The best way to stop your dog from digging, is to prevent him from starting. The biggest reason a dog starts digging is because the animal is hot, and digging up fresh dirt to lie in is a relief to them. The top soil is always burning hot for them, but the dirt underneath is nice and cool. Have a source of shade, and water, so tht the dog stays cool will prevent them from starting to dig. If your dog is already digging, and there is a problem area, put something other than dirt there. For example, I had a german shephard that loved to dig. He had one hole that was his favorite. I filled it with marbles and he stopped digging there.