In the early 1900s farmers switched from horses to tractors. While much of the world continued to rely on human brawn or draft animals, Americans adopted the new technology of gasoline-powered tractors, motivated by clever ads, competitive prices, and a desire to be modern.
The plow and agricultural implement maker Deere and Co. experimented with tractor design in the early teens but got into tractor sales by buying the Waterloo Gasoline Engine Co. in 1918. The investment was a success. By 1936 a whopping 40% of John Deere's sales came from tractors.
As is common with new technology, a large number of early developers competed for a small market. In 1916 nearly 100 manufacturers sold tractors. By the 1930s only two major companies dominated the field: John Deere and International Harvester.