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The soil beneath our feet is a critical resource but
subject to many threats. What are they, and what can be done?
Even among the ecology-minded, soil falls well below
the radar of important causes, but the relationship between soil
quality and both environmental and human health is intricately entwined.
From the food we eat and the clothes we wear to the air we breathe and
water we need to drink, we depend upon the dirt beneath our feet. Soil
nurtures and feeds all life on earth while undergirding our cities,
forests, waterways, and crucial agricultural activities. Further, healthy
soil and the plant matter it holds steady act as important “carbon
sinks” that lock vast amounts of carbon up that would otherwise
contribute to global warming. Throughout history, great civilizations prospered where
soils were fertile and fell when soils could no longer sustain rough
treatment. In Mesopotamia, poor land management caused soils to become
degraded, leading to loss of agricultural productivity, migrations, and,
ultimately, civilization collapse. Ancient Greece suffered a similar fate.
Many experts also blame the fall of the great Mayan civilization on soil
exhaustion and erosion resulting from agricultural practices and
clear-cutting of forests. Today we face many of the same issues: forest loss,
overconsumption, overpopulation, and overworked soils nearing collapse.
Although factors such as logging, construction, off-road vehicles, floods,
and droughts do threaten the soil, high use of agricultural pesticides,
fertilizers and other chemicals, as well as livestock grazing and the
“factory farming” of food animals, are primary culprits. Chief among the threats to the soil is damage to or
loss of fertile topsoil. According to the American Society of Agricultural
and Biological Engineers, topsoil erosion today reduces productivity on 29
percent of U.S. cropland and negatively affects 39 percent of rangeland. In
West Africa, fertilizer overuse is causing already acidic soils to become
even more so, making the farming of even native crops difficult. In
sub-Saharan Africa, declining soil fertility from intensive farming is a
main cause of poverty and hunger.
Urban erosion is equally significant and is becoming
more serious as population growth fuels urban development. Housing and
building projects gouge the soil and strip its vegetation. Rain then washes
the soil into sewers and then waterways. This doesn’t just lead to
water pollution; the glut of nutrients the soil carries with it causes
“algae blooms” that use up oxygen and choke out aquatic life. Educating farmers in the U.S. and abroad about the
damaging effects of intensive agriculture and overapplication of synthetic
fertilizers and pesticides is a good place to start to try to make things
right. Converting more farming to organic methods that eschew chemicals
altogether is an even better solution. Supporting local farms also promotes
better land stewardship, because megafarms make heavy use of synthetic
fertilizers and factory animal farms generate huge amounts of animal waste,
which pollutes the surrounding land and soil. Cities and towns can do their
part by supporting low-impact development and mandating greener design
standards.
For more information:
ASABE, www.asabe.org; E — The
Environmental Magazine, “The Scoop on Dirt:
Why We Should all Worship the Ground We Walk On,”
www.emagazine.com/view/?3344.
Send questions to Earth Talk at P.O. Box 5098, Westport, CT 06881 or e-mail earthtalk@emagazine.com.
This article appears in Oct 4-10, 2007.
