Spatiotemporal dynamics of carbon imbalance in agricultural cultivation and its driving factors: a study based on Hunan Province, China

Against the backdrop of global warming, the imbalance in agricultural carbon budgets poses a dual threat to ecological security and food security. As a major grain-producing region in China, Hunan Province is confronted with substantial CH₄ emissions derived from rice cultivation, a problem further exacerbated by industrialization, urbanization, and shifts in farming practices. Consequently, investigating the carbon imbalance in Hunan's agricultural cultivation is of great significance for advancing the sustainable development of agriculture in the province. This study constructs and quantifies the agricultural carbon imbalance index (CII), and employs exploratory spatiotemporal data analysis, the PLS-VIP method, and the GTWR model to analyze the spatiotemporal evolution and driving factors of agricultural cultivation carbon imbalance of Hunan Province in China from 2001 to 2022.

(1) The CII for agricultural cultivation in Hunan Province decreased from 0.41 in 2001 to 0.26 in 2022. Its spatiotemporal pattern shifted from "high in the north and low in the south" to "high in the west and low in the east," with the gravity center of CII moving southwestward. (2) Over the study period, the spatial correlation characteristics of CII underwent three stages: significant positive correlation, random distribution, and weak positive correlation. LISA time path and spatiotemporal transition analyses showed that the spatiotemporal clustering pattern of CII remained relatively stable from 2001 to 2011; however, its stability weakened slightly from 2012 to 2022. (3) Key factors influencing the agricultural cultivation CII in Hunan Province include GPA, GST, IARDF, PAOV, FUI, and PUI. These factors exhibit significant spatiotemporal heterogeneity in their effects. For example, the FUI and PUI had significant impacts on CII in the Xiangbei region, whereas their influence was relatively weaker in the Xiangxi region.

To alleviate the persistent carbon imbalance in Hunan's agricultural cultivation systems, differentiated carbon sequestration and emission reduction strategies should be formulated by integrating the significance hierarchy of CII drivers and their spatial heterogeneity patterns. Special emphasis ought to be placed on tackling the re-emergence of carbon imbalance in specific municipal regions, which stems from urban expansion encroaching on farmland and the persistence of traditional cultivation practices. This targeted optimization will effectively facilitate the sustainable and low-carbon development of Hunan's agricultural sector.