Abstract/Summary

The choice of irrigation water sources is crucial in rice farming as water availability and cost can vary across water sources. Groundwater caters three-quarters of the total irrigated land in Bangladesh, where rice area alone occupies 80% of the total irrigated land. The present study compares productivity and efficiency differences and determinants of surface and groundwater irrigation users based on a sample of 6947 dry-winter rice growing plots from the nationally representative Bangladesh Integrated Household Survey-2018 database. A range of methods was adopted to correct for heterogeneity in irrigation water source choice decision, self-selection and observable biases. This involved an estimation of a Stochastic Production Frontier (SPF) model with the pooled sample first, then an application of Propensity Score Matching (PSM) to remove self-selection and observable biases, then a test of heterogeneity in irrigation source choices was conducted, and finally estimated two SPF separately for matched samples of groundwater and surface water irrigation users. Results revealed a robust effect of groundwater irrigation in enhancing rice productivity and efficiency. Seed and its quality, fertilizer and soil type are also significant drivers of rice productivity. The significant drivers of efficiency are plot ownership, irrigation frequency, subsidy and family size. Large farms with groundwater-irrigated plots are relatively more efficient. Significantly lower efficiency exists in areas vulnerable to drought. These results raise sustainability concerns owing to the high level of groundwater extraction and falling water table. Policymakers need to devise innovative strategies to increase use of surface water irrigation without sacrificing productivity and efficiency, which has been a priority policy drive in Bangladesh.