Soil erosion – its consequences and how it can be identified

40% of soil in Africa is degraded and susceptible to erosion

WHAT IS SOIL EROSION?

Soil erosion is the removal of the top layers of surface soil from an area through the actions of water or the wind. This process is occurring all the time at a slow rate but can sometimes happen very quickly. This can result in large losses of fertile soil and even cause desertification to occur (the process by which land is turned into desert).
Changing climates decreasing the amounts of rainfall over many parts of Africa are a large factor in increasing levels of soil erosion. Human activities are also important in increasing erosion rates through the removal of vegetation for agriculture as well as the construction of cities and other urban areas.

HOW TO IDENTIFY SOIL EROSION

Soil erosion will often occur within unhealthy soils with a dry and dusty appearance. Three signs can offer an indication of the occurrence of soil erosion:

  1. Bald Spots – if there are patches of land where no trees or plants have grown then this may be due to erosion. You might notice a build-up of soil below these areas that is not currently being used by any vegetation.
  2. Exposed rocks – Soil erosion brings items from under the ground (such as rocks) to the surface where they can be seen. Any such changes to the landscape may indicate soil erosion in an area.
  3. Exposed roots – Soil erosion can cause plant roots to become visible by the removal of the soil at the base of a plant or tree.

HOW IS IT CAUSED?

Soil erosion occurs when wind or rain carry loose topsoil away. The amount of soil that is removed depends on how strong the rain or wind is as well as the health of the soil. Healthy topsoil (like moist soil covered with plants) is at lower risk of erosion as it sticks together better and can absorb more water.
If land is cleared of vegetation (such as deforested land) such as when natural land is converted to farmland, then soil erosion can increase as there are less barriers to reduce wind speeds. The roots of plants and trees also help to hold soil in place and make the land more stable.

THE IMPACT OF SOIL EROSION

The erosion of topsoil leads to a direct loss of fertile soils that are available for farming. This leads to a decrease in the productivity of an area and may reduce the success of future agricultural practices.
The loss of nutrient-rich topsoil can lead to desertification occurring. This process causes huge problems for local ecosystems with the loss of habitats for many animal species.
The dry and arid ground conditions that allow soil erosion to occur as well as lack of vegetation, may also increase the risks of flash flooding. If there is a large amount of rainfall over a short period of time then eroded soils may not be able to absorb water effectively. This can lead to the flooding of farmland areas as well as people’s homes and buildings costing a lot of time and money to repair.

BENEDICT MACLEOD

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