SR-1/2008-09 : Status report on irrigation practices in India and options for more crop and income per drop of water

Abstract

Irrigation constitutes the main use of water and presently accounts for 84% of the total water withdrawals in India. One of the major concerns in irrigated agriculture is the generally poor efficiency with which water resources have been used for irrigation. Traditional irrigation technologies usually result in substantial water losses and limited uniformity in water distribution. Water use efficiency is presently estimated to be only 38 to 40% for canal irrigation and about 60% for ground water irrigation schemes. It is estimated that with 10% increase in the present level of water use efficiency, an additional 14 million ha area can be brought under irrigation from the existing irrigation capacities. One of the more evident problems in the future is the growth of alternative demands for water such as urban and industrial needs. Irrigation science in the future will undoubtedly face the problem of maximizing efficiency. The annual food grain requirement of India is projected at 450 million tonnes by the year 2050. The method, frequency and duration of irrigations have significant effects on crop yield and farm productivity. In view of the limited land and water resources, the pathway for achieving the target of 450 million tonnes of food grain production has to be higher productivity per units of arable land and water.

The present status report discusses the standard irrigation methods (e.g. basin, border, furrow, sprinkler and drip systems) and the criteria for their selection under various conditions of topography, water availability, and type of crops etc. The existing irrigation practices in India, major issues and problems in irrigation management both from surface and ground water, agriculture sector performance and scope to increasing water use efficiency are also discussed. The major shortcomings in the irrigation systems include inadequate design, use of inappropriate technology, system layouts that do not adequately reflect existing conditions, inappropriate governance arrangements, and poor management practices. The most obvious manifestations of these shortcomings in irrigation are unreliable main system water supply, water wastage, water logging and poor maintenance practices.

The agricultural growth rate during the past five years has decelerated to about 1.5 percent from about 3 to 3.5 percent during the preceding 20 years, thus dropping below the population growth rate, for the first time during the past 40 years. The total factor productivity growth rate particularly in the main Green Revolution belts of rice wheat or rice- rice systems has decelerated. Technology fatigue in agricultural development is 1- eing felt widely which is further compounded with huge technology transfer gaps at various levels. Average national yields of most agricultural commodities in India are about 40 to 50 percent of the corresponding World averages. The gaps between potential and realizable and between realizable and average realized yields in the country are generally around 50 to 100 percent, respectively (Swami Nathan Sub-Committee, 2006). The existing exploitable yield gaps should be seen as an opportunity for future growth that is consistent with agro-ecological, environmental, socio-economic, political and technological settings in the major production regimes. Modem irrigation technologies, particularly sprinkler and drip irrigation, increase water use efficiency. They have opened up opportunities to cultivate soils with low waterholding capacity (sandy and rock soils) and to farm low quality lands and steep slopes. This technology has also enabled regions facing limited water supplies to shift from low-value crops with high water requirements (e.g. cereal) to high value crops with lower water requirements such as fruits, vegetables and oil seeds. The interventions are, therefore, required to help produce more crop and income per drop of water by increasing the water use efficiency and by managing the water demand of crops through improved irrigation practices and the improved farming technologies.

Under the 'Advisory Council on Artificial Recharge of Ground Water', a SubCommittee was constituted in 2006 under the chairmanship of Dr. M.S. Swami Nathan, with its members from various ministries and research organizations. The sub-committee in their report titled "More Crop and Income per Drop of Water" focused attention on the scope available for improving the efficiency of use of irrigation water in a manner that both the productivity and profitability of farming are enhanced. The report gives details of implementable action plans incorporating technologies along with their economics. The viable technologies and the action plans suggested in their report are reproduced in the present report. The interventions are suggested through both (i) supply management and (ii) demand management. The supply augmentation and management lays emphasis on improvement in water control structures for increasing the water use efficiency through efficient water conveyance, application and distribution systems coupled with geometrically efficient irrigation layouts; watershed development; and, desilting and management of a large number of existing tanks. The demand management concentrates on improved irrigation practices including sprinkler and drip with fertigation; the improved farming technologies such as Sustainable Rice Intensification (SRI) technology; improving soil health through composting, green manuring, and by integrated farming activities with animal, poultry and fisheries production; crop diversification and multiple uses of water e.g. rice and fish culture. Timely and dependable forecasting of weather for planning sowing and other farming operations; provision for credit, insurance and marketing are some other measures suggested in the report to help farmers increase their productivity and profitability. The need for reducing the gap between irrigation potential created and utilized in irrigation projects through better management practices; artificial recharge of groundwater resource; inter basin transfer of water; and the need for research on biotechnology approach that have tremendous potential to save water by reducing the water consumption of plants and by treating the waste water, are also highlighted in the report. The recommended action plans and implementation structure for proposed plans are presented.

The experiences and success stories of proposed technologies, including the micro irrigation, gathered from researchers and various states are also presented for the benefit of stake holders and the planners.