Whatever he plants .....more than likely the deer will be interested in it to some extent. I would be far more concerned if he is doing any fall spraying or tillage. That can turn essentially a large food plot.....into a virtual parking lot as far as food value is concerned. Another option - is IF you can talk to those involved - is to broadcast some basic brassica and cereal grains (turnips and oats or wheat or even rye) as soon as harvest is complete. It won't produce a ton of food, but it can hold the deer's attention. You don't need to do the entire field just where you want it and in most cases it's organic matter for the farmer.... You may need to put a little spin on this plan.....use the "help me, help you" spin. By allowing you to broadcast something for the deer to eat, you can be more successful in killing deer...which most farmers will appreciate as they see deer as profit robbers. You can also offer to do it in areas that might see some erosion as well if that works for you.....this will help retain the top soil that may help the farmer agree as well. Don't expect him to cooperate just because he is a nice guy, give him some upside in the deal if possible. You may even want to use the term "cover crop" as they will understand that as well......especially in the erosion prone areas. Good luck.