Geography

Soil – Types of Soils in India (Indian Soils)

Soil – Indian Soils

Types of Soils in India (Indian Soils)

  • Geologically, Indian soils can broadly be divided into soils of peninsular India and soils of extra-peninsular India.
  • The Peninsular Indian Soils are formed by the decomposition of rocks in situ, i.e. directly from the underlying rocks.
  • Peninsular Indian Soils are transported and re-deposited to a limited extent and are known as sedentary soils.
  • The soils of the Extra-Peninsula are formed due to the depositional work of rivers and wind. They are very deep. They are often referred to as transported or azonal soils.
  • Major groups of the Indian soils in India are –
    • Alluvial soils,
    • Black soils,
    • Red soils,
    • Laterite and Lateritic soils,
    • Forest and Mountain soils,
    • Arid and Desert soils,
    • Saline and Alkaline soils and
    • Peaty and Marshy soils.

Soil map of India, Indian Soils, Types of Soils found in India

A. Alluvial Soils

  • Alluvial soils are formed mainly due to silt deposited by Indo-Gangetic-Brahmaputra Rivers. In coastal regions some alluvial deposits are formed due to wave action. Thus they are azonal soils.
  • The parent material of these soils is of transported origin (Himalayan Rocks).
  • Largest soil group in Indian Soils.
  • They support more than 40% of the India’s population by providing the most productive agricultural lands.

Characteristics

 

  • They are immature and have weak profiles due to their recent origin.
  • Most of the soil is loamy. Sandy and clayey soils are not uncommon.
  • Pebbly and gravelly soils are rare. Kankar (calcareous concretions) beds are present in some regions along the river terraces.
  • The soil is porous because of its loamy nature.
  • Porosity and texture provide good drainage and other conditions favourable for agriculture.
  • These soils are constantly replenished by the recurrent floods.

Chemical Composition

Distribution

Crops

 

  • The proportion of nitrogen is generally low.
  • The proportion of Potash, phosphoric acid and alkalies are adequate
  • The proportion of Iron oxide and lime vary within a wide range.

 

 

 

  • Covering about 15 lakh sq. km or about 45.6 % of the total area.
  • Occur along the Indo-Gangetic Brahmaputra plains except in few places where the top layer is covered by desert sand.
  • They also occur in deltas of the Mahanadi, the Godavari, the Krishna and the Cauvery, where they are called deltaic or coastal alluvium.
  • Some alluvial soils are found in the Narmada, Tapi valleys and Northern parts of Gujarat.
 

  • They are mostly flat and regular soils and are best suited for agriculture.
  • They are best suited to irrigation and respond well to canal and well/tube-well irrigation.
  • They yield splendid crops of rice, wheat, sugarcane, tobacco, cotton, jute, maize, oil seeds, vegetables and fruits.

 

Soil Colour and texture

 

  • Varies from the light grey to ash grey depending on the depth of the deposition, the texture of the materials, and the time taken for attaining maturity.
  • Differ in nature from sandy loam to clay. These soils are more loamy and clayey in the lower and middle Ganga plain and the Brahmaputra valley.
  • The sand content decreases from the west to east.

 

Geological divisions of alluvial soils

    • Geologically, the alluvium of the Great plain of India is divided into younger Khadar and older Bhangar soils.

Geological divisions of alluvial soils

1. Bhabar

    • The bhabar belt is about 8-16 km wide running along the Shiwalik foothills. It is a porous, northern most stretch of Indo-Gangetic plain.
    • Rivers descending from the Himalayas deposit their load along the foothills in the form of alluvial fans which have merged together to build up the bhabar belt.
    • The porosity of bhabar is the most unique feature which is due to deposition of huge number of pebbles and rock debris across the alluvial fans.
    • The streams disappear once they reach the bhabar region because of this porosity. Therefore, the area is marked by dry river courses except in the rainy season.
    • Area not suitable for agriculture and only big trees with large roots thrive in this belt.

2. Terai

    • Terai is an ill-drained, marshy and thickly forested narrow tract (15-30 km wide) to the south of Bhabar running parallel to it.
    • Underground streams of the Bhabar belt re-emerge in this belt. It is a swampy lowland with silty soils.
    • The Terai soils are rich in nitrogen and organic matter but are deficient in phosphate.
    • These soils are generally covered by tall grasses and forests but are suitable for a number of crops such as wheat, rice, sugarcane, jute etc.
    • This thickly forested region provides shelter to a variety of wild life.

