With the increasing promotion and adoption of cover cropping practices, some growers are seeking novel ways to terminate their cover crops.

Roller crimpers are one strategy, but a new 30-foot roller crimper is currently priced at around $30,000. According to Ryan Schmid, growers are reluctant to make this investment since the technology is relatively new.

Schmid is a research scientist and agroecologist at Ecdysis, a North Dakota-based research foundation. Ecdysis’s research focuses on redesigning agroecosystems to be more resilient and to profitably produce healthier food by increasing biodiversity and reducing disturbance to farmland.

To address the cost barrier associated with experimenting with a roller crimper, Ecdysis Foundation collaborated with farmers in eastern South Dakota to develop a how-to guide for farmers or machine shops to build an affordable roller crimper by repurposing tillage equipment. The project was funded by a Sustainable Agriculture Research & Education (SARE) grant, and their allotted budget to build a roller crimper was $6,000.

The foundation of the DIY roller crimper is a set of discs. In North Dakota, discs under 30 feet have no trade-in value and are available at a scrap price. Schmid found a 490 International disc with fold wings for $1,500.

“We had to put a few new tires on it, grease the bearings, put a few new hydraulic hoses on it and we had a working piece of machinery for $2,600. So now that we had our equipment, we had our frame, it’s time to start working on it,” Schmid said.

They next removed three sets of discs from the frame and started fabricating rollers in a shop. The blades on a commercial roller crimper are installed in a zig-zagging chevron pattern that reduces bouncing and ensures a smooth passage across a field.

Schmid, more scientist than welder and fabricator, decided that the chevron pattern was too difficult to replicate in a farm shop. Instead, he went with straight blades. The quarter-inch crimping blades are plate steel, welded on edge to the three drums (5/16-inch thick) in an alternating pattern. The center drum is 11 feet wide with 66 blades, and the 6’8” wing drums each have 44 blades.

Each of the roller sections was fabricated with an axle shaft running the full length through it, supported by the carrier bearings on the disc frame. Custom brackets welded onto the frame hold the rollers in place.

Roller crimpers work most effectively at a specific stage of cover crop growth. For example, to terminate rye, the anthers should be coming off the rye head.

The roller crimper works to terminate the cover crop in two ways. First, it rolls the crop down. Second, the blades crimp the stalks. Crimping damages the stems and limits the water flow through them. The goal is that the cover crop stays on the ground and creates a dead straw mat for the subsequent crop.

Once Schmid’s roller crimper was finished, he started advertising its availability to local growers. One of the first people to use it was a certified organic grower with a stand of rye. The roller crimper successfully terminated the rye, but the weeds were not impacted. Schmid said, “It’s not going to kill those weeds. So don’t expect it to be this magical tool.”

As more growers borrowed the roller crimper, they discovered a flaw. The blades were designed to crimp every 6.5 inches, but it was only crimping every 12 inches. To address this issue, they added bungs to the hollow drums and filled them with water.

“The farmers that borrowed it from us said it worked much better. It had the weight to crimp a substantial rye crop,” said Schmid. The extra weight also helped the roller crimper to better reach the plants in depressions created by uneven terrain.

Schmid noted that the roller crimper is more effective in thicker stands, although he’s not sure why. He’s found that the implement works best when driven at 8 to 9 mph. If they were moving it short distances, they did not remove the water from the drums, but for transport on the road, they did drain them.

The complete schematics for the DIY roller crimper are available at projects.sare.org/sare_project/onc21-093.

“There’s plenty of room for improvement. And if anybody decides to do this, let me know. I’d love to see what you produce and what you learn about it, so that we can keep adding to that report for SARE,” said Schmid.