Over the past few years, numerous benefits have been demonstrated for seeding annual ryegrass as a cover crop in a no-till system. However, another exciting benefit may be the use of this cover crop as an alternative method for controlling soybean cyst nematodes (SCN), which can cost a no-tiller as much as 15 bushels per acre in lost soybean yields.
Research done in Ohio and Illinois shows that planting annual ryegrass in the fall disrupts the life cycle of the SCN. It causes the eggs to hatch when no host plant is available to support them and leads to a reduction in CSN populations of at least 50 percent. Plus, a 5-year Canadian research study completed in the late 1990s determined that seeding annual ryegrass as a cover crop was the most effective and cost efficient method for eliminating this costly parasite.
University of Illinois natural resources management educator Mike Plumer conducted a 2-year cover crop study on the effectiveness of annual ryegrass and cereal rye. After the first year, annual ryegrass plots had reduced the SCN count by more than 70 percent compared to soybean plots with no cover crop. The former National No-Tillage Conference speaker also found that annual ryegrass was 30 to 60 percent more effective than cereal rye in controlling the parasite.
In addition, 2 years of tests at Ohio State University produced similar results, resulting in more than a 50 percent drop in the nematode populations in soybeans.