Harnessing the water sources and delivering the water to the fields for raising crops is known as irrigation. It has been estimated that the present resources of water are enough to irrigate about 50% of the world area suitable for agriculture. Therefore, the present day irrigation practices need improvement to produce more food, and new technologies like sea water desalination and weather modification will have to be evolved.
There are two sources of water namely, surface sources of water which comprise lakes, streams and rain water stored in various ways including snow on earth surface; and ground sources, which include wells, springs and horizontal galleries. Irrigation systems can be developed to harness all sources of water.
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Advantages of Irrigation System
The following are the usual benefits of an irrigation project:
- General development of the country, prosperity of the people and wealth of the nation.
- Protection against famine and attainment of self sufficiency in food.
- Improvement in yield of crops and appreciation in land value.
- Generation of hydroelectric power: Canal fall may sometimes be utilized for generation of power.
- Inland navigation: It is possible that some large irrigation canals may be developed for navigation purposes.
- Domestic water supply: At many places irrigation canals are the only source of supply for domestic water.
- Improvement of communication: Roads provided along-side the important canals primarily for inspections, are utilized for general communication also.
- Plantation: Tree are planted along canal banks, field boundaries, etc increasing timber, fuel and fruit supplies.
- Improvement in the ground water storage: Canal and irrigation water seep through the soil and raises the water table. This is desirable in arid and semiarid zones.
Irrigation is in fact the key input on which modern agriculture practices such as use of chemical fertilizers and multiple cropping of high yielding varieties depend. In predominantly agricultural countries, the growth of cottage industries, technical institutions, cold storages, and other developmental activities and socio-economic uplift of the people centers around it.
Disadvantages of Irrigation system
Excess irrigation and improper use of irrigation water may, however, create the following ill effects and should be avoided:
- Careless irrigation may lead to creation and breeding places for mosquitoes.
- Over irrigation may lead to water logging and salt efflorescence.