Irrigation

The process of supplying water to crops by artificial means such as canals, wells, tube-wells, tanks, etc. from the sources of water such as rivers, tanks, ponds, or underground water is called irrigation.

Types of irrigation techniques

Surface irrigation: Surface irrigation utilizes gravity flow to move water across land, wetting and infiltrating soil. It encompasses furrow, border strip, and basin irrigation, also known as flood irrigation.
Localized irrigation: Localized irrigation involves the distribution of water through a network of pipes, utilizing low pressure, and delivering water in a predetermined pattern to each individual plant or in close proximity to it.
Drip irrigation: The technique of delivering water drop by drop at or near the root zone of plants is known as drip irrigation or trickle irrigation. When managed properly, this method can be highly efficient in terms of water usage since it minimizes evaporation and runoff.
Sprinkler irrigation: In sprinkler or overhead irrigation, water is piped to one or more central locations within the field and distributed by overhead high-pressure sprinklers or guns.
Sub-irrigation: Sub-surface irrigation also sometimes called seepage irrigation has been used for many years in field crops in areas with high water tables. It is a method of artificially raising water table to allow the soil to be moistened from below the plant root zone.

S.N.	Traditional Irrigation / Water Conservation methods	Region
1.	Jhalara	Jodhpur (Rajasthan)
2.	Talab/Bandhi	Bundelkhand
3.	Bawari	Rajasthan
4.	Tanka	Thar Desert (Rajasthan)
5.	Ahar Pynes	Bihar
6.	Johads	Karnataka, Odisha
7.	Panam Keni	Wayanad (Kerala)
8.	Khadin	Jaisalmer (Rajasthan)
9.	Kund	Rajasthan, Gujarat
10.	Baoli	Rajasthan
11.	Bhandara Phad	Maharashtra
12.	Zing	Ladakh
13.	Kuhls	Himachal Pradesh

Sources of irrigation

Tank irrigation: A tank consists of water storage which has been developed by constructing a small bund of earth or stones built across a stream. The water impounded by the bund is used for irrigation and for other purposes. The tank irrigation is practiced mainly in peninsular India due to the following reasons:

The undulating relief and hard rocks make it difficult to dig canals and wells.
There is little percolation of rainwater due to hard rock structure and ground water is not available in large quantity.
Most of the rivers of this region are seasonal and dry up in the summer season. Therefore, they cannot supply water to canals throughout the year.
There are several streams which become torrential during rainy season. The only way to make best use of this water is to impound it by constructing bunds and building tanks.
The scattered nature of population and agricultural fields also favors tank irrigation.

Merits of Tank irrigation	Demerits of Tank irrigation
Most of the tanks are natural and do not involve heavy cost of their construction.Tanks are generally constructed on rocky bed and have long life span.	Many tanks dry up during the dry season and fail to provide irrigation when it is needed the most.Silting of tank bed is a serious problem and it required desilting of the tank at regular intervals.Lifting of water from tanks and carrying it to the fields is a strenuous and costly exercise.

Wells and Tube wells: A well is a hole dug in the ground to obtain the subsoil water. It is popular in areas where sufficient ground water is available. It accounts for about 16.6% of the net irrigated area in the country. A tube well is a deeper well from which water is lifted with the help of a pumping set operated by an electric motor or a diesel engine.

Merits of Well and Tube well irrigation

Demerits of Well and Tube well irrigation

It is the simplest and cheapest source of irrigation.It is an independent source of irrigation and can be used as and when the necessity arises.A well can be dug at any convenient place.

Only limited area can be irrigated.The well may dry up and may be rendered useless for irrigation if excessive water is taken out of it.In the event of a drought, the ground water level falls and water is not available in the well.Tube wells can draw a lot of groundwater from its neighboring areas and make the ground dry and unfit for agriculture.Well and tube well irrigation is not possible in areas of brackish groundwater.

Canals: Canals can be an effective source of irrigation in areas of low-level relief, deep fertile soils, perennial source of water and extensive command area. Canals in India are of two types, viz. (i) Inundation canals, which are taken out from the rivers without any regulating system like weirs. (ii) Perennial canals are those which are taken off from perennial rivers by constructing a barrage across the river. The percentage of canal irrigation in the country is about 23%.

Accelerated Irrigation Benefits Programme (AIBP)

The programme was launched in 1996-97 to provide assistance to major/medium irrigation projects in the country, with the objective to accelerate implementation of such projects which were beyond resource capability of states or were in advanced stage of completion.

Pradhan Mantri Krishi Sinchayee Yojana (PMKSY)

It was launched in 2015-16 which aimed at enhancing physical access of water on farm and expand cultivable area under assured irrigation, improve on farm water use efficiency, introduce sustainable water conservation practices, etc.
Objectives:

Achieve convergence of investments in irrigation at the field level.
Enhance the physical access of water on the farm and expand cultivable area under assured irrigation.
Enhance the adoption of precision – irrigation and other water saving technologies.
Enhance recharge of aquifers and introduce sustainable water conservation practices.
Ensure the integrated development of rainfed areas using the watershed approach towards soil and water conservation.
Promote extension activities relating to water harvesting, water management and crop alignment for farmers.
Attract greater private investments in precision irrigation.