You can also add a wire apron to a tractor, to prevent digging. Just have it in sections that are hinged at the bottom and fold up when you need to move it. If you walk on hardware cloth it flattens it, so the cut pieces are like panels. You can use metal rings to attach it to the bottom edge of the tractor fencing. I've also seen people make frames for the apron and use regular hinges, too. Just tie them up to move it.