Soil as a Resource
Soil is the most important renewable resource.
It is the medium of plant growth.
It supports different types of living organisms on the earth.
Soil is a living system
Factors responsible for Soil Formation
It takes millions of years to form soil upto a few cm in depth
Weathering or disintegration of parent rock by physical, chemical and biological agents.
Soil formation influenced by plants, micro organisms, animals and humans
Temperature affects the rate of weathering and organic decomposition
Action of running water, wind and glaciers
Soil consists of organic (humus) and inorganic materials
Classification of soils
On the basis of factors responsible for soil formation color, thickness, texture, age, chemical and physical properties, the soil of India can be classified in different types.
1) Alluvial Soil
Areas :
Northern region of India
Gujarat and Rajasthan
Deltas of Mahanadi, Godavari, Krishna and Kaveri
Characteristics :
Consists of sand , silt and clay
On the basis of age (Khadar-new alluvial soil, fertile) and Bangar-old alluvial)
Very fertile
Most suitable for cultivation of sugarcane, paddy wheat
Areas with this type of soil are highly populated and intensively cultivated
2) Black Soil
Areas:
North-West Deccan Plateaus
Plateaus of Maharashtra, Saurashtra, Malwa, Madhya Pradesh and Chhatisgarh
Characterstics:
Black in color
Ideal for growing cotton
Made up of clayey material
Develop deep cracks which helps in aeration of the soil
Is sticky when wet
3) Red and Yellow soil
Areas:
Parts of Odisha, Chhattisgarh
Middle Ganga Plain
Piedmont zone of western ghats
Characteristics:
Reddish colour due to diffusion of iron into crystalline and metamorphic rocks
They develop on cryst
Looks yellow when it occur in hydrated form
4) Laterite Soil
Areas:
Western regions of Maharashtra, Odisha
Parts of West Bengal
North -East regions
Characterstics:
Derived from Latin word later, which means brick
Result of intense leaching due to heavy rain
Humus content is low as decomposers like bacteria get destroyed due to high temperature
Manures and fertilizers make them suitable for cultivation
Prone to erosion and degradation
Useful for growing tea and coffee
5) Arid Soil
Areas:
Rajasthan
Characterstics:
Red and brown in color
Salt content is high
Soil lacks humus and moisture
Kankar layer at the bottom, the penetration of water is restricted
Become cultivable after proper irrigation (western Rajasthan)
6) Forest Soil
Areas:
Hilly and mountainous region
Characterstics:
Loamy and silty in the valley side
Coarse grained in the upper slopes
Low humus content in the upper slopes of Himalayas
Experience denudation and are acidic in snow covered areas
Soil on the river terraces is fertile
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