3. Bhangar

    • The Bhangar is the older alluvium along the river beds forming terraces higher than the flood plain (about 30 m above the flood level).
    • It is of a more clayey composition and is generally dark colored.
    • A few m below the terrace of the Bhangar are beds of lime nodules known as Kankar.

4. Khadar

    • The Khadar is composed of newer alluvium and forms the flood plains along the river banks.
    • The banks are flooded almost every year and a new layer of alluvium is deposited with every flood. This makes them the most fertile soil.
    • They are sandy, clay and loams, more dry and leached, less calcareous and carbonaceous. A new layer of alluvium is deposited by river flood every year.

B. Black Soils

  • The parent material for most of the black soil are the volcanic rocks that were formed in the Deccan Plateau.
  • In Tamil Nadu, gneisses and schists form the parent material. The former are sufficiently deep while the later are generally shallow.
  • These are the region of high temperature and low rainfall. It is, therefore, a soil group typical to the dry and hot regions of the Peninsula.
  • These soils are locally known as the ‘Regur Soil’ or the ‘Black Cotton Soil’. Internationally, these are known as ‘tropical chernozems’. These soils are famous for the cultivation of cotton.

Characteristics

 

  • A typical black soil is highly argillaceous with a large clay factor, 62 % or more.
  • In general, black soils of uplands are of low fertility while those in the valleys are very fertile. These soils are rich in minerals and known for their fertility.
  • The soil depth varies from place to place. It is very thick in lowlands but very thin on highlands. Also, in the upper reaches of the Godavari and the Krishna, and the northwestern part of the Deccan Plateau, the black soil is very deep.
  • The black soil is highly moisture retentive. It swells greatly on accumulating moisture. In summer, the moisture evaporates, the soil shrinks and is seamed with broad and deep cracks. The lower layers can still retain moisture.
  • This helps in self-aeration, which leads to absorption of nitrogen from atmosphere. Thus, there occurs a kind of ‘self-ploughing’. This aeration and oxidisation to deep levels contributes to maintenance of fertility of the soil. This continued fertility is favourable in the area of low rainfall for cotton cultivation even without irrigation.

Chemical Composition

Distribution

Crops

 

  • Rich in lime, iron, magnesia and alumina. But they lack in phosphorous, nitrogen and organic matter.
  • 10 % of alumina,
  • 9-10 % of iron oxide,
  • 6-8 % of lime and magnesium carbonates,
  • Potash level varies (less than 0.5 %)
  • Phosphates, nitrogen and humus are low.
 

  • Spread over 5.46 lakh sq. km (16.6 %) across Gujarat, Maharashtra, Madhya Pradesh, parts of Karnataka, Telangana, Andhra Pradesh, and Tamil Nadu.

 

 

  • Best suited for cotton crop. Hence these soils are called as regur and black cotton soils.
  • Other major crops grown include wheat, jowar, linseed,
    Virginia tobacco, castor, sunflower and millets.
  • Rice and sugarcane are equally important where irrigation facilities are available.
  • Large varieties of vegetables and fruits are also successfully grown on the black soils.
  • This soil has been used for growing a variety of crops for centuries without adding fertilisers and manures, with little or no evidence of exhaustion.

Colour of Black Soils

  • The black colour is due to the presence of a small proportion of titaniferous, magnetite or iron and black constituents of the parent rock.
  • In Tamil Nadu and parts of Andhra Pradesh, the black colour is derived from crystalline schists and basic gneisses.
  • Various tints of the black colour such as deep black, medium black, shallow black , a mixture of red and black may be found in this group of soils.

 

 

C. Red Soils

  • Red soils along with its minor groups form the one of the largest soil group of Indian Soils.
  • The main parent rocks are crystalline and metamorphic rocks like acid granites, gneisses and quartzite.

Characteristics

 

  • The texture of these soils can vary from sand to clay, the majority being loams.
  • On the uplands, the red soils are poor, gravelly, and porous. But in the lower areas they are rich, deep dark and fertile.
  • The fine-grained red and yellow soils are normally fertile, whereas coarse grained soils are poor in fertility.
  • Have a porous structure.
  • They are generally poor in nitrogen, phosphorous and humus.
  • These soils are airy and need irrigation for cultivation.
  • Intense leaching is a menace in these soil areas.

