Here is a compilation of essays on ‘Irrigation in India’ for class 6, 7, 8, 9, 10, 11 and 12. Find paragraphs, long and short essays on ‘Irrigation in India’ especially written for school and college students.
Essay on Irrigation in India
Essay Contents:
- Essay on the History of Irrigation
- Essay on the Meaning of Irrigation
- Essay on the Advantages of Irrigation
- Essay on the Disadvantages of Irrigation
- Essay on the Importance of Irrigation
- Essay on the Methods of Irrigation in India
- Essay on the Purpose of Irrigation
- Essay on Reasons for Practicing Irrigation
- Essay on the Role of Irrigation in India
- Essay on the Potential and Utilisation of Irrigation
- Essay on the Adverse Effects of Irrigation
- Essay on the Present Status of Irrigation in India
Essay # 1. History of Irrigation:
Irrigation was invented in Sumer, now known as Iraq, probably around 5,500 BC by the ancient Sumerians. They invented the irrigation systems because they needed a system that could control the water necessary for domestic use and for saving the crops at times of drought.
Ancient civilisations flourished in the valleys of great rivers – Nile valley of Egypt, Tigris-Euphrates valley of Mesopotamia, Indus valley of India and Pakistan and Huang He valley of China. All these civilisations were built up of large irrigation systems, made the land productive and prospered. Civilisations crumbled when water supplies failed or were poorly managed.
Global Scenario:
Archaeological investigation has identified evidence of irrigating barley crop in Mesopotamia, Egypt and Iran as far back as the 6th millennium BC. In the Zana Valley of the Andes Mountains in Peru, archaeologists found remains of three irrigation canals radiocarbon dated from the 4th millennium BC, the 3rd millennium BC and the 9th century BC.
These canals are the earliest record of irrigation in the New World. Sophisticated irrigation and storage systems were developed by the Indus Valley Civilisation in Pakistan and north India, including the reservoirs at Girnar in 3000 BC and an early canal irrigation system from Circa in 2600 BC. Large scale agriculture was practiced and an extensive network of canals was used for the purpose of irrigation.
There is evidence of the ancient Egyptian Pharaoh Amenemhet III in the twelfth dynasty (about 1800 BC) using the natural lake of the Faiyum Oasis as a reservoir to store surpluses of water for use during the dry seasons, as the lake swelled annually as caused by the annual flooding of the Nile.
The Qanats, developed in ancient Persia in about 800 BC, are among the oldest known irrigation methods still in use today. They are now found in Asia, the Middle East and north Africa. The system comprises a network of vertical wells and gently sloping tunnels driven into the sides of cliffs and steep hills to tap groundwater.
The noria, a water wheel with clay pots around the rim powered by the flow of the stream (or by animals where the water source was still), was first brought into use at about this time, by Roman settlers in North Africa. By 150 BC, the pots were fitted with valves to allow smoother filling as they were forced into the water.
The irrigation works of ancient Sri Lanka, the earliest dating from about 300 BC, in the reign of King Pandukabhaya and under continuous development for the next thousand years, were one of the most complex irrigation systems of the ancient world. In addition to underground canals, the Sinhalese were the first to build completely artificial reservoirs to store water.
Due to their engineering superiority in this sector, they were often called ‘masters of irrigation’. Most of these irrigation systems still exist undamaged up to now, in Anuradhapura and Polonnaruwa, because of the advanced and precise engineering. The system was extensively restored and further extended during the reign of King Parakrama Bahu (1153 – 1186 CE).
The oldest known hydraulic engineers of China were Sunshu Ao (6th century BC) of the Spring and Autumn Period and Ximen Bao (5th century BC) of the Warring States period, both of whom worked on large irrigation projects. In the Szechwan region belonging to the State of Qin of ancient China, the Dujiangyan Irrigation System was built in 256 BC to irrigate an enormous area of farmland that today still supplies water.
By the 2nd century AD, during the Han Dynasty, the Chinese also used chain pumps that lifted water from lower elevation to higher elevation. These were powered by manual foot pedal, hydraulic waterwheels or rotating mechanical wheels pulled by oxen. Water was used for public works of providing water for urban residential quarters and palace gardens, but mostly for irrigation of farmland canals and channels in the fields.
