One possibility of increasing land productivity in Illinois is to double crop soybeans following wheat. This practice has been limited to the southern half of the state because of the shorter growing season in the northern half. A modification of double cropping known as relay cropping might allow the earlier establishment of soybeans in wheat or oats and extend the northern limit of double cropping in the state.
McBroom, R. L.; Hadley, H. H.; and Brown, C. M.
"Research notes: Relay cropping of soybeans and oats,"
Soybean Genetics Newsletter: Vol. 6
, Article 18.
Available at: http://lib.dr.iastate.edu/soybeangenetics/vol6/iss1/18