Let's understand flood, in Indian context

A flooded area in Bihar. (Photo credit: Facebook/WHO Bihar Region)

According to the Indian Meteorological Department (IMD), flood is a meteorological situation when water of a river begins to flow above the danger mark. The danger mark is fixed on the basis of average flow of the river over 25 to 50 years during monsoon period.

Drought is the situation, according to the IMD, having less than 5 cm rainfall for four continuous week any time between mid-May and mid-October. If the rainfall is less than 5 cm for any month (four continuous weeks), it is meteorological drought situation.

Flood prone areas are located practically in all parts of the country excluding the internal plateau regions. However, there has been varying tenure of flood and from that point of view, eastern India, northeastern India and eastern coastal plains are the worst affected areas as far as flood is concerned.

The IMD has divided flood into four tenures of flood and affected geographical regions:

Six-week flood region: Assam valley

4-6-week flood region: Eastern Uttar Pradesh, Bihar plain, West Bengal and isolated plain areas of the Northeast – Loktak basin and Tripura basin.

1-4-week flood region: Eastern coastal plain, Punjab, western Uttar Pradesh, Delhi Union Territory, South Gujarat especially Narmada and Tapi basins, and Kashmir Valley.

Less than one-week flood region: Central and northern Gujarat, Rajasthan, Haryana and peripheral parts of peninsular plateau.

There are some rivers, which are highly flood prone. Brahmaputra and Ganga cover about 60 per cent of flood prone areas of the country. Some flood prone rivers are Teesta, Kapoli (a tributary of Brahmaputra), Dihang and Burhi Dihang (known for flash floods).

In the Ganga system of the Himalayan rivers, the main flood causing rivers are, Mahananda, Kosi, Gandak, Burhi Gandak, Kamla Balan, Saryu, Ghaghra, Gomati, Ramganga and Yamuna. Kosi was once called the sorrow of Bihar.

In the peninsular India, the main flood causing rivers are, Son, Punpun, Ajay and Damodar, which was known as the sorrow of West Bengal once. At present, both Kosi and Damodar rivers have been managed and controlled to some extent but others continue to play the same role.

Among the East Coast river, Mahanadi, Godawari, Krishna, Cauvery and Brahmi are highly flood prone. Among west flowing peninsular rivers, Tapi and Sabarmati are highly flood prone.

In the Punjab plains, Sutlej and Beas are highly flood prone while in Haryana Ghaggar and Yamuna bring floods. The Jhelum is flood prone in the Kashmir Valley.

Besides these rivers, there are several short-distance rives, which flow on high slope and create flash flood during monsoon season.

Total area under flood-prone category, according to the Seventh Five-Year Plan papers is 320 lakh hectares where flood happens every year. Total flood-affected area is 2.42 crore hectares where flood occurs but not every year.

Causes of flood:

Flood is the manifestation of many geographical factors and, to many geographers and geologists it has become an ecological factor. This does mean that flood is bound to come in this part of the world every year. It is a flood-ecology region.

Factors:

1. Erratic behaviour of monsoon -- Sometimes the catchment area receives very high rainfall and then flood arrives. In the western India – Rajasthan, Gujarat and Haryana –torrential rain brings sudden outburst of rain which leads to flashfloods. In contrast, in the North-East, even the regular rainfall brings heavy rainfall and that is responsible for flood situation in the region.

2. Geomorphology -- Flood occurs due to geomorphological profile of central plain of India. Brahmaputra Valley is a narrow ramp valley. Similarly, the Ganga basin is sandwiched between the Himalayas and the peninsular plateaus. Both river valleys are bordered by steep rising slopes while the plains are among the flattest ones in the world.

This topographical feature brings rapid run-off from the catchment areas while the run-off in the plain moves at a slow speed. Consequently, these river basins overflow bringing flood over large areas during monsoon season.

3. Deforestation -- Deforestation in the Siwalik Himalaya has increased the volume of the run-off and therefore frequency and tenure of floods in many of Himalayan rivers.

Several peninsular rivers including small ones have become flood prone in recent years due to loss of trees in the past few decades, e.g. Ajay river has become flood-prone due to deforestation in the catchment area. Jhelum was not flood-prone earlier.

Mahananda was not so acute in bring floods. But at present all these rivers bring flood almost every year and that is related to deforestation. Several plateau districts of Jharkhand and Madhya Pradesh have fallen under flood due to deforestation and rapid run-off in these areas.

4. Soil Erosion and Siltation -- These are responsible for increased flood-frequency mainly in the central plain of the country. According to the UNEP, River Kosi is the second-most affected siltation affected river in the world, only after Hwang-ho of China.

Bed siltation occurs due to soil erosion in the catchment area and the deposition of silt in the plains owing to rivers’ inability to carry the load any further. It makes the valley shallow and whenever there is voluminous flow of water, it brings flood and water spreads in the surrounding areas.

5. Drainage Pattern -- It is responsible for the flood in the central plain. Most of the rivers make meandering courses. So, overflow brings waters of different rivers close and vast areas, thus, get inundated.

