what Fukuoka did to keep down weeds was to plant a succession of green manure crops, (including daikon radish which penetrates deeply into the soil. And, you probably could use kudzu (a legume) as a soil builder also, just plan to have some animals ready to graze it after it has done its job, or you will have kudzu city, like we do here in rural Alabama. The roots of kudzu can penetrate to 150 ft below the soil surface, so it would be good for turning bed rock into soil. Kudzu has a large round flat leaf that resists gully washing erosion from rain.
