Initially farm had just many types of weeds, later thought leguminous cover crop may be better and introduced pureria javanica. Now there is napier fodder grass which also produces enormous amount of grass mulch.
In natural way of farming book, under chapter Fruit Trees, Fukuoka San says, to establish while clover as cover crop. White clover remains hardy for 6-7 years or 10 years with good management and after that weeds reemerge, mainly climbing and vine weeds, bindweed, kudzu and sorrels. Those plants resistant to clover survive and re-establish themselves.
Thus after 10 years weeds takes over again and this is not a problem as long as weeds do not interfere with farming operation. According to Fukuoka San soil becomes unbalanced when clover is grown year after year on the same land, emergence and succession of different weeds is more natural and conducive to soil enrichment and development.
Fukuoka San also says he has no intention of insisting a cover of clover, a weed cover will probably do just as well. Only issue is that weed cover may become very thick and cutting is very hard and it may also interfere with farming i.e fruit picking and tending trees. If weeds take over again he suggest to sow clover again or sow vegetable seeds.
Basically it may be just enough to grow weeds without disturbing soil, basic idea is to grow as many plants as possible so that all the sunlight is harvested and put back to soil.
