Among the stationary sources, water was first used for milling, pounding, and grinding in the first century B.C. in China. Water-powered milling was also invented in France in the fourth century A.D., though not until the twelfth century was it adopted throughout Europe. Wind power has historically been used almost exclusively for milling and for lifting small amounts of water. Mills and threshers were the most common users of steam power in the late nineteenth and early twentieth century in both Europe and the United States.
Different crops vary widely, however, in the type of labor required-that is, in their power- and control-intensity. Harvesting of root crops is probably the most power-intensive, although it still requires significan control. At the other extreme, cotton, fruit, and vegetables require intensive control: in the case of apples, the threat of damage is so large that their harvesting has still not been successfully mechanized.
The training of operatives involves a partnership between equipment users, equipment suppliers, maintenance and repair services, extension services (where available), research and educational institutions, and the communications media (farming press, radio, TV, Internet). Farm relief services are an integral part of a backup system where illness or other difficulties prevent a farmer from operating equipment effectively.Agricultural employment also fell substantially, both in absolute and relative terms, and labor was redeployed outside agriculture. The number of workers per farm was stable, while farm sizes grew rapidly from an average of 167 acres in 1950 to 401 acres in 1978.On the other hand, a contractor servicing many small growers in a local region can spread the capital cost accordingly and provide a service at an affordable price. For individual farmers who cannot afford a new and expensive item of equipment and who prefer not to depend on contractor availability, purchase of second hand equipment is an option where the support of a local finance agency may be required.
However, although the renewable alcohols can be produced from agricultural byproducts (cereal straw, sugarcane bagasse) the economics are even more unfavorable given the complex manufacturing process that includes fermentation and distillation.