For proper development of agriculture of a country the first and the foremost need is to develop a strong infrastructural base. This includes the facility of irrigation, availability of fertilisers, improved seeds, insecticides, pesticides etc. at reasonable price, use of new farm machineries and provision for credit facilities and crop insurance etc. through financial institutions and government.
One of the main considerations for the importance of irrigation in India is scanty rainfall in large parts of the country and erratic monsoon elsewhere, In India the failure in monsoon is the failure in agriculture. Irrigation not only helps to extend the net sown area in areas of inadequate rainfall but promotes multi-cropping by making it possible to raise a second crop in the dry season. In both these ways it plays a key role in bringing about an increase in the gross cropped area.
The irrigated land also shows much higher crop-yields than unirrigated land. For example, in the Seventh Five Year Plan (1985-90), while working out the food grain targets for 1989-90, the average crop-yields per hectare on irrigated and unirrigated lands were assumed as follows : rice 2237 kg and 1152 kg, wheat 2210 kg and 1059 kg, coarse grains 1478 kg and 766 kg, and pulses 1130 kg and 573 kg.
Irrigation water comes from two sources: surface water and ground water. Surface water is provided by the flowing waters of rivers or the < water of tanks, ponds, lakes and artificial reservoirs, the surface water is carried to the fields by canals, distributaries and channels. Ground water is tapped by sinking wells where draught animals, diesel or electric power is utilised to take out water.
In India canals, tanks, wells including tube wells are the principal sources of irrigation. Table 8.IX shows the areal coverage and percentage share of different sources of irrigation in the country. Since 1950-51 much emphasis has been placed on the expansion of canal irrigation as a result of which the area under canal irrigation increased from 8.29 million hectares in 1950-51 to 16 million hectares in 2000-01 B.IX showing an increase of 93% during the last 50 years. But its relative importance has come down from 44 per cent to 29.2 per cent.
During this period it is well irrigation, particularly tube well irrigation which has made the most remarkable progress. The areal coverage under this source (wells and tube wells) has increased from 5.98 million hectares in 1950-51 to 33.3 million hectares in 2000-01 showing a net increase of 417 per cent.
The percentage share has also risen from 31.7 per cent to 60.9 per cent during these 50 years. On the contrary the area and percentage share under tank irrigation have witnessed declining trends. Infect there has been phenomenal growth of tube well irrigation at the cost of irrigation from tanks and wells since the launching of First Five Year Plan.
These tube wells using diesel and electric power are either government or private owned and are very important source of minor irrigation. Much of the credit for present development of agriculture in Punjab, Haryana and western Uttar Pradesh may be attributed to this popular source of minor irrigation.
When India started planned economic development in 1951 the total irrigation potential was 23 million hectares (10 million ha. by major and medium irrigation and 13 million ha. by minor irrigation). At the end of the ninth five year plan the total irrigation potential rose to 94 million hectares (37.1 million ha. by major and medium irrigation works and 56.9 million ha. by minor irrigation works) (Table 8.X).
While there has been 316% increase in total irrigation potential during the last fifty-one years (1950-51 to 2001-02) the gain has been spectacular (341%) in case of minor irrigation (cf. 282.5% in case of major and medium irrigation). This clearly exemplifies the growing importance of minor irrigation in agricultural development. The table 8.X also shows that out of the total 94 million ha. Of.
The total net irrigated area in the country was 20.85 million ha which was about 17.6% of the net cropped area in 1950-51. With the development of irrigation facilities during different plan periods the total net irrigated area increased to 31.1 million ha in 1970-71, 46.70 million ha. In 1990-91, and 54.7 million ha. In 2000-01 which accounted for 22.2%, 32.6% and 38.7% of the total net cropped area respectively. Thus over 60 per cent of the net cropped area of the country still lacks irrigation facilities which are main constraint in agricultural development. About 23.4% of the country’s net irrigated area lies in Uttar Pradesh, followed by Rajasthan (9.0%), Andhra Pradesh (8.28%), Madhya Pradesh (7.56%), Punjab (6.59%), Bihar (6.63%), Gujarat (5.45%), and Haryana (5.41%). These eight states together account for 72% of the net irrigated area of India.
Infect highest development of irrigation has taken place in the north-western part of the country covering the Satluj and the upper Ganga plains. On the one hand this area is highly susceptible to the vagaries of the monsoon on the other hand it is endowed with fertile alluvial soil, laborious and progressive farmers, perennial rivers and rich aquifer of ground water.
Apart from old canals of the British days the Bhakra project, Indira Gandhi Canal, Beas-Satluj link canal, Ram Ganga project and the Sarda Sahayak project have played vital role in augmenting the net irrigated area. Tube wells and pumping sets are another major source of irrigation in this region. Peninsular states like Tamil Nadu (5.3%), Maharashtra (5.4%), Karnataka (4.8%) and Orissa (3.5%) together provide 19% of the country’s net irrigated area. Remaining states like Kerala. Goa and of the north-east are moist enough to contribute negligible proportion of net irrigated area of the country.
Table 8. XI presents a crop-wise progress of irrigation since 1970-71 onwards. According to this table maximum area under irrigation has been brought under wheat (from 9.9 million ha. in 1970-71 to 24.2 million ha. in 1999-00), rice (14.3 million ha in 1970-71 to 24.5 million ha. in 1999-00) and oil seeds (from 1.1 million ha. in 1970-71 to 6.7 million ha. in 1999-00).
In terms of percentage irrigated area to total area under different crops sugarcane comes on the top (91) followed by wheat (87.7), barley (57.1), rice (54.0), cotton (34.4), oil seeds (25.0), maize (21.2), pulses (13.1), jowar (7.8) and bajra (7.7). This clearly indicates that a major portion of the area under rice, cotton, oil seeds, maize, pulses, jowar and bajra etc is devoid of irrigation facilities. This also badly affects the use of HYV seeds and chemical fertilisers and lowers down the yield under these crops.
Irrigation in India is susceptible to a number of problems. These include long gap between the developed and utilised irrigation potentials, time lag and escalating cost in the construction of irrigation projects, wastage of irrigation water, ensuing disputes between neighbouring states on the utilisation of inter-sate river water, too much subsidy on irrigation water leading to great burden on state exchequer, lack of incentive to states for further irrigation development, and serious damage to physical environment by ill-planned irrigation schemes. Hence, there is a need for scientific development of irrigation, full utilisation of its developed potential and rational pricing of irrigation water.