Factors affecting Soil Degradation

Factors responsible for soil degradation

The concept of human induced soil degradation implies by definition of social problem. No person will intentionally destroy this precious natural resource. But increasing pressure on the land, the increased desire for better living conditions and higher standards of living, the search for lands to survive, have resulted in some kinds of intervention that have caused  the soil to degrade.

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Some important factors are:

• Deforestation or removal of natural vegetation: Clearing of the land for agricultural purposes, large scale commercial forestry, road construction, urbanization.
• Overgrazing: Actual overgrazing may not only lead to vegetation degradation but also can cause soil compaction, wind or water erosion.
• Agricultural activities: This includes a wide variety of agricultural practices, such as insufficient or excessive use of  fertilizers, use of poor quality irrigation water, improperly timed use of heavy machinery, absence of anti erosion measures on land which is susceptible to water and wind erosion.
• Over exploitation of the vegetation for domestic use: For fuel needs, fencing etc make human to clear the vegetation. Though there is not a complete removal of vegetation but the remaining vegetation does not provide sufficient protection against soil erosion or sealing and crusting of the topsoil.
• Bio industrial and industrial activities: This factor is already directly related to soil pollution.

More than 50% of soil degradation caused by deforestation is in Asia, while it is the dominant causative factor in South America.

In Africa, the major causative factor is overgrazing. Agricultural mismanagement is an important causative factor in Asia and Africa and is the most important cause of soil degradation in North America.

In Oceania, overgrazing is the dominant cause of soil degradation. Although industrial activities are minor problem compared to other causative factors, it is important to note that out of 23 million hectare worldwide 21 million hectare are located in Europe.

Deforestation, overgrazing and agricultural activities are all main contributors to water erosion, mainly as a result of exposing the soil to the aggressive forces of rainfall or as a result of cultivating steep slopes without proper anti-erosion measures. Overgrazing is the major cause of wind erosion, by exposing soil to the aggressive forces of wind.

Agricultural activities such as improper water management in irrigation schemes and insufficient application of fertilizers to restore nutrients removed by crops are major causes of chemical degradation.

Also deforestation leading to a rapid decline of organic matter in the topsoil, is an important cause of chemical degradation. Obviously industrial activities are the main causative factors of soil pollution. Physical degradation is mainly caused by agricultural activities and to a certain extent by overgrazing.