Spatiotemporal dynamics and environmental drivers of paddy rice cropping patterns in China: Essential indicators for agricultural sustainability

Accurate quantification of the paddy rice cropping pattern (PRCP), including field area, cropping intensity (CIPR), and cropping calendar, is critical for ensuring food security and informing agricultural policy. This study developed a novel framework to map PRCP across China with a refining phenological feature-based method. Specifically, we enhanced the identification of paddy field areas and introduced a simplified approach to derive CIPR and cropping calendar, establishing an integrated framework for comprehensive PRCP detection. The framework was validated through 2,977 ground samples and national agricultural statistics, demonstrating strong applicability at regional scales and effectively extracted PRCP. Key ecological findings are outlined below: (1) While the national paddy area remained stable, its centroid shifted northeastward (though the post-2015 migration rate declined by 96 %), driven by contraction in southern China (–0.47 kha/yr pre-2015) offset by northern expansion (+0.52 kha/yr) linked to urbanization, water scarcity, and climate adaptation. Over 75 % of paddies remained concentrated below 200 m elevation, yet high-altitude cultivation (>700 m) emerged notably in Inner Mongolia due to technological advances. (2) Double-cropping areas declined by 0.27 kha/yr (2000–2011), especially in major lake basins and southern coastal regions, associated with labor shortages and economic pressures, while single-cropping stabilized post-2012, reflecting adaptations to resource constraints. (3) Latitudinal gradients delayed first-season transplanting and harvesting by 0.77 days/yr, primarily due to CIPR reduction, whereas second-season dates remained stable within their southern confines (<28°N). The FSe framework provides a robust indicator system for agroecosystem sustainability assessment. The observed CIPR reduction, phenological delays, and spatial migration highlight adaptive responses to climate and socioeconomic pressures. This work establishes a transferable model for global rice monitoring, informing critical policies on water conservation, methane mitigation, and climate-resilient agriculture.