S David, 'Water for food, water for life: a comprehensive assessment of water management in agriculture: summary. In Mandarin', International Water Management Institute (IWMI); Earthscan, 2014

【Objective】Food production is the primary consumer of water resources in many countries. At the catchment and basin scale, understanding the spatiotemporal variation of food production and the underlying determinants is crucial for improving water resource use efficiency and promoting sustainable development. We propose a new method in this paper to analyze this issue.【Method】Our study focuses on the Yangtze River Basin. The water used for food production and its spatiotemporal variation from 2000 to 2020 in the basin were calculated based on crop water demand. Path analysis was used to elucidate the underlying determinants affecting the blue and green water footprint per unit area.【Result】① The annual average grain water footprint in the basin from 2000 to 2020 was 205.25×109 m3, with the green water footprint accounting for 66%. ② Due to differences in cultivation scales, the upper, middle, and lower reaches contributed 36.5%, 46.8%, and 16.7%, respectively, to the total grain water footprint of the basin. Additionally, the grain water footprints in the middle and lower reaches have increasingly relied on green water. ③ Meteorological factors positively influenced the density of the green water footprint and negatively affected the density of the blue water footprint. Social development and economic factors significantly impacted the density of the blue water footprint. 【Conclusion】 The middle reaches of the Yangtze River Basin, where irrigation demand for grain crop production is high, are likely to face growing pressure due to land and water resource shortages. This challenge is particularly acute in Henan, Hubei, Hunan, and Jiangxi provinces, where investments in agricultural infrastructure, such as irrigation systems and advanced water management technologies, are essential. In Gansu, Qinghai, and Henan provinces, where water scarcity and pollution persist, adopting technologies such as soil mulching, rainwater harvesting and water storage can enhance green water utilization and alleviate regional water resource pressures.