Punjab does not witness spread of water because of parallel, man-made, drainage of rivers. Although, the rivers often flow over danger mark during flood season but water does not spread. In Punjab, the doab line is always free from flood due to parallel pattern of drainage but the meandering courses of rivers in Bihar and Uttar Pradesh, and braided courses in all delta regions create floods.

Most of the rivers have wide V-shaped valleys. So, the depth of the valley is not great and any increase in the volume of water leads to overflowing and inundation of the neighbouring areas.

Again some of the rivers have created natural levee which protects one side of the valley from flooding but the other bank is flooded and cause flood over low lying areas adjacent to that bank. Bihar plain is noted for this type of flood. Western banks of rivers in Darbhanga have natural levee.

In the central Bihar, there is also flood due to overflow of the main consequent river. Its overflow prevents the inflow of tributary water channels. In fact, the water of the main river, Ganga, begins to enter the course of the tributaries and the tributaries’ water is pushed back and water spreads over vast areas, e.g. Tal area flood in South Bihar and Jharkhand, Chaur area flood in West Bihar and West Bengal. Chaurs are the floodplains situated in the abandoned courses of rivers. They form ox-bow lakes during floods.

6. Shifting Course of Rivers -- Such flooding is mainly important in regions where river have a history of shifting their course. Rivers like Kosi, Teesta, Gomati and Mahananda are facing this problem.

Kosi is now believed to have settled in its course but others are still active. All these rivers have westward shifting courses. These rivers have a tendency to migrate to west. Hence, the west banks of these rivers are constantly being eroded and the east bank extends to a huge low lying floodplain. These rivers cause phenomenal spread of water beyond eastern banks onto the vast plain.

Rotation of the earth is held indirectly responsible for the westward shifting of these rivers and the associated floodplains. Rotational impact brings westward shift of rivers. The eastern banks become low lying and vulnerable to floods.

Eastern coastal plains receive floods not simply due to deforestation and rapid run-off but also because of cyclonic rainfall and greater havoc is caused by the combination of these factors. If there is high tide situation along with cyclone, rainfall causes great damage.

Cyclone brings rainfall and high tide water on the coastal plains as well as increases the velocity of the sea waves. Tidal water enters the mouth of the rivers pushing back the river water. The water level of the river increases. The river goes in a spate. The flow of the river is reversed and low lying floodplain is taken over by the floodwater. Such tidal flooding is seen in the Mahanadi and the Godawari.

Western coastal rivers generally receive flash floods. The duration of such floods is about one week. The situation mainly occurs due to deforestation along the Western Ghats. Loss of vegetation means less obstruction to run-off.

Rapid run-off leads to greater water volume in the river valleys than the channel is capable of carrying off to the sea. This pushes the water level up in the river valleys leading overflow and inundation in the neighbouring areas.

7. Human Factors -- Floods are also caused by human factors. Ironically, flood control programmes and some other developmental programmes have indirectly contributed in greater spreading of flood. Although, multi-purpose vally projects and other power generation projects have controlled floods in the basins of some of the rivers and regions. But the problem has emerged in a different way.

Due to siltation on the beds, the reservoirs’ capacity has reduced and whenever excess water is released from that reservoir through canals and other outlets, flood is caused. Flood water even enters the areas where flood had never come previously.

The canals also face siltation problems, which get compounded by the seepage of river water from the sides of the canals into neighbouring agricultural lands. These agricultural fields become unproductive due to excess of water and behave like marshy land and are waterlogged at times even if water is not pulled from these canals. The excessive wet lands are not conducive for agriculture.

This type of flood brings greater loss as this is relatively new phenomenon and people dependent on such lands are neither prepared nor equipped to deal with such a situation. In 1995, Banka district of Bihar turned into a wasteland due to opening of two reservoirs – Chandan and Orhni.

Governmental approach to construct embankments for the protection of settlement and agricultural lands has also deteriorated the situation in many parts of the country. Now, the approach is being modified. Such programmes are now being called flood protection programmes instead of flood control programme.

Thus, several new regions, e.g. in northeastern towns of Bihar, many new settlements have fallen in the trap of flood. Flood control measures have brought new dimensions in floods in India.

Notes on agricultural land use policy in India

Picture for representation. (Source: ITM University)

The National Land Use and Conservation Board is mainly concerned for the framing of national land use policy. And, agricultural land use policy is, in fact, the part of this policy. India’s first land use policy was declared in 1988 – titled, Prospective Plan for Conservation, Management and Development of Land Resource.

Within the policy, agricultural land use was emphasized under the following heads –

1.  The policy did not propose to increase acreage under agricultural land use. It was already 54 per cent including the fallow lands. So, the basic aim was to improve agricultural productivity of the existing agricultural land. More emphasis was given over the improvement of degrading agricultural lands and the fallow lands which were about 95 million hectare of agricultural land.

