Cover crops are becoming increasingly popular as a key strategy for improving soil health, water quality, and climate resilience across a wide variety of farming systems. Many cover crop benefits depend on successful cover crop growth, or biomass. However, cover crop biomass can vary widely across farms because plant growth is influenced by multiple factors like climate, soil, and management practices.
Using a citizen science approach, researchers at the University of Michigan are partnering with farmers in the Great Lakes region (MI, OH, IN, IL, WI, MN) to learn about how and why cover crop growth varies from farm to farm. Our goal is to help farmers maximize benefits from their cover crops by identifying strategies for improving cover crop growth across different farming conditions.
Participating farmers serve as key collaborators in this data-driven effort to improve cover crop outcomes. In return for completing a short online survey and collecting a few photos and height measurements of their cover crops in the spring before termination, participants will receive a personalized cover crop performance report, including cover crop biomass and nutrient estimates, along with other findings from the study. Each participant will also receive $50 per field for the first two fields enrolled, though farmers are welcome to enroll as many fields as they wish and will receive data for each field in the final report.
Using a citizen science approach allows us to collect cover crop data from far more locations and types of farms than would be possible using typical research approaches. Participating farmers help us quantify cover crop growth and identify key factors driving cover crop outcomes by:
- completing a short online survey about their cover crop fields and management practices, and
- performing a simple field assessment to estimate overwintering cover crop biomass in the spring.
During spring 2022, we partnered with farmers to collect cover crop data from 129 fields across the region. This included 62 single-species cover crop fields, and 65 multi-species mixtures. We had strong participation in MI and WI, but would like to see greater representation from OH, IN, IL, and MN for our upcoming season of data collection in spring 2023.
2022 Cover Crop Research Results
Although 93% of the fields last season were used for row crops, participating farms still varied widely in terms of their management practices, such as tillage, crop rotation, and cover crop planting strategies and seeding rates. Cereal rye was the most common cover crop across all six states. As expected, cereal rye was typically planted following corn and soy, whereas cover crop mixtures were common after small grains.
Roughly 15% of participants reported using cover crops in their field for the first time last year; just over half had used cover crops between 2-5 years; another 15% for 6-10 years; and the 11-20 years and 20+ year categories each contained another 7%. The most common soil types were sandy loam, clay loam, and loam (33%, 25%, and 20% of fields, respectively), while sand, silt loam, and clay each represented about 7% of the dataset.
One of the things we are interested in investigating with this dataset is how multi-species mixtures perform compared to single-species cover crops. Mixtures in this study featured a wide range of species and combinations, with popular species including Austrian winter peas, hairy vetch, rapeseed, cereal rye, and several types of clovers. Overall, mixture biomass was less variable than for single-species cover crop fields. Even though mixtures had a lower maximum biomass value (4,365 lbs/ac for mixtures vs 7,248 lbs/ac for single-species covers), they had higher average cover crop biomass (983 lbs/ac for mixtures compared to 892 lbs/ac for single-species).
This suggests that mixtures may be more reliable than single cover crops, because having multiple cover crop species growing can increase the chances of at least one species growing well under a given set of conditions. However, both mixtures and single-species cover provided high levels of weed control across the region.
We are now gearing up for a second season of data collection this coming spring 2023, and we are inviting growers across the region to participate. Anyone currently growing fall-planted, overwintering cover crops in MI, OH, IN, IL, WI, or MN is eligible to enroll. This upcoming season of data collection will allow us to expand our dataset and build more robust models of cover crop growth that take into account the effects of different environmental and management factors. Click here to sign up, or email firstname.lastname@example.org.