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NCERT Solutions for Class 7th Science

 

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Chapter 9. Soil

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Chapter Review:


  • The rotten death material presence in soil is known as humus. 
  • The mixture of rock particles and humus is called the soil.

  • The breaking down of rocks by the action of wind, water, and climate. This process is called weathering.
  • A vertical section through different layers of the soil is called the soil profile. 

  • Each layer differ in feel (texture), colour, depth and chemical composition. These layers are referred to as horizons. 

  • The upper layer is generally soft, porous and can retain more water; it is called the topsoil or the A-horizon.

  • Absorbing water by the soil is known as percolation. 

  • The removal of land surface by water wind or ice is known as soil erosion.

  • The soil is formed by the breaking down of rocks by the action of wind, water and climate.

  • The best topsoil for growing plants is loam. Loamy soil is a mixture of sand, clay and another type of soil particle known as silt.

  • Clayey soil is used to make pots, toys and statues.

  • Soil is affected by wind, rainfall, temperature, light and humidity.

 

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