Historically, the U.S. farm sector has been a leader in meeting the challenges of the world's growing food demand. American farmers produced an impressive 24 percent of the total world food and feed grains in 1977. They also contributed 53.6 percent of total world exports of these farm commodities in the same year. This achievement was possible through a combination of past governmental policies and technological developments. In the beginning cheap land and other inexpensive inputs encouraged farmers to increase agricultural production by expanding the use of these inputs. Gradually, technological innovations and mechanization of agriculture accelerated its growth and productivity, creating a large capacity for agricultural production. Table 1 shows the indices of farm output, input, and productivity in the United States from 1910 to 1977. Output increased by 181 percent whereas input use increased by only 17 percent, resulting in a 140 percent increase in productivity during the 1910- 1977 period.