Ecology And Environment

How Human Activity Affects Soil Erosion



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Erosion is the process by which rock and soil are removed from the surface of the Earth as a result of water and wind action and thereafter deposited to other areas on the Earth’s surface. While erosion is a naturally occurring process, human activity can accelerate it. The problems caused by soil erosion include:

-Desertification: This is as a result of the removal of the fertile top soil which is beneficial for plant growth and agriculture.

-Sedimentation: The deposition of the top soils into water reservoirs downstream as a result of the removal of the top soils.

According to The Oregon State University, the construction of roads and buildings, logging, mining and agricultural production have resulted in large amounts of soil erosion in the world and in the United States. The following human practices aid in the acceleration of the soil erosion process:

*Agricultural practices

Agriculture involves tilling of land and breaking up soil particles into very small pieces. This can be done by hand or even mechanically. The smaller soil particles are easily carried by water or wind, resulting in soil erosion. Other detrimental agricultural practices include farming on slopes and usage of pesticides and insecticides. The slope farming allows water to flow in furrows along a farm, thus eroding the soil in the process. Insecticides and pesticides may destroy organisms which help in making the soil coherent thereby promoting erosion.

Excessive tillage also promotes soil erosion. This is as a result of breaking the soil into very small pieces during the dry seasons, allowing wind action to carry the top soil layer. Overgrazing is also very detrimental to the state of the soil. The livestock eat away the vegetation, thereby leaving the land bare for wind and water to act upon. This is a major problem, especially in regions which are semi-arid in nature.

 *Deforestation

The floor of a forest is composed of dead leaf and other organic matter called humus. This matter is essential in the absorption of rainwater droplets after rains, allowing the water to percolate into the soil instead of flowing like a river or a stream. The roots of the trees are able to hold the soil together, thus reducing the possibility of the soil particles' being carried off by fast running water. Also, the canopy of the forests lowers the impact of the falling water on the ground. The cutting of trees for firewood or even to feed industrial processes is a major reason for the increased levels of soil erosion in regions where trees have been cleared.

 *Urbanization

      Urbanization is a major accelerator of soil erosion. It is because, during construction, vegetation is often cleared off, leaving the land bare and susceptible to water and wind action. Also, the soil is covered with hard and impenetrable asphalt, tarmac or concrete, which increases the amount of surface runoff in case of a heavy downpour.  In cities and towns with poor drainage systems, the runoff from the rain is channeled to the surrounding countryside. This increases the amount of soil erosion, especially in regions without vegetation on the periphery of cities. 

 * Mining

Mining affects the stability of soil by removing the top layers when in search of precious minerals. Places where dynamite mining practices are carried out might experience a high level of soil instability, leading to the possibility of soil erosion. Removal of the top vegetation in a mining area leaves the ground bare and susceptible to wind and water action.

 * Desertification

The spread of deserts as a result of human activity is one of the major reasons of increased soil erosion instances on the planet. Desertification is increased by over-settlement, over-grazing and over-cultivation. Regions like the Sahel in West Africa have been experiencing increased desertification and thus high rates of wind erosion, especially due to the winds originating from the Sahara.

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