12. Is the Impact of Irrigation on Agricultural Output Declining in India?: A Disaggregated Analysis

The significant role of irrigation development in land use pattern, cropping pattern, cropping intensity, production and productivity of crops has been well documented by various studies in India. However, the contributions of irrigation to agricultural output and related parameters are fervently questioned in the recent years. Since the role of irrigation in increasing the value of agricultural output has not been studied by many scholars especially using disaggregated data covering different time points, an attempt has been made in this chapter to fill this gap by using cross-sectional data for 235 Indian districts, drawn from 13 states at six time points: 1962–65, 1970–73, 1980–83, 1990–93, 2003–05 and 2005–08. Both descriptive and regression analyses have been carried out to study the relationship. Descriptive analysis shows that the difference in value of agricultural output per hectare has narrowed down between less (<30 percent), medium (30–50 percent) and high (>50 percent) irrigated districts over the years, especially after 1990–93. The univariate regression analysis carried out treating irrigation (with and without dummy as well as with and without time lag) as an independent variable and the value of agricultural output per hectare as dependent variable shows that the impact of irrigation on the value of output has declined (both irrigation coefficient and R²) over time. During 1980–83 and 1990–93, irrigation alone has explained around 50 percent of variation in agricultural output, but the same declined to about 24 percent during 2003–05 and 2005–08. Multivariate regression analysis carried out by using different yield increasing and infrastructure variables suggests that although irrigation still plays a dominant role in increasing the value of output, its value of coefficients has been declining over time. Although both univariate and multivariate regression results show a declining trend of irrigation coefficient over time, one may not be able to firmly say that the role of irrigation in determining the value of agricultural output has reduced over time, as this could have happened due to acceleration in the productivity of crops cultivated in the rainfed/less irrigated districts.