Soil erosion and degradation: a global problem – Causes (Part 1)

soil-degradation-and-conservation-5-638

Soil degradation, defined as lowering and losing of soil functions, is becoming more and more serious worldwide in recent decades, and poses a threat to agricultural production and terrestrial ecosystem.

Particularly, soil degradation simply means the decline in soil quality, which comes about due to aspects such as improper land use, agriculture and pasture, urban or industrial purposes. It involves the decline of the soil’s physical, biological and chemical state. In other words, it is a process that leads to decline in the fertility or future productive capacity of soil, as a result of human activity.

It is well known that all soils undergo soil erosion, but some are more vulnerable than others, due to human activities and other natural causal factors. The severity of soil erosion is also dependent on the soil type and the presence of vegetation cover.

Here are few of the major causes of soil degradation:

  1. Physical factors: There are several physical factors contributing to soil degradation, distinguished by the manners in which they change the natural composition and structure of the soil.  Rainfall, surface runoff, floods, wind erosion, tillage, and mass movements result in the loss of fertile top spoil thereby declining soil quality. All these physical factors produces different types of soil erosion (mainly water and wind erosion) and soil detachment actions, and their resultant physical forces eventually changes the composition and structure of the soil by wearing away the soil’s top layer as well as organic matter.
  1. Chemical factors: The reduction of soil nutrients because of alkalinity or acidity or water logging, are all categorized under the chemical components of soil degradation. In the broadest sense, it comprises alterations in the soil’s chemical property that determine nutrient availability.
  1. Biological factors: Biological factors refer to the human and plant activities that tend to reduce the quality of soil.  Some bacteria and fungi overgrowth in an area can highly impact the microbial activity of the soil through bio-chemical reactions, which reduces crop yield and the suitability of soil productivity capacity. Also, human activities such as poor farming practices may also deplete soil nutrients thus diminishing soil fertility.
  1. Deforestation: Deforestation causes soil degradation on the account of exposing soil minerals by removing trees and crop cover, which support the availability of humus and litter layers on the surface of the soil. When trees are removed by logging, infiltration rates become elevated and the soil remains bare and exposed to erosion and the buildup of toxicities.
  1. Improper cultivation practices: There are certain agricultural practices that are environmentally unsustainable and at the same time, they are the single biggest contributor to the worldwide increase in soil quality decline. For example, due to shortage of land, increase of population and economic pressure, the farmers have adopted intensive cropping patterns of commercial crops in place of more balanced cereal-legume rotations.
  1. Misuse and Extensive cultivation: The excessive use and the misuse of pesticides and chemical fertilizers kill organisms that assist in binding the soil together. In other words, it increases the rate of soil degradation by destroying the soil’s biological activity and builds up of toxicities through incorrect fertilizer use. We all know that due to tremendous population increase, the use of land is increasing day by day.
  1. Overgrazing: The rates of soil erosion and the loss of soil nutrients as well as the top soil, are highly contributed by overgrazing. Overgrazing destroys surface crop cover and breaks down soil particles, increasing the rates of soil erosion. As a result, soil quality and agricultural productivity is greatly affected.
  1. Industrial and Mining activities: Soil is chiefly polluted by industrial and mining activities. For example, mining destroys crop cover and releases a myriad of toxic chemicals such as mercury into the soil thereby poisoning it and rendering it unproductive for any other purpose. Industrial activities, on the other hand, release toxic effluents and material wastes into the atmosphere, land, rivers, and ground water that eventually pollute the soil and as such, it impacts on soil quality. Altogether, industrial and mining activities degrade the soil’s physical, chemical and biological properties.
  1. Roads and Urbanization: Urbanization severely affects the erosion process. Land denudation by removing vegetation cover, changing drainage patterns, soil compaction during construction and then covering the land by impermeable layers of concrete or asphalt, all of them contribute to increased surface runoff and increased wind speeds.

Finally, taking into consideration all the above, we understand that soil erosion is a continuous process and may occur either at a relatively unnoticed rate or an alarming rate contributing to copious loss of the topsoil. So, we have to be careful and avoid all the above problems.

Dipla Aikaterini (Arid Zone Afforestation)

Sources:

 

 

 

2 replies
    • aza
      aza says:

      Thank you very much. Of course you can use whatever you need. At the end of some articles, there are the sources of origin, because some times, we repost articles of other sites 🙂

      Reply

Leave a Reply

Want to join the discussion?
Feel free to contribute!

Leave a Reply

Your email address will not be published. Required fields are marked *