[Answered]What is water-use efficiency? Describe the role of micro-irrigation in increasing the water-use efficiency.

Water use efficiency (WUE) is the measure of a cropping system’s capacity to convert water into plant biomass or grain. It includes both the use of water stored in the soil and rainfall during the growing season. Water use efficiency is about careful management of water supply sources, use of water serving technologies, reduction of excessive demand and other actions. In context of Indian agriculture, recognising the fast declining irrigation water potential and increasing demand for water from different sectors, a number of demand management strategies and programmes have been introduced. One such method is micro-irrigation that includes drip irrigation and sprinkler irrigation.

Role of micro-irrigation in increasing water use efficiency:

1. Micro-irrigation (MI) is proved to be an efficient method in saving water and increasing water use efficiency as compared to the conventional surface method of irrigation, where water use efficiency is only about 35-40%.
2. The on-farm irrigation efficiency of properly designed and managed drip irrigation system is estimated to be about 90%.
3. Productivity gain due to use of micro-irrigation is estimated to be in the range of 20 to 90% for different crops.
4. The reduction in water consumption in micro-irrigation also reduces the energy use (electricity) that is required to lift water from irrigation wells.
5. Farmers using a pumping systems to irrigate their fields should ensure that the pump and pipe size are fitting with their needs, thus avoiding water and energy overuse and consequent leakages.
6. Emerging computerised GPS-based precision irrigation technologies for self-propelled sprinklers and micro-irrigation systems will enable growers to apply water and agrochemicals more precisely and site specifically to match soil and plant status and needs as provided by wireless sensor networks.

Government of India has also accorded high priority to water conservation and its management. Pradhan Mantri Krishi Sinchayee Yojana (PMKSY) has been formulated with the vision of extending the coverage of irrigation ‘Har Khet Ko Pani’ and improving water use efficiency ‘More crop per drop’ in focused manner using sprinkler & drip method of irrigation. This irrigation method has several advantages over furrow systems, including reduced water use.