The actual experiences of some 400 farm operators, as shown by questionnaires obtained from these farmers in 1934 supplemented by financial records kept by each farmer in 1933 and 1934, form the basis for this economic study of farm practices.
Significant results were obtained when farmers followed some of the more important practices. Those farmers who planted corn varieties which had been tested for yield in state or county test plots obtained an average yield 6 bushels higher than those who did not. Testing for yield was found to be more closely related to yield than planting strains which were thought to be high yielding, but which had not been yield tested.
Hopkins, John A. and Goodsell, Wylie D.
"Practices on Iowa farms,"
Bulletin: Vol. 32
, Article 1.
Available at: https://lib.dr.iastate.edu/bulletin/vol32/iss360/1