Few other crops in Iowa have shown such rapid acreage increases as soybeans or proved as advantageous for so many different uses. Only 471 acres of the crop were grown in the state in 1919. By 1933 the area had expanded to 192,000 acres. Soybeans may be planted either alone or with corn. Alone, they may be used for seed, hay, pasture, silage, soiling, or as a green manure crop. The first two of these uses are by far the most important. Iowa farmers need a home-grown, high protein concentrate, and soybeans are the best crop available for that purpose. Soybeans also are grown extensively to provide a high protein roughage, because on many farms they are better suited to the soil and crop program than alfalfa and are more certain and productive than red clover.