During the past 30 years sweetclover has changed from its lowly position as a roadside weed to a respectable place among farm crops. The rise in importance of this crop has been the direct result of the realization that sweetclover fills a most important role in building and maintaining our soils—making possible large yields of corn, soybeans and other crops.
Johnson, I. J.; Wilsie, C. P.; and Leffler, Allan T.
"Sweetclover on Iowa Farms,"
Farm Science Reporter: Vol. 6
, Article 6.
Available at: http://lib.dr.iastate.edu/farmsciencereporter/vol6/iss1/6