I think I have to agree with hillbilly on the small foodplots, this comes from personal experiance.
Minerals are another matter, you can put out salt licks, buck grub, and other attractants that can provide nutriants for health and antler growth.
Whats planted in the fields you hunt already?
Heres a pic of my attempt at a food plot, its an annual/perrenial mix of clovers and grains meant for whitetail in northern climates, problem is I've never seen a deer in it or evidence that they use it, even before the local crops start to come up, I'm planning on approaching the farmer and seeing if he will disc the corner for me, say 100' x 150'