The author considers the adaptation of farming implements to the farm tractor the most important engineering problem confronting tractor manufacturers. The problems are intricate in their ramifications, all-inclusive in their scope and fundamental. They can never be solved by theoretical discussion and laboratory tests alone. Extensive field experiments are needed with the machines operated by the farmers themselves. It is the implement which does the work. The mold-board plow and the disk harrow are standard for soil preparation; the oscillating sickle, the reel and the knotter-head for harvesting; the revolving toothed cylinder and the oscillating rack for threshing. Power must be transmitted to these fundamental devices. The automotive tractor fills a place in the farm power field not successfully covered heretofore by any single prime mover. It furnishes power for both belt-driven and tractive machines, the latter in large number and operating under a wide variety of conditions with varying power demands.
The tractor industry is not unanimously agreed today on the range of farm operations which one prime mover should be able to cover. As a minimum it must be adapted to operating soil-preparation, harvesting and belt-driven machines. Row crops are purposely excluded from this classification, since all such work and all hauling should be done by specially designed machines like motor cultivators and trucks.
Four definite lines of development are suggested. The rapid depreciation of both tractors and implements leaves little room for argument over the need for improvement in the quality of the materials used in construction. This once secured, the mechanical efficiency and speed logically follow. Already there is a noticeable tendency toward increase in both the size of the machine used and the rate of doing the work. It becomes a question of economic balance between the size of the outfit and the speed.
One man should be able to drive the outfit and make the needed adjustments of the parts while in motion. He should center his attention on the work to be done rather than on the tractor. A genuine one-man outfit would be secured by driving the machinery directly from the engine instead of from a bull wheel running on the ground. Plowing, seeding and harvesting are discussed in detail by the author in the light of both tests and actual field work, and practical suggestions are made covering such weak spots as side-draft, vertical angle of hitch, satisfactory work at higher speeds, design of plow bottoms and width of swath.