Soil Erosion

Soil can appear to be mere dirt beneath your feet, but it is much more than that — it is one of the most valuable natural resources on the planet. It sustains all plant and animal life with its different characteristics, including filtering water and holding essential nutrients crucial for maintaining life. However, this layer is losing its topsoil slowly because of the different processes of the Earth, which effectively pose a threat to the environment and ultimately to plant and animal life. In this article, we will thoroughly comprehend the process, types, causes, and other details of soil erosion as a measure towards leading a sustainable life in the future.

1.0Soil Erosion Meaning

Soil erosion means the detachment, transport, and deposition of the topmost layer of soil (topsoil) from one location to another through wind and water as the chief agents. Soil erosion is an ancient process, dating back to the Earth's formation. However, over the past few decades, soil erosion has increased at an alarming rate as a consequence of human activities.

Topsoil is essentially the top layer of soil, high in humus. Humus is dead plants, leaves and other organic material. Thus, the top layer of the soil makes a significant contribution to maintaining agriculture, soil fertility, and hydrology cycles.

2.0Types of Soil Erosion

Depending on how the soil is removed from its natural point of origin, soil erosion has been classified into a number of types. Some of the prominent types are:

• Sheet Erosion: Sheet Erosion is defined as the removal of topsoil in thin uniform sheets from expansive areas by the flow of rainfall or surface water. Sheet erosion is never recognised until an expansive topsoil area has been lost.
• Rill Erosion: When water forms small channels, or rills, as it travels over the surface of the land. The rills will continue to widen and lead to more advanced forms of erosion.
• Gully Erosion: If the rills enlarge due to continuous flow of water, they form deep and wide ditches known as gullies. Gully erosion is a serious land degradation that can make land unsuitable for use in agriculture.
• Splash Erosion: It is the initial erosion phase caused by the impact of raindrops on the soil. Splash erosion loosens particles, preparing them for transportation by water or air.

3.0Causes of Soil Erosion

Causes of soil erosion may be either natural or anthropogenic, i.e., human-induced erosion. Some of the key factors that cause soil erosion on the planet Earth are:

Natural Causes

1. Rainfall and Surface Runoff: As a result of high-intensity or heavy rainfall, the ground cannot retain or infiltrate this additional water, so surface runoff occurs. This runoff makes eroded soil slide down and ultimately causes soil erosion. 
2. Wind: In arid areas with few plants, winds blow more intensely, making them pick up and transport more fine soil particles over large distances, leading to heavy soil erosion.
3. Slope Gradient: Slope gradient refers to the steepness of a valley; the steeper the slope, the greater will be the slope gradient, and the greater will be the soil erosion.

Human Activities

1. Deforestation: Vegetation and trees act as natural anchors, holding the soil together. Their removal exposes the soil to rainfall and wind action, greatly increasing erosion.
2. Overgrazing: Too many animals grazing on the land remove more vegetation faster than it can be replenished. The soil remains exposed and susceptible to erosion.
3. Unsustainable Agricultural Methods: Repeated ploughing, monoculture planting, and use of heavy machinery disorganise the soil structure and reduce its organic content, and hence its capacity to withstand erosion.
4. Urbanisation and Building: Building activities kill off vegetation and destabilise the soil. Soil left uncovered on building sites erodes easily in rain.
5. Mining Activities: Open-pit mining removes gigantic amounts of topsoil, exposing the land and rendering it extremely susceptible to erosion.

4.0Effects of Soil Erosion

While a natural and essential phenomenon, excessive soil erosion can trigger environmental degradation and ultimately impact climate, economy, and human health. It can cause a variety of disruptions to the environment, which include:

• Loss of soil Fertility: As already discussed, the topsoil is characterised by high organic matter and nutrients. Loss of the topmost soil through erosion then results in loss of soil fertility.
• Sedimentation of Water Bodies: The soil eroded finds its way most frequently into rivers, lakes, and other water bodies, thereby ultimately reducing the capacity of these water bodies. These sediments at times contain chemicals like pesticides, fertilisers, etc, contaminating water and affecting aquatic life.
• Desertification: If the deposition rate of soil is lower than the erosion rate of a particular region, then the possibility of that region turning into a desert increases.
• Loss of Biodiversity: The degradation of fertile soil also impacts plant life, decreasing the habitats of insects, birds, and animals, thus decreasing biodiversity.
• Economic Impact: Ongoing degradation of soil fertility also results in a reduction in crop yields, resulting in food shortages and financial losses to farmers. The cost of land restoration for soil erosion can also be extremely high.

5.0Prevention of Soil Erosion

With ongoing scientific research and environmental studies, scientists have created a vast array of techniques for the prevention of soil erosion. These techniques are:

• Restoring trees and plants to increase the anchoring of the soil by their roots.
• Using terrace farming in hilly regions, where crops are planted in the form of steps to minimise water runoff.
• Farming according to the natural slope of the land in plan areas can also minimise soil loss.
• Employing shrubs and trees as shelterbelts and windbreaks to slow down wind speed and inhibit erosion by wind.
• Constructing small barriers and sediment traps along slopes and streams to reduce the speed of water flow and trap sediments.