Being in NE Missouri, I assume you have a lot of ag in the area? I would focus more on fall-winter food sources since they will have more food than they could ever eat with the surrounding ag fields. Corn, soybeans, and clover are all good spring-fall choices, although clover typically struggles mid-summer and is better in spring and fall. In my experience, they will basically ignore the clover while the ag fields are full also, other than maybe a pass-through browsing on their way from bedding to ag field. I don't think you can beat soybeans as a summer food source. For later fall crops, I really like brassicas (can take the deer a year or two to find those) as well as cold season grains like cereal rye, winter wheat, etc.
Clover is by far the easiest to plant and maintain, IMO. I've had my best luck establishing in the fall. I spray the area once in early spring, once in early summer, and then broadcast a cover crop like buckwheat or oats. Once we start to cool down in late summer (probably August-ish in your neck of the woods), I spray the cover crop with Roundup and drive over it to knock it down (drag or roller for larger fields). Then just broadcast clover seed at a rate of 8 lb/acre into the thatch just before some rainy weather in the forecast. Once clover is established, you can spray it with glyphosate to control weeds and it won't kill the clover.
Planting brassicas grains I use the same method and planting rate. For winter grains I use the same method and broadcast 200 lb/acre if that's all I'm planting. I also use winter grains to fill in other food plots, for that just broadcast at a rate of 100 lb/acre right over the plot. If it's a taller plot of clover or other upright plants it helps to mow it to about 6" or so also. If you do cereal rye, it will come back really early in the spring and provide some food before anything else comes up.
