Classification of Indian Soils Many types of soils are found in India due to the nature of rocks and different types of local climate. The soils found in India are generally classified into six categories, which are as follows:
1. Mountain soil
2. Alluvial soil
3. Desert soil
4. Black soil
5. Red Soil
6. Laterite soil
7. Forest soil
1. Mountain soil
Mountain Soil-Just as we move away from the equator and find different types of soil zones due to differences in temperature and rainfall, similarly, we find many types of soil when we move from the bottom to the top of the mountains. Brown soil is found on the lower slopes, light brown soil above it and brown mixed soil on the mountainous region. Mountain soils are spread over an area of about 2 crore hectares in India. New, stony, porous and lime-rich soils are found in the mountainous region of the Himalayas. Airy soil with pebbles, stones and coarse particles is found in the southern part and lime-rich soil is found in Dehradun, Nainital and Pauri. Soil made of igneous rocks is found in the higher parts of the Himalayas. Tea cultivation, fruit cultivation and dry fruit cultivation are good on this soil. Wheat, rice etc. are cultivated well in this soil when irrigation facilities are available.
2. Alluvial
Alluvial soil-This soil is formed by the accumulation of land brought by rivers. It is new and fertile soil. This soil is important because it is extremely fertile and is spread over an area of 7.7 lakh square km in India. In the vast northern plains of India, fertile soil containing organic matter brought by rivers from the mountainous regions is found, which is called 'Coop' or 'Kachhari' soil. This soil is found on 40% of the country. Ganga, Yamuna and Sutlej rivers play an important role in the formation of this soil. Alluvial soil is commonly found in the eastern coastal plains, especially in the deltaic regions of Mahanadi, Godavari, Krishna and Kaveri rivers. During floods, the expansion of new alluvial soil increases on the banks of rivers.
In those areas where flood water does not reach, old alluvial soil is found. This is called 'Bangar Soil'. In those areas of rivers where deposits of new cop soil brought by rivers are found, it is called 'Khadar Soil'. New alluvial soil is more fertile than old alluvial soil. Alluvial soil is more fertile, which has the capacity to produce all types of crops. Lime, potash and phosphoric acid are found in large quantities in this soil. Nitrogen and organic matter are found in less quantities in these soils. Food for 50% of India's population is produced on this soil through agriculture. In this, wheat, sugarcane, rice, oilseeds, tobacco and jute are cultivated on a large scale.
3. Desert Soil
Desert Soil- Desert soil is found in the Thar Desert and the dry regions around it. The particles of this soil are large. This soil is called by the names Kallar, Usar, Thur and Rockad in the local language. The amount of alkaline and saline elements is found in large quantities in this soil. This soil does not have the capacity to absorb water. This soil also lacks organic matter. This soil is spread over 114 lakh hectares. The particles of this soil are not unorganized, due to which the wind easily blows it from one place to another. Air and light also enter this soil easily. The fertility of this soil is low, but crops like jowar, bajra, groundnut and urad etc. are cultivated in these soils through irrigation. This soil is spread in western Rajasthan, Gujarat, southern Punjab and south-western Haryana.
4. Black soil
Black soil- This soil is formed from lava-containing materials. In ancient times, due to volcanic eruption in the southern plateau, lava flowed and spread over the surface and cooled down and solidified, which has become evident in the form of black soil today. This soil is also called 'black soil' or 'regur soil'. This soil has a high moisture retention capacity. It contains high amounts of iron, phosphorus, lime, magnesium, aluminum and organic elements. This soil is spread over an area of about 5.1 lakh square km. This soil is spread in the plateau regions of Maharashtra, Saurashtra, Malwa and South Madhya Pradesh. This soil is found in the valleys of Godavari and Krishna rivers in the south. Climatic conditions are also important in the formation of this soil. For this reason, this soil is spread in other places besides the lava plateau. This type of soil is considered most suitable for cotton cultivation. That is why it is called 'black cotton soil'. This soil becomes sticky as soon as water falls on it. Being sticky, it remains moist for a long time. Therefore, there is less need for irrigation in this soil. This soil also has some defects. On drying, this soil becomes very hard and cracks, causing cracks in the land. In such a situation, ploughing becomes difficult. Due to fertility, this soil is most useful. Farming can be done in it without adding fertilizers.
5. Red or yellow soil
Red or yellow soil- This soil is red in colour because iron rust comes out on the soil through capillary pores during summer. The rust makes it seem that this soil must have been formed by the breaking of those rocks in which iron is found in large quantities. It is spread more in Tamil Nadu state. This soil is tropical which is found in abundance on the northern border of Tapti river. The soil obtained from Archaean rocks of Bundelkhand to the north of Tapti river and the soil found in Assam is also red in colour. This type of soil is found in the Chota Nagpur plateau, Odisha, Madhya Pradesh, Andhra Pradesh, Telangana, Karnataka and south-eastern Maharashtra state in the south. This soil lacks phosphorus, nitrogen and rotten parts of vegetation, so this soil is an infertile type of soil. Only millet and jowar (sorghum) are cultivated in this soil. The yellow colour of this soil is due to hydration.
