2021-04-302021-04-301968-03-01https://dr.lib.iastate.edu/handle/20.500.12876/104860<p>Single copies of the above publications are available through your local Cooperative Extension Service Office, or from the Bulletin Distribtion Room, Morill Hall, Iowa State University, Ames, Iowa 50010.</p>articleisulib-bepress-aws-west292721861402farmscience/vol22/iss9/9Agriculture