In fifteenth century Korea the world’s first water gauge, uryanggye (Korean), was discovered in 1441 CE. The inventor was Jang Yeong-sil, a Korean engineer of the Joseon Dynasty, under the active direction of the king, Sejong the Great.
It was installed in irrigation tanks as part of a nationwide system to measure and collect rainfall for agricultural applications. With this instrument, planners and farmers could make better use of the information gathered in the survey.
India Scenario:
The history of irrigation development in India can be traced back to prehistoric times. Vedas and ancient Indian scriptures made references to wells, canals, tanks and dams which were beneficial to the community. Civilisation flourished on the banks of the rivers and harnessed the water for sustenance of life. According to the ancient Indian writers, the digging of a tank or well was amongst the greatest of the meritorious acts of a man.
There is evidence of the practice of irrigation since the establishment of settled agriculture during the Indus Valley Civilization (2500 BC). These irrigation technologies were in the form of small and minor works, which could be operated by small households to irrigate small patches of land and did not require cooperative effort. Nearly, all these irrigation technologies still exist in India with little technological change and continue to be used by independent households for small holdings.
The following water lifts which are still in use in remote places of south India clearly indicates the efforts of small farmers for augmenting their farm production through irrigation.
Swing basket:
It is a simple, but very energetic method of water lift for irrigation. Bamboo stakes are slit into long thin blades and used for making the swing basket. Metallic baskets are also in use. On an average it can lift around 15 to 20 liters (l) of water for each swing from around 2 meters (m) depth. Two persons are required to operate it with two pairs of ropes (Fig 1.1).
Depending on the depth from which water is lifted, around 0.25 ha can be irrigated in a day. If necessary these devices can be arranged in series to irrigate relatively larger area. Even now it is in use in remote villages of Tamil Nadu, Andhra Pradesh, Karnataka and Kerala.
Picottah:
It is identical to the Egyptian shaduf. A bucket (or iron bowl) of about 10 l capacity drops down to the water in a shallow well. Two persons, one to handle the beam up and down from ground level to water source and another to fill and empty it to the channel at ground level, can operate it.
Raising it is made easier by the counterweight at the end of the balance beam (Fig 1.2). On an average it can lift around 15 to 20 l of water for each operation from around 2 m depth to irrigate about 0.25 ha in a day. If necessary these devices can be arranged in series to irrigate relatively larger area. Even now, it is in use in Tamil Nadu, Kerala and parts of Andhra Pradesh.
Mhot:
It is used for lifting water from deep water sources like deep open wells around 15 m deep. It consists of a water lifting container, leather or galvanised iron, of about 50 to 75 liters capacity attached to a flexible leather or rubber tubing for delivering the water into an irrigation water ditch (Fig 1.3).
Water lifting container is drawn out of the well by a pair of animals guided by a person. It can irrigate about 0.5 ha per day. For irrigating larger area, double mhot is used. In double mhot, while a pair of animals is drawing water from the well, the other pair walks up the ramp to lift water form the well. Two persons are required for operating a double mhot. It can irrigate around 1.0 ha per day. Even now it is in operation in remote villages of Tamil Nadu, Andhra Pradesh, Karnataka and Kerala.
Persian wheel:
A bullock or a pair of bullocks goes around in circles, turning a shaft connected through a spur gear to another shaft controlling the bucket line in the background (Fig 1.4). The buckets, each around 10 l capacity, descend to water in a dug well of 3 to 4 m depth. They spill into the ditch in the upper left. It can irrigate around 0.5 ha in a day. The Persian wheel is in use in the Ganges plain, Tamil Nadu and Karnataka even now.
While village communities and cooperation in agriculture did exist as seen in well-developed townships and economy, such cooperation in the large irrigation works was not needed, as these settlements were on the fertile and well-irrigated Indus basin.
The spread of agricultural settlements to less fertile and irrigated area led to cooperation in irrigation development and the emergence of larger irrigation works in the form of reservoirs and small canals. While the construction of small schemes was well within the capability of village communities, large irrigation works were to emerge only with the growth of states, empires and the intervention of the rulers.
In the south, perennial irrigation may have begun with construction of the Grand Anicut by the Cholas as early as second century to provide irrigation from the Cauvery river. Wherever the topography and terrain permitted, it was an old practice in the region to impound the surface drainage water in tanks or reservoirs by throwing across an earthen dam with a surplus weir, where necessary, to take off excess water and a sluice at a suitable level to irrigate the land below.
