Around the Globe, Farmers Losing Ground
Around the Globe, Farmers Losing Ground
WASHINGTON, Jun 27 (IPS) - 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 civilisations 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 described a site in northern
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 re-peopled again and the cities rebuilt, but now that the soils are gone, all is gone."
Now fast forward to a trip in 2002 by a United Nations team to assess the food situation in
Michael Grunwald reports in the Washington Post that nearly half of the children under five in
Whether the land is in northern
The thin layer of topsoil that covers the planet's land surface is the foundation of civilisation. This soil, measured in inches over much of the earth, was formed over long stretches of geological time as new soil formation exceeded the natural rate of erosion. As soil accumulated over the eons, it provided a medium in which plants could grow. In turn, plants protect the soil from erosion. Human activity is disrupting this relationship.
Sometime within the last century, soil erosion began to exceed new soil formation in large areas. Perhaps a third or more of all cropland is losing topsoil faster than new soil is forming, thereby reducing the land's inherent productivity. Today the foundation of civilisation is crumbling. The seeds of collapse of some early civilisations, such as the Mayans, may have originated in soil erosion that undermined the food supply.
The accelerating soil erosion over the last century can be seen in the dust bowls that form as vegetation is destroyed and wind erosion soars out of control. Among those that stand out are the Dust Bowl in the
Each of these is associated with a familiar pattern of overgrazing, deforestation, and agricultural expansion onto marginal land, followed by retrenchment as the soil begins to disappear.
Twentieth-century population growth pushed agriculture onto highly vulnerable land in many countries. The overplowing of the
Three decades later, history repeated itself in the
A similar situation exists in
Dust storms originating in the new dust bowls are now faithfully recorded in satellite images. In early January 2005, the National Aeronautics and Space Administration (NASA) released images of a vast dust storm moving westward out of central
Andrew Goudie, professor of geography at
The BodÃ©lÃ© Depression in
Severe wind erosion of soil on this newly plowed land made it clear that its only sustainable use was controlled grazing. As a result, Chinese agriculture is now engaged in a strategic withdrawal in these provinces, pulling back to land that can sustain crop production.
Water erosion also takes a toll on soils. This can be seen in the silting of reservoirs and in muddy, silt-laden rivers flowing into the sea. Pakistan's two large reservoirs, Mangla and Tarbela, which store Indus River water for the country's vast irrigation network, are losing roughly 1 percent of their storage capacity each year as they fill with silt from deforested watersheds.
Ethiopia, a mountainous country with highly erodible soils on steeply sloping land, is losing an estimated 1 billion tons of topsoil a year, washed away by rain. This is one reason Ethiopia always seems to be on the verge of famine, never able to accumulate enough grain reserves to provide a meaningful measure of food security.
Fortunately there are ways to conserve and rebuild soils. These will be discussed in the next Earth Policy Institute Book Byte.
*Lester Brown is founder and president of the Earth Policy Institute. This article originally appeared on earthpolicy.org.