Advice for planting corn after cereal rye

Corn Pest Beat: Planting corn after cereal rye requires high management skills. 
Feb 02, 2022
I’ve never planted corn after cereal rye but will this year. How can I avoid problems?
The Indiana certified crop adviser panel answering this question includes Gene Flaningam, Flaningam Ag Consulting LLC, Vincennes; Brian Mitchem, area manager for Nutrien Ag Solutions/Loveland Products, Decatur; Jeff Nagel, agronomist for Ceres Solutions, Lafayette; and Dan Quinn, Purdue University Extension corn specialist, West Lafayette.
Flaningam: Cereal rye can produce a toxin that competes with crop and weed growth. So, terminate it at least one to two weeks before planting corn. You can plant green and then terminate it, although you risk missing that window to timely kill the cover crop.
Mitchem: Terminate as early as possible to minimize above-ground growth. Early termination can help mitigate insect attraction to the grass and allow more sunlight penetration to warm soils quicker. Also, an insecticide can be included with the herbicide. Starter fertilizer should be considered necessary. Between 30 and 40 pounds of starter nitrogen should be applied in a safe zone away from the seed. Higher rates are needed farther north due to colder soil temperatures. Sidedress nitrogen applications should contain an additional 20 to 30 pounds of N to compensate for grass decomposition. Only 10% of the N assimilated by the above-ground portion in the grass cover will be available to corn.
Nagel: This can be done, but it’s best to start with something simpler. Here are things to consider:
What will your termination strategy be? Glyphosate works well, so ensure you have adequate supply for termination. Terminate early and/or before cereal rye exceeds 12 inches tall. It’s best to terminate two to three weeks before planting. If you can’t terminate early, plant and terminate within a day or two.
Does your planter have residue removers? It’s important to move residue away from the seeding area. There is debate over whether there is much of an allelopathic effect on corn growth. Still, corn doesn’t like decomposing residue around seedlings. Use an aggressive fungicidal seed treatment.
Are you equipped to apply adequate starter N? This can help mitigate temporary N tie-up by residue. Consider minimum rates of 40 to 60 pounds per acre.
Monitor early insect issues. A cover crop and/or winter weeds can be attractive for moths to lay eggs. Terminating early minimizes potential for small, early larvae to survive before corn emerges.
What is your nitrogen strategy? Sidedress N would be preferred. Consider bumping total N rates by 5% to 10%.
Quinn: The two biggest issues in corn following cereal rye are poor emergence and nitrogen stress caused by residue interference, nitrogen uptake and nitrogen immobilization by the rye. Terminate the cover crop timely — at least two to three weeks before planting — to allow for an adequate kill and minimize the potential for planting and nitrogen issues due to high biomass levels. Make sure residue is cleared from the seed furrow, adequate seed-to-soil contact occurs and seeding depth is consistent. This may mean making planter adjustments.
Nitrogen fertilizer applied in a starter is very beneficial following cereal rye, especially in a 2-by-2 starter. At least 40 pounds per acre of nitrogen applied as starter can help minimize potential early-season nitrogen stress caused by the cover crop. Lastly, in-season sidedress and subsurface applications of nitrogen can help reduce the yield penalty and nitrogen stress following rye. If nitrogen is applied too early and on top of rye residue, the potential for nitrogen loss can be significantly increased.