A rapidly growing demand for vegetable oils during the 1960-70'8 and new soybean varietal developments have been two major factors contributing to the large Increase in acreage of soybeans grown for beans in the United States during the past 20 years (Table 1)« In 1939, about 60 percent of soybean acreage was of the forage type, to be fed to livestock as hay. In the 1970'b about 98 percent of the soybean acreage was for beans* After being harvested, these beans are crushed commercially to obtain soybean oil for human consumption and soybean meal and cake for livestock feed.
Huffman, Wallace E., "U.S. Soybean Varietal Development" (1987). Economic Staff Paper Series. 17.