Crop water footprints and their driving mechanisms show regional differences

Abstract

Identifying crop water footprints and their driving mechanisms is of significant importance for regional water resources management and ecological sustainability. However, there is currently a lack of comparative studies on drivers of crop water footprint among multiple regional types. In this study, based on quantifying the crop water footprints in seven regions (North China, Northeast China, East China, Central China, South China, Southwest China, and Northwest China) in mainland China from 1996 to 2020, the path analysis method was used to reveal their driving mechanisms. The results showed that the average annual agricultural water footprint was 1448.2 Gm3, with blue water, green water, and grey water accounting for 10.1 %, 66.6 %, and 23.3 %, respectively. Fruits and cereals jointly contributed 80 % of the total water footprint. The crop water footprint in East China was significantly higher than in other regions, accounting for 29.3 % of the national water footprint. The average crop production water footprint was 1080.4 mm, with the highest values observed in East China and South China, and the lowest in Northeast China and Southwest China. Except for East China, the crop production water footprint in other regions showed an increasing trend over time. Irrigation area ratio had the greatest impact on crop production water footprint except for Northeast China, while chemical fertilizer consumption significantly influenced crop production water footprints in North, East, Central, Southwest and Northwest China. Additionally, per capita GDP, per capita net income and irrigation water use efficiency also had considerable effects on crop production water footprint in Northwest China. The research findings can provide a valuable reference for the development of strategies for the efficient and sustainable utilization of agricultural water resources in different regions.