Answer:

Irrigation is used to assist in the growing crops, maintenance of landscape, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall. Various Irrigation system in India are as follows:

♤ Border Irrigation: It uses land formed into strips which are located across the narrow dimension, but sloping along the long dimensions.

♤ Check Basin Irrigation: In this irrigation system, water is applied to a completely level or dead level area enclosed by dikes or boarders. This requires perfectly level field which becomes a limitation in many cases at fielded level.

♤ Furrow Irrigation: Furrows are sloping channels formed in the soil. Infiltration occurs laterally and vertically through the wetted perimeter of the furrow and plants get water in its root zone.

♤ Sprinkler Irrigation: In this system of irrigation, water is delivered through a pressurized pipe network to sprinklers nozzle or jets which spray water into the air.

♤ Drip Irrigation: It minimizes the use of water and fertilizer by allowing water to drip slowly to the roots of plants

♤ Fertigation : It is the process of application of water soluble solid fertilizer or liquid fertilizer through drip irrigation system.

The main sources of irrigations that are used in various parts of the country are

♤ Wells and tube-wells

Wells and tube-wells are method by digging a hole in the ground to get the subsoil water. Well irrigation is popular in the areas where sufficient sweet water is available this includes great northern plains, deltaic regions of mahanadi, krishna , godavari, narmada and tapi valleys.

Problems associated with wells and tube-wells are as follows: Limited area can be irrigated, normally a well can irrigate 1 to 8 hectares of land. Well may be dried up if excess water drain out of it like the water table decline and dark zones have been recently notified by the government due to overuse of ground water resources. Well and tube-wells is not possible in areas of brackish groundwater.

♤ Canals

It is the second most important source of irrigation in India. It is more effective in the areas of low relief, deep fertile soil, perennial source of water and extensive command area. They are mainly confined to the northern parts of India in Punjab, Haryana and Uttar Pradesh. The digging of canal in peninsular India is difficult and uneconomic. However deltaic regions of south India have some canals for irrigation.

Problems associated with canal irrigation are - canal water soaks into soil thus leads to the problem of water logging. Excess level of water flow leads to raising of

ground water level .capillary action brings alkali salts on the surface leads to the process of alkalinity, floods in surrounding areas during rainy season, it is suitable in plain areas only

♤ Tanks

This is popular in peninsular parts of India.

Problems associated with tank irrigation are - they dry up during the dry season when it is needed the most, silting, operational cost is high, water evaporation for large expanse, they cover large areas of cultivable land, lifting of water from tanks and carrying it to the fields is a strenuous and costly.

To improve the irrigation system in India there is an urgent need to improve the mechanism at three levels at the entry level, storage level and at the exit or the use value level. Three pronged strategy to tackle this problem:

1) To maintain the catchment area by improving the catchment area of any lake, tank, reservoir. Its conservation with maintenance and construction of the physical structures required for the conservation, management and functioning irrigation system.

2) To maintain the required level of carrying capacity that what has been prescribed for its functioning thus to maintain the potential of water holding capacity by these structures. It is the improvement in the water retention capacity and water storage enhancement through the addition of new structures and proper maintenance of the existing once.

3) To improve the water use efficiency in the region to manage the irrigation system. This aspect will consider the methods that need to be taken care of such sprinkler irrigation, drip-irrigation, and enhancement in water use efficiency by the application of drought resistance crops and by the development of new ways of crops and plough methods that conserve water.

Specific suggestion to improve the various irrigation system:

Well and tube wells irrigated region: The problem in this region is the water recharge capacity need to be developed by the efficient utilization of funds under the integrated water-shed management programme. There is a need to regulate the number, distribution and use of water in the tube well irrigated regions such as Punjab, Haryana, Rajasthan. Formation of dark zones due to over exploitation water needs to be controlled. There is a need to create the ground water recharge structure such as check dams. Formation of roof top-harvesting, run-off harvesting techniques by making the construction of these structures compulsory to all the owners of the irrigated system. Need to regulate the flat price policy of electricity as followed in Punjab to control the mis-utilization of government subsidies in this sector.

Canal irrigated regions Major problem are related to the over irrigation. The problem of water logging can be solved by the technique of sprinkler irrigation, drip irrigation rather than flood irrigation method. There is a need to manage the cropping pattern in the canal irrigation area such as rice is grown in the semi-arid areas of southern Punjab, southern Haryana etc. De-silting of the canals regularly can maintain the flow of water to the tail ends of the canal. There is a need to enhance the water use efficiency to distribute the water judiciously to various parts of canal irrigation system. The new experiment of Gujarat is the covering of canal by solar penal is helpful in preserving water from evaporation and the supply of solar power to the nearby areas.

Tank irrigated regions- To stop the siltation of tanks there is a need to maintain the plantation of trees, afforestation, restoration of nearby catchment areas by the application of MNREGA fund for the construction of tank areas, with the people participation we can improve the situation of dredging before every monsoon period. We have to develop new varieties of crops that are drought resistance and temperature resistance. Proper timely maintenance and covering of open area tank can also be followed. And last but not the least is the water use efficiency in dry areas has to considered by making regional water policy by proper auditing of water use and its utilization for the future roadmap of irrigation improvement.

There is an urgent need to improve the irrigation techniques according to the agro- climatic regions of India and subject to the topographical features and the potential to use those techniques effectively and efficiently.