人类的生活、生产和社会发展都离不开水、能源、粮食资源，三种资源之间相互关联，彼此制约，在人口增长、城市化、经济增长和气候变化等因素的驱动下，影响着经济发展和生态环境。长江经济带水资源禀赋较好，涵盖了我国粮食主产区近一半的省份，但由于是我国传统制造业的重要基地，存在大量高耗能、高污染的产业，一次能源生产量较低，能源消费结构复杂。水、能源、粮食资源间的供需矛盾阻碍了经济的协调发展，更是制约着长江经济带的绿色可持续发展。因此，本文通过分析水-能源-粮食系统的资源流通及消费特征和压力情况来解析长江经济带水-能源-粮食纽带关系。首先构建了长江经济带区域间投入产出表，利用投入产出模型核算了完全资源使用系数；然后通过虚拟资源贸易流计算模型解析了水-能源-粮食系统资源流通及消费特征；最后，对水-能源-粮食系统压力及虚拟资源流通对当地资源压力的缓解和加重情况进行了分析，并提出相应的资源压力调控建议。主要得到以下结论：

（1）长江经济带各行业的完全资源使用系数差异很大。完全用水、用能、用粮系数最高的行业分别是燃气和水的生产和供应业（2726m³/万元）、电力、热力的生产和供应业（2425kg标准煤/万元）、批发零售和住宿餐饮业（316kg/万元）。食品和烟草制造业、纺织业、纺织服装鞋帽皮革羽绒及其制品业、木材加工品和家具制造业、造纸印刷和文教体育用品业具有较高的完全用水系数和完全用粮系数，是农林牧渔业的下游加工行业，石油、炼焦产品和核燃料加工业、化学产品制造业、非金属矿物制品业、金属冶炼和压延加工业和金属制品业具有较高的完全用能系数，属于能源开采行业的下游加工制造业，这些行业都相应投入了大量的资源密集型产品。

（2）就全国而言，长江经济带虚拟水、虚拟能源和虚拟粮食贸易整体均呈现净流出，流出量分别为119.98亿m³、1548.26亿kg和9.48亿kg。长江经济带下游地区虚拟资源流通较为频繁，中上游流通量较低。就虚拟资源流动格局来说，虚拟粮食净流出的省份与粮食生产格局相匹配，虚拟粮食主要流出地为粮食主产区，但虚拟水和虚拟能源流通格局与资源禀赋不相符，水资源禀赋较好的地区呈现虚拟水净流入，能源条件较差的地区呈现虚拟能源净流出。长江经济带水相关行业消费了0.41%和0.17%的虚拟能源和虚拟粮食，能源相关行业消费了1.87%和0.63%的虚拟水和虚拟粮食，粮食相关行业消费了45.36%和11.20%的虚拟水和虚拟能源。

（3）长江经济带水-能源-粮食系统压力最大的是下游地区，其次是中游地区，上游地区压力最小。在上、中、下游中压力较大的地区分别为重庆、湖北和江浙沪地区。建议加强上游地区与中下游地区的贸易合作，打造立体交通运输网络，适当转移资源密集型产品加工制造业，利用人工智能科学技术赋能产业转型升级，提高资源利用效率并加强生态环境保护与治理。

Water, energy and food are all strategic and basic resources, which are interrelated and restricted mutually. Driven by factors such as population growth, urbanization, economic growth and climate change, they are affecting human production, life and ecological environment. The Yangtze River Economic Belt is rich in water resources, covering nearly half of the provinces in China’s major grain-producing areas. However, as an important base of China's traditional manufacturing industry, the Yangtze River Economic Belt has plenty of industries with high energy consumption and high pollution. At the same time, the primary energy production in the Yangtze River Economic Belt is low, and the structure of energy consumption is complex. The contradiction between supply and demand of water, energy and food resources hinder the coordinated development of economy and restrict the green and sustainable development of the Yangtze River Economic Belt.Therefore, the water - energy - food nexus in the Yangtze River Economic Belt was analyzed by analyzing the resource circulation and consumption characteristics and pressure of the water - energy - food system. First, the multi-regional input-output table of the Yangtze River Economic Belt was constructed, and the complete resource utilization coefficient was calculated by using the input-output model. Then the resource circulation and consumption characteristics of water-energy-food system were analyzed by the virtual resource trade flow calculation model. Finally, the pressure of water-energy-food system and the alleviation and aggravation of local resource pressure by virtual resource circulation were analyzed, and resource regulation suggestions were put forward. The main conclusions are as follows:

(1) The complete resource utilization coefficient of each industry in the Yangtze River Economic Belt is very different. The highest total consumption coefficient of water, energy and food aregas and water production and supply industry (2726m³/ ten thousand yuan), power and heat production and supply industry (2425kg standard coal/ten thousand yuan), wholesale, retail trade industry and accommodation and catering industry (316kg/ ten thousand yuan) respectively. Food processing and tobaccos industry, textile industry, textile, clothing, shoes, hats, leather, down and their products industry, wood processing and furnishing industry, paper making, printing, cultural, educational and sporting goods industry have high total consumption coefficient of water and food, and they are downstream processing industry of agriculture, forestry, animal husbandry and fishery. Petroleum, coking products and nuclear fuel processing industry, chemical products manufacturing industry, nonmetallic mineral products industry, metal smelting and calendering industry, metal products industry have a high total consumption coefficient of energy and belong to the downstream processing and manufacturing industry of the energy exploitation industry, which have invested a large number of resource-intensive products.

(2) As for the whole country, virtual water, virtual energy and virtual food trade in the Yangtze River Economic Belt all showed net outflows, with outflows of 11.998 billion m³, 154.826 billion kg and 948 million kg, respectively. The flow of virtual resources is frequent in the lower reaches of the Yangtze River Economic Belt, while the flow in the upper and middle reaches is low.In terms of the flow pattern of virtual resources, the provinces with the net outflow of virtual food matched the pattern of food production, and the main areas of virtual food outflow were the major grain producing areas.However, the circulation pattern of virtual water and virtual energy are not consistent with the resource endowment.The regions with good water resources endowment show a net inflow of virtual water, while the regions with poor energy conditions show a net outflow of virtual energy.Water-related industries in the Yangtze River Economic Belt consumed 0.41% and 0.17% of virtual energy and virtual food, energy-related industries consumed 1.87% and 0.63% of virtual water and virtual food, and food-related industries consumed 45.36% and 11.20% of virtual water and virtual energy.

(3) In the Yangtze River Economic Belt, the pressure of water-energy-food system is the greatest in the lower reaches, followed by the middle reaches, and the pressure in the upper reaches is the least. In the lower reaches, Jiangsu province, Zhejiang province and Shanghai are under the greatest pressure. Hubei province is the province with high pressure in the middle reaches. Chongqing is an area with high pressure in the upper reaches. Therefore, strengthen the trade cooperation between the upper reaches and the middle and lower reaches, build a three-dimensional transportation network, transfer the processing and manufacturing industry of resource-intensive products properly, enabling the transformation and upgrading of industries with science and technology, improve resource utilization efficiency and strengthen ecological environmental protection and governance were proposed to control the resources.