[Geography] Soil Erosion, Causes and Measures to Prevent Soil Erosion

  • When things erode, they wear away due to some force acting on them. Just look at any coastline and you will notice how the constant pounding force from wind and waves causes erosion of the rocky structures, leaving behind all kinds of interesting cliffs, caves and structures. Soil is not immune to erosion, and like rocks along a coastline, soil can erode due to the effects of forces, such as water, wind and farming practices. In this lesson, we will learn about soil erosion and the factors that cause it.
  • Soil is naturally created when small pieces of weathered rocks and minerals mix with organic materials from decaying plants and animals. Soil creation is a slow process, taking many years. However, the soil that is created is constantly subjected to natural and manmade forces that disrupt it.
                                                                   fig: Soil Erosion

" Soil erosion is defined as the wearing away of topsoil. Topsoil is the top layer of soil and is the most fertile because it contains the most organic, nutrient-rich materials. Therefore, this is the layer that farmers want to protect for growing their crops and ranchers want to protect for growing grasses for their cattle to graze on."

Causes of soil erosion :
Soil Formation is a slow but continuous process which results in removal of soil and its replacement by a new soil layer. When the denudation of the surface layer of the soil takes place faster, it is known as soil erosion.

Factors:

 1. Topography
  • Hilly regions suffer from erosion due to heavy rainfall which causes slip erosion and thus landslides, and from the rivers which flow at a fast speed compared to the plaisn.
  • The plains, even though they get reduced rainfall, soil erosion occurs due to over flowing of rivers.
2. Rainfall
  • The sudden and continuous nature of monsoons add in soil erosion, esp in plains where lack of forest cover. Also, the prolonged dry spell which precedes monsoon causes sheet erosion when monsoon occurs.
3. Nature of soil
  • Porous water absorbing soil are least affected by erosion while impervious soil erode gradually by action of water.

4. Human factors like.
  •  Overgrazing : Removal of grass by animals makes the top soil more susceptible to erosion.
  •  Deforestation : For mining activities, infrastructure building, loosed the soil and cause erosion.
  •  Improper farming techniques: Traditional methods of ploughing make water more easier for running down causing erosion. Most of Indian agriculture consist of small and marginal farmers who use traditional methods.


Measures to prevent soil erosion :


1. Regulation of land use, which accords different types of land according to their land use capability, thus minimising the risk of soil erosion without hampering developmental efforts.

e.g. restriction of grazing in eroded forests, closed grazing fields, settlement of shifting agriculturist to permanent cultivation, retrieving highly eroded areas and bringing them under forest cover.

2. Afforestation and preservation of forests.

3. Improved land use practice in farming, like ploughing along the contours, adequate use of manures and fertilizers, crop rotation etc.

4. Engineering measures- construction of bunds and terraces, check damn, proper drainage channels etc.

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