The entire landscape in the central and southern India is studded with numerous irrigation tanks which have been traced back to many centuries before the beginning of the Christian era. In northern India also, there are a number of small canals in the upper valleys of rivers which are very old.
Essay # 2. Meaning of Irrigation:
Irrigation is defined as artificial application of water for the purpose of supplying moisture essential to plant growth.
They further stated that irrigation also serves other purposes:
1. To add water to the soil for supplying the moisture essential for plant growth
2. To provide crop insurance against short duration drought
3. To cool the soil atmosphere, thereby making more favourable environment for plant growth
4. To washout or dilute salts in the soil
5. To reduce the hazards of soil piping
6. To soften the tillage pans.
Other definitions of irrigation include:
1. Irrigation is defined as artificial application of water to the land, in accordance with the crop needs during the crop period.
2. Irrigation is artificial exploitation and distribution of water at project level aiming at application of water at field level to agricultural crops in dry areas or in periods of scarce rainfall to assure or improve crop production.
3. Irrigation is artificial abstraction of water from a source followed by its distribution at scheme level aiming at application at field level to enhance crop production when rainfall is scarce to meet the crop needs for optimum growth and development.
4. Irrigation is the supply of water to agricultural crops by artificial means, designed to permit farming in arid regions and to offset drought in semiarid or sub-humid regions.
Essay # 3. Advantages of Irrigation:
1. Irrigation plays a key role in increasing food production to feed the expanding population
2. Irrigation can ensure a stable production in traditional dryland farming systems, subjected to frequent vagaries of rainfall
3. Irrigation can prolong the effective crop growing period in areas with dry seasons, thus permitting multiple cropping and employment generation
4. With the security of cropping under irrigation, additional inputs (tillage, fertilisers, plant protection etc.) become economically feasible
5. Irrigation reduces the risk of expensive inputs being wasted by drought.
Essay # 4. Disadvantages of Irrigation:
Excess irrigation causes several changes in the soil and plant resulting in reduced growth and in some cases death of plants.
1. Adverse effect on seed germination, as waterlogging limits oxygen supply to germinating seed
2. Reduction in crop yield due to low oxygen supply and accumulation of toxic substances in soil and plant
3. Leaching loss of nitrate nitrogen
4. Reduced microbial activity, affecting nutrient transformations and availability
5. Excess irrigation leads to shoot elongation, senescence and abscission
6. Decrease in water and nutrient uptake leading to poor yield of several crops.
Provision of one or two irrigations at times of prolonged drought to save dryland crops is referred to as supplemental irrigation or lifesaving irrigation. Irrigation projects are designed, keeping in view the expenditure likely to be incurred and the benefits likely to occur. There is hardly any point in emphasising the importance and advantages of irrigation.
Essay # 5. Importance of Irrigation:
A liter of water produces about a kilocalorie of food. South Asia (2,500 kcal) and Saharan Africa (2,200 kcal) lie below the 2,800 kcal food security threshold. They need substantial increases in water supply even to achieve security. No wonder world rice, wheat and pulses prices are set to rise by around 40 per cent.
It is estimated that irrigation contributed 60 per cent to the growth in agricultural productivity. Irrigation can make a significant contribution towards reducing poverty and hunger. According to FAO, irrigated agriculture provides 40 per cent of world food production.
Around 66 per cent of the extra required to sustain a world population of about eight billion by 2025 must come from irrigated agriculture. The fact is that the demand for quality water is raising and its availability continuously dwindling, stressing the importance of irrigation in agricultural productivity.
For more than 70 per cent Indian population, living in rural area and dependent on agriculture directly or indirectly, monsoon controlled their purchasing power year after year. Even now, when agriculture contributes less than 20 per cent to the national economy, more than 600 million (M) people are dependent on agriculture for their livelihood.
Therefore, irrigation infrastructure, which has the potential to insure the farmer against vagaries of monsoon and increase his income from the small (and diminishing) land holding, is the most critical infrastructure for rural India. Immense benefits of irrigation have been well established. Increased food security of the country, increased agricultural income in irrigated are as the success of green revolution, are all linked to timely availability of water for crops not dependent on rainfall alone.