Chemical Composition

Distribution

Crops

 

  • They are acidic mainly due to the nature of the parent rocks. The alkali content is fair.
  • They are poor in lime, magnesia, nitrogen, phosphates, and humus.
  • They are fairly rich in potash and potassium.
 

  • These soils mostly occur in the regions of low rainfall.
  • They occupy about 3.5 lakh sq. km (10.6 %) area of the country.
  • These soils are spread on almost the whole of Tamil Nadu.
  • Other regions with red soil include parts ofKarnataka, south-east of Maharashtra, Telangana, Andhra Pradesh, Madhya Pradesh, Chhattisgarh, Odisha, Chota Nagpur plateau; parts of south Bihar, West Bengal, Uttar Pradesh; Aravalli’s and the eastern half of Rajasthan (Mewar or Marwar Plateau), parts of North-Eastern states.
 

  • The red soils are mostly loamy and hence cannot retain
    water like the black soils.
  • The red soils, with the proper use of fertilizers and irrigation techniques, give good yield of cotton, wheat, rice, pulses, millets, tobacco, oil seeds, potatoes and fruits.

Colour of Black Soils

 

  • The red colour is due to the presence of iron oxide.
  • When limestone, granites, gneisses and quartzite are eroded the clay enclosed within the rocks remains intact with other forms of non-soluble materials.
  • In oxidizing conditions, rust or iron oxide develops in the clay, when the soil is present above the water table giving the soil a characteristic red colour.
  • The colour is more due to the wide diffusion rather than high percentage of iron oxide content.

 

 

D. Laterite – Lateritic Soils

  • Laterite soils are mostly the end products of weathering. These are zonal soils.
  • The lateritic soils are particularly found on high flat erosion surfaces in areas of high (>200cm) and seasonal rainfall.
  • They are formed under conditions of high temperature and heavy rainfall with alternate wet and dry periods.
  • ‘Laterite’ means brick in Latin. They harden greatly on loosing moisture.

Economic value of Laterite – Lateritic Soils

    • Laterite and lateritic soils provide valuable building material.
    • These soils can be easily cut into cakes but hardens like iron when exposed to air.
    • As it is the end-product of weathering, it cannot be weathered much further and is durable.

Characteristics

 

  • These soils represent the end product of decomposition and are generally low in fertility.
  • Heavy rainfall promotes leaching of soil whereby lime and silica are leached away and a soil rich in oxides of iron and aluminium compounds is left behind.
  • The pebbly crust is the important feature of laterites which is formed due to alteration of wet and dry periods.
  • These soils are acidic in character due to leaching.
  • Application of manures and fertilisers is required for making these soils fertile for cultivation.
  • These soils are poor in organic matter, nitrogen, phosphate and calcium, while iron oxide and potash are in excess.

Chemical Composition

Distribution

Crops

 

  • Rich in bauxite or ferric oxides.
  • Very poor in lime, magnesia, potash and nitrogen.
  • Sometimes, the phosphate content may be high in the form of iron phosphate.
  • In wetter places, there may be higher content of humus.
 

  • Laterite soils cover an area of 2.48 lakh sq. km.
  • Continuous stretch of laterite soil is found on the summits of Western Ghats at 1000 to 1500 m above mean sea level, Eastern Ghats, the Rajmahal Hills, Vindhyan, Satpura and Malwa Plateau.
  • They also occur at lower levels and in valleys in several other parts of the country.
  • They are well developed in south Maharashtra, parts of Karnataka etc. and are widely scattered in other regions.
 

  • These soil lack fertility due to intensive leaching.
  • When manured and irrigated, some laterites are suitable for growing plantation crops like tea, coffee, rubber, cinchona, coconut, areca-nut, etc.
  • In some areas, these soils support grazing grounds and scrub forests.

Colour

 

  • Reddish brown in colour due to the presence of iron oxide.
  • Laterite soils are red in colour due to little clay and more gravel of red sand-stones.

