Nature has gifted our country with many valuable resources, such as land, water, natural vegetation, wildlife, soils, minerals, etc. These natural resources are very important, as they fulfill our needs directly or indirectly. Soil is a very important natural resource.
Formation of Soil:
Soil is the top covering of the surface of the Earth. It is formed due to the wear and tear of rocks by natural and man-made forces. The formation is mainly related to the parent rock material, surface relief, climate, natural vegetation, animals, insects and man. Fine vegetal and animal remains called humus add to the fertility of the soil.
Soil formation is a slow process. It takes thousands of years to evolve a very thin layer of soil. It is seldom more than one to three metres in depth. The importance of the soil lies in its fertility. The agricultural production is dependent on the fertility of the soil.
Constituents of Soil:
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Almost all soils have developed from the mantle rocks and consist of fine particles. It has four basic elements inorganic material (derived from parent rocks), organic material (formed due to the decomposition of plant remains, animal manures and dead animals), air and water. The fine particles in the soil are in varying proportions of silica, clay, chalk and humus. The abundance of each component and its importance in the functioning of soil system vary from one type of soil to another.
Types of Soils in India:
India is a big country with varied conditions of relief, rocks, climate and vegetation. Thus, the soil in India varies from place to place and differs in colour, texture, composition and fertility.
In ancient India, the soils were classified on the basis of their fertility, as urvara (fertile) and usara (sterile). Soils can also be classified on the basis of their texture, such as sandy, clayey, loamy, etc. or on the basis of colour, such as red, yellow, black, etc.
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It is difficult for the pedologists (one who studies soil including their origin, characteristics and uses) to give an accurate, complete, comprehensive and generalised classification of the soils in India.