In terms of food security in India, the 35 per cent irrigated area provides more than 60 per cent of the food production. Studies show that at village level, irrigation provides higher and more stable employment and the poor are the major beneficiaries. In fact, the contribution of irrigation to employment is greater than even high yielding varieties.
Studies show that there is an increase in number of days work required per ha with irrigation compared rainfed condition ranging from 60 per cent to more than 150 per cent. The increase in value and income which irrigation provides can also be judged by two other indicators – increase in land prices after a rainfed area got access to irrigation and the large private investments made by individual farmers in groundwater irrigation.
Irrigation multiplier is estimated to be 4.5 (returns per ha per season) and 3.15 (returns per ha per year). In earlier case, the farmers’ share of the total marginal benefits of irrigation to the society is between 22 and 32 per cent. This means that the economy-wide benefits of irrigation are much higher than what a farmer gets in terms of increased crop output in a crop season or year.
However, it should be noted that while there is strong correlation between increased irrigation and reduction in poverty in India, the ultimate impact of irrigation on reduction in poverty depends on other factors such as the structure of agricultural production, rural institution, the consumption feedback and labour mobility.
It appears that around 40 per cent of the beneficiaries with major irrigation (large dams) are small and marginal farmers. Large farmers form only 12 per cent of the command area of the major irrigation schemes. In addition, increased income of labourers who are not direct beneficiaries of the irrigation system is substantial.
Besides, with the increase in number of working days, the wage rate is also likely to increase when there is provision for irrigation. These are great benefits, especially, for the landless who have to migrate every year to urban areas to get employment during the non-monsoon period leading to fragmentation of the families. Groundwater based irrigation largely has the same benefits as surface irrigation. However, groundwater brings greater benefits for small and marginal farmers.
Essay # 6. Methods of Irrigation in India:
The manner in which irrigation water is applied to the land is commonly referred to as method of irrigation. Scientific irrigation aims at efficient use of irrigation water in conjunction with other essential inputs to enhance and sustain crop production. Several irrigation methods are adapted towards this end under different set of circumstances.
Selection of appropriate irrigation method for any given combination of physical and socio-economic conditions involves numerous complex and often conflicting considerations. Since the economic considerations, along with physical conditions and cropping pattern are necessarily specific to each location, an irrigation system optimal in a particular region may not be so in another.
Applicability of a particular irrigation method depends on several physical, human and economic factors. Important physical factors associated with selection of irrigation method include soils, crops, climate, topography, water quality and availability, depth of water table, field size, maintenance and repairs.
Human and economic factors involved are labour and management skills, availability and cost, capital and energy costs in relation to expected returns. All these factors cannot be defined or weighed quantitatively in each case. As such, decision as to which method to select rests on personal judgment and subjective preference rather than on completely objective analysis.
There are three main ways of applying irrigation water:
(1) Run the water over the soil surface and allow it to infiltrate, a method known as surface irrigation.
(2) Spray the water into the air and allow it to fall on to plants and soil as simulated rainfall, a method called sprinkler irrigation.
(3) Apply the water directly to the root zone, a method known as drip or sub-irrigation.
i. Surface Irrigation:
Surface irrigation (gravity irrigation) is the most ancient method of irrigation and this method still holds good for more then 95 per cent of the irrigated area in the world. It can be defined as the process of introducing a stream of water at the head of a field and allowing gravity and hydrostatic pressure to spread the flow over the surface throughout the field.
Water application efficiency is usually higher on fine textured (clayey) soils than on coarse textured (sandy) soils because of their lower infiltration rates and more water retention per unit depth within the root zone. However, clayey soils are more prone to excessive wetness, compaction and impeded aeration.
Land levelling and smoothing are essential operations for successful surface irrigation. On regularly sloping lands, graded long furrows and borders can significantly reduce levelling cost.
Surface systems have advantages over others:
1. Initial capital investment for a surface irrigation system is usually lower than for sprinkler or drip systems.
2. Surface irrigation systems have relatively low energy requirements in routine operations.
3. Certain fruits and vegetables which can be damaged by sprinkling because of leaf scorch from salt residue of sprinkled water can be safely irrigated by surface systems.
