Healthy soils contain countless organisms including microbes, insects and other arthropods, worms, fungi, bacteria, and other various biota. They also contain many vital orgainic and inorganic nutrients, which are necessary for plant growth.
Soil degradation is loss of these elements, rendering the soil incapable of supporting plant life. Causes of soil degradation include soil erosion, pollution, poor agricultural practices, and changes in climate. When soil is degraded, it no longer supports plant life; the result is a disruption in the food and water supplies and damage to eco-systems.
Loss of Agricultural Land
Fertile soil is necessary for growing food. Soil is made fertile by the long process of natural decomposition as follows:
- Trees and plants drop leaves, fruits, and twigs onto the soil;
- Insects and microbes that inhabit the soil throughout their lifecycles contribute to breaking down materials into usable plant nutrients;
- Bedrock beneath the top layers of soil break down and feed minerals into the soil.
When decomposition is disrupted due to natural and man-made forces, the land becomes degraded, resulting in "sterile" soil. The event known as the "Dust Bowl " during the decade of the 1930s is a result of a convergence of poor agricultural practices and climate change. The land in the Great Plains was so badly eroded due to high wind, drought, over-planting and over-grazing, the result was severe dust storms and loss of top soil for over 10 years.
Loss of Biodiversity
Soil degradation includes the loss of forest lands, wet lands, meadows and other wildlife habitats. As lands are cleared for urban development and agriculture, they become susceptible to erosion and pollution, both of which cause soil degradation. Local flora and fauna are forced to relocate or die out.
Relocation disrupts the ecological balances of both the original habitat and the newly adopted one. If large groups of species are forced to break down into smaller groups, extinction becomes a distinct danger. Local eco-systmes suffer from a loss of biodiversity, causing an imbalance in the symbiotic relationships within those systems.
Loss of Soil Absorption
One of the results of soil degradation is soil sealing, in which the soil surface is resistant to absorption of rainfall, resulting in run-off. The soil does not rehydrate and so remains degraded. Any run-off from nearby irrigated land or urban areas also passes over the sealed soil. If the run-off contains pollutants, those pollutants are carried into local waterways, resulting in polluted water supplies.
Regaining Lost Land
Though deforestation and poor agricultural practices denude the land and render it incapable of sustaining plant and animal life, such lands may be remediated back to health. Agencies around the world are developing strategies to address the issue of soil degradation. International and continental agencies such as New Alliance to Combat Land Degradation in Africa and the EU (European Union) Thematic Strategy work to address the problem on a large scale, while smaller agencies such as the Iowa Daily Erosion Project look for solutions on a local scale.
References
- Food and Agricultural Organization of the United Nations. "The Problem of Land Degradation" published on FAO.org, accessed July 19, 2011
- Parliamentary Office of Science and Technology. "UK Soil Degradation" published on Parliment.uk, accessed July 19,2011
- New York Times. "High Prices Sow Seeds of Erosion" published on nytimes.com, accessed July 19,2011
Shelly McRae - Shelly McRae has a background in technical writing and design. As a writer she covers several topics including home improvement, gardening ...
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