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What is soil?
Did u all know, what’s soil mean ?From where soil comes? How soil form? ’’The soil is the skin of our earth” Yes ; As the forms the surface of land and make up the top layer of earth surface. Soil is the natural resources and are the complex mixture of minerals, gases and liquid. It is helpful for the survival of living organism.
The soil form by different layers and this layer is studied by using soil profile.
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Soil profile :
The soil profile is the vertical section of soil which shows different layers of soil. The layers we see in soil profile is called horizons .The soil profile contain five horizons .i.e humus , top soil ,sub soil ,rock fragments and bedrock .
a) Humus :
Humus is dark brown and black organic material which form the top most layer of soil .It is form in soil because of decayed material of plants and animals i.e falling leaves, animal faeces ,death animal ,drop twigs of plants ,etc .The all materials is decomposed and from spongy and soft layer rich in nutrients and promotes plants growth. Some small creatures get there shelter from humus like worms ,beetles ,etc .
b) Top soil :
Top soil layer is usually present under humus .It is the outermost layer of soil .It contain good amount of organic material .It is the mixture of sand , pebbles ,clay ,etc .Some small plants roots are submerge in top soil that’s way it’s easily extirpate .It is the home of some living organism i.e rodents ,moles etc .
c) Sub soil :
Sub soil horizon is present just under the top soil horizon .It contain low amount of organic matter .It contain clay , minerals ,etc .The shrubs and bushes like wise middle sized plants roots reaches the sub soil layer.
d ) Rock fragments:
Rock fragments layer is also known as parent material layer because the upper layer is made from this layer.This layer is located below the sub soil layer .It is made up of rocks and clay .
e) Bedrock :
Bed rock layer is the bottom layer of soil profile .It is situated under the rock fragment layer .It is made up of large rocks only .It is the hard layer in all horizon.
- Question based on topic :
1) Explain detail about soil ?
2) What is soil profile ?
3) Define humus horizon.
4) What is top soil layer?
5) Give information about sub soil and rock fragment layer .
6) Define Bedrock horizon.