Soil Erosion

Soil erosion caused by wind and water is the most destructive phenomenon worldwide because it is like a slow death. Civilizations have been lost as a result of the scourge of soil erosion. Barren hills in central India, parts of Greece, Lebanon, and Syria are some of the civilizations lost because of washed-away deep and productive topsoil, a result of ignorance or mismanagement of soil. Soil erosion is a major environmental concern in industrialized nations, as well as in developing countries. A good-quality (fertile) soil is essential to meet the objectives of attaining self-sufficiency in food and keeping the food price low. Excessive soil erosion is responsible for topsoil loss and subsequent decrease in agricultural production. According to a study conducted by R. Morgan (1986), the rate of soil erosion in developing and developed countries is at an alarming level—more than the allowable limit of around 5 tons/hectare/year. Countries like the United Kingdom, the United States, and Belgium have succeeded in arresting the soil loss close to the allowable limit, but soil loss from cultivated and bare land is still very high in all the countries of the world. The soil erosion rate is higher in the developing countries, where the farmers are less engaged in soil conservation programs and practices.

This scientist with the U.S. Department of Agriculture Agricultural Research Service (standing) consults with a farmer in the Lower Rio Grande Valley who demonstrates the effects of severe wind erosion on his land.

Source: U.S. Department of Agriculture Agricultural Research Service/Jack Dykinga

Soil erosion is a natural phenomenon of detachment and transportation of soil particles by natural agents like water, snow, or wind. Not only does it reduce productivity, but it [Page 401]also has much more destructive effects such as siltation in reservoirs; deposition of infertile materials on good land; harmful effects on water supply, fishing, and power generation; and above all, increased flood potential of rivers. However, soil erosion has become more ominous since 1960. The burgeoning world population is responsible for this because farmers of the world are now desperate to grow double or triple the amount of food they once grew, using intensified cultivation. They achieve this by expanding the land for cultivation by clearing forests and other bushy areas, plowing grasslands, and performing slash-and-burn culture on mountain or hill slopes. Incessant population growth is paving the way for overgrazing of rangelands and overexploiting timber resources. Thus, more and more land is becoming devoid of natural vegetation, making it an excellent medium for soil erosion reduction. This is a downward cycle of deterioration. The soil erosion process accelerates as a result of such land degradation, and food production diminishes; as a consequence, people become desperate to grow more food, clear more forested land, and cultivate grasslands, indirectly encouraging overgrazing by cattle.

There are two types of soil erosion—geological erosion and accelerated or man-made erosion. Canyons, buttes, rounded hills, river valleys, deltas, plains, and pediments are examples of geologic erosion. Accelerated erosion is the consequence of livestock overgrazing, forest clearing for agriculture, hillside plowing, and creating impervious surfaces like roads and buildings by tearing up pervious land cover. Accelerated erosion is 10 to 1,000 times as destructive as geologic erosion.

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