4. Surface systems can avoid wind drift and canopy interception losses common in sprinkler irrigation.
5. Most important advantage of surface irrigation is its mechanical simplicity and easy adaptation to small land holdings.
Principal disadvantages of surface irrigation systems are their low application efficiencies, waste of water, water table raise, water-logging and Stalinization.
ii. Sprinkler Irrigation:
Sprinkler irrigation or overhead irrigation is application and distribution of water over the field in the form of spray created by expelling water under pressure from an orifice (nozzle).
In effect, it is simulated series of rainfalls of controllable frequency, duration, intensity and range of drop sizes. In contrast to surface irrigation, sprinkler systems are designed to deliver water to the field without depending on the soil surface for water conveyance or distribution. Sprinklers are designed and arranged to apply water at rates lower than soils infiltrability to prevent ponding and surface runoff.
Advantages over Surface Systems:
1. Elimination of channels, bunds and their maintenance and conveyance losses of water.
2. Controlled water application leading to higher application efficiency.
3. Areas at higher elevation than the source can be irrigated.
Disadvantages over Surface Systems:
1. High initial capital cost, high maintenance requirements and high operating pressure (energy cost).
2. During day time, when air is warm and dry and the droplets are small and application rate is low, application efficiency is affected by high wind speed (more than 15 km per hr).
3. Sensitive crops to soluble salt concentration may suffer leaf scorch because of salt deposit on leaves as the intercepted irrigation water containing appreciable amount of soluble salts evaporates. It is also not ideal for crops sensitive to fungal diseases.
Most commonly used sprinklers spread the water over a circular area at a rate that diminishes with radial distance from the sprinkler. For uniform distribution over the field, sprinkle circles must be overlapped. Alternative geometric pattern (square, rectangular or triangular) can be used to obtain optimum overlap among adjacent units.
iii. Drip Irrigation:
It can be defined as the process of slow application of water in the form of discrete, continuous drops, tiny stream or miniature sprays through mechanical devices called emitters or applicators located at selected points along water delivery lines. Fertilisers and other chemical amendments can be effectively applied to individual or several plants using trickle irrigation.
Trickle system has few characteristics in common with flood or sprinkler irrigation. Water advances in the soil around emitter only after the amount of water applied exceeds the infiltration rate at a point. Then it advances until the infiltration rate of ponded area equals the emitter flow rate. Typically, a wetted diameter of less than 1.0 m, depending upon the soil properties and emitter application rate, will become saturated on the soil surface.
Drip irrigation, like other methods, will not fit every crop, specific site or objective. Presently, trickle system has greatest potential where water is expensive or scarce, soils are sandy, rocky or difficult to level and high value crops are produced. Principal crops under trickle irrigation are avocado, citrus, stone fruits, grapes, strawberry, sugarcane and tomato.
Each irrigation method has possible advantages and limitations with respect to technical, economical and crop production factors.
Advantages of Drip Irrigation:
1. Increased beneficial use of available water.
2. Enhanced plant growth and yield.
3. Reduced salinity hazard to plants.
4. Improved fertiliser and other chemical applications.
5. Limited weed growth.
6. Reduced operational labour.
7. Decreased energy requirement.
8. Improved cultural practices.
Disadvantages of Drip Irrigation:
1. Persistent maintenance requirements.
2. Salt accumulation near plants.
3. Restricted soil water distribution and plant root development.
4. Economic and technical limitations.
A typical drip irrigation system is illustrated in Fig. 7.41. Water is delivered to the plants via a set of plastic lateral tubes laid along the ground or buried at a depth of 15-30 cm and supplied from a field main.
The tubes are usually 10-25 mm in dia, either perforated or fitted with emitters designed to drip water into the soil at rates as close as possible to the mean rate of water consumption by the crop. The trickling rate, generally, in the range of 1-10 1 hr-1 per emitter, should not exceed soil intake rate to avoid runoff, if any.
Essay # 7. Purpose of Irrigation:
Irrigation also serves the following purposes:
a. It adds water to the soil for supplying the moisture essential for plant growth.
b. It provides crop insurance against short duration drought.
c. It cools the soil atmosphere, thereby making more favorable environment for plant growth.
d. It aids in washout or dilution of salts in the soil.
e. It reduces the hazards of soil piping.
f. It softens the tillage pans.
