CORE Irrigation as a Geographic System
Irrigation is the controlled supply of water to fields, but in Indian geography it is better understood as a chain: source, storage or diversion, conveyance, command area, on-farm distribution and drainage. A dam that stores water but lacks field channels does not by itself create secure crop water. A tube well that lifts groundwater may serve a single holding immediately, but repeated pumping can lower the aquifer. A canal may cover a wide command, yet seepage, poor levelling and absent drainage can produce waterlogging or salinity. Rajasthan makes this chain visible because western districts receive canal water from distant rivers while many eastern and southern districts still depend on tanks, wells, small reservoirs and micro-irrigation. The Pradhan Mantri Krishi Sinchayee Yojana, launched during 2015-16, sits at the policy end of this chain. It links assured irrigation access, Har Khet Ko Pani, Per Drop More Crop and watershed development. The Command Area Development Programme, launched in 1974-75, sits inside the command itself: field channels, drains, land levelling and water-user participation help convert irrigation potential into actual irrigation. The 6th Minor Irrigation Census adds a source-based view: groundwater schemes include dug wells and tube wells, while surface schemes include surface flow and lift irrigation. That classification explains why Tube-well irrigation in Indo-Gangetic alluvium differs from Tank irrigation in hard-rock red-soil south India and from Canal irrigation in north Indian alluvial plains. Rajasthan's low-rainfall districts need all three ideas at once: large canals for command transformation, micro-irrigation for water-use efficiency and groundwater management where extraction exceeds recharge. Classification also prevents common project mistakes. Major and medium irrigation projects are usually public works with river regulation, dam safety and inter-state allocation questions. Minor irrigation is closer to the farmer and includes wells, small lift schemes and local surface-flow structures. Micro-irrigation is not a source category; it is a field-application technique that can use canal, well or farm-pond water. In arid Rajasthan, this distinction is practical because the same village may receive canal water in one command, pump groundwater from a declining aquifer nearby and use drip irrigation for orchard plots.