8 Main Types of Soil Found in India

This article throws light upon the eight main types of soils found in India. The types are: 1. Alluvial Soils 2. Black Soils 3. Red Soils 4. Laterite Soil 5. Mountain and Hill Soil 6. Arid and Desert Soil 7. Saline and Alkali Soil 8. Peaty and Other Organic Soil.

Type # 1. Alluvial Soils:

These soils have been found in Major parts of Punjab, Haryana, U.P., Bengal, Assam, North Bihar and small areas in the other States of the Indian Union. The main features of alluvial soils have been derived as silt deposition laid down by the Indian river systems like the Indus, the Ganges, the Brahmaputra and the rivers like Narmada, Tapti, Mahanadi, Godavari, Krishna and Cauvery.

These rivers carry the products of weathering of rocks constituting the mountains and deposit them along their path as they flow down the plain land towards the sea. Most of the alluvial soils do not possess a well-developed horizon.

Geologically alluvial soils have been divided into two broad groups, namely old and new alluvium, which are also called Bangar and Khadar respectively in North India. Some of the old alluvial soils possess well developed horizons.

The surface soil of these old alluvial soil are reddish brown of grey brown sandy loam or loamy in texture, and the sub-soil contain more clay than the surface soil. The texture of the new alluvium is very coarse on the river banks and very fine in the low lying marshy lands.

Alluvial soils usually contain lime nodules intermixed with soil at different depths. Frequently drainage is restricted and soluble salts accumulate in the soils of more arid regions i.e. Uttar Pradesh, Punjab and Haryana. Alluvial soils are usually deficient in humus and nitrogen, occasionally in phosphorus but not in potash and lime.

Type # 2. Black Soils:

Almost the whole of Maharashtra, the western half of Madhya Pradesh, the southern parts of Gujarat and some areas in Andhra Pradesh, Karnataka and Tamil Nadu and Bundi and Tonk districts of Rajasthan and Bundelkhand division of U.P. are covered by black soils which have been divided into three broad groups i.e.

(i) Shallow black soil of a depth of 30-50cms,

(ii) Medium black soils of depth of 50-120 cm, and

(iii) Deep black soil of a depth of more than 120cms.

In many places, black soils often occur in close proximity to red soils. In the vicinity of the hills, the red soils merge interceptibly into the black soil.

Shallow black soils of a texture that varies from silty loam to loam and colour that varies from dark yellowish-brown to dark brown, have formed from basalts of the Deccan trap.

Parent materials of medium black soils include basaltic trap, Dharwar Schist, basic granite gneisses, hornblende and chlorite schists, whereas deep black soils consist of basaltic trap.

The soil texture in both cases varies from silty clay to clay. Both contain 40 to 60 per cent or more clay. Gypsum accumulates in association with lime in some of the soil profiles.

The colour of these soils varies from deep black to light black. The exact cause of the black colour of these soils is unknown.

Probably it is due to the presence of titeniferous magnetite, organic compounds of iron and aluminum, humus and colloidal hydrated double iron and aluminum silicate.

Black soils are rich in the smectite group of clay minerals and therefore possess a high cation exchange capacity (40 to 60 meg/100gms) and high base status. They are very sticky and plastic when wet and form very wide and deep cracks when dry.

Black soils are very rich in iron, lime, magnesia and alumina. They are deficient in organic matter, nitrogen and phosphorus but not in potash. Soluble salts alkaline in reaction accumulate in medium and deep black soils.

Black soils, especially deeper ones, can retain a high amount of moisture and are fairly fertile giving reasonably good yields of crops despite continued Cultivation without proper manuring. These soils are well suited for cultivation of cotton, cereals and oil seeds. Deep black soils are often called black cotton soils because cotton is most extensively grown on them.

Type # 3. Red Soils:

Red soils cover almost the whole of Tamil Nadu, Karnataka, Andhra Pradesh, Orissa, Nagaland, Manipur, Mizoram and Tripura, eastern and southern parts of Madhya Pradesh, Bundelkhand division and Mirzapur district in Uttar Pradesh, Chota Nagpur division and Santhal Parganas districts in Bihar, parts of West Bengal, Arunachal Pradesh and Meghalaya, Karbianglong districts of Assam, Thane and Kolaba districts of Maharashtra and also parts of Rajasthan.

Red soils include:

(i) Red loam soils,

(ii) Red and yellow soils, and

(iii) Red sandy soils.