2.  Introduction of crop rotation. Crop rotation is essential to maintain the health of land resource. For example, for dry zones of India having no canal irrigation, cultivation of coarse grain or millets is suggested as the main crop. It is to be followed by gram or masoor (lentil) cropping. This crop rotation would maintain the nutrient level of the land. Rajasthan implemented such scheme at block level to maintain the crop rotation.

3.  Emphasis was given over to improve the intensity of crops in India.

4.  To work for diffusion of agricultural infrastructure for improving the productivity and efficiency of the agricultural land of India.

5.  Big landholders are now being persuaded not to leave thin lands unused. Land reform is taken as part of the agricultural land use policy. Landlords have not been using the land scientifically. Vast lands of the landlords remain unused creating land-degradation. Despite all these only three per cent of landlords have 20 per cent agricultural land and 59 per cent farmers have only 14 per cent of agricultural land. This is the cause of rural distress in India. In some parts of the country, this problem has taken the form of maoist violence or naxalism. It is emphasized to bring land reform in these areas.

6.  Levelling and bunding of degraded agricultural land. The programme was suggested for the Himalayan states, Madhya Pradesh, Rajasthan and South-West part of Uttar Pradesh.

7.  Land use development was suggested to be carried out on the basis of agro-climatic regionalization of India. India is divided into 15 agro-climatic regions. For every region, sustainable agricultural land use map was to be prepared at state and district level.

8.  Sustainable agricultural land development was emphasized where programmes like greater use of bio-fertilizers are promoted for green revolution belts of India including the command areas in particular, and agricultural land in general.

9.  Some other programme is watershed management programme under which land resource units of micro-level is to be developed on drainage lines.

10. National land use and conservation board has suggested the state governments to prepare micro-level watershed units and to take 5,000 hectare-size land as the standard unit for the purpose of development of land resource. Rajasthan was one state which framed policy in accordance with this suggestion.

11. Crop diversity is to be promoted in the tribal regions. Tribals have the tradition of crop-association and diversity. In such regions, economically viable association of crops was suggested to tribal farmers.

At the turn of the century, the then government brought some changes in the existing agricultural land use policy and now apart from target areas, target years were also fixed. Emphasis was given on economic and ecological management of land resource.

In 2013, a new land use policy was formulated.  The goal of the National Land Utilisation Policy was defined as to achieve improvement of livelihood, food and water security, and best possible realization of various developmental targets so as to ensure sustainable development of India. (Draft of Policy: http://dolr.nic.in/dolr/downloads/PDFs/Draft%20National%20Land%20Utilisation%20Policy%20(July%202013).pdf)

The specific objectives of the policy were set out as under:

Objectives related to social concerns

1. Protection of agricultural lands from land use conversions so as to ensure food security and to meet consumption needs of a growing population and to meet livelihood needs of the dependent population.

2. To identify and protect lands that are required to promote and support social development, particularly of tribal communities and poor section of society for their livelihood.

3. To preserve historic and cultural heritage by protecting, places/sites of religious, archaeological, scenic and tourist importance.

Objectives related to environmental concerns

4. To preserve and conserve lands under important environmental functions such as those declared as National Parks, Wild Life Sanctuaries, Reserved Forests, Eco Sensitive Zones, etc and guide land uses around such preserved and conserved areas so as not to have land use conflicts or negative environmental impacts.

5. To preserve the areas of natural environment and its resources that provide ecosystem services.

Objectives related to developmental/economic concerns

6. To promote properly guided and coordinated development in a sustainable manner of all developmental sectors including agriculture, urban, industrial, infrastructure and mining so as to minimise land use conflicts or negative environmental impacts.

Objectives related to enforcement and implementation of the policy

7. To suggest a general implementation framework for implementing land utilisation policy by all concerned at different levels, viz, national, state, regional and local, and undertaking capacity building.

The following six types of Land Utilisation Zones (LUZs) are to be identified on the basis of predominant land use:

a) Predominantly Rural and Agricultural Areas

b) Areas Under Transformation

c) Predominantly Urban Areas

d) Predominantly Industrial Areas

e) Predominantly Ecological Areas, Landscape Conservation and Tourism Areas. Heritage Areas

f) Major Hazard Vulnerable Areas

Besides, the “Land-use Management Areas” (LMAs) are to be identified within the identified Land Utilisation Zones, during the planning process, so as to ensure proper management of various land uses.

For the purpose of ensuring proper management of lands, the Land-use Management Zones are categorised into:

a) Protected Areas;

b) Regulatory Areas;

c) Reserved Areas; and

d) Guided Development Areas

The implementation and success of the agricultural land use policies depend on politico-administrative commitment, people’s participation and cooperation of NGOs.

How much you know about floods, explained here with pics

A flooded area in Bihar. (Photo credit: Facebook/WHO Bihar Region)

According to the Indian Meteorological Department (IMD), flood is a meteorological situation when water of a river begins to flow above the danger mark. The danger mark is fixed on the basis of average flow of the river over 25 to 50 years during monsoon period.

