Background: Water productivity improvement is fundamental to agricultural water use control, and the water footprint provides a new and comprehensive method for identifying the crop-water relationship. This study is intended to explore the spatiotemporal pattern and driving forces underlying the rice water footprint productivity (WFP) in China during the years 1996-2015 based on calculations of the provincial blue, green, gray, and white water footprints.
Results: The national water footprint in paddy rice cultivation was 240.97 Gm3 , and green water accounted for 43.9% of the total. The WFP was 0.795 kg m-3 and increased over time in all 30 provinces for which it was calculated. The growth rate in the northern provinces was greater than that in the southern part of the country. The WFP clustered geographically in all years observed. High-value provinces were concentrated to the south of the Yangtze River, whereas most of the provinces that showed a low WFP were distributed in the north China and northwest subregions. Precipitation and sunshine hours were the most obvious driving factors of rice WFP. The effects of agricultural input, e.g., agricultural machinery power, pesticides, and irrigation efficiency, on WFP also could not be ignored.
Conclusion: The WFP is a comprehensive and useful index of the crop-water relationship and water-use efficiency. Improving agricultural input and irrigation technology are reliable approaches for WFP promotion. Areas in northeast China showed the most urgent need for improving the rice WFP, and the inclusion of the main grain producing areas in the Yangtze River Basin will further reduce ineffective water occupancy to improve water-use efficiency. © 2019 Society of Chemical Industry.
Keywords: blue-green water; partial least-squares regression (PLSR); rice production; water-use efficiency; white water footprint.
© 2019 Society of Chemical Industry.