There are many cover crop seed choices when planting after small grain harvest or on prevent plant fields. You can get complex with various mixtures or keep it simple. An easy to manage, simple cover crop mix that does well this time of year in wheat stubble is oats (1 bu/acre), crimson clover (12 lb/acre), and radish or rape (2 lb/acre). Mixtures provide a variety of benefits that outperform single species plantings.
When using legumes, be sure to inoculate seed with rhizobia for maximum nitrogen gain. Also, be careful about hosting soybean cyst nematode if planting to soybeans next year.
Cereal rye is a versatile choice as a cover crop. It has a wide seeding window from now until late November. Cereal rye will survive the winter and continue growing next spring. Seeding can be accomplished by aerial or land application to a standing crop. Also, direct seeding after grain crop harvest is possible.
The Midwest Cover Crop Council has an online cover crop decision tool that can be used to make comparisons when selecting species. Combining warm and cool season, grass, brassica, and legume species will provide the greatest diversity for soil health.
Have a plan in place for cover crop termination if not winter killed. Spring growth can be managed to maximize nutrient cycling and soil protection before grain crop planting.
Check with your crop insurance agent to make sure you comply with termination requirements.