How Soil Erosion Contributes to Desertification and Dust Storms

Disappearance of topsoil causes desert expansion and crop reduction in regions across the world.


| April 2016



Livestock Grazing in Nigeria

Grazing Livestock in Nigeria, 1961-2010.


Graph by W.W. Norton and Company

Full Planet, Empty Plates: The New Geopolitics of Food Scarcity (W. W. Norton and Company, 2012) by Lester R. Brown explains why world food supplies are tightening, and what we need to do about it. A leading environmentalist, Brown examines the factors contributing to global food shortages. The following selection take from Chapter 5: Eroding Soil Darkening Our Future explains how important topsoil is to our environment, and the negative effects that occur in its absence.

Eroding Soil Darkening Our Future

In 1938 Walter Lowdermilk, a senior official in the Soil Conservation Service of the U.S. Department of Agriculture, traveled abroad to look at lands that had been cultivated for thousands of years, seeking to learn how these older civilizations had coped with soil erosion. He found that some had managed their land well, maintaining its fertility over long stretches of history, and were thriving. Others had failed to do so and left only remnants of their illustrious pasts.

In a section of his report entitled “The Hundred Dead Cities,” he describes a site in northern Syria, near Aleppo, where ancient buildings are still standing in stark isolated relief, but they are on bare rock. During the seventh century, the thriving region had been invaded, initially by a Persian army and later by nomads out of the Arabian Desert. In the process, soil and water conservation practices used for centuries were abandoned. Lowdermilk noted, “Here erosion had done its worst. If the soils had remained, even though the cities were destroyed and the populations dispersed, the area might be repeopled again and the cities rebuilt. But now that the soils are gone, all is gone.”

The thin layer of topsoil that covers the earth’s land surface was formed over long stretches of geological time as new soil formation exceeded the natural rate of erosion. Sometime within the last century, soil erosion began to exceed new soil formation. Now, nearly a third of the world’s cropland is losing topsoil faster than new soil is forming, reducing the land’s inherent fertility. Soil that was formed on a geological time scale is being lost on a human time scale.

Scarcely six inches thick, this thin film of soil is the foundation of civilization. Geomorphologist David Montgomery, in Dirt: The Erosion of Civilizations, describes soil as “the skin of the earth — the frontier between geology and biology.”

The erosion of soil by wind and water is a worldwide challenge. For the rangelands that support 3.4 billion head of cattle, sheep, and goats, the threat comes from the overgrazing that destroys vegetation, leaving the land vulnerable to erosion. Rangelands, located mostly in semiarid regions of the world, are particularly vulnerable to wind erosion.





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