Drought is the situation, according to the IMD, having less than 5 cm rainfall for four continuous week any time between mid-May and mid-October. If the rainfall is less than 5 cm for any month (four continuous weeks), it is meteorological drought situation.

Flood prone areas are located practically in all parts of the country excluding the internal plateau regions. However, there has been varying tenure of flood and from that point of view, eastern India, northeastern India and eastern coastal plains are the worst affected areas as far as flood is concerned.

The IMD has divided flood into four tenures and affected geographical regions:

Six-week flood region: Assam valley

4-6-week flood region: Eastern Uttar Pradesh, Bihar plain, West Bengal and isolated plain areas of the Northeast – Loktak basin and Tripura basin.

1-4-week flood region: Eastern coastal plain, Punjab, western Uttar Pradesh, Delhi Union Territory, South Gujarat especially Narmada and Tapi basins, and Kashmir Valley.

Less than one-week flood region: Central and northern Gujarat, Rajasthan, Haryana and peripheral parts of peninsular plateau.

A bus plying on a flooded road in Bihar. (Photo credit: FB/Darbhanga Medical College)

There are some rivers, which are highly flood prone. Brahmaputra and Ganga cover about 60 per cent of flood prone areas of the country. Some flood prone rivers are Teesta, Kapoli (a tributary of Brahmaputra), Dihang and Burhi Dihang (known for flash floods).

In the Ganga system of the Himalayan rivers, the main flood causing rivers are, Mahananda, Kosi, Gandak, Burhi Gandak, Kamla Balan, Saryu, Ghaghra, Gomati, Ramganga and Yamuna. Kosi was once called the sorrow of Bihar

In the peninsular India, the main flood causing rivers are, Son, Punpun, Ajay and Damodar, which was known as the sorrow of West Bengal once. At present, both Kosi and Damodar rivers have been managed and controlled to some extent but others continue to play the same role.

Among the East Coast river, Mahanadi, Godawari, Krishna, Cauvery and Brahmi are highly flood prone. Among west flowing peninsular rivers, Tapi and Sabarmati are highly flood prone. 

(Photo credit: FB/Ashish Jha)

In the Punjab plains, Sutlej and Beas are highly flood prone while in Haryana Ghaggar and Yamuna bring floods. The Jhelum is flood prone in the Kashmir Valley.

Besides these rivers, there are several short-distance rives, which flow on high slope and create flash flood during monsoon season.

Total area under flood-prone category, according to the Seventh Five-Year Plan papers is 320 lakh hectares where flood happens every year. Total flood-affected area is 2.42 crore hectares where flood occurs but not every year.

Causes of flood:

Flood is the manifestation of many geographical factors and, to many geographers and geologists it has become an ecological factor. This does mean that flood is bound to come in this part of the world every year. It is a flood-ecology region.

Factors:

1. Erratic behaviour of monsoon – Sometimes the catchment area receives very high rainfall and then flood arrives. In the western India – Rajasthan, Gujarat and Haryana –torrential rain brings sudden outburst of rain which leads to flashfloods. In contrast, in the North-East, even the regular rainfall brings heavy rainfall and that is responsible for flood situation in the region.

2. Geomorphology – Flood occurs due to geomorphological profile of central plain of India. Brahmaputra Valley is a narrow ramp valley. Similarly, the Ganga basin is sandwiched between the Himalayas and the peninsular plateaus. Both river valleys are bordered by steep rising slopes while the plains are among the flattest ones in the world. 

This topographical feature brings rapid run-off from the catchment areas while the run-off in the plain moves at a slow speed. Consequently, these river basins overflow bringing flood over large areas during monsoon season. 

Flood in Siliguri, West Bengal. (Photo credit: FB/Naresh Kumar)

3. Deforestation – Deforestation in the Siwalik Himalaya has increased the volume of the run-off and therefore frequency and tenure of floods in many of Himalayan rivers. Several peninsular rivers including small ones have become flood prone in recent years due to loss of trees in the past few decades, e.g. Ajay river has become flood-prone due to deforestation in the catchment area. 

Jhelum was not flood-prone earlier. Mahananda was not so acute in bring floods. But at present all these rivers bring flood almost every year and that is related to deforestation. Several plateau districts of Jharkhand and Madhya Pradesh have fallen under flood due to deforestation and rapid run-off in these areas.

4. Soil Erosion and Siltation – These are responsible for increased flood-frequency mainly in the central plain of the country. According to the UNEP, River Kosi is the second-most affected siltation affected river in the world, only after Hwang-ho of China. 

Bed siltation occurs due to soil erosion in the catchment area and the deposition of silt in the plains owing to rivers’ inability to carry the load any further. It makes the valley shallow and whenever there is voluminous flow of water, it brings flood and water spreads in the surrounding areas.

5. Drainage Pattern – It is responsible for the flood in the central plain. Most of the rivers make meandering courses. So, overflow brings waters of different rivers close and vast areas, thus, get inundated. 

