Abstract: Climate change has brought about alteration in rice water consumption, and thus affected the demand for irrigation water in paddy field. In this study, the changes in rice water consumption and irrigation water demand from 1955 to 2013 in Gaoyou irrigation area under water-saving irrigation (WSI) and flood irrigation (FI) were investigated by means of water balance calculation in the paddy field and Mann-Kendall analysis. Results indicated that air temperature presented significant increasing trends during the past six decades, and rainfall presented slight decreasing trends. Rice evapotranspiration and percolation under WSI and FI both presented gradual increasing trends, but rice water consumption decreased significantly under WSI; irrigation water demand in paddy field declined gradually under WSI while increased slightly under FI. Moreover, precipitation utilization efficiency has remarkably improved under WSI regimes. We conclude that the adverse effects of climate change on rice production can be effectively mitigated by using WSI technology, which would be an important measure of sustainable development for irrigation areas under changing environment.

Key words: climate change, water-saving irrigation, water consumption, irrigation water demand, paddy