Not to be sarcastic, but it's spring already. Everything here in North Central MO is green and full of life, so the deer are eating good right now,,, really good. In fact, there are probably deer out there who would pass on the corn and go for something fresher.
Now are you talking about doing this for next winter? If so, I would go against clover and go with turnips. You more than likely get some good snow in eastern Iowa every year... therefore, deer aren't going to scratch down to eat clover. They WILL however, scratch down to get to turnips. Plant them sometime between late August to late September.
Good luck brother!