Function Evolution of Oasis Cultivated Land and Its Trade-Off and Synergy Relationship in Xinjiang, China

Cultivated land (CL) performs irreplaceable manifold functions in social stability, economic development, and ecological security, which is also essential for the accomplishment of the United Nations Sustainable Development Goals 2030 Agenda. China is the world's most populous country, and it has important reference significance for the realization of the multi-function synergistic management of CL in China by revealing the evolution characteristics of cultivated land functions (CLFs) and the interaction between CLFs. However, the research to date has tended to focus on the eastern coastal areas and the central traditional agricultural areas of China. This study focuses specifically on Xinjiang, the main area of the arid region of northwest China. The connotations of social, economic, and ecological functions of oasis cultivated land (OCL) in Xinjiang were first discussed from a system theory perspective. Then, an evaluation index system of CLFs was constructed. On this basis, the evolution characteristics of CLFs and the interaction between CLFs in Xinjiang from 1990 to 2018 were quantitatively evaluated. Findings suggest that: (1) the economic function of the OCL in Xinjiang is strengthening, while the ecological function is degrading and the social function remains stable. Overall, the evolution of CLFs in Xinjiang was first dominated by ecological and social functions and then became economic-function-oriented; (2) the synergistic relationship between CLFs is weakening and the trade-off relationship is increasing over time. The trade-off effect between the economic function and other functions of OCL is strengthened gradually due to the OCL-use activities dominated by the economic function. This study not only enriches the regional content of CL multi-function research but can also provide reference for decision-making for the sustainable utilization and multi-function synergistic management of OCL in Xinjiang, China.