Erosion is another reason for the lower grain production. The large-scale framing of a single crop creates the perfect conditions for erosion. In dry areas,especially,the loss of top soil has lowered the productivity of the land. In these areas,also,grain production has been limited by the lack of water. The new types of grain,in fact,require much more water than the grain people used to grow.
Yet another reason for lower production lies in the nature of the chemicals that farmers have used. Though these fertilizers and pesticides raise production levels at first,they must be used in increasing amounts after that. Many farmers cannot afford to buy more,and so production decrease. These chemicals have other effects that are expensive in the long run. They flow into the ground water,causing pollution and health problems. As people learn about these problems,they put pressure on farmers to further limit their use of chemicals.