Water Saving and Yield Enhancing Micro Irrigation Technologies in India: Theory and Practice
In this chapter, we attempt to determine the potential benefits from the use of MI systems in India. This is done through assessing: (a) the conditions that are favourable for MI system adoption and the constraints to adoption; (b) the field level and aggregate level impacts of the systems on water use; and (c) the yield and economic benefits from adoption of the system. The research also assesses the future potential coverage of MI systems in India. An analysis of the scope of MI adoption in erstwhile Andhra Pradesh, including its likely impact on water saving is also attempted. The constraints in MI system adoption are: (i) lack of independent source of water and pressurizing device for many farmers; (ii) poor quality of groundwater in many semiarid and arid regions; (iii) the mismatch between water delivery schedules in surface irrigation systems and irrigation schedules required in MI systems; (iv) cropping systems that dominate field crops in semi arid regions; (v) dominance of small and marginal farmers, and small plot sizes; (vi) low opportunity costs of pumping groundwater due to lack of well defined water rights; (vii) negative technical externalities in groundwater use; (viii) poor extension services; and (ix) poor administration of subsidies. The future potential of MI systems to improve basin water productivity is primarily constrained by the physical characteristics of the basins vis a vis the opportunities they offer for real water saving at the field and basin level water productivity improvements, and area under crops that are conducive to MI in those basins. The potential area under water saving MI in India was assessed at 7.98 million hectares. For erstwhile Andhra Pradesh, the potential estimated was estimated to be a mere 0.88 million hectares, in well irrigated areas. What is more important is that adoption is unlikely to result in real water saving at the farm level as farmers would expand the area under irrigation, in lieu of the fact that the area irrigated by groundwater is a small fraction of the cultivable land in the region.