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Fresh water is consumed during agricultural production. With the shortage of water resources, assessing the water use efficiency is crucial to effectively managing agricultural water resources. The water footprint is a new index for water use evaluation, and it can reflect the quantity and types of water usage during crop growth. This study aims to establish a method for calculating the region-scale water footprint of crop production based on hydrological processes. This method analyzes the water-use process during the growth of crops, which includes irrigation, precipitation, underground water, evapotranspiration, and drainage, and it ensures a more credible evaluation of water use. As illustrated by the case of the Hetao irrigation district (HID), China, the water footprints of wheat, corn and sunflower were calculated using this method. The results show that canal water loss and evapotranspiration were responsible for most of the water consumption and accounted for 47.9 % and 41.8 % of the total consumption, respectively. The total water footprints of wheat, sunflower and corn were 1380–2888 m3/t, 942–1774 m3/t, and 2095–4855 m3/t, respectively, and the blue footprint accounts for more than 86 %. The spatial distribution pattern of the green, blue and total water footprint for the three crops demonstrated that higher values occurred in the eastern part of the HID, which had more precipitation and was further from the irrigating gate. This study offers a vital reference for improving the method used to calculate the crop water footprint. |
