Sustainable evaluation of agroecosystem in the Yangtze River Economic Belt, China based on the Emergy Theory

The economic development level of the Yangtze River Economic Belt is relatively high, and the modern agricultural production has brought serious pressure to the agricultural ecological environment. At present, there is no research on the sustainable status of agroecosystem in the Yangtze River Economic Belt, based on the emergy theory, this paper analyzes and evaluates the input–output structure and sustainable status of the Yangtze River Economic Belt by calculating the input–output factors and relevant emergy indexes from 2010 to 2018. The results show that the total input and output emergy of the Yangtze River Economic Belt shows an upward trend from 2010 to 2018. The input of non-renewable industrial auxiliary emergy is too high which has been more than 80%, and the structure of agriculture, forestry, animal husbandry, and fishery industry is unreasonable, which makes the net emergy yield rate of the system very low, its value was only 0.23 in 2018, far less than 1, and the agroecosystem is in an unsustainable state. Except for Shanghai, most provinces and cities of the Yangtze River Economic Belt are in an unsustainable state, and the status of the agricultural ecological environment is not optimistic. From 2010 to 2018, the overall ecological environment of the agricultural ecosystem in the Yangtze River Economic Belt is not optimistic. Among them, the most affected agricultural ecosystem’s sustainable development index is the cash-crop area, total population, and agricultural fixed asset investment. Relevant departments and agricultural practitioners need to change the resource input structure of the agricultural ecosystem, reduce the dependence on industrial auxiliary energy, improve resource utilization efficiency, adjust the industrial structure of agricultural output and increase the production of high-emergy products, to realize sustainable development of the agricultural ecosystem.