1. Institute of Water Saving Agriculture in Arid Regions of China, Northwest A & F University, Yangling 712100, China.2. Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100 , China.3. National Engineering Research Center for Water Saving Irrigation at Yangling, Yangling 712100, China.4. College of Water Resources and Architectural Engineering, Northwest A & F University, Yangling 712100, China
Water shortage has become a significant constraint to grain production in China. A more holistic approach is needed to understand the links between grain production and water consumption. Water footprint provides a framework to assess water utilization in agriculture production. This paper analyzes the spatiotemporal variation in water footprint of grain production (WFGP) in China from 1951 to 2010. The results show that, jointly motivated by the improvement of agricultural production and water use efficiency, WFGP in all areas showed a decreasing trend. National average WFGP has decreased from 3.38 to 1.31 m ·kg . Due to regional differences in agricultural production and water use efficiency, spatial distribution of WFGP varies significantly and its pattern has changed through time. Moreover, WFGP may show significant differences within areas of similar climatic conditions and agricultural practices, indicating that there is a strong need to improve the management of water use technology. Statistical analysis revealed that regional differences in grain yield are the main cause for variations in spatiotemporal WFGP. However, the scope for further increases in grain yield is limited, and thus, the future goal of reducing WFGP is to decrease the water use per unit area.