Hmm not sure about a long term solution but try moving his food and water bowls to the worst spot (say your back door) and after giving the area a good clean first. Dogs don't mess where they eat usually so that could be one trick.

as for getting rid of the smell hose the mess away then squirt some detergent on the spot and scrub. Thats what we had to do after we doggy sat our SIL dog.

Another thing could be some citronella spray - spray that in the areas you don't want doggy to poop the most - if doggy is tethered you will need to give him an option of where to do his business but if he has free run of the yard then mark your territory with the spray.

Naex