Water footprint of crop production for different crop structures in the Hebei southern plain, North China
The North China Plain (NCP) has a serious shortage of freshwater resources, and crop production consumes approximately 75 of the region's water. To estimate water consumption of different crops and crop structures in the NCP, the Hebei southern plain (HSP) was selected as a study area, as it is a typical region of groundwater overdraft in the NCP. In this study, the water footprint (WF) of crop production, comprised of green, blue and grey water footprints, and its annual variation were analyzed. The results demonstrated the following: (1) the WF from the production of main crops was 41.8 km3 in 2012. Winter wheat, summer maize and vegetables were the top water consuming crops in the HSP. The water footprint intensity (WFI) of cotton was the largest, and for vegetables, it was the smallest; (2) the total WF, WFblue, WFgreen and WFgrey for 13 years (2000 2012) of crop production were 604.8, 288.5, 141.3 and 175.0 km3, respectively, with an annual downtrend from 2000 to 2012; (3) winter wheat, summer maize and vegetables consumed the most groundwater, and their blue water footprint (WFblue) accounted for 74.2 of the total WFblue in the HSP; (4) the crop structure scenarios analysis indicated that, with approximately 20 of arable land cultivated with winter wheat summer maize in rotation, 38.99 spring maize, 10 vegetables and 10 fruiters, a sustainable utilization of groundwater resources can be promoted, and a sufficient supply of food, including vegetables and fruits, can be ensured in the HSP.