Red soils have been formed from varieties of rocks which include granite, gneiss, schist, sandstone, hornblende, shales etc. under a forest of broad leaved trees in warm humid climate. As basic elements have been leached from most of these soils, they become acidic in reaction.

The soil organic matter has decomposed and they are poor in humus, and nitrogen, phosphorus and lime. Whenever water soluble phosphates are added to these soils, they react with ferric and aluminum ions and their hydrous oxides and are precipitated as insoluble ferric and aluminum hydroxyl phosphate.

Kaolinite and hydrous oxides of iron and aluminum are the dominant clay minerals in red soils, responsible for the excellent physical condition of red soils. A number of kharif crops are thus grown on these soils, even though they cannot retain enough moisture for their growth. These soils differ greatly in fertility and depth.

Type # 4. Laterite Soils:

Laterite soils occur in small patches in almost all the states of north-eastern, eastern, southern and western India. They are formed from several kinds of rocks like basalt under a hot, humid climate when the basic elements and silica have been washed down and iron is precipitated and oxidized.

Whenever drainage is restricted, a soft deposit of iron oxide occurs at or near the water table, which hardens when it dries. In some places like Malabar, this is cut in the form of bricks and used as a building material.

The word Laterite has originated from the Latin word “Later” which means bricks. This possesses an indurated honey combed mass of iron oxides. Laterite soils are usually shallow and gravelly at higher lands, but are very deep loam to clay soils in the valleys where good paddy crops are produced on them.

Laterite soils are deficient in basic elements like lime, magnesia, potash and nitrogen and available phosphorus. These soils are not sticky and plastic when wet. They are in excellent physical condition due to the presence of hydrous oxides of iron and aluminum and kaolinite as the dominating clay minerals.

Type # 5. Forest and Hill Soils:

Forests cover nearly 14 per cent of the total area of this country. They mainly occur in Himachal Pradesh, Uttar Pradesh, West Bengal, Assam, Arunachal Pradesh, Meghalaya, Mizoram, Nagaland, Tripura, Orissa, Madhya Pradesh, Karnataka, Kerala and Tamil Nadu.

Forest soils are constantly enriched by fallen leaves. Hence they are usually rich in organic matter and total nitrogen. Forest soils developed from acidic parent material, are poor in basic elements and acidic in reaction while some developed from basic parent material, are fairly rich in basic elements, neutral to slightly alkaline in reaction and are fairly fertile.

Type # 6. Desert Soils:

Desert soils cover major areas in Rajasthan. They are also found in Haryana, Gujarat and Uttar Pradesh. These soils consist mainly of sands which have been blown mainly from coastal areas. Soil fertility improves in the eastern and north-eastern direction.

Some of these soils are saline or alkaline and contain calcium carbonate. The phosphate content of the Aeolian sand may compare favourable with some of the alluvial soils. They contain low amounts of organic matter and total nitrogen and are alkaline in reaction. Some of them contain nitrates. These soils may be cultivated if irrigation water is available.

Type # 7. Saline and Alkali Soils:

Saline and alkali soils of India occur mainly in the arid and semi-arid regions of Uttar Pradesh, Haryana, Punjab, Rajasthan, Gujarat and Maharashtra soluble salts accumulate on the surface, of the saline soils as salt efflorescence’s which are mainly chlorides and sulphate of sodium, calcium and magnesium.

Salts move upwards, along with the capillary water and reach the surface in the case of saline soil in the areas where canal or well irrigation is practiced and also near the sea coast.

Saline soil or solonchek contain neutral sodium and other salts, whereas alkaline soils contain exchangeable sodium and sodium carbonates, (e.g. in Uttar Pradesh, Punjab, and Haryana) which are impermeable to water in contrast to saline soils, which are permeable to water.

Type # 8. Peaty and Marshy Soils:

Large amounts of organic matter have accumulated in low lying areas. This organic matter has decomposed in the presence of excess moisture to form the Peaty and Marshy soils.

Marshy soils are blue due to their ferrous iron content. They contain varying amounts of organic matter. Marshy soils of this type are found in the coastal areas of Orissa, West Bengal and Tamil Nadu, the central portions of north Bihar and the Almora district of Uttar Pradesh.

Saline peat soils called the Kari soils in Kerala, which occur in Ambalapuzha, Kunnathanad, Vaikom and Shertallai, generally remain submerged during the rainy season.

These black soils are highly acidic in reaction, rich in organic matter (10 to 40 per cent) and sesquioxide and poor in phosphorus. These soils contain high amounts of ferrous and aluminum sulphate which are toxic for plant growth.