The grain boom ended in the mid-1920s. It was followed by a long drought that lasted from 1932 to 1941 on the Southern Plains, and from 1928 to 1936 on the Northern Plains. The drought brought dust storms and economic collapse, leaving families with failed crops, dead cattle, and eroded soil to desert their farms. The drought also led to massive Federal government efforts to change the environment, society and economy. While all might not agree that those were the only causes, or that the greatest areas of wheat farming suffered the worst drought and dust storms, there was a causal relationship.
Plowed land is a much greater source of blowing dust than uncultivated grassland.
Humans responded to the problems of the 1930s. Those who remained changed their farming techniques between the 1930s and 1970s. The data used in this project came at a variety of scales, and these have a strong influence on the research. Demographic data constitute the primary source for much of the analysis. While there are many kinds of demographic data available, population census data constitute the most important source in this work.