Spatiotemporal evolution characteristics and influencing factors of eco-efficiency of cultivated land use in southern mountainous regions of China

Against the backdrop of multiple pressures on cultivated land protection and the advancement of ecological civilization construction, enhancing the ecological efficiency of cultivated land utilization (ECLU) is crucial for sustainable agricultural development in the hilly and mountainous regions of southern China. This study takes 76 counties/districts in Fujian Province, a typical hilly and mountainous province, as research units. Based on panel data from 2013 to 2022, it employs the Super-SBM model considering undesirable outputs to measure ECLU. Combined with Exploratory Spatial Data Analysis (ESDA), Random Forest (RF), and Geographically and Temporally Weighted Regression (GTWR) models, the study reveals the spatiotemporal evolution characteristics and influencing factors of ECLU. The results indicate that: (1) The overall ECLU in Fujian Province is relatively low (0.54–0.73), showing a fluctuating upward trend. Spatially, it exhibits a significant “higher in the northwest, lower in the southeast” differentiation pattern, with efficiency generally higher in inland areas than in coastal areas. (2) ECLU demonstrates significant positive spatial autocorrelation. High–High (HH) clusters are mainly distributed in the northwestern inland region, while Low–Low (LL) clusters are concentrated in the southeastern coast. (3) The Random Forest model identified agricultural planting structure, cultivated land management scale per laborer, and proportion of agricultural output value as key influencing factors. The GTWR model further revealed significant spatiotemporal heterogeneity in the effects of these factors, with fertilizer input level being the primary negative driver. This research provides a scientific basis for optimizing cultivated land resource allocation and enhancing ecological efficiency in southern China’s mountainous regions. Key recommendations include controlling fertilizer input, optimizing planting structure, developing moderate-scale operations, and strengthening regionally differentiated policy guidance.