written by: Anurag Ghosh•edited by: Sarah Malburg•updated: 1/19/2011
What is soil erosion and what are the key causes of soil erosion. Learn why soil erosion occurs and how accelerated erosion is one of the major environmental concerns faced by the world today.
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Soil Erosion: Some Statistics
We are all aware of the ill-effects of soil erosion, from degraded agricultural land to damaged drainage networks. But, what is soil erosion? What are its causes? Unless we understand what soil erosion is and what are the key reasons behind the erosion of soil, we won’t be able to adopt conservation measures and land management practices to reduce it.
According to the United Nations (UN), climate change, drought and deforestation are the major reasons for the degradation of fertile land and around 40 percent of the earth’s farming land is seriously damaged. By 2025, only 25 percent of Africa’s total population will be able to feed themselves if the current trends of soil degradation continue.
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What is Erosion of Soil?
Various forms of soil degradation such as compaction, salinity, loss of nutrients and soil acidity render serious damage to fertile soil. Soil erosion, which is another type of soil degradation, occurs naturally on all land. There are several layers of soil, but soil erosion occurs when the topmost layer of the soil (the fertile soil) is removed by the action of flowing water and wind. The erosion of soil can be explained as the process of detachment of the topmost layer of soil due to rainfall and overland water flow. One of the major drivers of severe soil erosion is water runoff—excess water from snowmelts and other sources that flow over the surface.
Soil erosion is a natural process occurring for some 400 million years, ever since the first soil was formed by the first terrestrial plants. Even before the formation of the first soil, rocks were moved off our planet’s surface by natural processes.
The geological or ‘background’ soil erosion is basically a slow and natural process, where soil gets removed roughly at the same rate as it is formed. Recently, however, the major problem faced is the “accelerated" soil erosion, i.e. removal of topsoil at a much faster rate than geological soil erosion.
Accelerated soil erosion is the result of unwise human activities such as overgrazing and wrong cultivation techniques. Natural reasons for accelerated erosion include windstorms and erosive rainfall. Due to windstorms and other natural disasters, the uppermost layer of the soil is detached and transported to a far-off place. Using sophisticated agricultural equipment on agricultural land is also one of the key causes of moving soil down-slope.
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Can Certain Conservation Measures Reduce Soil Erosion?
By now you may have understood what is soil erosion. However, it is of utmost importance to follow certain soil conservation tactics in order to reduce soil erosion. Changing tillage practices and following excellent land management methods may be a good solution. But, combining different approaches, for example terracing, contour plowing and strip cropping, are some of the best practices to reduce soil erosion to some extent.