Optimizing land use patterns for the grain for Green Project based on the efficiency of ecosystem services under different objectives

In the 20 years since the implementation of the Grain for Green Project (GFGP), the ecological environment in western China has improved. It is important to study the interaction between the spatial distribution of land use and ecosystem services as well as the interaction among ecosystem services under the GFGP for the purpose of improving regional ecosystem services. In this paper, we explore the influence of topography, climate and social demographic factors on ecosystem services, analyze the trade-offs and synergies among different ecosystem services, and choose suitable regional land use optimization strategies from hundreds of land use scenarios for GFGP from the efficiency of ecosystem services with different objectives viewpoint. Three key findings were obtained. First, grain supply has a trade-off relationship with soil conservation, and so as with carbon sequestration, while soil conservation and carbon sequestration have a synergistic relationship. Second, the implementation of GFGP strengthened the functions of carbon sequestration and soil conservation but weakened the function of grain supply. Third, the conversion schemes for retired farmland under different scenarios provide land use optimization strategies for the development of different ecosystem service objectives.