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Research Highlights

Research Highlights
Incorporating Rye into a Northern Minnesota Wheat-Soybean System

A look at residual rye biomass about two weeks after the last rye termination timing during 2019 Minnesota trials.

By Barb Baylor Anderson

Interest in cover crops among Minnesota soybean farmers continues to increase, given favorable prospects for protecting soil from erosion and improving soil health. But the limited time between harvest and the end of the growing season in the north makes cover crops a challenge.

“Within the rotation sequences in northwestern Minnesota, cover crops will most likely establish best and provide the greatest environmental benefits when planted after harvesting wheat in fields where soybeans will be grown the following spring,” says Joel Ransom, retired North Dakota State University Extension small grains agronomist, who together with Melissa Carlson, Minnesota Wheat On-Farm Research Network, are principal investigator for a project funded by the Minnesota Soybean Research & Promotion Council and Minnesota Wheat Council.

“When incorporated into the current wheat-soybean system in that region, cover crops have the potential of not only protecting the soil for several weeks, but also growing sufficiently to scavenge much of the residual soil nitrate, reducing nitrate loss through leaching and runoff and establishing enough biomass to reduce soil blowing during the winter,” says Ransom.

Objectives of the research were to determine best management practices for spring cover crop termination timing and termination method in both small-plot and in-field-scale on-farm trials.

Ransom says rye as a cover crop offers promise in northwestern Minnesota. He found that when rye was used as a cover in the fall and terminated before planting soybeans the next spring, it developed little biomass. The biomass was largely gone within a week or two of soybean planting. Terminating rye at or after soybean planting, on the other hand, resulted in a dramatic increase in biomass and reduced weed development within the soybean field.

However, Ransom cautions delayed termination during dry years can reduce soybean emergence, while during wet years will not likely have an impact during any of the termination timings.

“When rye is planted as a cover crop after wheat, delaying its termination beyond soybean planting will not have a detrimental impact on soybean establishment and yield and will provide very good cover while the soybean crop is developing,” he says. “This can reduce the potential for soil erosion during the time when soybeans are beginning to grow.”

Additional research is still needed to fine-tune the cover crop strategy.

“Continued testing of termination timing in larger scale plots and more environments that vary in precipitation and soil moisture conditions would help us hone in on how different termination timings affect weeds and soybean yields under varying conditions year to year,” Carlson says.

This project was funded by the soybean checkoff. To find research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.