Around
The Globe,
Farmers Losing Ground
By Lester R. Brown
30 June, 2007
Earthpolicy.org
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 Syria, near Aleppo, where ancient buildings were still standing
in stark isolated relief, but they were 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 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 Lesotho,
a small country of 2 million people imbedded within South Africa. Their
finding was straightforward: “Agriculture in Lesotho faces a catastrophic
future; crop production is declining and could cease altogether over
large tracts of the country if steps are not taken to reverse soil erosion,
degradation, and the decline in soil fertility.”
Michael Grunwald reports
in the Washington Post that nearly half of the children under five in
Lesotho are stunted physically. “Many,” he says, “are
too weak to walk to school.”
Whether the land is in northern
Syria, Lesotho, or elsewhere, the health of the people living on it
cannot be separated from the health of the land itself. A large share
of the world’s 852 million hungry people live on land with soils
worn thin by erosion.
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 U.S. Great Plains during the 1930s,
the dust bowls in the Soviet Virgin Lands in the 1960s, the huge one
that is forming today in northwest China, and the one taking shape in
the Sahelian region of Africa.
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 U.S. Great Plains during the late nineteenth
and early twentieth centuries, for example, led to the 1930s Dust Bowl.
This was a tragic era in U.S. history, one that forced hundreds of thousands
of farm families to leave the Great Plains. Many migrated to California
in search of a new life, a move immortalised in John Steinbeck’s
novel “The Grapes of Wrath”.
Three decades later, history
repeated itself in the Soviet Union. The Virgin Lands Project between
1954 and 1960 centred on plowing an area of grassland for wheat that
was larger than the wheatland in Canada and Australia combined. Initially
this resulted in an impressive expansion in Soviet grain production,
but the success was short-lived as a dust bowl developed there as well.
Kazakhstan, at the centre
of this Virgin Lands Project, saw its grainland area peak at just over
25 million hectares (44 millions acres) around 1980, then shrink to
14 million hectares today. Even on the remaining land, however, the
average wheat yield is scarcely one tonne per hectare, a far cry from
the nearly eight tonnes per hectare that farmers get in France, Western
Europe’s leading wheat producer.
A similar situation exists
in Mongolia, where over the last 20 years half the wheatland has been
abandoned and wheat yields have also fallen by half, shrinking the harvest
by three fourths. Mongolia — a country almost three times the
size of France with a population of 2.6 million — is now forced
to import nearly 60 percent of its wheat.
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
Africa. This vast cloud of tan-coloured dust stretched over some 5,300
kilometres. NASA noted that if the storm were relocated to the United
States, it would cover the country and extend into the oceans on both
coasts.
Andrew Goudie, professor
of geography at Oxford University, reports that Saharan dust storms
— once rare — are now commonplace. He estimates they have
increased 10-fold during the last half-century. Among the countries
in the region most affected by topsoil loss from wind erosion are Niger,
Chad, Mauritania, northern Nigeria, and Burkino Faso. In Mauritania,
in Africa’s far west, the number of dust storms jumped from two
a year in the early 1960s to 80 a year today.
The Bodélé
Depression in Chad is the source of an estimated 1.3 billion tons of
wind-borne soil a year, up 10-fold from 1947 when measurements began.
The 2 to 3 billion tons of fine soil particles that leave Africa each
year in dust storms are slowly draining the continent of its fertility
and, hence, its biological productivity. In addition, dust storms leaving
Africa travel westward across the Atlantic, depositing so much dust
in the Caribbean that they cloud the water and damage coral reefs there.
In China, plowing excesses
became common in several provinces as agriculture pushed northward and
westward into the pastoral zone between 1987 and 1996. In Inner Mongolia
(Nei Monggol), for example, the cultivated area increased by 1.1 million
hectares, or 22 percent, during this period. Other provinces that expanded
their cultivated area by 3 percent or more during this nine-year span
include Heilongjiang, Hunan, Tibet (Xizang), Qinghai, and Xinjiang.
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.
Copyright © 2007 IPS-Inter
Press Service
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