I assume there is a reason you can' t ambush him when he goes to or from the field. If not, that would be the easy solution since he seems to do the same thing every day. If that is not the case I have heard of hunters who have had this problem and got to the field at night and concealed themselves either in a natural blind of some sort or even digging a hole, getting in and covering the top. They then ambushed the turkey when he pitched to the field. I know it sounds sort of extreme but I guess it depends on how badly you want the bird.

FYI, Ray Eye was one of the ones who dug a hole and hid in it the point of his story was that he doesn' t give up in tough situations (I am not sure I would go that far).