Here is a list of soil groups available in India:- 1. Alluvial Soils 2. Black Soils 3. Red Soils 4. Laterites & Lateritic Soils 5. Other Groups.
India is a vast country where different types of soils and climates are being found. The soils of any region determine the crops, cropping systems and the socio-economic features of that particular locality. Soil is a gift provided by nature to the mankind and is a one of the premier natural resources. From agriculture point of view, the soil has to be favourable to the crops. Appropriate crop growth & development is possible only with the suitability of the soil which ultimately determines the economic product of the crops.
As different types of soils are being found in our country, their distribution is also in the different parts of the country. The formation of every soil is there due to specific conditions/processes. These soils are known by their different names in the different parts of the country.
The nature and properties of the soils are different according to their types. According to these nature and properties of soils; these soils are being used for raising the different crops, however, there are specific problems of each soil groups which need specific management practices to solve them.
The name of the soil groups of India are as follows:
1. Alluvial Soils:
Origin:
Alluvial soils are originated from such types of parent materials which are being transported from one place to another. The transportation of these parent materials may be from different means viz. water, ice, wind, gravitation etc. Alluvial soils are formed due to transportation network of water courses and rivers and get deposited either on flood plains or on river banks.
The parent material of Gangetic plains is newly-formed and it is originated due to deposition of erosion products which has been transported by different river networks and deposited on the plain regions. Another type of alluvium recognized is the coastal alluvium which represents heterogeneous types of sediments brought by rivers and deposited near their mouth where they join the sea.
Types:
These are of two types whose descriptions are given below:
i. New Alluviams:
It is locally known by the name of ‘Khadar’. These are newly formed alluviams. These are sandy and light in colour. These are coarse textured soils. Less kankers are found in these soils. Soil horizonation either is very little or absent in these soils. These soils are very productive in nature.
ii. Old Alluviams:
Locally this is known as ‘Bhangar’. Clay content is more in these types of soils; hence, these are fine textured soils. These are dark in colour and contain kankers in sufficient quantities. Hard and impervious layer is found in lower horizons of these types of soils. Due to the presence of this impervious layer, the drainage becomes difficult. This hard and impervious layer is only formed if the sodium content is more in the soil.
From agriculture point of view, alluvial soils are the largest and most important soil groups.
Distribution:
The acreage of alluvial soils in India is about 75 m ha. These soils are mainly found in the Gangetic plains and in the valleys of Brahmaputra. These soils are extensively distributed in North-western and North-east India, which includes Punjab, Haryana, Uttar Pradesh, Delhi, Madhya Pradesh, Assam, Bihar and West Bengal. Apart from this, these soils are also found in the coastal regions of Andhra Pradesh, Tamil Nadu, Kerala and Gujarat.
Important Soil Characteristics:
These soils are very deep and are found in different colours. The colour of the soil is dependent on their parent materials. The colour of these types of soils varies from light-brown to yellow-brown or dark brown in colour. These are the lime containing soils. Some of the alluvial soils are excessively saline and sodic in nature. The formation of hard and impervious layer in lower horizons is the common characteristics of these soils.
The formation of hard layer is frequently observed in those soils which are being used for cultivation for long time. The formation of hard layer is commonly due to the aggregation of soil particles resulted from leached silica. Sometimes, there is formation of hard layer due to the lime surface or because of the accumulation of calcium carbonate in solid form.
The texture of the alluvial soils is variable. The texture of these soils varies from very coarse to fine-texture which is favourable for the growth of the plants. These soils are inherently rich in plant nutrient elements. Phosphorus, potassium and calcium are found in sufficient quantities in these soils, however, nitrogen and organic matters are deficient. The alluvial soils are alkaline in nature, but these soils may be acidic in nature in North-east regions where annual rain fall is more than 2000 mm.
Land Use:
These soils are considered as the most suitable soils for farming. These soils are used for the raising of different types of crops. Crops like; wheat, rice, sugarcane, maize, jute, groundnut, potato, sunflower, berseem etc. are mainly grown in these soils.
