Irrigation is the process of supplying water to crop plants in the fields, by means of canals, reservoirs, wells, tube-wells, etc. 

It depends on the following two factors: 

1. Crop-based irrigation, i.e., on the nature of crop plants. 

2. Soil-based irrigation, i.e., on the nature of soil of the crop fields. 

The various irrigation systems in India are as follows: 

The common method of irrigation in India is well, tube wells, pumps, canals, tanks, river-valley system and river-lift systems. Irrigation is essential at various levels of crop production, such as sowing, tilting, flowering and fruiting. 

(a) Wells: Wells are bored at such places, where groundwater is enough. 

These are of two types: 

1. Dug wells: Dug wells have their bottom surface below the ground water table. Water accumulates here from surroundings. Water is lifted for irrigation by mechanical means, e.g., Persian wheels operated by bullocks, horses and camels 

2. Tube wells: Tube wells are dug very deep. Water is lifted from these wells by diesel or electric run pumps.

(b) Tanks: These are small storage reservoirs. They store run-off water from the surrounding catchment areas. Small dams are constructed below the catchment areas, to regulate the flow of water for agriculture. 

(c) Canal system: Canals mostly get water from large rivers. Doors are .fitted at the mouth of canal joining the river to regulate the flow of water. A canal is distributed into branch canals, distributaries or field channels. These field channels irrigate the fields. For irrigation, the fields of various farmers, a rotation system is followed, so that each and every farmer may irrigate his field. 

(d) River valley system: In the western ghat mountains for South India, are present many steep and narrow riverine valleys. In this region, rainfall is very heavy during June to September and again in November and December. On the slopes and in the valleys, perennial crops, like supari are cultivated. Rice crop is also grown in the bottomlands of the valley. 

(e) River lift system: Water is lifted directly from the river for irrigation of nearby fields. It is done due to inadequate flow of water in canal or due to insufficient release of water from the river reservoir. 

(f) Sprinkler irrigation system: It is introduced in canal irrigated areas of Haiyana, Rajasthan and Madhya Pradesh. Drip irrigation system is in use in Maharashtra, Karnataka, Andhra Pradesh, Orisa and Tamil Nadu. It is in practice with the help of Isral technical, known Indian Agricultural Research Institute, New Delhi. They are also providing training to the people of various states. Here, they are cultivating different varieties of roses, tomatoes, capsicum of yellow and red colour, gourd, etc.