Optimizing cultivated land under non-grain expansion in rural China: unveiling the spatial dynamics of trade-offs and synergies among ecosystem services

Non-grain expansion in rural China has affected the stability of cultivated land structure and the sustainability of ecosystem services (ESs). Delving into the spatio-temporal heterogeneity of ES interactions is essential for refined and differentiated cultivated land management practices. Taking Tongxiang City as an example, this study mapped the variations of four ESs of cultivated land from 2000–2020, identified their socio-ecological drivers, explored the spatial non-stationarity characteristics of trade-off/synergy among different ESs, and proposed a zoning control framework for cultivated land. The results indicated that (1) food supply (FS) and habitat quality (HQ) decreased by 40.40% and 1.27%, respectively, while carbon sequestration (CS) and soil conservation (SC) increased by 8.5% and 26.21%, respectively. Areas of decreased ES were mainly concentrated in the southwest, while areas of increased ES supply were dispersed. (2) CS-SC and CS-FS ES pairs exhibited obvious trade-offs, with concave trade-offs dominating between 2000 and 2010, and convex trade-offs prevailing from 2010 to 2020. These ES trade-offs were mainly distributed in the southeast and northern regions. HQ-CS and FS-SC presented significant synergies, predominantly characterized by linear synergy and situated in the northern and central areas. (3) The spatial differentiation of ESs was mostly explained by landscape configuration drivers. (4) Different cultivated land zones were delineated based on the spatial non-stationarity of trade-offs/synergies and ES advantage areas. This study contributes to our understanding of the changes in ESs resulting from non-grain expansion and offers valuable guidance for implementing differentiated measures for cultivated land zoning and management.