Cover cropping offers many benefits, such as weed suppression, building soil organic matter and biodiversity, reducing erosion, and decreasing nutrient loss. But selecting the best species and variety for a farm’s location and goals can be tricky, especially given increasingly erratic weather conditions. 

Despite this challenge, the number of U.S. farmers using cover crops has been rising steadily since the mid 2000s, prompting seed company leaders to wonder whether there are adequate options and sufficient seed supply for the diversity of U.S. growing regions. 

In 2023, the University of Missouri’s Center for Regenerative Agriculture launched the National Cover Crop Variety Project, funded by the USDA. Over a five-year period, UVM Extension researchers and others across the country are partnering to evaluate cover crop species and varieties designed for specific regions and uses. 

“We encourage farmers to use cover crops, but there’s a lot to learn about what varieties will perform well in our region,” says UVM’s Ivy Krezinski. 

She and Professor Heather Darby, both of UVM Extension’s Northwest Crops and Soils Program, are partners in the National Cover Crop Variety Testing Program, part of the USDA-funded project. “We’re evaluating cover crop varieties over multiple years to see how they perform in different conditions,” Krezinski says. Increased precipitation can make timely fall planting difficult, for example, and changing weather conditions can affect winter survival rates. 

Other project researchers are based in New York, Pennsylvania, Maryland, North Carolina, Tennessee, Indiana, Texas, Missouri, Nebraska, North Dakota, and California. All are evaluating cover crop varieties on key characteristics (or metrics): fall establishment, spring stand, aboveground biomass, flowering at termination, stand height, weed suppression, and disease incidence.

National Results

In the 2024-2025 cover crop growing season, the first year of data collection, researchers at most sites planted five varieties each of cereal rye, clover (crimson and balansa), hairy vetch, winter peas, and brassicas (canola and radish) for a total of 25 varieties. (The exceptions: Researchers in North Dakota did not plant clover varieties, and those in Tennessee did not plant brassicas.)

Overall, national data show significant differences between varieties due to climate and breeding. Authors of the 2024-2025 National Cover Crop Variety Trial Report[ES1]  write “there can be significant benefits to using regionally adapted varieties, especially in terms of biomass production and winter survival.” They also note that selecting varieties to meet specific goals or to fit in different cropping systems and rotations may be very effective.

Darby and Krezinski are conducting their research trials at Borderview Farm in Alburgh, VT, on the U.S.-Canada border, where the soil is Amenia silt loam and Covington silty clay loam. They planted all 25 varieties in September of 2024, did not add amendments, and let nature do the watering.

They found no significant differences in biomass in the cereal rye varieties, though the one undisclosed (unnamed) variety was significantly shorter.

“The only metric that differed across crimson clover varieties was spring biomass, for which 19MDCC, an experimental variety from Maryland, lagged behind,” the researchers write.

The hairy vetch varieties performed well. Winter peas underperformed in most metrics compared to the other cover crop species.

Legumes and brassicas had higher winter survival and spring biomass than is typical in Vermont, probably due to thick snow cover last winter. The brassicas offered excellent spring weed control, including the two radish varieties (Aerifi and Driller, a daikon) that winterkilled but left behind substantial residue.

This chart shows the varieties and data from the Vermont research trials.

Future Years

In coming years, the project will expand to include more research sites  and cover crop species and varieties. In the 2025-2026 season, researchers will plant the same five species groups: clover, cereal rye, hairy vetch, winter peas, and brassicas. In each species group, they’ll plant the same five varieties and add two more, for a total of 35 varieties. This nationally coordinated effort will catalyze more rapid and effective progress in meeting demand for regionally adapted, high-quality cover crop seed.

For more information about the cover crop varieties, research design, evaluation metrics, results, and statistical analyses, see the 2024-2025 National Cover Crop Variety Trial Report (https://cra.missouri.edu/variety_testing_report_24_25/).

This national collaborative project is funded by the USDA National Institute of Food and Agriculture (NIFA) Sustainable Agricultural Systems (SAS) Coordinated Agricultural Project (CAP), Grant No. 2023-68012-38993, https://www.nifa.usda.gov/. The project title is “Cover Crop Variety Development Coordinated Agricultural Project” (or National Cover Crop Variety Project). For more information, visit https://cra.missouri.edu/cover-crop-variety-development-project/.

Questions about Vermont results? Contact ivy.krezinski@uvm.edu.

Questions about results in other states? Contact etiennesutton@missouri.edu.