Problems & Management:
Some of the alluvial soils get waterlogged due to improper utilization of irrigation water which increases the salinity or/and sodacity. As, these soils are deficient in nitrogen and humus, therefore, there is need to proper utilization of manures and fertilizers. Some soils are deficient in zinc and sodium.
As these soils are intensively cultivated, hence, deficiency of sulfur and zinc are seen. The ground water level comes up due to the improper utilization of irrigation water which increases the soil salinity. Punjab & Haryana in our country have been affected with the problem of soil salinity due to the non-judicious use of irrigation water.
2. Black Soils:
Origin:
These soils are locally known by the name of ‘Regurs’ in central India. These soils are formed insitu mainly from basalt trapped rocks or from the transportation of parent materials. These types of soils are formed from two types of parent rocks; first, from Deccan and Rajmahal traps which are volcanic rocks, like; basalt and other alkaline metamorphic rocks and second from granite, gneisses and schists. Lime and soda lime feldspar are found in these rocks which are alkaline in nature.
Distribution:
Black soils are generally found in India in its central, Western and Southern states. These states include; Maharashtra, Western part of Madhya Pradesh and some parts of Andhra Pradesh, Karnataka and Tamil Nadu. The acreage of black soils in India is about 72 m ha (720000 km2).
Important Soil Characteristics:
The clay content is more in this soil which varies from 35 to 60%; however, sometimes it may be up to 80% in lower portions of valleys or depressions. Black soils have such types of clays which are swelling & shrinking in nature. Due to this property of clays, a 50 cm or even more wide cracks are formed. Owing to formation of cracks, continuous churning process goes on these soils.
Crumb or granular structure is found in black soils. These structures are found on the upper layers of the soil, whereas, from sub-angular to angular blocky structures are found in the lower horizons. Black soils do have the properties of swelling & shrinking, plasticity and stickiness. These soils have the problems of poor drainage and low permeability.
The black colour of the black soils is due to the clay-humus complexes and/or titaniferrous magnetide mineral and some extent because of the organic matters (0.5 to 1.0%). These soils generally contain lime and are of slight alkaline in reaction. The Cation Exchange Capacity (CEC) of these soils is high which may vary from 30-50 m eq.
Exchangeable quantities of calcium and magnesium are more in black soils. These soils are deficient in nitrogen, phosphorus and organic matters. The productivity of these soils is more under irrigated conditions. As the water holding capacity of these soils is high, hence, this can be used for the production of cereals and legumes under rain fed conditions.
Land Use:
Black soils are very fertile. Cotton, cereals, sorghum, soybean etc. are mainly grown in these soils in Madhya Pradesh, Gujarat and Maharashtra. Sugarcane is being grown in black soils under irrigated conditions in the states of Maharashtra and Andhra Pradesh.
Problems & Management:
The main problem of these soils is the very narrow limit of soil moisture in which ploughing of field, intercultural operations or field preparation could be done. If these soils are ploughed at excess moisture, the soil came out of ploughing becomes very hard after drying.
On the other hand, if black soils are ploughed at lower moisture levels, the big clods are formed. Thus, good field preparation is not possible by ploughing of black soils both at higher or lower moisture levels. The soil structure gets deteriorated under both the conditions. An appropriate moisture level is thus, required for any tillage operations in these soils.
Good ploughing can only be obtained with this appropriate moisture level in which clods are automatically broken while ploughing. This moisture level in black soils is available for very short period. The soil is prepared within this period otherwise; later on it cannot be prepared.
Infiltration of water is very slow in black soils. There is problem of drainage in these soils. The water holding capacity of these soils is high, however, plants are unable to absorb this water after a certain limit, thus, plats show the symptoms of water deficit. Organic carbon, nitrogen and sulfur are deficient in these soils. The availability of different micro nutrients is being affected negatively in black soils due its alkaline nature.
Many black soils are highly fertile, however, the black soils located at upland situations may have very poor fertility level and somewhere these soils are unproductive. As these soils are with poor drainage inherently, therefore, soil salinity & sodicity may develop if proper drainage is not provided under irrigated conditions.