Irrigation is also defined as supply of water to agricultural crops by artificial means, designed to permit farming in arid regions and to offset drought in semiarid or semihumia regions.
It can also be defined as artificial application of water to the land, in accordance with the crop needs during the crop period. Provision of one or two irrigations at times of prolonged drought to save dryland crops is referred to as supplemental irrigation or life-saving irrigation.
Essay # 8. Reasons for Practicing Irrigation:
Three major reasons for practicing irrigation are:
1. Irrigation only can ensure a stable system of crop production:
Even in areas where the total seasonal precipitation is adequate on the average, it is often unevenly distributed during the year and variable from year to year so that dryland farming is a high risk enterprise and only irrigation can ensure a stable system of production.
2. Longer effective crop growing period:
Irrigation can prolong the effective crop growing period in areas with dry season, thus permitting multiple cropping
3. Additional inputs become economically feasible:
With the security of cropping under irrigation, additional inputs become economically feasible. Irrigation reduces the risk of these expensive inputs being wasted by drought.
In some areas, the soil is either saturated with water or has more moisture than required for optimum crop growth due to inadequate natural disposal of excess water. Artificial measures to drain out excess water from soil are termed drainage. The purpose of irrigation and drainage is to maintain soil moisture within the range adequate for optimum crop growth and productivity.
Essay # 9. Role of Irrigation in India:
Production and productivity of agricultural lands is mainly dictated by the availability of irrigation water to crops. Irrigation acts as an intervention that modifies the soil moisture regime to increase productivity and production and stabilise the production against the weather based parameters. Expansion of irrigation has paid rich dividends in India.
After independence, production registered nearly four times increase from around 50.8 Million tones (M t) in 1950-51 to about 203 M t in 1998-99 and to around 230 M t in 2010 with an annual compound rate of 2.51 per cent.
This has been mainly attributed to three factors: high yielding cereals, expansion of area under irrigation and fertiliser use (Fig 1.5). Irrigation may be considered as the major factor of modern intensive agriculture as it aids in efficient use of costly fertilisers and other inputs besides meeting crop water needs.
Of the total 16.2 M t of fertiliser nutrients (NPK) consumed in agriculture during 1997-98 in the country, 9.65 M t was used in irrigated agriculture. Despite production gains, productivity levels under irrigation are still low. Nevertheless, irrigated agriculture while sharing 55 per cent of net sown area in India, contributes 56 per cent to total foodgrain production. It has also been estimated that at national level, 72.3 per cent of cereals and 20.5 per cent of pulses are produced under irrigated conditions (Fig 1.6).
Increasing demands for foodgrains and water due to increase in population and per capita consumption of water and increase in industrial development provide opportunities and challenges for agricultural scientists and hydrologists.
Essay # 10. Potential and Utilisation of Irrigation:
India has created an irrigation potential of about 123.623 M ha (up to 2007) against ultimate irrigation potential of 140 M ha. Broad assessment places required potential at about 180 M ha, indicating additional potential of about 50 M ha, which has to come from additional major and medium irrigation projects, where 34.4 M ha is utilised out of 42.3 and 58.2 M ha of created and ultimate irrigation potentials, respectively.
An area of 14.2 M ha of potential under minor schemes using surface water and 66.9 M ha from minor schemes groundwater was created till March 2007 (ICAR 2009).
Present utilisation of water (surface and groundwater) is about 606 billion m3, leaving 536 billion m3 of utilisable water as unutilised. Of this, the use for irrigation, domestic, industrial, energy and other purposes was 501.0, 30.4, 20.0, 34.0 billion m3 and 20.0 respectively. State- wise net area irrigated (thousand ha) according to sources is given in Table 7.12.
For administrative convenience, irrigation projects are classified into three classes:
(i) Major,
(ii) Medium and
(iii) Minor irrigation projects.
Projects having cultivable command area (CCA) up to 2,000 ha are classified as minor irrigation projects, those having CCA of more than 10,000 ha major irrigation projects and those between 2,000 and 10,000 ha as medium irrigation projects. Based in the purpose served, irrigation projects are classified into two: single purpose and multipurpose projects.
Single purpose irrigation projects are mainly for irrigation, while multipurpose irrigation projects are aimed at more purposes such as irrigation, flood control, power generation, navigation, domestic, industrial water supply etc.
