[Spatiotemporal Evolution and Driving Factors of Net Carbon Sink in Rice Production in Hunan Province: An Externality Perspective].

The environmental impact of rice production has predominantly been studied in terms of ecosystem service functions and non-point source pollution, with limited research addressing net carbon sinks through the lens of externalities. Assessing this dimension is crucial for facilitating the ecological transition of rice production and achieving the "dual carbon goals." Utilizing panel data from 14 prefecture-level cities in Hunan Province spanning 2000 to 2021, this study employs standard deviation ellipse and trend surface analysis to investigate the spatiotemporal dynamics of net carbon sinks in rice production. Geographic detectors and geographically and temporally weighted regression were applied to identify the driving factors. The findings revealed that： ① Throughout the study period, the net carbon sink in Hunan Province's rice production exhibited a pattern of "initial decline followed by fluctuating increase," with an overall growth rate of 14.17%. Regions with advanced rice production showed trends more closely aligned with the overall pattern. ② The spatial distribution of the net carbon sink followed a "northwest-southeast" orientation, generally shifting northwestward, indicating stability and concentration. ③ Since 2010, the net carbon sink has displayed a "high in the north and south, low in the east and west" configuration, with increasing regional disparities. ④ Economic, social, technological, and natural factors all impacted the net carbon sink of rice, with agricultural financial support and mechanization level being the primary determinants, each accounting for over 0.667 of the variance, and exhibiting strong interaction effects. ⑤ The net carbon sink was significantly influenced by variations in driving factors, demonstrating marked spatial heterogeneity. Formulating location-specific policies, optimizing fiscal support, improving irrigation techniques, monitoring changes in driving factors, and promoting regional cooperation are recommended. Through innovative carbon reduction and sequestration measures, the sustainable development of the rice industry can be achieved.