3. Red Soils:
Origin:
Red soils have been formed from granites, gneiss and other metamorphic rocks. These soils have been formed either insitu or disintegrated matters of rocks washed from rain water which are accumulated at lower places after transportation. These soils are originated under hot, semi-arid to hot, wet and sub-tropical climatic conditions. Apart from this, these soils are formed under well drained conditions only. The main processes involved in the formation of red soils are eluviations and illuviation of clay, iron and bases.
Distribution:
Red and yellow soils are mainly found in the Southern peninsular of India which includes the states of Tamil Nadu, Karnataka, Maharashtra, Andhra Pradesh, Madhya Pradesh, Goa, Pondicherry, Dadra & Nagar Haveli, Daman & Diu etc. Occasionally, these soils are also seen in the North-eastern states of India i.e. in Bihar, West Bengal, Assam and Uttar Pradesh.
Important Soil Characteristics:
Red soils include red loams, red gravelly soils and red earths. These soils are medium to excessively weathered. These soils are dominated by iron or aluminum or both. Red soils are deficient in humus. These soils are red to yellow in colour because soil particles are coated with the layer of ferric oxides.
Red colour of the soil is there if ferric oxide is present in the forms of hematite or anhydrous iron oxides, whereas, yellow colour is there because of the presence of ferric oxide in the form of its hydrated form (limonite). Texture of red soils varies from sandy loam to heavy clay; however, its texture is loam to clay loam, in general. Red soils are shallow to very deep and are having good drainage.
The pH of these soils varies from 6.0 to 7.5. Generally, these soils are neutral in reaction, but some of the red soils are slightly acidic to alkaline in nature. Iron and aluminum are generally found in larger quantities (30-40%). Cation Exchange Capacity (CEC) and base saturation is medium to low in these soils.
However, these values are more in red soils as compared to lateritic soils. These soils are dominated by kaolinite and illite clays and they have the Carbon- Nitrogen ratio of about 10. These soils are deficient in nitrogen and phosphorus, however, sufficient potassium is present in these soils. Organic matter and lime are deficient in these soils.
Land Use:
Despite, so many limitations in red soils, these soils are capable in growing of cereals (minor millets) rice, groundnut, maize, soybean, jute, gram, potato and plantation crops, like; tea, cocoa, cashew, grapes, banana, papaya, mango etc.
Problems & Management:
After drying, these soils form the hard crust which affects the germination of sown seeds and aeration in the soil. These soils are shallow in hill slopes and on the top of the hills. Lower horizons of these soils become hard due to illuviation which restricts the proper root development. As these soils are dominated by kaolinite & illite types of clays, hence, their water holding capacity is less.
These soils are erosive in nature due to excessive drainage and surface run off. Natural soil fertility in these soils is poor and these soils are deficient in nitrogen, sulfur, calcium, zinc etc. Cation exchange capacity of red soils is also less. There is more fixation of phosphorus in these soils.
4. Laterites & Lateritic Soils:
Origin:
The literal meaning of laterites is ‘rock’. These soils are formed in sub-tropical and tropical climates. The climate of these regions is of alternatively wet & dry seasons. Under high rain fall situations, the alkaline silica gets leached from parent rocks and there is majority of iron and aluminum oxides on the surface horizons of the soil. The end product of this process is termed as ‘laterites’. In this process, sesquioxides are remained which upon drying get converted in to irreversible oxides of iron and aluminum.
Distribution:
These soils are found in Odisha, Maharashtra, Kerala, Tamil Nadu and on the peaks of hills and plateau of North-east region. These soils can be locally seen in Andhra Pradesh, Karnataka, Assam and West Bengal. The acreage of red soils in our country is about 25 m ha (250000 km2).
Important Soil Characteristics:
Hydrated oxides or the mixture of iron and aluminum are essentially found in the soil profile of red soils. Sometimes, these are also called as the ‘honey comb structure’. Generally these soils are purplish (a mixture of red and blue colour) or brick red or they are brown to yellowish in colour. Ferruginous clays are being found in these soils. When it is wet and not in the contact of air, it is soft, but it becomes very hard as it comes in to the contact with air and this is the reason, these soils are used in the construction of houses.
