Iowa farmers are hiring more custom work done on their farms than they used to. And it's a logical adjustment. Farmers can't always afford to invest in a complete line of invest of a complete line of machinery just for their own needs. The size of their operation may not justify it.
Heady, Earl O. and Barger, E. L.
"Custom Rates for Farm Machinery,"
Iowa Farm Science: Vol. 2
, Article 5.
Available at: https://lib.dr.iastate.edu/farmscience/vol2/iss12/5