The size and number of tractors is dictated by the size, nature and profitability of the farming enterprise as well as by how many (if any) operations (e.g. plowing, planting, spraying, harvesting) will be serviced by local contractors. For example, the capital cost of purchasing a harvester to harvest a small area of a moderate value crop is often prohibitive.
Precision farming applications promise to conserve energy and reduce agricultural inputs but much remains to be done before these claims can be sustained and the technology commercialized at an affordable price to the farmer. Further exciting developments in farm machinery are under way with particular emphasis on communications and information technology applications.

And in China the number of threshers alone exceeded the combined total of tractors and power tillers, even in 1980. In all of Asia mechanical rice milling for large trade quantities had already been introduced in the late nineteenth century, usually based on steam and later on internal combustion engines. Smaller rice mills have swept across Asia since the 1950s; it is hard to find villages where rice is still pounded by hand. During the twentieth century and especially since World War II, the speed with which farmers adopt new machines has quickened. In Japan, for example, the number of motors, threshers, and hullers increased fiveto tenfold between 1939 and 1955. Power tillers grew from less than 100,000 to more than 3 million between 1955 and 1975.

Source 1 | Source 2 | Source 3

Video

Source 1 | Source 2 | Source 3