Mitigating climate disaster vulnerability in grain production through high-standard farmland construction: impact mechanisms and spatial spillover effects

High-standard farmland construction (HSFC) is a critical initiative for mitigating climate disaster risks of grain production and ensuring national food security. Using panel data for 30 Chinese provinces from 2003 to 2020, this study measures the climate disaster vulnerability of grain production (CDVG) with an improved vulnerability assessment framework, and systematically examines the impact mechanisms and spatial spillover effects of HSFC on CDVG. The results reveal that: (1) Temporally, the evolution of CDVG is characterized by an initial rapid decline followed by slow, fluctuating decreases. Spatially, it exhibits pronounced regional disparities and spatial clustering, with the eastern coastal areas, central major grain-producing regions, and Xinjiang displaying lower vulnerability than other regions. (2) Baseline regression results confirm that HSFC significantly reduces CDVG, and this conclusion remains robust after a series of robustness tests. (3) Mechanism tests demonstrate that HSFC reduces CDVG through ecological regulation effects, infrastructure guarantee effects, and technological support effects. (4) Spatial econometric analysis reveals that HSFC exerts a significant spatial spillover effect on CDVG. It not only mitigates local vulnerability but also reduces vulnerability in neighboring regions. (5) Heterogeneity analysis reveals that vulnerability-reducing effect of HSFC is more pronounced in provinces with medium-to-low vulnerability quantiles, in major grain-producing areas, and in regions with relatively flat terrain. Based on these findings, this study recommends optimizing the spatial layout of HSFC, improving supporting systems, and tailoring strategies to local conditions to better mitigate climate disaster risks and ensure national food security.