Here's a report on how much Iowa farmers might produce if the demand arose and if all farmers fully adopted the improved practices and techiniques in crop production and soil management that would be profitable and practical.
Cheney, H. B. and Heady, Earl O.
"How Much Corn Can We Produce?,"
Iowa Farm Science: Vol. 7
, Article 2.
Available at: https://lib.dr.iastate.edu/farmscience/vol7/iss1/2