I'm finding dirt in my dachshund's poop. He eats his regular kibble and sometimes doesn't finish it all, and he does get snacks and a vitamin pill. I'm finding areas in the yard that have been slightly pawed at and the black dirt (sand, tiny pebbles, loam, soil, dirt) I find in his poo matches the dirt from the digging areas. I'm concerned he may pick up a parasite from this habit. He'll stop when I catch him in the act, but he can't be constantly monitored. He isn't kept as an outdoor dog.
Why is he eating the dirt?
How do I stop him from eating the dirt?
What else should I be concerned about with this situation?