Water Footprint Assessment of Major Crops in Henan Province and Reduction Suggestions

Henan Province, located in the North China Plain, as one of the most important grain production bases in China, is facing severe challenges of water pressure and sustainable development caused by agricultural production. In this study, water footprint (WF) estimation and sustainability assessment of crop production were carried out for wheat and maize, two major crops in the Henan Province. Based on a set of global WF benchmark values for various crops which were established by previous studies, we calculated a set of benchmark values of blue water footprint (BWF, surface water, and groundwater) for major crops in Henan Province. Four benchmark values were calculated for each crop, and we selected two of them as the optimal and sub-optimal benchmark levels. Additionally, potential blue water savings were estimated by reducing the crop-specific BWF to different benchmark levels. According to our simulations with CROPWAT 8.0, the average annual blue water footprint of wheat production in Henan Province from 2006 to 2016 was 7914 Million m(3), of which about 77% is unsustainable, and that of maize production is 703 Million m(3), of which about 70% is unsustainable. When reducing the water footprint of wheat production to optimal or sub-optimal benchmark levels, approximately 2742 Million m(3) or 375 Million m(3) blue water can be saved, and reducing that of maize production to optimal or sub-optimal benchmark levels could save approximately 214 Million m(3) or 44 Million m(3) blue water.