Natural resource of Class 9


Soil is another natural resource, which is rather most precious of all resources, as it is essential for our survival as well as all other life forms. It is the top surface layer of the Earth’s crust. Rock particles make a large part of the soil.

It provides:

  • Food and fodder
  • Clothing
  • Provides anchorage to the plants
  • Water and minerals to the plants, and water for various human needs, irrigation and industry
  • Home to a number of soil organisms.

Soil is formed from parent rock material over millions of years by a process called weathering.

Weathering occurs by.

Physical means, such as temperature, rain, wind, frost

Biological means, through the action of plants, animals and micro-organisms.

The other constituents which make up the soil are:

Mineral matter    =    45%

Organic matter    =    5%

Water        =    25%

Air        =    25%

Living organisms

Soils are derived from rocks by weathering. Percolating water is especially important in the formation of soils Young soils are stabilised when they become colonised by plants and animals. Eventually dead organic matter builds up and a mature soil as formed. Although the underlying parent rock influences the type of soil formed, the climate and vegetation are just as important.

The soil is classified on the basis of its nature and composition. The six major types of soil in our country are:

  • Alluvial soil – rich in loam and clay; the soil is highly productive.
  • Black soil – rich in clay; very fertile soil.
  • Red soil – rich in sand to loam; soil supports rain forests and grasslands.
  • Mountainous soil – rich in stone-sand; fertility low.
  • Desert soil – rich in sand; fertility low due to water scarcity.
  • Laterite soil – rich in clay (which is porous and rich in iron and aluminium hydroxides); rich in organic matter and fertility.

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