India being an agricultural country mostly depends on monsoons rain that is very much uncertain. Therefore, Indian agriculture needs artificial watering of the fields.
The artificial way of supplying water to the agricultural farm or field at the right moment in an appropriate volume for the proper growth of the plants in order to get the maximum yields of cultivation is technically called irrigation.
Various factors that have made irrigation indispensable are:
Uncertain monsoon rain: In India, major portion of the total annual rainfall occurs in the monsoon season and lasts for around four months in a year. But it is uncertain; sometimes it causes flood and also droughts.
Spatial variation in rainfall: Many parts of our country such as Rajasthan, Punjab, Haryana, north-western part of Gujarat, interior parts of the Deccan plateau receive very low monsoon rain even less than 75 cm. This rainfall deficiency also makes it necessary to provide irrigation to the fields.
Low winter rain: To grow rabi crops like wheat, pulses, oil-seeds, etc. in long and dry winter irrigation is also necessary.
Lack of moisture retaining capacity of the soils: Oils like laterite, red soils are poor in moisture retaining capacity and, as such, without irrigation it is impossible to cultivate this type of soils.
Cultivation of high yielding variety crops: H.Y.V. seeds require regular and adequate water supply unlike any other normal seeds. This can only be achieved by irrigation.
Multiple cropping: In this method of cultivation more than one crop are cultivated. It is requires regular water supply throughout the year and this can be made possible only through irrigation.