摘要
Changing precipitation patterns and shortages of surface and groundwater in important cropping regions pose a serious threat to China’s future food security. This paper presents a comprehensive analysis of water used for food production over the period 1998-010 with a view to identifying pathways for achieving the national target of 580 million tons of grain output by 2020. The analysis was based on modelling of agricultural water use coupled with national and provincial statistics. The present situation was defined by (a) a slow declining trend in national precipitation and internally renewable water resources, (b) 12 out of the 13 so-called breadbasket provinces (which currently produce 74 % of national grain output) already facing water shortages and increasing competition for water from non-agricultural sectors, (c) national crop water productivity (CWP) increases of 19.5 % over the 13 years to 2010, and (d) a widening gap in CWP between breadbasket and non-breadbasket provinces. By 2020 an estimated 510 to 680 km3 of water will be required for food production depending upon future gains in CWP. A concern is that in many of the breadbasket provinces, recent CWP gains have already been substantial and additional large gains may prove difficult especially considering current environmental concerns related to agricultural intensification in China. That said, the historic efficiency gains give reason for optimism provided that there is continued investment in genetic improvement and innovation of farming systems. Keywords Crop water consumption Crop water productivity Crop water use efficiency Agricultural water management Sustainable agriculture Food security