A soil may be classified as lateritic when layers of cellular concretion of iron and vesicular honey comb ferriginous masses are formed in the soil profile. The bases like; calcium, magnesium, potassium and sodium get leached down in these soils. Silica gets separated from the soil and there is heavy accumulation of sesquioxides, resulting in to acidic reaction of the soil. The pH value in laterite soils is less.
As we go on, the upper height from soil surface, soil is becoming more acidic in nature. These soils are dominated by kaolinite and illite clays, hence, water holding capacity and cation exchange capacity of these soils is less. These soils are generally deficient in phosphorus, calcium and magnesium. These soils are well drained and porous in nature.
Land Use:
These soils are suitable for the cultivation of rice, banana, coconut, arecanut, cocoa, tea, rubber etc.
Problems & Management:
These soils are deficient in phosphorus, and there is problem of high capacity of phosphorus fixation in red soils. More acidity is found in these soils. Under acidic conditions, the solubility of iron and aluminum is increased; hence, they become available in excessive amounts so they become toxic to the plants.
These soils are deficient in potassium, calcium, magnesium, zinc and boron. As these soils are coarse textured in nature, therefore, their water holding capacity is less. These soils have the problem of surface crustation, hence, seed germination and soil aeration, both are affected negatively.
5. Other Groups:
Indian soils have been grouped in to four major groups as above, however, other soils from lesser to larger acreages are also found in addition to four major groups above which are having their own soil characteristics and problems.
All such soils have been put under ‘other groups’ whose descriptions are given below:
Origin & Distribution:
Desert soils are found in hot and deserted regions. These soils are found in North-western part of India. These soils are mainly found in major portions of Rajasthan, Southern parts of Haryana and Punjab and Northern portions of Gujarat. The annual average rain fall of these regions is 10 to 50 cm; however the Potential Evapotranspiration (PET) in these regions is 162 to 206 cm which reflects the net aridity of these regions. The high level of temperature remains throughout the year in these regions.
Important Soil Characteristics:
These soils have less organic matter content. Sand dunes are formed in these soils. Desert soils are formed from alluviums. These soils are pale brown to yellow-brown in colour. The texture of these soils varies from fine sand to fine loams. These soils are considered as the structure-less soils.
There is accumulation of lime in these soils at the depth of 60-120 cm. The quantity of clay in desert soils is very less. The pH value ranges in these soils from 8.0 to 8.8. Soil particles get dispersed due to the presence of sodium clays which reduces the permeability of the soil. Kaolinite and illite are the major clays found in these soils.
Land Use:
These soils are suitable for pastures. The cultivation of ber and pomegranate can be done under limited irrigation resources.
Problems & Management:
Formation of sand dunes and undulating topography are the major problems of these soils. Water holding capacity of these soils is less. There is a problem of leaching losses in these soils. Generally, these soils are found in drought prone areas. The fertility status of these soils is very less and deficiency of nitrogen and phosphorus is the common problem in these soils.
Origin & Distribution:
The total area of forests in India is about 75 m ha which accounts about 18% of the total geographical area of the country. The major forest area possessing Indian states include Himachal Pradesh, Jammu & Kashmir, Uttrakhand, Arunachal Pradesh, Assam, Nagaland, Meghalaya, Kerala, Andaman & Nicobar etc. The major soils found in these states are brown hilly/forest soils, podzolic (in the Himalaya) and red and lateritic soils (in Deccan plateau).
These are the brown soils found in the forests. These are neutral to acidic in reaction. The pH of these soils varies from 6.0 to 7.0. Organic matter content is high in these soils. Nitrogen is found in sufficient quantities in these soils. Cation Exchange Capacity of these soils is high. These soils are suitable for trees of forest species; like Tictona & Shorea etc.
Podzolic soils are medium to extremely acidic in nature and their pH ranges from 4.5 to 6.0. There is more organic matter content in these soils which may be up to 3 to 5%. The clay content found in these soils is in medium to high range which may vary from 20-30 per cent. The base saturation of these soils is below 50%. Phosphorus is deficient in these soils.
These soils are found in humid regions. There is accumulation of organic matters in these soils. Apart from this, there is good accumulation of soluble salts as well. The marshy soils are generally found in the depressed regions formed by dried rivers and lakes in alluvial and coastal tracts.
