Tuesday, November 3, 2009


CONSERVING WATER Irrigation need not be wasteful. Water may be saved by using the following methods of irrigation.
Drip Irrigation Drip irrigation involves the slow ap­plication of water, drop by drop, to the root-zone of a crop. It is also called 'trickle irrigation'. This method of irrigation was initiated in Israel and is now being tried in other countries, including India.
In this method, water is used very economically, since losses due to deep percolation and surface evaporation are reduced to the minimum. This method is, therefore, very much suited to the arid regions of India and is being followed for irrigating orchard crops at present. The successful growing of orchards even on saline soils has been made possible by the drip system of irrigation. Drip irrigation can also be used for applying fertilisers in solution.
Work is in progress in India to design, and to adapt drip irrigation to conditions in this country. The initial high cost of equipment and its maintenance are the major limitations of this system. It may still prove to be cheaper than the sprinkler system, especially for orchards and other widely spaced crops.

Sprinkler Irrigation Sprinkler irrigation is a system whereby water pressure is applied to the surface of any crop or soil in the form of a thin spray from above. This method is advantageous, as water can be applied at a desired rate and a uniform distribution of water and high efficiency can be ensured. The sprinkler system can be adopted in case of almost all crops, especially cash and orchard crops. The system is especially suited to shallow sandy soils of uneven topography, where levelling is not practicable. It is useful in effective leaching of salt in saline soils, cooling the crops during high temperature, and controlling frost during freezing temperatures.

The sprinkler system is classified on. the basis of the portability of its equipment as (i) portable, (ii) semi­portable, and (iii) stationary or permanent. The stationary system is more expensive than the portable one. The portable and semi-port~ble systems are again divided into manual (hand-moved) system and power-moved system. There are self-propelled sprinkler systems which move laterally or radially around a central pivot feeding line. The portable systems can be a useful mode of irrigation in an area ranging from 3-4 hectare to 50-60 hectare or more.
There are boom type sprinkler systems which employ one boom sprinkler head on each lateral. These systems irrigate an area of 75 to 100 ID radius.

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