Question 7

Sketch the cross section of soil and label the various layers.



Several layers or also called sequence of soil horizons of the soil develops one over th eother in the progression state of maturity. Usually there are three main horizons and the parent bedrock is present.

The 'A' horizon: It is very loose, fertile horizon or layer of soil. It contains plant roots, small insects, animals etc. This layer is composed of fresh and partially decomposed organic matter; and is dominant reservoir for the plant nutrients.

The 'B' horizon: It is the subsoil which contains few plant roots, some micro flora and fauna with less organic matter. It is composed of mineral soil where mineralization can occurs. it is also known as zone of Illuviation.

The 'C' horizon: It contains or represents unmodified freshy weathered parent material.

Bedrock is the last layer in the soil profile with or without small amount of organic matter and without it no life occurs.  

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