“The land is harrowed after the plowing. Tractors are coming in rapidly but four to eight horse teams are still widely used for this purpose”

By Irving Rusinow, Shelby County, Iowa, May 2–7, 1941

Agricultural mechanization such as the introduction of tractors, combines, and cotton pickers greatly reduced the need for farm labor and was in large part responsible for an enormous population shift from the countryside to the city between 1910 and 1950. This was especially true in the South where two great migrations of African Americans brought around 3 million blacks to northern and western cities.

National Archives, Records of the Bureau of Agricultural Economics (83-G-44272)