6. Laterite Soil
Laterite Soil-The colour of laterite soil is red and light yellow. This soil has large particles. Pebbles and pieces of stone are found in large quantity in this soil. This soil is of infertile type, that is why there is lack of population and vegetation in the areas of laterite soil. This laterite soil lacks magnesium, nitrogen and lime which are the main food of plants. Laterite soil is the main soil of the plateau and hills of the south. This type of soil is found mostly in those parts of the tropics where monsoon rainfall is more. Due to more rainfall, the silica found in the soil gets washed away with water. It contains more amount of aluminium, iron oxide and magnesium. This soil is found in the Eastern Ghats of Madhya Pradesh, Malabar coast, Southern Maharashtra, Odisha, Rajmahal and Assam. Crops of jowar, bajra, wheat, pulses etc. are grown in it by ploughing and using fertilizers. This soil is spread over an area of 8 lakh square km in India.
7. Forest Soil
Forest Soil- This type of soil is usually found in hilly and mountainous areas where there is sufficient rain forest. The composition of forest soil changes according to the mountain environment. In river valleys, these soils are loamy and silty but on the upper slopes, they are coarse grained. In the snow-covered areas of the Himalayas, these soils are highly eroded and are supersilicic and humus-less. These soils are fertile in the lower regions of river valleys, especially in river steps and alluvial fans, etc.
Properties of Indian Soil The following properties are found in the soils found in India:
1. The mountain soil found in India is brown colored mixed fertile soil in which rice and tea cultivation is good.
2. The alluvial soil found in India has high amount of potash, lime and phosphorus. It is world famous for its fertility. 50% of India's population is sustained by the crops grown on this soil. Crops like wheat, rice, sugarcane, jute etc. are grown in this soil.
3. The desert soil found in India is alkaline in nature. It contains high amounts of sodium, magnesium and calcium. Sorghum, millet, peanuts and black gram are cultivated in it. This soil is blown from one place to another by the wind.
4. The black soil found in India is formed from the lava emitted by volcanic eruption. That is why this soil is fertile. It has high moisture retention capacity. Cotton is cultivated in it, hence it is called black cotton soil. This soil develops cracks when it dries.
5. The red soil found in India lacks phosphorus, organic matter and nitrogen, that is why this soil is less fertile. Sorghum, millet, pulses and oilseeds are cultivated in this soil.
6. The colour of laterite soil found in India is yellow. Laterite soil is less fertile. Coarse grains like tea, rubber, cashew, coffee and sugarcane are cultivated in it.
7. Soil erosion occurs rapidly in the areas of high rainfall in India. Soil erosion occurs rapidly in the plains of India. In the desert region, the role of wind is most important in soil erosion.
8. High temperatures are found most of the time in India due to which physical and chemical disintegration of soil takes place.
9. Due to continuous agriculture in India, the fertility of the soil is decreasing.
10. Most of the soil found in India is ancient alluvial soil, which is very deep and fertile. Apart from alluvial soil, the soil found in India is less fertile and has a thin layer.
The process of erosion and flow of soil is called soil erosion. The processes of soil formation and erosion usually go hand in hand and there is a balance between the two. But sometimes this balance is disturbed due to human activities like deforestation, overgrazing, construction and mining etc. and natural elements like wind, glaciers and water erode the soil. Flowing water cuts through clay soils and creates deep channels, which are called ravines. Such land is not suitable for cultivation and is called bad land. In the Chambal basin, such land is called ravine land. Sometimes water flows down the slope covering a wide area. In such a situation, the upper soil of this area dissolves and goes with the water. This is called sheet erosion. The process of the wind blowing away soil from a plain or sloping area is called wind erosion. Soil erosion also occurs due to wrong methods of agriculture. Wrong methods of ploughing, such as ploughing from top to bottom on a slope, create channels through which flowing water easily erodes the soil.
Conservation of Indian Soil
In India, the fertility of the soil is decreasing due to continuous agriculture, rainfall, physical and chemical degradation. It is very important to maintain this fertility. Maintaining the fertility of the soil is called soil conservation. Ploughing parallel to the contour lines on sloping land reduces the speed of water flow along the slope. This is called contour ploughing. Terraces can be made on sloping land. Terraced agriculture controls erosion. Terraced agriculture is quite developed in the western and central Himalayas. Large fields are divided into strips. Strips of grass are grown between the crops. These weaken the force generated by the winds. This method is called strip agriculture. Creating a protective belt by planting trees in rows also reduces the speed of the winds. These protective strips have played an important role in the stabilization of sand dunes in western India.
The following measures should be taken for soil conservation-
1. To increase the fertility of the soil, organic fertilizers should be used instead of chemical fertilizers.
2. To prevent soil erosion, bunds should be made in the fields, dams should be constructed and uncontrolled grazing of animals should be prohibited.
3. There should be proper arrangement for drainage of water from the fields.
4. The fertility of the soil should be maintained by ploughing against the slopes.
5. Drains and pits should be leveled.
6. Green manure crops should be grown in the fields.
7. Crops should be grown in different ways every year so that the fertility of the fields is maintained.
In India, the Central Conservation Board was established in 1953 to prevent soil erosion and to conserve soil permanently. It had mainly three objectives-
1. Converting eroded land into agricultural land.
2. To control the expansion of deserts.
3. There should not be any decrease in the fertility of the present cultivable land. To fulfil this objective, many research laboratories have been established in Jaipur, Jodhpur, Dehradun and Kota.