Macro nutrients like nitrogen, potassium and phosphorus should be contained in the soil.
The fertility of the soil increases with the increase of humus content.
Major Types of soil
According to their areal extent and their agricultural importance, soils of India are classified into five major groups.
They are as follows.
Alluvial Soil
Black Soil
Red Soil
Laterite Soil
Arid
Desert Soil.
Alluvial soil
Alluvial soil consists of sediments deposited by rivers along the river course, flood plains, delta and coastal plains.
It contributes the largest share to the agricultural production of India.
Alluvial soil is divided into two types they are:
Khaddar
Bhangar
Khaddar is the newer alluvium of sandy, light-coloured soil,
Bhangar is the older alluvium of ore clayey soil.
The alluvial soil differs greatly in texture.
It is suitable for the cultivation of rice, Wheat, Sugarcane, cotton and oilseeds.
In the lower Ganga Brahmaputra valley, they are useful for jute cultivation.
In this valley, the alluvial soils are brought by the Sutlej, Ganga, Yamuna, Gandak, Ghaghara and other rivers.
The parts of Punjab, Haryana, U.P. Bihar and West Bengal are located in this valley have alluvial soils.
In south India, Kaveri river deposits alluvial soil along its course.
Black Soil
Black soil is formed from the weathering of igneous rocks.
It is found in the valleys of the Godavari, Krishna, Narmada and Tapti.
The soil is deposited at about six meters depth.
They vary in colour from deep black to chestnut brown.
It is fine-grained and generally rich in lime, iron, potash, alumina, calcium and magnesium carbonates, but lack in phosphorus, nitrogen and organic matter.
It has a special property of holding moisture. Hence it is suitable for the cultivation of Virginia Tobacco, oilseeds like linseed, Sunflower, fruits and vegetables.
Black soil is more suitable for the cultivation of cotton, rice, wheat, jowar, millets, sugarcane
Black soil is also found in the Deccan trap, comprising the greater part of Maharashtra, Gujarat, part of Madhya Pradesh, Andhra Pradesh and southern districts of Tamil Nadu.
Red Soil
Red soil is formed from the weathering of the ancient crystalline and metamorphic rocks.
The red colour is due to its very high iron content.
The colour varies from brown to yellow. This soil is porous and not retentive of moisture.
It is generally poor in lime, nitrogen, phosphorus and humus but when suitable fertilizers are added, it becomes rich infertility. Wheat, rice, cotton, sugarcane and pulses are grown in this soil.
Red soil covers in most parts of Tamil Nadu, Southern Karnataka, Goa, Northeastern Andhra Pradesh, Madhya Pradesh and Orissa.
Laterite Soil
Laterite soil formation takes place under typical monsoon conditions. It is mostly found in peninsular plateau of India.
Laterite is a porous soil from which the silica has been removed by chemical action.
It is coarse in texture and red in colour owing to the presence of iron oxides.
The crops like coffee, Rubber, Cashew and tapioca are cultivated in this soil.
Laterite is found in Andhra Pradesh, Tamil Nadu, Karnataka, on the Summits of the Eastern Ghats and Parts of Orissa, Kerala and Assam.
Desert Soil
Desert soil is found an arid zone of the north-western part of India, Rajasthan, Gujarat (Kutch region) and South Punjab.
It is sandy, alkaline and porous in nature.
Through it is highly infertile, Crops are cultivated with the help of irrigation in some areas.
Crops grown are:
wheat
barley
grapes
melons
Soil Erosion
Soil erosion means “removal of fertile content from the soil by nature and man”.
The proper use of soil resources has now become a matter of importance to all of us because it directly affects our food production.
Running water, wind and human beings are the principal, contributing factor of soil erosion.
In many parts of our country, for instance, in Uttar Pradesh, Rajasthan and the Deccan vast areas have been devastated by soil erosion.
The nature of soil erosion depends much upon the texture and structure of the soil.
It also depends on the conditions of climate, slope, methods of cultivation and several other factors.
Sustainable Development
Sustainable development is defined as “Development that meets the needs of the present without compromising the ability of future generation to meet their own needs”.
It means ‘development should take place without damaging the environment and development in the present time should not affect the needs of the future generation’.
Soil Conservation
Soil conservation is an effort made by man to prevent soil erosion in order to retain the fertility of the soil. It may not be possible to stop soil erosion entirely.
But steps; can be taken to reduce the rate of erosion by taking preventive measures.
The following are some of the preventive measures:
Construction of dams or check dams across the river course.
Step cultivation will prevent soil erosion.
Bunds should be constructed according to contours.
Avoiding excessive grazing should be avoided
Trees reduce the force of strong winds and prevent glowing away of soil particles.
Roots of trees plants and grasses hold soil particles and strengthen the soil. Hence deforestation should be avoided to increase forestation.
Plants, grass and shrubs control the speed of flowing water. Therefore such plants should not be removed Steps should be taken to plant the trees wherever it doesn’t exist.
Avoiding the application of chemical fertilizer and applying natural manure successively to the field is one of the best methods of soil conservation.
