System dynamic relationship between service water and food: Case study at Jinghe River Basin

Water resources and food are the most important and basic resources for human beings and society. In recent decades, due to the growth of global population and economy, water resources and food shortages have become a global resource problem. Under this background, the significance of exploring the relationship between water-food in ecosystem services becomes more and more prominent. In view of this, this study used the SWAT model and the spatialized food production model to quantitatively evaluate the supply, demand, and supply-demand ratio of water and food production in the Jinghe River Basin in 2020, and built a system dynamics model of the watershed ecosystem services to simulate the coupling of water and food. According to the socio-economic conditions, nine different population economic development scenarios were set up to simulate the development of the water-food relationship between the ecosystem services of the river basin in 2030. The results showed that ① the spatial differences in water supply-demand ratio and food self-sufficiency rate in Jinghe River Basin in 2020 were obvious, and the supply-demand ratio in the upper reaches of the basin was significantly higher than that in the lower reaches. ② Through model simulations of three water supply-demand ratios and three food self-sufficiency rates, it was found that the water supply-demand ratios and food self-sufficiency rates showed obvious synergistic relationships both in time and in spatial distribution. ③ Under nine economic and demographic development scenarios, the optimal simulation effect was achieved under scenario E1P3 for both water-food supply and demand in the Jinghe River Basin in 2030. That was, when the economy and population develop in opposite directions, the supply-demand ratio of the two achieved the best simulation effect. The results provided a scientific basis for the sustainable development of water-food relationship in Jinghe River Basin in the future.