7th Class Science Soil

Soil

Synopsis

• Soil is the uppermost layer of earth's crust. It is formed of rock particles and organic matter called humus.

• Soil is a good habitat. Plants depend on soil for nutrients like mineral salts and water.

• We depend on soil for agricultural and construction purposes, making utensils and toys.

• Soil is important for life on the earth. It supports the existence of living organisms. It is essential for agriculture.

• Soil is formed by the weathering of rocks by the action of wind, water and climate. It contains coarse particles, clay, moisture and humus. Soil contains three important layers: top soil, subsoil and bed rock.

• Soil profile consists of three horizons. Top soil or Horizon-A, Middle layer or Horizon-B. Third layer or Horizon-C.

• Soil is of different types: Clayey, loamy and sandy

• Soil holds water in it, which is called soil moisture. Holding capacity of water is important for various crops.

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

• Clay and loam are suitable for growing wheat, gram and paddy, cotton is grown in sandy loam or black soil.

• Removal of top soil by wind, water or any other means is known as soil erosion.