtures help buffer against variable precipitation, likely by improving soil water infiltration and retention and providing “insurance” across heterogeneous conditions, respectively. There were significant, yet minor, differences in mixture performance across soil textures, with mixtures in clay loam soils showing slightly worse performance than those planted in other soil textures. Drilling was significantly more successful than other planting methods, likely because drilling allows for more effectively planting different species at appropriate depths to promote better establishment. Lastly, a manure application immediately before or during the cover crop growing season had a small, positive impact on mixture performance.
Educational & Outreach Activities
Participation summary:
Since the initiation of this grant in September 2024, the project leadership has been invited to deliver six in-person presentations and three virtual presentations on various aspects of this project to a wide range of farmers and agricultural professionals. Specifically, we have given talks at the Great Lakes Crop Summit; the Forage Seed Production Forum; Conservation Tillage and Technology Conference; Midwest Cover Crop Council annual meeting (in both winter 2025 and 2026); Cultivating Resilience Western Michigan Conference; the Wisconsin Vegetable Producers webinar series (both winter 2025 and 2026); and two local cover crop and soil health field days. Prior to spring 2025 data collection, we offered a virtual training to help farmers prepare for completing the field survey. We also posted a progress report on our project website in fall 2025 summarizing participation during the 2024-2025 data collection season, and then hosted a webinar in January 2026 sharing new data analysis results. We have continued hosting the Virtual Cover Crop Chat series, and our project was featured in the NOAA Nutrient Runoff Bulletin and in Morning Ag Clips. Following the 2024-2025 data collection season, we updated the Interactive Cover Crop Map to include new sites and data. The map is publicly available online as an education and outreach tool to help farmers and agricultural professionals identify what types of cover crops and management strategies work best across different locations and growing conditions.
Learning Outcomes
Farmers have reported improved understanding of how to evaluate cover crop performance in their fields; greater appreciation for relationships between cover crop biomass and nutrient recycling; and increased awareness of what is achievable across the NCR in terms of cover crop biomass and nutrient supply and retention.
Project Outcomes
This project will contribute to agricultural sustainability in multiple ways. By generating context-specific management recommendations for improving cover crop performance, farmers across the north-central region will reap greater environmental and economic benefits from their cover crops. For example, high biomass cover crops contribute to greater weed control and nutrient cycling, which can then reduce the need for expensive inputs like herbicides and fertilizers that also harm the environment. Strong cover crop growth is crucial for building soil health and organic matter, which then increases the long-term resilience of farms by buffering against extreme and unpredictable weather patterns. We are also in the process of translating the methods and findings of this project into an app that will allow farmers to monitor cover crop performance in their fields in real time, which could be used to inform management decisions, support performance-based incentive programs, and facilitate farmer-led experimentation. Importantly, our community science approach will contribute to improved farmer wellbeing. The Virtual Cover Crop Chats and Interactive Cover Crop Map support farmer-to-farmer learning and help participants build a trusted network of peers. Farmers will also benefit from engaging in collective action through this project, which can foster a sense of community and empowerment, along with being highly effective at catalyzing change.
In response to personalized cover crop reports:
Farmer from northern MI: “Interesting and helpful data. Thank you!”
Farmer from OH: “Thanks for the report. Lots of nice work here.”
In response to the interactive map:
Farmer from southern MN: “GLCCP map is great. I spent (too much) time evaluating and digesting results.”
Farmer from SW MI: “If I had known about it before now I definitely would have been using it”
Extension educator from MN: “I'm reaching out to see if you know when I can expect to see the measurements recorded in this spring's collections updated on the interactive map. I am eager to share the information with farmers and the county commissioners who support my role. It would be great to have this information to share with folks later this summer as they make plans for planting covers this fall. Thanks again, for helping to coordinate these efforts.”
In response to the winter 2026 webinar:
Farmer from central OH: “I almost didn't come because 'haven't I heard it all before?' but I was wrong there and would have missed out. I am an excellent person to try out your App because if there is a way to screw it up, I will find it. I can see real utility in using the app in real time as we try to hold off terminating as long as possible post planting. As you know, the cover is growing rapidly in the spring, and instead of terminating the day after planting but waiting until a week or even two after will really add to the biomass. Having the app would be really helpful in demonstrating that to ourselves. I have found doing the on farm biomass checks really useful. I also found the way you presented the most important to least important factors to biomass useful. It doesn't really matter if you do everything else perfect and don't give it long enough to grow.”