Use of efficient water saving techniques for production of rice in India under climate change scenario: A critical review

Abstract

Rice uses 34 to 43 per cent of the global irrigation water and is responsible for the withdrawal of 24–30 per cent of the of World's total freshwater. In Asia, irrigation consumes greater than 80% of the freshwater resources available and among that rice irrigation accounts for more than 50%. The amount of water applied to produce 1 kg of rice ranges from 800 to 5000 L, with an average value of about 2500 L. Earlier studies indicated that seasonal water requirement for rice ranged from 660 to 5280 mm depending on the climatic features, growing season, hydrological framework and type of soil conditions, with the average value range from 1000 to 2000 mm as a mean value in most cases. Several approaches of water saving techniques such as, AWD- Alternate Wetting and Drying, SSC- Saturated Soil Culture, aerobic rice, ground-cover systems, SRI- System of Rice Intensification, raised beds, etc. are discussed in lieu of frequent occurrence of extreme weather events and depleting water resources globally. Climate change and variability alters the water requirement, a simulation study by CROPWAT for temperature increase from 0.5 to 3.0 °C resulted in an increase in the irrigation water requirement from 0.6 to 3.7%, respectively. Future climate models showed that the rice growing area and yield of paddy tends to have a minor increase (1.55%) in some of the RCPs. Adopting innovative water saving techniques are absolutely essential for maintaining the food security (future rice production) due to increasing water scarcity under the changing climate scenario. Water savings in rice farming through different approaches are discussed and even adoption of any of these practices will transform into saving of larger quantity of water, since huge quantities of fresh water is used for rice cultivation. Because of the continuously depleting water table due to natural and anthropogenic factors, here we have explored to exploit the potentials of various water-saving approaches and the strategies for improving the water productivity along with the improved yield of rice in this review.