Desertification is the spread of desert conditions into formerly fertile regions. The human and ecological disaster that struck the southwestern Great Plains of the United States in the 1930s and came to be known as the “Dust Bowl” (Fig. 16E) is a vivid example of desertification brought about by a combination of poor land management and sustained drought. In the decades before the drought, thousands of settlers were lured to the grasslands of the southern plains by the promise of rich soils and prosperous farming. But the farming practices adopted by the new residents dramatically increased the region’s vulnerability to drought. Periods of wet weather led the settlers to misjudge the region’s climate and the settlers plowed millions of acres of former grassland using techniques that had worked well in the wetter climates where they had previously farmed. During these wet years, low crop prices and the high cost of farm machinery forced the settlers to plow ever more marginal farmland in order to make ends meet. This compounded the problems and depleted the soil of its nutrients and further increased the likelihood of crop failure.
Figure 16E: The Dust Bowl.
The Dust Bowl was the name given to that portion of the southern plains most severely impacted by desertification in the 1930s.
While the rains fell, wheat was plentiful. But in 1931, the midwestern and southern plains were hit by a period of severe drought that was to last for 8 years. As the crops died, the overplowed land was left without a protective cover of vegetation and the topsoil began to be blown away. Huge dust storms brought devastation to western Kansas, eastern Colorado, northeastern New Mexico, and the Oklahoma and Texas panhandles (Fig. 16F), carrying away hundreds of tons of topsoil from each square mile. Dense black clouds of choking dust darkened the sky as far east as New York City and hundreds of millions of acres of former farmland were rendered uninhabitable (Fig. 16G). In 1934, when the drought was at its most severe, an estimated 250 million acres of land was either rapidly losing its topsoil or had lost its topsoil entirely. Farm families in the hundreds of thousands fled west to California in a mass exodus that inspired John Steinbeck’s epic novel The Grapes of Wrath.
Figure 16F: Dust Storm.
An approaching dust storm darkens the sky during the Dust Bowl of the 1930s.
Figure 16G: Abandoned Farm.
Buried machinery on an abandoned farm testifies to the destruction brought about by dust storms of the Dust Bowl.
By 1938, a variety of conservation methods that included planting trees to form “shelterbelts” and plowing the land into furrows had substantially reduced the amount of blowing soil. In 1939 the rains returned, bringing the drought to an end. Improved farming practices and the exploitation of the vast groundwater resource known as the High Plains aquifer, which underlies the High Plains from Nebraska south to the Texas Panhandle (see Chapter 14), have greatly reduced the effects of subsequent droughts.