I've used carpet with some degree of success early. The problem I had was that the carpet fibers weren't bio-degradable. Or at least some weren't. When the inevitable decaying occurred, it seemed to be more on the backing and the end result was carpet debris not staying in place. It's been years since I used it and I still find those fibers. The first year or two it worked well. I think different types of carpet might work differently, depending on how they are manufactured. Not necessarily a 'one size fits all' scenario.
