Soil Erosion
How does the rate soil
loss compare to the rate at which it is created?
What are the general causes of erosion? Why is erosion a problem?
What are some alternative agricultural practices that would reduce erosion?
What is "no-till" agriculture? How is this being used in PA?
PA case study
In
the U.S., poor soil management can result in the loss of several tons
of topsoil per acre each year. In comparison, undisturbed forests and
natural grasslands lose a small fraction of a ton per acre annually.
Topsoil is made continuously, but at a much slower rate than its rate
of loss due to erosion. Estimates suggest that one inch is created every
1000 years.
Erosion occurs whenever soil is openly exposed to wind and rain. Agricultural
erosion is caused by exposure of soil due to cultivation and by overgrazing,
and is a problem for numerous reasons. First, loss of fertile soil can
lead to a loss in soil productivity, thereby decreasing crop production.
Second, soil that is carried away by wind or water can end up in steams
or lakes and damage aquatic ecosystems. Soil that has been treated with
pesticides or herbicides may damage aquatic life to an even higher degree.
There are many alternatives to conventional cultivation that can prevent erosion. Crop remnants can be left on top of the soil, thus reducing exposure. Contour strip cropping and shelterbelts can also be used ways to combat erosion. Contour strip cropping is the cultivation of strip fields along the contours at a right angle to a slope. Shelterbelts are rows of trees along fields that prevent wind erosion.
No-till
agriculture, planting seeds with reduced cultivation, can be used,
and in Pennsylvania, more and more farmers are considering this alternative.
They are finding that not only does no-till have multiple environmental
benefits, but that it can also be more economically efficient than conventional
methods. Joel Myers, Agronomist with the USDA N
atural
Resources Conservation Service, said, "Pennsylvania was one of
the first states to begin studying and working with no-till. They pioneered
the concept, helped to get things started here, and helped to spread
the concept to the Midwest."
A nine year case study of alternative farming practices conducted by the World Resources Institute, the Rodale Research Center of Kutztown, PA, Purdue University, and the University of Nebraska, concluded that alternative practices cut production costs by 25 percent, eliminated inorganic fertilizer and pesticide use, reduced erosion, and increased yields after the transition from conventional systems had been completed. However, Rodale also documented the difficulties, such as short-term income loss, that Pennsylvanian farmers faced while switching to alternative systems.
To read more about soil erosion, please visit the following sites:
http://www.pacd.org/news/profile_hoffman.htm
http://www.pacd.org/
http://www.dep.state.pa.us/dep/subject/pubs/water/wqm/fs1841.doc
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