Carson, there's guys in our area that plant potholes and PP ground to the mix you are speaking of. Generally it consists of radishes, turnips, and peas. The readishes will really open up the ground too. Look at how deep they get. The picture below is peas, a radish, and a turnip planted by a friend of dads in July of 2007. Picture was taken at the end of October 2007. The only problem with them that I've heard is that the field sure stinks come spring. I bet the Pluribus would make a nice strip though them though.