I think what GR8atta2d is saying is that ag fields are not planted for the benefit of the deer but planted as a cash crop for the farmer. If something is planted for the benefit of the deer then it can be construed as baiting while, if planted for other reasons, then it would not be considered baiting.

I, for one, don't necessarily see it as whether it is indigenous or not, but look to the reason for the planting of the crop/food source. IMO, if a food source was planted by a human for the purpose of feeding/luring deer then it is bait. If the food source exists for other reasons then it is not bait.