So long! It’s been good to know you.
This dusty old dust is a gettin’ my home.
And I’ve got to be drifting along.
—Woody guthrie, 1940
The dust storms that hit the Great Plains of the U.S.
occurring fast enough to reduce future productivity. As
during the 1930s were responsible for one of the great
we discussed earlier, erosion is also an organic-matter
migrations in our history. As Woody Guthrie pointed
issue because it removes the richest soil layer, the top-
out in his songs, soil erosion was so bad that people saw
soil. The soil removed from fields also has huge negative
little alternative to abandoning their farms. They moved
effects off the farm, as sediment accumulates in streams,
to other parts of the country in search of work. Although
rivers, reservoirs, and estuaries, or blowing dust reaches
changed climatic conditions and agricultural practices
towns and cities. In fact, sediment remains the number
improved the situation for a time, there was another
one contaminant for most waters around the world, and
period of accelerated wind and water erosion during the
it often also carries other contaminants like nutrients,
1970s and 1980s. Also, in many other countries land
pesticides, and other chemicals.
degradation has forced families off the farm to urban
Climate and soil type are important factors affect-
areas or caused them to seek out new lands by develop-
ing erosion. Intense or prolonged rainstorms are major
ing natural areas like rainforests.
causes of water erosion and landslides, while drought
Erosion by wind and water has occurred since the
and strong winds are critical factors in wind erosion.
beginning of time. Although we should expect some soil
Soil type is important because it influences the suscep-
loss to occur on almost all soils, agriculture can greatly
tibility to erosion as well as the amount that can occur
aggravate the problem. Erosion is the major hazard
without loss of productivity. In chapter 6 we discussed
or limitation to the use of about half of all cropland
how some soils (especially silts) with poor aggregation
in the United States. On much of that land, erosion is
are more susceptible than other soils, especially those
Photo courtesy Harold van Es
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Building SoilS for Better CropS: SuStainaBle Soil ManageMent
