Early variation

• it wasn't easy to build a machine to replace horses in a muddy field
  
• steam tractors were a success for logging and for farms in the western great plains in the 1890s
  
• tractors with internal combustion engines were on the market as early as 1904
• D.M. Hartsough built a multicylinder tractor that evolved into a successful model called "the big four"

• period of many different companies trying different approaches

Henry Ford

• produced his first experimental tractor, which he called an automobile plow , in 1907
• Fordson model F production started in 1917

 Fordson Model F

• this was good timing, just when World War I was causing a desperate manpower shortage for farmers and higher prices so they could afford to buy equipment
• Like the Model T, Ford made a smaller, less expensive, easier to maintain tractor

• tractors were most useful on larger farms in relatively flat terrain with hard soil
• in the south they weren't necessarily more economical than mules for small farms even in the 1930s
• the more farmers have to spend on equipment the more dependent they are on crop prices