Sometimes, due to these circumstances, special types of waterlogged soils are formed. Commonly, these soils are blue in colour. This blue colour is because of the presence of ferrous iron under anaerobic condition and the presence of organic matters in varying quantities.
Marshy soils are found in coastal areas of Odisha, in Sundarban of West Bengal, central portion of Eastern Bengal and in South-east coastal areas of Tamil Nadu. These soils vary from dark to black in colour. These soils are finely textured and organic matter content of these soils may vary from 20-40%. There is formation of sulphuric acid due to oxidation of pyrites when these soils are dried; hence, the pH of the soil drops to very lower levels.
Sometimes pH drops below 4.0 scales. It is, therefore, these soils are very acidic in reaction and their pH value may vary from 3.5 to 4.0 scales which are mainly because of the decomposition of the organic matters. This decomposition process takes place under anaerobic conditions where there is no possibility of any nitrification process. These soils are also called as the “Cat Clays OR Acid Sulphate Soils”.
Land Use:
Acid tolerant crops like; rice and pineapple are cultivated in these soils. These soils also support mangroves in coastal areas.
Problems:
These are very problematic soils. There is formation of sulfuric acids in these soils due to oxidation of pyrites. Under such situations, the solubility of iron and aluminum is increased and thus, their availability is also increased and become toxic to plants. There is deficiency of phosphorus in these soils. Rice is being cultivated in Kerala in these soils after receding of flood water.
Distribution:
Salt affected soils include saline and alkaline soils. The total acreage of these soils in India is about 7 m ha. These soils are mainly found in the states of Uttar Pradesh, Gujarat, West Bengal, Rajasthan, Punjab, Maharashtra, Haryana etc.
Important Soil Characteristics:
There are many categories/groups of salt affected soils; the major ones are saline soils, non-saline alkali soils, saline alkali soils, degraded alkali soils etc.
The pH values of these soils may vary from 8.5 to 10.0 scales. These soils have high Sodium Adsorption Ratio (SAR). The quantity of total soluble salts is also high in these soils. Compared to the normal soils, the organic matter content of the salt affected soil is lower. Physical condition of these soils may vary from compact to dispersed state.
Infiltration of water and its permeability in the soil is also less in these soils. The major salts found in these soils are sulphate, chloride, nitrates and carbonates of sodium. There is deposition of white crust on the surface of the salt affected soils. Comparative soil characteristics of different salt affected soils.
Land Use:
Sodium tolerant and semi-tolerant crops; such as rice, sugar beet, rhodes grass, wheat, pearl millet, cotton etc. can be grown in these soils. There must be drainage provisions in these soils. Judicious use of irrigation water and fertilizers is required in these soils.
Problems & Management:
The productivity of these soils gets deteriorated due to the presence of sodium and/or soluble salts in the soil. As the soil structure gets dispersed in these soils, it affects the availability of water and nutrient elements. The deficiency of micro nutrients in these soils is the common problem.
A hard kanker layer at a depth of 1.5 m is found in these soils which creates the drainage problem in the soil. Gypsum is used as the soil amendment for amelioration of these soils. The lower horizons of the soil is impervious, hence, it is helpful in raising the ground water level.
Distribution & Characteristics- These soils are found in the foot hills. These soils are mainly found in the states of Jammu & Kashmir, Bihar, West Bengal and foot hills of the Himalaya (Uttrakhand and Uttar Pradesh). These soils are rich in terms of their organic matter contents. Texture of these soils varies from sandy loam to silty loam. These soils are very fertile, well drained and highly productive. The pH of these soils varies from 4.7 to 5.8. The bases are deficient in tarai soils.
Land Use:
These soils are suitable for grasses and trees. Rice is being cultivated in these soils in Jalpaiguri and Koochvihar. As the good moisture level is maintained in these soils throughout the year, hence, there is good growth of tall grasses.
Problems & Management:
Tarai soils are acidic in reaction and are deficient in bases. Apart from this problem, there is deficiency of plant nutrient elements. These soils may become productive if appropriate drainage system is provided to them.