Well....you guys are no fun.  I was kinda hoping for a step 1-step 2 pat answer.........

The removal might be doable........and Thunderhut touched on it.

This year we mowed the cereal rye ahead of the soybeans, so if my brilliance failed, we could recover with single sweep cultivators.

Chopping the cover crop........but still allowing it to grow.......could be a viable alternative.

Well........back to the drawing boards.......but the underlying question of whether or not there is a cover crop that can be used ahead of corn, that still takes out some phosphorous.........was answered........and that appears to be a legume that would over-winter in central Iowa.........but now we need to add the step of removal.

Thanks to all.........much appreciated.

I'm starting to understand why my father laughed his tail off when I asked him when I was in high school------"things DO get easier when a person gets older, don't they?"