Based on financial returns, irrigation projects are of two types: productive irrigation projects with cost benefit ratio not less than 1.5 and protective irrigation projects for protection against famine, financed from famine relief fund. Groundwater schemes contribute to more than 72 per cent of the total ultimate potential through minor irrigation.
Essay # 11. Adverse Effects of Irrigation:
No irrigation system can be considered sustainable, particularly areas prone to high water table, waterlogging and soil salinisation.
Some of the adverse effects of irrigation are:
1. Irrigation without appropriate drainage leads to land degradation (waterlogging and soil salinisation) leading to reduced crop productivity
2. Groundwater pollution, especially with nitrates, due to seepage of water carrying nitrate from applied fertiliser to the groundwater
3. Irrigation may lead to colder and damper climate conducive to outbreak of pests and diseases.
The term irrigation management/water management in its broader usage includes development, application and utilisation of water resources, water conservation, drainage, water quality and other aspects such as participatory irrigation management.
Irrigation water management is defined as the integrated process of intake, conveyance, regulation, measurement, distribution, application and use of irrigation water to farms and drainage of excess water, with proper amounts and at right time, for the purpose of increasing crop production and water economy in conjunction with improved agricultural practices.
A well-managed irrigation system is one that optimises the spatial and temporal distribution of water so as to optimise crop growth and yield and to enhance the economic efficiency of crop production. The aim is not necessarily to obtain highest yields per unit area of land or per unit volume of water, but to maximise the net returns in long run.
Various means such as principle of high frequency with low volume applications in precise are being developed to achieve higher level of control in irrigation water management. Where precipitation occurs during or just prior to the growing season, conjunctive use of rain and irrigation can result in a large saving of irrigation water and an increase of the land area, which can be effectively irrigated.
Irrigation is the supply of water to the crops by artificial means to permit farming in arid regions and to offset drought in semiarid or semihumid regions. As such, it already plays a key role in feeding the increasing population.
Essay # 12. Present Status of Irrigation in India:
In India, an upheaval in the history of irrigation was observed during the British rule in eighteenth century. After independence, several small, medium and multi-purpose irrigation projects were completed to supply water to about 90 Million hectares (M ha) as against 22.6 M ha in 1950.
Depending on the natural water resources, two distinct irrigated regions can be recognised in India:
1. Indo-Gangetic plain region comprising the states of Punjab, Haryana, plains of Uttar Pradesh, West Bengal and plains of Jammu and Kashmir.
2. Coastal areas of Andhra Pradesh and Tamil Nadu.
The principal crops having considerable area under irrigation (percentage) in the country are:
Punjab ranks first with 95.2 per cent cropped area under irrigation followed by Haryana (78.2%) and Uttar Pradesh (65.8%).
Seven states (Punjab, Haryana, Uttar Pradesh, Bihar, West Bengal in Gangetic plains and Andhra Pradesh and Tamil Nadu in the south), which share major part of irrigated area, have significant role in Indian agriculture. Put together, they share 32 per cent of the total geographical area, but 38 per cent of net cropped area of the country. Of the total 53.51 M ha net area reported in the country, 30.12 M ha (56.3%) exists in these states.
Intensive cropping is practiced due to well-developed irrigation facilities. Average cropping intensity is 145 per cent as against national average of 130 per cent. Approximately 50 per cent area under cereals, 31 per cent under pulses, 74 per cent under sugarcane. 20 per cent under cotton and 45 per cent under groundnut in the country belongs to these states.
In India, irrigated area (Table 7.13) is 34 per cent of the net area sown. Gross irrigated area is 80 M ha which gets India the prize for the largest extent of irrigated area in the world.
According to latest statistics, it appears that groundwater provides 60 per cent of the net irrigated area. In the last two decades, 85 per cent of the addition to net irrigated area has come from groundwater.
Among the states, three have achieved 70 per cent or more of the ultimate irrigation potential with TN recording 100 per cent achievement followed by Punjab (84%) and Rajasthan (74%). Four states (Haryana, Karnataka, J&K and WB) are in the range of 63 to 71 per cent and two states (UP and Maharashtra) have achieved 56 per cent each. Other states achieved less than 50 per cent achievement.