 

 

E. Forest – Mountain Soils

  • Forest soils are formed in the forest areas where sufficient rainfall is available.
  • They are mainly heterogeneous soils found on the hill slopes covered by forests.
  • The formation of these soils is mainly governed by the characteristic deposition of organic matter derived from forests and their character changes with parent rocks, ground-configuration and climate.

Characteristics

 

  • In the snow-bound areas of the Himalayas, they are acidic with low humus content. This is because humus is rawer at higher levels.
  • These soils are subjected to denudation due to landslides and snowfall.
  • The soils found in the lower valleys are fertile and rich in organic content.
  • Due to sharp differences of hill slopes and climates, these soils may differ greatly even when in proximity.
  • These soils exist in thin layers because of their development on the mountain slopes.
  • Soil erosion is a major problem in these areas.

Chemical Composition

Distribution

Crops

 

  • The forest soils are very rich in humus.
  • They are deficient in potash, phosphorus and lime.
  • They require good deal of fertilizers for high yields.
 

  • These soils occupy about 2.85 lakh sq. km or 8.67% of the total land area of India.
  • In the Himalayan region, such soils are mainly found in valleys, less steep and north facing slopes. The south facing slopes are very steep and exposed to denudation and hence do not support soil formation.
  • Forest soils occur in Western and Eastern Ghats also.
 

  • They are suitable for plantations of tea, coffee, spices and tropical fruits in peninsular forest region.
  • Wheat, maize, barley and temperate fruits are grown in the Himalayan forest region.
  • The slopes are used for horticulture and plantations crops like tea, coffee, spices, apple, peach etc. Rice and wheat are grown in valleys. Potatoes are grown in mostly all areas.

 

 Colour and Texture of Soil

 

  • The soils vary in structure and texture depending on the mountain environment where they are formed. They are loamy and silty on valley sides and coarse-grained in the upper slopes. Their colour is dark brown.

 

 

F. Arid – Desert Soils

  • These are derived from the disintegration of adjacent rocks and are largely blown from coastal regions and Indus valley.
  • The desert soils consist of Aeolian sand (90 – 95 %) and clay (5 – 10 %).
  • The presence of sand inhibits soil growth. Desertification of neighboring soils is common due to intrusion of desert sand under the influence of wind.

Characteristics

 

  • These are saline in nature. In some areas, the salt content is so high that common salt is obtained by evaporating the saline water.
  • Due to the dry climate, high temperature and accelerated evaporation, they lack moisture and humus.
  • These soils are rich in minerals but the main limitation is the lack of water.
  • The soils exhibit poorly developed horizons.
  • Plants are widely spaced.
  • Chemical weathering is limited.

Chemical Composition

Distribution

Crops

 

  • Usually poor in organic matter.
  • Some desert soils are alkaline with varying degree of soluble salts like calcium carbonate.
  • Calcium content increases downwards and the subsoil has ten times more calcium.
  • The phosphate content of these soils is as high as in normal alluvial soils.
  • Nitrogen is originally low but some of it is available in the form of nitrates.
 

  • Cover a total area of 1.42 lakh sq. km (4.32%).
  • Occur in arid and semi-arid regions of Rajasthan, Punjab and Haryana. The sand here is blown from the Indus basin and the coast by the prevailing south-west monsoon winds.
  • Sandy soils without clay factor are also common in coastal regions of Odisha, Tamil Nadu and Kerala.
 

  • Phosphates and nitrates make these soil fertile wherever moisture is available.
  • There is a possibility of reclaiming these soils if proper irrigation facilities are available.
  • In large areas, only the drought resistant and salt tolerant crops such as barley, cotton, millets, maize and pulses are grown

Colour and Texture of Soil

 

  • Range from red to brown in colour.
  • Generally sandy to gravelly in texture and have a high percentage of soluble salts.

 

 

G. Saline – Alkaline Soils

  • They are also known as Usara soils. Various local names for saline soils are Reh, Kallar, and Chopan, Rakar, Thur, Karl etc.
  • In Saline and Alkaline Soils, the top soil is saturated with saline and alkaline efflorescence i.e. covered with salt particles.
  • The accumulation of these salts makes the soil infertile and renders it unfit for agriculture.
  • In Gujarat, the areas around the Gulf of Khambhat are affected by the sea tides carrying salt-laden deposits. Vast areas comprising the estuaries of the Narmada, the Tapi, the Mahi and the Sabarmati have thus become infertile.
  • Along the coastline, saline sea waters infiltrate into coastal regions during storm surges (when cyclones make landfall) and makes the soil unfit for cultivation. The low lying regions of coastal Andhra Pradesh and Tamil Nadu face this kind of soil degradation.

