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 m3·kg-1. 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.