By Don Donovan
Across Indiana, farmers who’ve become comfortable in the management of cover crops are taking an additional step on their soil health journey. They use a roller crimper to terminate cereal rye cover crops in the spring.
To facilitate crimping of cover crops, the Vermillion County Soil and Water Conservation District purchased a 20-foot roller crimper for local farmers to use to terminate their cover crops. This past spring, that roller crimper ran over about 1,000 acres of cereal rye. Since everyone involved was new to roller crimping, several lessons were learned that can help other farmers with this process. Those lessons include:
• Every year is different. 2018 was a difficult year to learn how to roller crimp in west-central Indiana. Cereal rye tended to break winter dormancy late. It finally started growing, and then growth slowed when it turned dry. There never was that growth spurt where it goes from 2 feet to head-high seemingly overnight.
Rye was less than 4 feet tall when it headed out. Dry weather seemed to cause it to go into a dormant stage, making it difficult to crimp.
• Timing is everything. Cereal rye must be at the right stage of maturity to be terminated with a roller crimper. That may mean running the crimper later than you would like to plant beans. A rule of thumb: Plant when it’s time to plant; crimp when it’s time to crimp. Those may be two drastically different times. The key is making it work in your operation. For complete termination, rye must be mature enough to shed pollen.
• Variety is important. There hasn’t been as much discussion about what variety of cereal rye to use as there has been about what variety of annual ryegrass to seed. The issue with using “variety not stated” cereal rye seed is it can mean you have a mix of several varieties, resulting in plants breaking dormancy at different times, growing at different rates and maturing at different times. While you can deal with this if you’re terminating with herbicides, if you want to use a roller crimper, you want every plant as close to the same stage of maturity as possible.
If you want to terminate with a roller crimper, you may need to use a variety stated cereal rye that will mature around the time you wish to plant. While you will pay more for seed, you will hopefully improve your chances of complete termination with a roller crimper.
• Rates are important. If you’re looking for that season-long mat of cereal rye residue to provide erosion control and weed control, conserve moisture, and keep the soil surface cooler, you may have to increase your normal seeding rate. This will probably become more vital as microbiology in the soil becomes more active, breaking down residues more quickly.
• Soybeans don’t care. Soybeans don’t care to a point. A roller crimper can be used after soybeans have emerged and are growing. Farmers who crimp are finding that beans up to the third trifoliate aren’t harmed by running a crimper over them. It may even provide a yield advantage due to soybeans responding to early stress events.
Are you looking to take an additional step on your soil health journey? A roller crimper may be the next cover crop tool to add to your arsenal.
Donovan is a district conservationist with the Natural Resources Conservation Service based in Parke County, Ind.