Erosion is indeed a natural process. To say, however, that it should not be a concern of resource management is to ignore the ways in which human impacts have accelerated the rates of erosion. Natural erosion is also referred to as geological erosion, which occurs at a very slow rate overall, estimated by scientists to be at about 0.0008 of an inch per year. When you compare that to events like the Dust Bowl of the Great Plains in the 1930s, where two to 12 inches of topsoil were lost in just a few short years (Chiras & Reganold, 2010), the negative impacts of human activity become obvious, and the need for resource management of soil becomes apparent.
The costs of soil erosion are numerous. The Dust Bowl alone cost taxpayers over $1 billion in relief funds, which in today’s dollar would be equivalent to over $15 billion (measuringworth.com). The ecological costs are much more difficult to measure, but their impacts are probably more significant in the long run than the dollar cost in relief funds mentioned above. Ecological costs include such issues as habitat and species loss, which can be devastating in areas where erosion has gone unchecked and left entire regions all but devoid of life. Soil erosion also has a cost to sustainability, as with every centimeter of topsoil lost, the cost to adequately feed the world’s population becomes even higher.
The primary causes of soil erosion are wind and water, and both can be devastating. The Dust Bowl, as mentioned earlier, was caused by wind erosion, precipitated by the combined effects of drought and unsustainable tilling practices. Prior to the events of the 1930s, the American Great Plains made up some of the most productive farmland on the globe. After, it was little more than a comparatively worthless and abandoned wasteland (Chiras & Reganold, 2010).
Sadly, the devastation that occurred in the 1930s may have been avoided, or at the very least minimized, had the farmers done two things differently – specifically, used more sustainable tilling practices and utilized windbreaks . The tilling practices at the time were such that fields were plowed deeply and completely, leaving zero ground cover and exposing the entire soil surface to the elements. Windbreaks were not utilized as they took up valuable crop land and were seen as obstacles to working the land and harvesting the crops (Chiras & Reganold, 2010).
Water erosion can also have devastating effects, and in fact, accounts for more soil erosion than wind. More sustainable farming methods can also be employed to minimize erosion due to water, and they include such practices as terracing, strip cropping, contour farming and conservation tillage.
Since the time of the Dust Bowl, many farmers in the United States have embraced more sustainable agricultural practices, and soil erosion due to both wind and water has been dramatically reduced. However, a study done in 1995 to measure all onsite and offsite costs of soil erosion, including such items as cleaning up water pollution, loss of wildlife habitat and the replacement value of nutrients lost, showed that the annual cost of soil erosion in the United States was approximately $44 billion (Chiras & Reganold, 2010). Clearly, there is still much work to be done if our goal of sustainable agriculture is to be achieved. To reach that goal we must adopt a systems-level approach, however – one that fulfills our ecological and sustainable needs, as well as our economic ones.
Chiras, D. D. & Reganold, J. P. (2010). Natural Resource Conservation (10th ed.). Upper Saddle River, NJ: Pearson Prentice Hall.
Measuringworth.com. (n.d.). Purchasing power of money in the United States from 1774 to 2008. Retrieved November 9, 2009, from http://www.measuringworth.com/ppowerus/