Water Efficient Irrigation and Environmentally Sustainable Irrigated Rice Production in China

Rice is one of the most important food crops contributing over 39% of the total food grain production in China. Out of 113 million hectares of area sown under food crops 28% is covered by rice. The traditional irrigation regime for rice, termed as “continuous deep flooding irrigation” was applied in China before 1970s. A tremendous amount of water was used for the rice growing and only a low yield of rice was obtained under this regime. Since 1980s, the industry water supply, urban and rural domestic water consumption have been increasing continuously. The shortage of water resources became an important problem and many water efficient irrigation regimes for rice have been tested, advanced, applied and spread in different regions of China. Based on the results of experiment and the experience of spread of these new irrigation regimes, the following three main kinds of water efficient irrigation regimes were found to be contributing to the sustainable increased water productivity viz. (1) combining shallow water depth with wetting and drying, (2)alternate wetting and drying and (3) semi-dry cultivation. In this paper, the standard of controlling field water, conditions and the attention points of the application for the three regimes are introduced and explained.. The causes of sustainable increase in water productivity and the environmental impacts by adopting these regimes are analyzed and discussed.