Geography

What are the factors responsible for Soil Formation ?

Factors Affecting Soil Formation
Written by UPSCOPTIONAL

What are the factors responsible for Soil Formation ?

There are five major factors which are responsible Soil Formation :-

1. Nature of parent rock Black Cotton Soil is one of the finest examples of parent material controlled soil.

2. Climate The role of climate is to vary the inputs of heat and moisture. Climate affects the rate of weathering of parent rock with the most rapid climate being a hot and humid environment.

3. Topography Slope and Aspect. – Aspect of a place refers to its position viz – a – viz the sun’s rays. For example – the southern slopes of the Himalayas are sun facing slopes.

4. Biota Plants and Animals. ( both living and nonliving ) – Alluvial soil which is a transported soil lacks humus in general ( except Ganga – Brahmaputra delta of Sundarban region ). Since alluvial soil lacks humification, therefore it also lacks nitrogen. This explains the wide use of nitrogenous fertilizer in north Indian plains. Alluvial soils are very efficient in fixing N2 from the atmosphere if leguminous plants are grown in them. Leguminous plants like peas / beans / cloves have root nodules which contain N2 fixing bacteria.

5. Time ( in undisturbed condition ) – Alluvial soil which is a transported soil does not have good soil profile development as it lacks time in undisturbed condition. It is on continuous move from Himalayas to plains and in plains it has been in continuous use since Indus Valley Civilization. Despite lack of soil profile development, alluvial soil is very fertile as it gets replenished by river every time. Time is a passive factor in soil formation. Climate in general is the most important factor of soil formation. 

FAQ : –
1. How do organisms affect soil formation ?
Ans – Soil organisms helps in degradation of organic matter and thus helps in formation of soil humus. This increases the fertility of soil.

2. Is soil texture a factor of soil formation ?

Ans – Soil texture is not a factor of soil formation.

3. Which factors lead to soil degradation ?

Ans – Soil degradation is the serious environmental problem. Deforestation and indiscriminate use of chemical fertilizers and pesticides lead to soil degradation.

4. What determines soil texture ?
Ans – Percentage of sand, silt and clay determines the soil texture.

5. What is the definition of soil formation ?
Ans – In the easy language, the transformation of rock material into soil is called soil formation.

6. Mention any four methods of soil conservation.
Ans – Following are the four methods of soil conservation : – 

1. Afforestation
2. Checking overgrazing
3. Constructing dams
4. Changing agricultural practices – Crop rotation , Terrace farming, etc
7. What are the causes of soil erosion ?
Ans – The main causes of soil erosion are as follows : – 
1. Overgrazing
2. Deforestation
3. Agricultural activities 
4. Climate Change
5. Developmental Activities
8. Why are alluvial soil very fertile ?
Ans – Alluvial Soil are very fertile because alluvial soil is rich in humus and has loamy texture. Alluvial soil has good water absorbing capacity and water retention capacity.

9. How does red soil develop its red colour ?

Ans – Because of diffusion of iron in crystalline and metamorphic rocks.

10. What are the main components of soil ?
Ans – The main components of soil are : – 

1. Minerals 
2. Soil organic matter
3. Living organisms
4. Gas
5. Water.
11. Which factor are not responsible for soil formation ?

Ans – Colour of the rocks, water accumulation, etc

ConclusionAll these are very important factors that affect soil formation. Russian believe in trinity of Climate, Vegetation and Soil i.e. Climate, Vegetation and Soil represent an integrated reality of nature.

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