my 2 cents
This year we had some property that was too wet to plant this spring, mostly low spots or boarders along ditches/fence lines. Late July came along and the areas finally dried out enough to work the ground. We disked this ground and then put down some Buckmaster turnips/radishes in a few spots and rye grass and a clover small grain mix. The rains came and almost all of the areas came up thick. We harvested the corn and soybeans which left these strips of food plot, some area four foot wide some up to 16 foot wide. Pheasants loved to use these boarders after the crops were harvested as transition areas. I thought the deer would really like the turnips because they stayed green well after the first freeze, but the deer didn't really touch these areas. Ok long story I know, but it cost probably 100 dollars for seed 20 dollars of diesel and 3 hours of time to put out about 2 acres of food plots. Yes we over-seeded so seed cost was higher. Most farmers disk or dig up areas that were too wet to plant just to control the weeds. So If the farmer has already turned the ground black, and if you have a broadcast seed spreader, making these unproductive crop free spaces productive isn't all that expensive, just a little time consuming.
Pictures to explain.
715 Pheasants forever western blend next to slough
012 rye grass along soybeans
411 sorghum in old abandon barn yard
310 sorghum corn mix along corn and fenceline
SD Viking