Soil Resources- Geography Guide for Class 8

Soil Resources- Geography Guide for Class 8

Information about Soil Resources


Soil Resources


Class 8


Class 8 Geography

Topics Covered

  • Soil Resources
  • Factors affecting Soil Formation
  • Soil Conservation

Soil Resources

A large part of the earth's land surface is covered with soil. As a resource, soil is of immense value to the farmers. Agricultural production is mainly dependent upon the fertility of soil. Rich and deep soil cover, with a high degree of fertility, favours agricultural production. On the other hand, if the soil cover is shallow and lacks fertility, agricultural production will be less. Therefore, a thick layer of fertile soil is very important for the growth of plants.
Though indirectly, animals also depend upon the soil to satisfy their basic needs, as soil gives nutrients to plants. It gives shelter to insects and animals like rats, snakes, ants, earthworms, etc. Soil is also used for making bricks and pottery. 

Factors affecting Soil Formation

Soil formation is influenced by five factors — the parent rock, the topography, the climate, the vegetation cover and time. Let us study each one of them.

1. The Parent Rock

The original rock from which soil is formed by the process of weathering is known as the parent rock.
For example, the black soil of India is derived from the lava rock. 

2. The Topography

Topographical variations, such as mountains, plateaus and plains affect the thickness of a soil cover. In mountainous regions, on the steep slopes, the top layer of soil is shallow and thin. On the other hand, at gentle slopes, the soil cover is thick and deep. Soil cover is always thick in plains.
For example, the northern plains of India have thick soil cover as compared to the Himalayas. Even within mountains, river valleys have thick soil cover. 

3. The Climate

Climatic factors, like temperature and rainfall, affect the soil formation. In the areas of high rainfall and extreme temperature, rocks are easily weathered. In Rajasthan, due to extreme difference in day and night temperatures, rocks expand and contract, which results in quick formation of the soil. In regions of heavy rainfall, soluble rock material easily gets dissolved and washed away by the running water. Thus, it affects the soil formation. 

4. The Vegetation Cover

At times, plants grow in the cracks existing in a rock. With time, roots of these plants start penetrating in the cracks and make them wider. As a result, cracks disintegrate into smaller pieces and help in the soil formation. Remains of dead or decomposed plants and animals provide humus to the soil, which enriches the fertility of the soil. The soil of densely forested area is generally very rich in humus content.

5. Time

Time gives maturity to the soil. Although, soil is a renewable resource, yet it takes thousands of years to develop a very thin layer of soil on the earth's surface.
For example, the Nile delta and delta formed by the Ganga and Brahmaputra rivers have very deep and fertile soil.

Fertile soil is essential for agriculture. It helps in maintaining food security of the world. But it has been observed that the fertility of soil is severely damaged by soil erosion.
  • In soil erosion, the top layer of the soil is removed by natural agents, such as water, wind, glacier, etc., and by mankind's unwise actions, such as deforestation, over-grazing and mining.
The need to conserve soil from erosion has become one of the major environmental concerns.

Soil Conservation

Soil conversation means prevention of soil from being eroded. Various methods for soil conservation are:
  • Afforestation is the process of planting more trees and seeds on the land. It reduces the surface runoff and binds the soil.
  • Rows of trees or shelter belts are planted in desert regions to protect the fields from wind erosion.
  • Overgrazing by animals like sheep and goats must be checked. Fodder crops should be raised. The free movement of animals in the fields should be restricted.
  • Steps should be taken to check reckless cutting or felling of trees.
  • Floods should be avoided by building dams across the rivers.
  • Terrace farming and contour ploughing should be encouraged across the hill slopes.
  • Scientific agriculture practices like rotation of crops, strip cropping, etc., should be systematically followed.
Terrace farming means growing of crops on level steps or terraces constructed on hill sides.
Contour ploughing is a technique of ploughing parallel to the contours of a hill slope rather than up and down the slope, so as to reduce soil erosion. 
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