In Iowa soybeans have more uses than any other legume. They may be grown either alone or in combination with corn. The seed is one-third protein and contains two important vitamines, making it a high grade, home grown supplemental feed for any kind of livestock. The soybean plant is as high in feeding value as alfalfa and may be used in the form of hay, pasture, silage or soilage, or as a protein concentrate.
Hughes, H. D. and Wilkins, F. Scott, "Soybeans" (1923). Circular. Paper 84.