I am experimenting with a Landscape Fabric from Agway, which has Farm supply stores here in the Northeast. It comes in 3 foot by 100 foot long rolls, and is guaranteed for 5 years. I plan to pick it up just before the harvest of these dry beans in the Fall. Some versions of fabric weed barriers are guaranteed for 20 years, and paper weed barriers are made which break down and are just plowed in, so you don't have to pick them up.