Here are cost figures for various farm operations based on cost accounting records of Iowa State University. Hourly charges for most tractors and implements up 5 to 15 percent from last year.
Hull, Dale O.; Martin, Donald L.; and Caldwell, Maurice C.
"1966 Costs for Field Work,"
Iowa Farm Science: Vol. 20
, Article 4.
Available at: https://lib.dr.iastate.edu/farmscience/vol20/iss7/4