If your competition is that far away and you get plenty of birds in your area that's half the battle. IMHO you are probably better off with rice, buckwheat, or milo. Corn will cost 10x your budget to do it right. I'm from IL so corn country here lol. You shouldn't need it where you're at. Maybe try to split your field up some and try 2 or 3 different foods and let the ducks tell you what they like best. I can tell you that buckwheat gets over looked too much and waterfowl LOVE it and it's about the easiest thing in the world to do. 100 acres is a big place to play with and variety is the spice of life lol. I'm sure you will have some good hunting regardless.