Irrigation Scenario in India
In the last forty years, the share of Indian agriculture in gross domestic product has decreased, but extensive use of HYV seeds, modern irrigation tech, and fertilizer have contributed in increasing the agricultural productivity and achieving self sufficiency in meeting food demand. Given increasing trend of population, policy makers find it imperative for India to achieve higher agriculture production and continue to meet the food security objective of the country; and indicated that irrigation will play a key role in future in achieving higher yield and sustaining the food security (Persaud et al, 2003). During the last fifty years, gross irrigated area (GIA) of India has increased more than three folds from 22 to 76 million Hectares. Gross irrigated area is a straightforward multiplicative function of net irrigated area (NIA) and irrigation intensity (IRI), and thus the relevant equation which may arise is regarding the contribution of net irrigated area (NIA) relative to the irrigation intensity (IRI) in increasing the GIA.
There are state wise variations in irrigation; the level of irrigation is measured in terms of irrigation intensity and irrigation ratio, defined as NIA/NSA. Latest research shows high proportion of irrigated land of more than 70% in agricultural states like Punjab, Haryana and Uttar Pradesh where agriculture constitutes more than 30% of the state GDP. Among the southern states, proportion of irrigated land is below 30% in Karnataka and Kerala; while in Andhra Pradesh and Tamil Nadu, NIA/NSA is above 40%. Among the western states, Maharashtra has the lowest proportion of irrigated land where only 17% of the net cropped area is irrigated. Most of the eastern states are well endowed with irrigation where average NIA/NSA is 0.40. In the north-eastern state of Assam; however, less than 10% of net cropped area is irrigated. Many climatic factors like rainfall, drought affects irrigation.
Many states register a decrease in irrigation intensity (IRI), and much of the decrease are noticed in states like Himachal Pradesh, Orissa, Tamil Nadu and Maharashtra. In these states, the proportional irrigated area is not high except in Tamil Nadu. The opportunity cost of increasing the irrigation intensity is higher than increasing the net irrigated area. As a result, NIA has increased in these states with the development of minor irrigation. In West Bengal, however IRI has increased by 39% in the post 1997 period. One may argue that the higher opportunity cost of increasing the extensive margin leads to higher irrigation intensity. The alternative hypothesis is that high endowment of irrigation land increases the reliability of irrigation water and induces higher irrigation intensity. Hypothesis testing is done using regression. Increase in irrigated area could be the cause of higher irrigation intensity. We also hypothesize whether endowment of irrigated area is factor in the marginal effect on irrigation intensity.