Punjab does not witness spread of water because of parallel, man-made, drainage of rivers. Although, the rivers often flow over danger mark during flood season but water does not spread. In Punjab, the doab line is always free from flood due to parallel pattern of drainage but the meandering courses of rivers in Bihar and Uttar Pradesh, and braided courses in all delta regions create floods.

Most of the rivers have wide V-shaped valleys. So, the depth of the valley is not great and any increase in the volume of water leads to overflowing and inundation of the neighbouring areas. 

Again some of the rivers have created natural levee which protects one side of the valley from flooding but the other bank is flooded and cause flood over low lying areas adjacent to that bank. Bihar plain is noted for this type of flood. Western banks of rivers in Darbhanga have natural levee.

In the central Bihar, there is also flood due to overflow of the main consequent river. Its overflow prevents the inflow of tributary water channels. In fact, the water of the main river, Ganga, begins to enter the course of the tributaries and the tributaries’ water is pushed back and water spreads over vast areas, e.g. Tal area flood in South Bihar and Jharkhand, Chaur area flood in West Bihar and West Bengal. Chaurs are the floodplains situated in the abandoned courses of rivers. They form ox-bow lakes during floods.

6. Shifting Course of Rivers – Such flooding is mainly important in regions where river have a history of shifting their course. Rivers like Kosi, Teesta, Gomati and Mahananda are facing this problem. Kosi is now believed to have settled in its course but others are still active. All these rivers have westward shifting courses. 

Flood in Darbhanga. (Photo credit: FB/Pankaj Mishra)

These rivers have a tendency to migrate to west. Hence, the west banks of these rivers are constantly being eroded and the east bank extends to a huge low lying floodplain. These rivers cause phenomenal spread of water beyond eastern banks onto the vast plain

Rotation of the earth is held indirectly responsible for the westward shifting of these rivers and the associated floodplains. Rotational impact brings westward shift of rivers. The eastern banks become low lying and vulnerable to floods.

Eastern coastal plains receive floods not simply due to deforestation and rapid run-off but also because of cyclonic rainfall and greater havoc is caused by the combination of these factors. If there is high tide situation along with cyclone, rainfall causes great damage. 

Cyclone brings rainfall and high tide water on the coastal plains as well as increases the velocity of the sea waves. Tidal water enters the mouth of the rivers pushing back the river water. The water level of the river increases. The river goes in a spate. 

The flow of the river is reversed and low lying floodplain is taken over by the floodwater. Such tidal flooding is seen in the Mahanadi and the Godawari. 

Floodwater enters Rampatty village of Darbhanga, Bihar. (Photo credit: FB/Mukul Choudhary)

Western coastal rivers generally receive flash floods. The duration of such floods is about one week. The situation mainly occurs due to deforestation along the Western Ghats. Loss of vegetation means less obstruction to run-off. 

Rapid run-off leads to greater water volume in the river valleys than the channel is capable of carrying off to the sea. This pushes the water level up in the river valleys leading overflow and inundation in the neighbouring areas.

7. Human Factors – Floods are also caused by human factors. Ironically, flood control programmes and some other developmental programmes have indirectly contributed in greater spreading of flood. Although, multi-purpose vally projects and other power generation projects have controlled floods in the basins of some of the rivers and regions. But the problem has emerged in a different way. 

Due to siltation on the beds, the reservoirs’ capacity has reduced and whenever excess water is released from that reservoir through canals and other outlets, flood is caused. Flood water even enters the areas where flood had never come previously. 

Flood-prone regions face massive water-logging problems during rainy season. This is a scene of water-logging at Darbhanga, Bihar on a rainy day. (Photo credit: FB/Er Jitendra Kumar)

The canals also face siltation problems, which get compounded by the seepage of river water from the sides of the canals into neighbouring agricultural lands. These agricultural fields become unproductive due to excess of water and behave like marshy land and are waterlogged at times even if water is not pulled from these canals. The excessive wet lands are not conducive for agriculture. 

This type of flood brings greater loss as this is relatively new phenomenon and people dependent on such lands are neither prepared nor equipped to deal with such a situation. In 1995, Banka district of Bihar turned into a wasteland due to opening of two reservoirs – Chandan and Orhni.

Governmental approach to construct embankments for the protection of settlement and agricultural lands has also deteriorated the situation in many parts of the country. Now, the approach is being modified. Such programmes are now being called flood protection programmes instead of flood control programme.

Thus, several new regions, e.g. in northeastern towns of Bihar, many new settlements have fallen in the trap of flood. Flood control measures have brought new dimensions in floods in India.

Soils of India: Basic characteristics and their expanse

Topmost layer of the continental crust is called soil. It is made up of weathered particles, clay minerals, air, humus, water and micro-organisms. These constituents are present in soils in different composition and proportion due to varying environmental conditions. The composition of soil has been the basis of classification of soils.

