Soybean acreage has shown a sharp uptrend with the great expansion occurring during the last decade. A major factor has been the development of new varieties of soybeans better suited to both old and new production areas. Another factor, especially in the Corn Belt, has been the shifting of acreage formerly in oats and hay to soybeans. Acreage restrictions on corn, wheat, and cotton during the 1950's encouraged farmers to shift into soybeans, which have no acreage controls. The Corn Belt is the main production area for soybeans although since 1949 rapid acreage increases in the Delta, Lake, and other States have reduced its relative importance.