Oats (spring cropping), turnip (winter feed) and clover (increasing nitrogen nutrients using nitrogen-fixing bacteria by cultivating forage legumes on fallow ground) were grown to provide feed for draught animals, and animal-powered tillage, supplying barnyard manure, etc., This new system required close cooperative work by farm families, transforming formerly dispersed rural hamlets into centralized villages. One of the benefits of this three-field system was that, during the fallow stage, the use of ploughs to perform deep ploughing and overturn the soil removed weeds (fallow-period weeding work).