According to the Indian Council of Agricultural Research (ICAR), Indian soils are of eight types. This classification was put forth in 1956 on the basis of the All India Soil Survey Committee set up by the ICAR in 1953. The classification is based on three factors:

-          Geological structure of soil

-          Components of soil

-          Colour of soil

The eight types of soils are as follows:

1.       Alluvial

2.       Red

3.       Black

4.       Laterite

5.       Forest soil

6.       Saline or alkaline 

7.       Desert soil

8.       Peat or organic soil

Alluvial and peat soils are azonal (separated from their region of origin) soils of India. Peat and saline soils are intra-zonal soils. The rest are zonal soils. Here, primary minerals have become secondary minerals. Magnetite is the primary mineral but it has become limonite, the secondary mineral.

Alluvial soil covers 24 per cent of land of India. In area, this soil is spread over 7.7 lakh sq km. It is a deposited soil caused by rivers. There are four main regions of alluvial deposition in India. These are:

-    Central plain: this plain is extended from Indo-Pakistan border to Dimapur district of Nagaland. Dimapur is the only plain district of Nagaland. It is spread over from the Siwalik foothills in the north to upto 500 feet contour lines in south India.

-          Coastal plain: The demarcation line between river plain and coastal plain is 500 feet contour lines.

-          Older alluvial plain in the western Rajasthan districts of Ganganagar and Bikaner.

-          Inter-mountain alluvium: this type of soil is found in Kashmir, Kangra and Doon valleys.

Alluvial deposits of central India are divided into three types and each has regional name. These are Khadar, Bangar and Bhabar.

Khadar is Holocene alluvial deposits. It is characterised by very fine clay deposits,mainly found in the flop prone valleys. Eastern Uttar Pradesh, Bihar plain, almost all non-delta plain of West Bengal, lower Brahmaputra valley, flood prone areas of eastern coastal plain and lower valleys of Tapi and Narmada.

Bangar is an old alluvium. It is a loamy soil. It is found in northwest plain, Rajasthan and western Uttar Pradesh. Bangar is also found in Rajasthan and southern Punjab, where it is sandy loam soil. In western Uttar Pradesh, clayey loam soil is found.  Here silt and clay are dominant.

Water body inside Ranthambore National Park at Sawai Madhopur in Rajasthan. (Photo: Prabhash K Dutta)

Bangar is also called doab soil. It was deposited during Pleistocene and early Holocene periods. Similar soil is found in the upper Brahmaputra valley, Gujarat and upper plain of coastal regions.

Bhabar is terai soil. Greater content of sand and silt is found in Bhabar soil. Similar soil is found in inter-mountain valley. It is a soil known for coarse texture. They are just off alluvial fan, downwards.

Constitutional character of Indian soils: Indian alluvial soil is deficient in nitrogen and humus. But lime and potash content is adequate in alluvial soil. Lime content is very favourable in terai. Significant phenomenon with alluvial soil is presence of finer grains which make a region flat plain.

Alluvial soil is suitable for most of the crops. However, Khadar is more suitable for rice and jute crops. Terai soil is suitable for sugarcane while Bangar is favourable for those crops which depend on soil moisture like wheat, sugarcane, oil seeds and pulses.

In the inter-mountainous valley (intermontane), the soil is very suitable for sugarcane like in Doon valley and for paddy in other valleys like Kashmir and Kangra’s where clay is the dominant constituent.

In plateau India, three more types of alluvium are found. These are called red alluvium – in Cauvery and Vagai valleys, black alluvium – Wainganga, Wardha, Narmada and Tapi valleys, and laterite alluvium – found in Kerala coastal areas and Santhal Pargana region of Jharkhand.

The colour of red soil comes from the parental rocks. As the parental rocks weather, particles dominating the rocks spread and give the red alluvium its colour. Red alluvium is suitable for paddy but due to low rainfall coarse grains are raised in Cauvery and Vagai basins. In blck alluvium region paddy and cotton are raised. Laterite alluvium is commonly used for paddy culture.

Red soil:

It has the second largest acreage in India. Its acreage is about 5.2 lakh sq km. basically, it is the soil of archean  plateau region of the country. Pre-Cambrian structure are either igneous or the gneiss and schist. They have greater content of iron which is greater in metamorphosed granite. Due to the presence of iron ore, the weathered and loosened particles have gained the red colour.

Tamil Nadu has the largest acreage of red soil in India. About two-third of Tamil Nadu is covered by red soil including red alluvium. Other areas of red soil are, Travencore Hills of Kerala, Karnataka plateau excluding a ribbon shaped area located between Bangalore and Mysore, Rayalseema and Dandakaranya plateau area of Andhra Pradesh, Ratnagiri and Bhanda region near Nagpur in Maharashtra, patches in Kutch, Eastern Rajasthan and Aravalis, Durg and Bastar in Chhattisgarh, Balaghat and Gwalior in Madhya Pradesh, Jhansi and Lalitpur in Uttar Pradesh, Dharawar rocks of Jharkhand, Singhbhum and northern plateau of Odisha, plateau region on West Bengal, patches in Meghalaya and Nagaland.

