Rob, I have always heard that discing seed in the ground buries them too deep and most will not make it thru. Just saw Dr. Grant Woods speaking on this very subject on a Drury DVD.I would just spread it and then roll or cultipac it in and hope for a rain. That was his advice.

But you will get the best stand by using a planter no doubt. But if that is not an option, I would roll it in.

Also corn likes A LOT of nitrogen, or you will get small stunted stalks and not many ears.