I see that no one answered your excellent question, that's probably because you're describing a difficult situation, most of the land in corn and not much other wildlife food. There's not many great options to seed into standing corn. Seeding something into the corn in the spring when it's planted is not an option because corn doesn't grow well with competition. There's really only three options left;
1. Walk the corn rows in August with a handheld spinner spreader and seed something that grows well if it's broadcast into standing corn. In our area that choice would be rye, may mixed with radishes or clover. This system will mean a lot of work, because you will have to walk every other row.
2. Do late summer aerial seeding into the tall corn with an airplane or drone. This is going to be very expensive.
3. Get the corn crop off sooner and seed a fall crop into the field with conventional equipment. This means farming sileage corn, which defeats the purpose of feeding deer because sileage corn harvest leaves nothing for the deer.
This wildlife food desert in and after standing corn is a dilemma that every property manager faces, growing corn ties up that field for most of a year with nothing else there. The best solution is to farm the corn and have a separate small plot with a year round deer attractant mix growing that is used as the primary hunting plot.