Turnips work very well, however, this past year they didn't amount to much at all in the growing season. My garden was the same way here in Missouri. I planted probably 25 tomato plants and got maybe 30 tomatos TOTAL the whole summer. Green beans did ok, so I'm guessing soybeans did well this year too. Even my cucumbers were lacking.
Turnips work the best for deer if you plant them late season. I think I planted mine in early august. Those deer will eat the tops off after the first freeze, then they will DIG them out of the ground during snow to eat the bulb! I keep a close eye on places that have turnip seed on sale. I found a place in eastern MO this past mid-summer that had turnip seed on sale for $1 / pound! That's pretty good...
btw... I also planted some turnip seed (from store-bought seed) and they didn't amount to much this year either... for those of you who thought the seed was bad.... :)