Natural Resources Notes

• Soil is the uppermost layer of the Earth's crust which is composed of different minerals/ nutrients that helps in generation of biodiversity. A layer of dead and decayed plant and animal remains called humus is also present in the soil.

Soil

Humus

• Soil also provides the vital nutrients required for the growth of the plants. All living organisms depend directly or indirectly on soil.

• Soil is one of the most valuable natural resources.
• It can get polluted by various means, including careless human activities.
• Necessary measures should be adopted to control soil pollution.
• Soil pollution is defined as the addition of unwanted components or removal of essential components from the soil due to human activities that can affect the survival of organisms.
• It can also be defined as the presence of materials in the soil which are harmful to the living organisms when they cross their threshold concentration levels.

Sources of soil pollution:

• Soil erosion is defined as the removal of top soil due to running water and wind reducing the productivity of the soil in that area.
• Generally, the rate of removal of fine particles from the surface is the same as the rate of formation of soil.
• But sometimes disturbance in this balance, usually man-made, lead to a greater rate of removal of soil.

Causes of soil erosion:

Deforestation:

• The excessive cutting of trees on a large scale is known as deforestation.