Spatiotemporal Evolution, Nonlinear Driving Mechanisms, and Targeted Remediation of Cropland Fragmentation in the Sichuan Basin: A Temporally Enhanced Index and <scp>GeoXAI</scp> Approach

ABSTRACT Cropland fragmentation (CLF) constitutes a critical manifestation of land degradation and poses a major challenge to agricultural modernization and food security in topographically complex grain‐producing regions. However, long‐term fine‐scale evidence on the spatiotemporal dynamics of CLF and its spatially explicit nonlinear associations remains limited. Focusing on the Sichuan Basin, this study addressed this gap by integrating the 30‐m China's Annual Cropland Dataset (CACD) from 1986 to 2021 with a 1‐km analytical framework. A temporally enhanced cropland fragmentation index (tCFI) was developed based on temporal principal component analysis (tPCA), and was further combined with emerging hotspot analysis, piecewise breakpoint detection under a non‐seasonal setting, and an XGBoost‐GeoShapley framework to characterize long‐term fragmentation patterns, temporal transitions, and nonlinear spatial associations. The results showed that: (1) basin‐wide mean CLF intensified by 22.5% over the study period and exhibited a clear central aggregation‐peripheral fragmentation pattern; (2) cold spots accounted for 40.93% of the study area and were concentrated mainly in the central plains, whereas hotspots dominated the northeastern mountainous belt; (3) trend classification indicated an increase‐dominated pattern, with monotonic increase accounting for 32.14% of the study area and 52.6% of structural breakpoints concentrated during 2007–2014; and (4) GeoShapley results showed that topography provided a relatively stable spatial background for fragmentation, while the relative contributions of nighttime lights and temperature became more pronounced in the later benchmark years analyzed. Overall, the findings suggest that cropland fragmentation in the Sichuan Basin was jointly associated with persistent topographic constraints and time‐varying pressures related to urban development and hydrothermal variability. This study provides a fine‐scale and temporally comparable framework for long‐term CLF assessment and supports differentiated land‐remediation strategies in topographically diverse agricultural regions.