What is irrigation? what are the important sources of irrigation in India?
Answers
It accounts for 60% of irrigated areas of the country. This means of irrigation correlates to more than 80% of water use efficiency. It is more popular in Sutluj-Ganga plains.
Locationally, this means of irrigation is well developed in western, north-western part of the country wherein Gujarat has maximum of its area as tube-well irrigation. UP account for maximum tube-well irrigated area of the the country.
It is however, expensive and diminishes the underground water-table, high energy cost for pumping groundwater.
Canal Irrigation:
It marks its formal beginning way back in 1948 with country's 1st multipurpose river valley project - DVC coming into being. This means of irrigation presently accounts for 30% of the total irrigated area with well developed network in the alluvial lowland.
It is an effective source of irrigation in the areas of low and leveled relief, productive plain areas where perennial source of surface drainage is available.
Locationally, Chhattisgarh has maximum of its irrigated area as canal irriagated. However, UP accounts for largest share of country's canal irrigated region.
This means of irrigation has low water-use efficiency of 20-30%, high construction and maintenance cost, unclear ownership rights as restricting factors. Also there is emerging inter-state dispute, water-logging in command area and other ecological problems.
However, in region like the Northern Plains of India with consecutive agricultural field, this is the best means of irrigation, which also sustain multiple water requirement of cultivated crops.
Tank Irrigation:
It is developed in crystalline plateau interior of Andhra Pradesh and Tamil Nadu, catering to the requirement of scattered agricultural field and crops that require single watering forms traditional means.
In recent times this led to decline in ground water table as farmers are storing water in tanks from well or tube-wells. Again silting and evaporation losses are the major constraints.
Sprinkler Irrigation:
It has primarily evolved in the states of Rajasthan, Madhya Pradesh and reveals the limitation of 'randomness of watering', negatively influencing quality and quantity of yields.
This sprinkler irrigation has over 90% water-use efficiency. This is suitable for arid and semi-arid region, undulating topography and it reduces the chances of runoff, erosion and inundation.
High initial cost, huge power requirement, not suitable under high wind velocity are limiting factors.
Drip Irrigation:
It has been successful as pilot project in Kerala and largely lacking in its potentialities in multiple cropping patterns of the country.
It has highest water-use efficiency of nearly 100%. It is well suited for plantation crops and in areas of acute water shortage.
In this the surface run-off, evaporation losses are minimum and it is suitable means by which herbicides and fertilizers are applied through HERBIGATION & FERTIGATION.
Salt accumulation at plant root, inadequate root development, high initial cost and frequent installation and retrieval are limiting factors.
States under Canal irrigation. Canals are second most important source of irrigation in India after wells and tube wells. The Canals are irrigating those lands which have large plains, fertile soils and perennial rivers. The plains of North India are mostly canal irrigated.