No and Yes, No you have no shortage of food in the area so a food plot is not necessary. Yes it would help to leave some crop standing, like corn. In my opinion a deer will eat corn only second to acorns in the fall. If you could pay the farmer to leave an acre of corn in the right area you would have a goldmine come november when everything else has been chisel plowed or combined. Also if you leave corn, use the direction of the rows to help your hunting. A deer would much rather go down a row of corn than have to go through them. That is why were I hunt, we have left the long rows, and not end rows, because that is the direction the deer liked to travel naturally.