Three-dimensional agricultural water scarcity assessment based on water footprint: A study from a humid agricultural area in China

The comprehensive assessments of quantitative and qualitative water scarcity have been agreed upon in many parts of the world. However, most of the previous studies on water scarcity focus on quantitative water scarcity and arid regions. In this study, based on the water footprint theory, we proposed three-dimensional agricultural water scarcity indexes by simultaneously considering water quantity and water quality, blue water scarcity, green water scarcity, and grey water scarcity. With the help of CROPWAT 8.0, we calculated the three-dimensional agricultural water scarcity index of Liuyang City, a humid region in China, from 2010 to 2019. Meanwhile, the STIRPAT model was used to investigate the effect of human and natural factors on the agricultural water scarcity index. The results show that: (1) During the study period, the agricultural water resources had a shortage of water quantity in Liuyang City, and the blue water scarcity index (WSIblue) exceeded the water shortage threshold in drought years. The green water scarcity index (WSIgreen) exceeded the water shortage threshold from April to July in most years; while the grey water scarcity index (WSIgrey) did not exceed the threshold, which means there was no water qualitative water scarcity during the study period. (2) The natural meteorological conditions have the greatest influence on the three-dimensional scarcity index, among which meteorological factors inhibit the WSIblue and WSIgrey, and promote the WSIgreen. (3) Green water contributes significantly to crop growth, accounting for 42 % of the crop's total water footprint. According to the change law of the green water scarcity index on the monthly scale to guide agricultural production, it plays an important role in regional water resources management. This study is expected to provide scientific suggestions for alleviating regional water resources pressure by considering virtual water use.