The advent of chemical fertilizers led the farmers in a certain region to abandon the practice of periodically growing a green-manure crop, such as alfalfa, in a field to rejuvenate its soil  As a result, the soil structure in a typical farm field in the region is poor
So to significantly improve the soil structure, farmers will need to abandon the use of chemical fertilizers
many, if not all, farmers in the region will not grow green-manure crops unless they abandon the use of chemical fertilizers