Cover Crop Variety Research

 

On July 1, 2025, Ohio Governor Mike DeWine signed a new bill refunding the Ohio H2O Program. However, the 2024-2025 budget was for 270 million dollars. The new bill authorizes only $165 million dollars for the 2026-2027 time period, a 40% overall decrease. The Ohio H2O program will continue but expect major changes and possibly lower rates of compensation.

Dr. Etienne Sutton, University of Michigan, at a recent field day shared some national research on cover crop varieties. This research was conducted in 12 states across the country. Ohio was not included; however, both Indiana (Purdue, West Lafayette) and Pennsylvania (Penn State, College Station) participated in the study.

The goals were to evaluate performance of commercially available cover crop varieties, determine where they work the best, and try to get more cover crop diversity. Plots were very small (5 feet by 15 feet), replicated 3 times, and generally done on one soil type. In Ohio, it is not uncommon to have multiple soil types in one field. However, the research is still valuable for seeing how certain cover crop varieties do under Midwest weather conditions.

Researchers looked at cereal rye (5 varieties), crimson clover (5), hairy vetch (5), winter peas (5), winter canola (3), and radish (2). A big issue for farmers is getting cover crops established in the fall. Second is getting adequate biomass. The following parameters were measured: fall establishment, above ground biomass, flowering at termination, and weed suppression.

Here is a quick summary of the results. Results varied by region due to different climates and soil conditions. This is why regional or local cover crops genetically developed with certain traits can be beneficial. For example, on cereal rye, Elbon and Wrens Abruzzi (two early maturing cereal rye varieties good for corn) did very well in states with milder climates (Ohio included) while Gardner did much better in North Dakota (colder climate, harsh winters, late maturing) where it was developed. Hairy Vetch consistently outperformed crimson clover and winter peas in terms of winter survival and biomass at all northern locations. However, with new breeding programs on cover crops, some varieties of crimson clover and winter peas did relatively well, showing the advantage of genetic research over time.

Winter canola showed some promise for overwintering and had significant biomass and weed control, rivaling cereal rye. Although radishes died out at all the northern sites, surviving on some southern states (Tennessee), it produced a lot of fall biomass and was the best at suppressing weeds in the spring.

Individually, there are at least 67 species of cereal rye, perhaps more. Cereal rye is used not only as a forage in some states, but also for erosion control through high biomass and also weed control. There are a lot of differences among cereal rye varieties in maturity, stand height, and how it is bred and managed. Many cereal rye varieties have a high allelopathic effect on weeds which is good for soybeans but can hurt corn. For other cover crops, especially legumes (clover and peas), weather and herbicides make getting a good stand difficult. Again, that is why breeding is so important.

Here is what was found to work the best in Indiana. Both cereal rye and hairy vetch had strong winter hardiness and significant spring biomass. Biomass adds soil organic matter, suppresses weeds, and improves water infiltration and water storage. Elbon and Wrens Abruzzi had great biomass, were earlier maturing, and suppressed weeds. Both are good before corn. Kentucky Pride was the best crimson clover variety followed by Heussers Ostaat. These varieties survived the cold weather. On hairy vetch, all varieties did well, not much difference except for Au Merit (performed poorly in Indiana). However, Au Merit did well in Pennsylvania while Purple Bounty did poor. On winter peas, WyoWinter survived the cold the best followed by Survivor, and then Austrian Winter peas. On winter canola, KS 4989 was superior while all the radishes were similar (Aeriff, Driller).

In Pennsylvania, Wrens Abruzzi was the earliest cereal rye with the most biomass while Gardner was the latest maturing cereal rye variety and the poorest biomass. In many cases, most farmers want an early maturing variety to suppress weeds, and to keep soil in place for erosion control. Also, there are a lot of nutrients in the biomass. WyoWinter and Survivor were again the best winter peas while for hairy vetch there was not much difference except for Purple Bounty which performed poorly. All three canola varieties performed well in Pennsylvania and both radishes (Aerifi and Driller) winter killed but had significant biomass to control spring weeds.

For more information visit: https://cra-missouri.edu/cover-crop-variety-development-project