I use winter wheat in the rotation for a "cover crop" after beans and then have plenty of time to raise my N needs after wheat harvest. It also gives me a 3 year lapse, so I can raise conventional corn without bug problems. Usually have volunteer wheat growing after the cover crop dies in the fall, which allows a growing root most of the time and allows green planting. No neighbors for miles that raise wheat, so I don't worry about my volunteer wheat cover.

Raising corn on 15" rows doesn't allow me to have a living root during that winter, that I can come up with to use.