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Resource Management :: Water :: Source and Necessity of Irrigation

SOURCE AND NECESSITY OF IRRIGATION

Rainfall is the primary sources of water for irrigation. It is not available though out the year. The stored rain water either in tank or in sub-surface is used as resources of irrigation water for an indefinite period. Following are the sources of irrigation water.


  1. Surface water: It may be by flowing river or from still waters of tanks, ponds, lakes, pools or artificial reservoirs such as dams, barrages and diversionary bunds with different storage capacity.
  2.  Ground water: Water stored in the underground is known as groundwater.

Objectives of irrigation

  • to supply the water for the nutrition and growth of plant
  • to hasten the decomposition of organic matter in the soil and to keep activity of the microbes at the optimum level.
  • to remove the stress condition of plants.
  • to leach or wash out injurious salt form the soil.
  • to maintain the temperature and humidity of the soil.
  • to control the harmful soil insects.
  • to reclaim fallow land and
  • to bring soil condition for tillage.



Necessity of irrigation

i) Uncertainity of monsoon rainfall:

80% of rainfall in India is received during monsoon period. Monsoon rainfall is very uncertain. So irrigation is very important to supply water to plants also and when needed.

ii) Uneven distribution of rainfall:

To compensate the uneven distribution in an area, supplemental irrigation is needed.

iii) Effect of winter rainfall (N India)/ Effect of SWM in S. India:

Supplemental irrigation is inevitable in the regions due to poor rainfall.

iv) Cultivation of high yielding crops:

High yielding crops produce heavy biomass and economic yield. Higher biomass need more water for its production. Hence supplementation of water as irrigation is essential.

v) Difference in water holding capacity of the soil:

Sandy soil - low WHC – frequent irrigation. Clay soil - high WHC - frequency is less.