This article deals with ‘Soil Erosion ’ This is part of our series on ‘Geography’ which is an important pillar of the GS-1 syllabus. For more articles, you can click here
The removal of the top 15 to 30 cm thick layer of soil by natural agents such as water, wind, glaciers and human activities is called soil erosion.
Agents of Soil Erosion
Wind and water are the most powerful agents of soil erosion
- Wind Erosion: It is the most potent agent of soil erosion in arid and semi-arid regions
- Water Erosion: In areas with heavy rainfall and steep slopes, water erosion becomes significant
Types of Erosion
a. Sheet Erosion
- In this type of erosion, a thin sheet (layer) of soil is eroded uniformly from a large area by wind or running water.
- It is not easily noticeable but is harmful since it removes the finer and more fertile topsoil.
b. Rill Erosion
- During heavy rainfall, water flows in the form of narrow channels along the slope of the land. Many finger-shaped grooves are formed over the surface.
c. Gully Erosion
- It is an extreme type of rill erosion.
- In areas of the steeper slope, Rills deepen with rainfall to form ravines, cut the agricultural lands into small fragments and make them unfit for cultivation.
- A region with a large number of ravines is called a badland topography. It is widespread in the Chambal basin.
Reasons of Erosion
- Deforestation: Deforestation is one of the major causes of soil erosion. Plants keep soils bound in locks of roots and, thus, prevent erosion.
- Brick making: Top layer of soil used in making bricks.
- Overgrazing: Loss of grass cover exposes soil to erosion.
- Faulty Agro-practice: Like Shifting Agriculture or Ploughing along the slope with no barrier to the movement of loose soil particles by wind and water
- Water & Wind erosion
- Landslides, Volcanic eruptions and flooding
- Side-cutting of river banks
Implications of Erosion
- Eroded materials are carried down to rivers, lowering the river’s carrying capacity and causing frequent floods.
- It leads to the loss of topsoil, which is the most fertile. Hence, the productivity of the soil is reduced.
- Soil erosion from agricultural land causes eutrophication in ponds, tanks, oceans & other water bodies.
- Events of landslide increase.
- Natural hideouts to carry out nefarious activities are formed in the case of Gully Erosion (Chambal Valley is famous for dacoits).
Methods to prevent Soil Erosion
Methods to prevent soil erosion can be divided into structural and non-structural solutions.
a. Structural Solutions
1. On the Slopes
- Construction of retaining wall along slopes.
2. On the Coastal Areas
- Using Tripods & Tetrapods: Wave action is held back & erosion is prevented
3. On the Rivers
- Strengthening slopes of river banks using stone pitching or wire netting.
b. Non-Structural Solutions
- Vegetation holds the soil particles firmly and restricts soil erosion.
- Creating windbreaks: Trees are planted in rows to create windbreaks to reduce the velocity of winds in Punjab, Haryana, Rajasthan, Gujarat, Uttaranchal and Uttar Pradesh.
- Agroforestry: Tree plantations on the sides of agricultural field act as barriers to fast-moving winds
2. Along Slopes
- Terrace farming: Slows the speed of the water
- Contour bunding: Barriers at the edge of the slope are created to slow down water.
3. Agricultural practices
- Relay farming: Multiple crops are grown in the same field, and the field is never left open. It is practised in Uttarakhand.
- Strip farming: The field has a layer of one crop and then of another.
- Avoiding overgrazing of grasslands
4. Other Solutions
- Allowing indigenous plants to grow along the river banks.
- Encouraging biological diversity by planting several different types of plants together.