It has low moisture retaining capacity. Its humus content is moderate. It is deficient in nitrogen and phosphorous. It has adequate to excessive iron and moderate lime content. On the whole the red soil is not very favourable for agricultural activities. Only rainy season is cultivable.

Dry forest vegetation inside the Ranthambore National Park. (Photo: Prabhash K Dutta)

Red soil regions don’t have much prospect of irrigation because the basement rock is granite. So, the ground water table is very deep. Due to low humus after two-three years of agriculture or cultivation, there is a sudden deterioration in land’s capability. By providing external inputs, its capability can be maintained.

With inputs and irrigation facilities, coffee is cultivated on red soil in Chikmagalur district of Karnataka. Even rubber plantation has been successful here. The same experiment was replicated in Chitradurga and Karwar of Karnataka. Kaiga nuclear power plant is located near Karwar in Uttara Kannada district.

Chitradurga is famous for manganese ore while Coorg is known for rubber and coffee plantation.

Black soil: 

It is also called Regur in Maharashtra and Gujarat. India has the largest acreage of black soil in the world. Total area under black soil in India is 5.18 lakh square kilometres.

Black soil came into existence due to fissure eruption of lava. It attained its present shape and texture due to weathering and decay of basaltic structure.

Largest acreage of black soil is found in Maharashtra in continuity with some patches in eastern Gujarat, where black alluvial soil is dominant. Other areas under black soil include Malwa plateau of Madhya Pradesh, an elongated stretch from Satpura and Panchmahal in Gujarat to Hoshangabad in Madhya Pradesh, patches on the Pat plateau and Rajmahal hills in Jharkhand and adjoining areas of Bihar and West Bengal, Telangana plateau, ribbon-shaped plateau of Karnataka between Bangalore and Mysore, Coimbatore-Madurai uplands in Tamil Nadu and patches on Meghalaya plateau.

On the basis of thickness and structural characteristics, black soil is divided into four types:

Deep black

Medium black

Light black

Alluvial black

Deep black soil is found in the west central Maharashtra. It is also found in Pune and Miraj districts. Miraj is in south Maharashtra. Here is the thickness is greater compared to other types of black soil. Thickness gives deep black colour to the soil. This is also found in Telangana region, which also has greater thickness of soil. Though the deep black soil is suited for agricultural activities, these regions don’t have intense cultivation due to low rainfall. Both in Maharashtra and Telangana, the deep black soil regions are drought prone areas.

Medium black soil is found over Malwa plateau, in Karnataka’s black soil regions, central Maharashtra and Satpura regions of Gujarat and Madhya Pradesh.

Light black soil is found in Gujarat, eastern Maharashtra, Coimbatore-Madurai uplands of Tamil Nadu. Some of the most isolated areas in peninsular India too have light black soil. It is not much thick giving the light colour to the soil. The productivity of black soil varies according to thickness – more the thickness, more productivity soil has.

A lion sleeping inside Delhi zoo. (Photo: Prabhash K Dutta)

Alluvial black soil is a fertile soil. When the constituent particles are considered, alluvial black soil has adequate lime, potash and iron. But, it is low in humus. Water retaining capacity is high. Top structure of soil is coarse. The coarseness of top soil attributed to dryness in the upper layers. The bottom of the black alluvial soil has clay and silt, which improve moisture retaining capacity.

Black soil is very suitable for dry-land farming. Cotton is the main crop. After 1960, sugarcane has also emerged as the major crop on black soil. Sugarcane requires more moisture. Consequently, tube-well irrigation has developed in peninsular India. 

In fact, there has been massive exploitation of ground water especially in Maharashtra, where sharp deterioration of ground water level has been found. This trend has adverse impact on not only the capability of black soil but the ecology and the humans also.

Laterite soil:

It is found in the laterite structure region of India with a total area of 2.5 lakh sq km. it is found in Western Ghats, Anaimalai and Cardamom Hills, laterite plateau in Kerala – which has maximum acreage of laterite soil in India and about two-third of Kerala is covered with laterite soil, Eastern Ghats with Odisha having the second largest acreage of laterite soil, laterite structure of Karnataka particularly in Belgaum district of the state, patches of similar soil in northern Tamil Nadu, Pat plateau of Jharkhand, and also in Meghalaya plateau region.

Laterite soil consists of mixture of hydrated oxides of aluminium and iron. Iron oxides are generally present in nodular form making laterite gravelly soil. Laterite soil is poor in nitrogen, phosphoric acid, potash and lime. It has adequate iron and aluminium but they don’t make the soil fertile. Humus is not adequate in laterite soil. Consequently, it is not a favourable soil for agriculture.

However, due to presence of gravelly alluvium, laterite soil has become favourable for crops like groundnut. India’s most of the groundnuts are cultivated on laterite soil, which is also suitable for coffee and spices in high or moderate rainfall regions. Kerala is famous for spices grown on its laterite and forest soils.

