YERKES, A., "THE TRACTOR FROM THE VIEWPOINT OF FARM MANAGEMENT," SAE Technical Paper 170039, 1917, doi:10.4271/170039.
The author first considers the size of farm on which tractors can be used profitably. Confining his remarks to certain of the central and north central states, he points out the fact that there is a strong tendency for farms from 20 to 100 acres to be combined with others to make units of a more efficient size for the application of modern farming methods. Farms from 100 to 500 acres, representing 65 per cent of the total farm acreage, are the greatest users of tractors. Farms over 500 acres contain 25 per cent of the farm land, and also represent an important tractor market. Efficient sizes of tractors are next treated; three and four-plow sizes are generally preferred. Belt work, representing 50 per cent of a typical tractor's work, and other special duties performed by the tractor are next referred to.In the section devoted to the service problem the author quotes several letters from users and points out the necessity for high grade service and, in conclusion, he points out the need for better operators.