Characteristics

 

  • Because of capillary action, the salts are sucked up in solution to the surface and form white encrustations on the surface.
  • Undecomposed rock fragments, on weathering, give rise to sodium, magnesium and calcium salts and sulphurous acid. 
  • The salt efflorescence of calcium, magnesium and sodium makes these soils infertile.
  • Saline soils contain an excess of neutral soluble salts of chlorides and sulphates whereas sodic or alkali soils contain sodium carbonates/ sodium bicarbonates.
  • They lack in nitrogen and calcium and have low water bearing capacity.
  • The saline and alkaline soils may occur in any group of soils.

Formation

Distribution

Crops

 

  • These soils have developed in areas with dry climatic conditions (in areas having a little more rainfall than the areas of desert soils) accompanied by lack of proper drainage. In this situation, salts of sodium, calcium and magnesium are deposited on the upper layer of the soil by capillary action.
  • In the Rann of Kuchchh, the Southwest Monsoon brings salt particles and deposits there as a crust.
  • These soils are also formed when saline water spreads on the land at the time of high tide in coastal areas. Also, seawater intrusions in the deltas promote the occurrence of saline soils.
  • Salinization also occurs because of over-irrigation and in areas of high water table
 

  • Occupy 68,000 sq. km of area.
  • They occur in arid and semi-arid regions, and in
    waterlogged and swampy areas.
  • These are more widespread in western Gujarat, deltas  of the eastern coast and in Sundarban areas of West Bengal.
  • Parts of Andhra Pradesh, Telangana, Karnataka, Bihar, Uttar Pradesh, Haryana, Punjab (side effects of improper or excess irrigation), Rajasthan and Maharashtra have this kind of soils.
 

  • In coastal areas, coconut trees are found in plenty in these soils. As discussed above, cultivating salt resistant crops like barseem, dhaincha and other leguminous crops can help in reclaiming these soils

Soil Texture

 

  • Ranges from sandy to loamy.

 

 

H. Peaty – Marshy Soils

  • These soils are locally called Kari in Kottayam and Alleppey districts of Kerala.
  • These are soils with large amount of organic matter and considerable amount of soluble salts.
  • The most humid regions have this type of soil.
  • They are black, heavy and highly acidic.

Characteristics

 

  • These soils are characterised by a rich humus and organic content.
  • There is a presence of iron and varying amounts of organic matter (10-40%). The organic matter in these soils may go even up to 40-50 %.
  • These soils are generally acidic in nature. But at many places, they are alkaline also.

Formation

Distribution

Crops

 

  • These are marshy soils and are a result of water logging and anaerobic conditions (which leads to partial decomposition of
    organic matter).

 

 

  • Found in the areas of heavy rainfall and high humidity, where there is a good growth of vegetation.
  • It occurs widely in the northern part of Bihar, the southern part of Uttaranchal and the coastal areas of West Bengal, Orissa and Tamil Nadu. Kottayam and Alappuzha districts of Kerala.
  • Also occur in the coastal areas of Odisha and Tamil Nadu, Sundarbans of West Bengal, in Bihar and Almora district of Uttarakhand.
 

  • These are generally submerged during the rainy season and utilised for the cultivation of rice.

 

Soil Texture and Color

 

  • normally heavy and black in colour
  • They are deficient in potash and phosphate.

 

Characteristics of Indian Soils

  • Most of the Indian soils are old and mature. Soils of the peninsular plateau are much older than the soils of the great northern plain.
  • Indian soils are largely deficient in nitrogen, mineral salts, humus and other organic materials.
  • Plains and valleys have thick layers of soils while hilly and plateau areas depict thin soil cover.
  • Some soils like alluvial and black soils are fertile while some other soils such as laterite, desert and alkaline soils lack in fertility and do not yield good harvest.
  • Indian soils have been used for cultivation for hundreds of years and have lost much of their fertility.

 So, this was all about the types of Soils in India or Indian Soils.

In the next post (Click Here) we will study in details about the Degradation of Indian Soils and Conservation of Indian Soils.

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