Tribes living in Western Ghats, Odisha, Jharkhand and adjoining areas of Bihar grow coarse grains on this soil. Laterite soil needs adequate external inputs of potash, nitrogen and phosphorous in 4:2: proportion to make it suitable for cultivation. Also required is adequate and proper irrigation. So, though its capability is low but productivity of the laterite soil can be high with quality inputs.

Forest soil:

It is also known as forest and mountain soil of India. This type of soil is internationally classified as mountain soil. Its acreage in India is about 2 lakh sq km.

It is found on the mountain slopes. It has thin layer of soil due to mountain slope. It has coarse structure. Clay, sand and even weathered drop particles are mixed in this type of soil. It has adequate humus. O1 layer is very rich. It is favourable for cultivation of those crops which do not need greater penetration of roots.

The favourable factor with this soil is its air and water drainage. This factor favours plantation cropping. India’s most of Jhoom Farming is carried out on forest soil which is an unscientific practice. 

What is needed is to develop such land under plantation, food-grain and vegetation farming.

Three important crops are grown on forest soil in northern India – tea, apples and pineapples. In south India, tea and rubber are cultivated. Nilgiri is famous for tea, Anaimalai for rubber plantation and Cardamom slopes for spices.

Such soil is found on the slopes at an altitude of 500m – 3,000m. Entire Siwalik Himalaya is characterised by forest soil. Northeast India too is covered with forest soil. Greater and Lesser Himalayas don’t have forest soil.

A view of Carmona Zalor beach of Goa. (Photo: Prabhash K Dutta)

Saline soil:

It is also known as saline and alkali soil. Its acreage in India is about 1.4 lakh sq km. it has mainly developed in the inland basins of the country. Patches is found in different parts of Rajasthan, western Gujarat, southern Haryana, southwest Uttar Pradesh (in trans-Yamuna tract in Mathura and Agra).

Saline soil emerges due to capillary action of the soil in which salt comes onto the top layer of soil. It is mostly alluvial having dominance of sand and clay. It is region of Bolson and Playa.

Alkali soil has greater accumulation of sodium chloride. This is particularly evident in southern Haryana and southwest Uttar Pradesh and in some parts of Bihar. In Uttar Pradesh and Bihar such soil is called Usar. No agriculture is possible on Usar soil.

In Rajasthan and Uttar Pradesh, the soil’s quality is improved by giving adequate water. Proper watering of alkali soil dissolves salts present in the top soil forcing it to move downwards. With this, the humus containing soil becomes favourable for agriculture. Short duration crops are possible on alkali soil such nurtured.

The Rajasthan Agricultural Marketing Board experimented with such soils with good effect. Areas with alkali soil are producing fruits, flowers and also have some vegetation. Another way of improving this soil is to develop water drainage through it. 

This ensures that the landform is not subjected to intense evapo-transpiration and thus retains some moisture. There is no need for digging up canals through the region. Drip irrigation can be used to grow flowers and fruits.

Desert soil: 

It is mainly found in western Rajasthan and the Rann of Kutch. Total area under desert soil in India is about 1 lakh sq km.

It is basically a sandy soil. It has excess salt content. Suspended salt and solid particles are in ample quantity in desert soil. Clay is scarce. Consequently, the soil is not suitable for agriculture. Northern part of the desert of India in Ganganagar, Bikaner, Kishangarh and some parts of Barmer districts of Rajasthan has adequacy of clay. Humus is also available there along with phosphorous.

Thus, the northern part of desert has some compositional property of fertility. The real problem in this region is the shortage of surface moisture. Horizon B provides adequate moisture due to which it is a region of shrubs. Development of irrigation with Indira Gandhi canal has proven the importance of this soil in India. Similar characters are found in Kalahari desert and Arabian desert but not in Sahara or Australian desert.

Peat/Organic soil:

It is also named Peaty and Marshy soil. Its acreage in India is about 1 lakh sq km. It is also known as delta soil. But, it is not found in all delta regions of the country. It is found in those delta regions only which are submerged during high tide.

Deltas formed by Ganga, Mahanadi, Brahmi, Godawari and some parts of Krishna delta have peat soil. Cauvery delta does not have much peat soil. In some parts, it  is also called mangrove delta soil.

It is the region of clay and mud. It has suspended solids of salts and excess of moisture. 

A tiger taking rest at Bannerghatta National Park in Bengaluru. (Photo: Prabhash K Dutta)

Due to excessive moisture content and salt, the region has not been conducive for bacterial activities that are essential to decompose organic components of the soil. The soil carries wooden pieces, skeletons of plants, dead organic tissues and the like.

Owing to lack of decomposition of dead organic materials, it has no humus. No nitrogen content is present in the soil. Excessive moisture and salt have made it infertile type of soil. Only hydrophytes which have tolerance for salts grow in these regions.

Peat soil regions can be, however, developed for coconut plantation farming. Only problem is that coconut plantation needs much more content of sand in soil while peat has more clay than sand.