The Plow That Broke The Plains is an important historical document on several levels. It shows the state of the art in the documentary and the political orientation of government civil servants of its day. It includes some of the best raw footage of the environment and agricultural practices in the American West. The soundtrack by Virgil Thomson connects the otherwise dry narration with many important themes and trends in American society.
I show this film to my students in Environmental Science in order to introduce them to the complex economic causes for many environmental causes. Both the script, a pastiche of contemporary headlines and campaign slogans, and Pare Lorentz's "montage" style editing connect the booming World War I economy to the environmental crisis that followed. The film does not provide answers, and subsequent research has provided new insights on the Dust Bowl crisis.
The links above provide a streaming version which I am currently providing to my students. Several versions can also be downloaded from the U. S. National Archives webage.