Optimizing Amendment Strategies for Vegetable Continuous Cropping Obstacles: A National-Scale Meta-Analysis in China

Intensive vegetable production in China is seriously affected by continuous cropping obstacles (CCOs), yet the effectiveness of amendment strategies for mitigating CCOs varies widely across environments and crop types. To address this heterogeneity, we conducted a nationwide meta-analysis of 200 peer-reviewed studies (published in 2000–2025) comprising 921 effect sizes. A random-effects model was used to quantify the overall efficacy of four amendment categories on vegetable yield and quality, and spatial analysis (using Global Moran’s I and Getis–Ord Gi*) was integrated to identify geographical hotspots and coldspots of amendment efficacy, with meta-regression further employed to assess the moderating roles of soil and climatic factors. Overall, amendments significantly increased vegetable yield by 26.9% and vitamin C content by 23.4%. Efficacy was highly dependent on specific crop–amendment combinations; Autotoxin Mitigation (AM) was most effective for leafy vegetables, while Soil Physicochemical Property Improvement (SPPI) optimally enhanced soluble sugar in root and tuber crops. Soil pH emerged as the primary environmental driver, with greater yield responses observed in acidic soils, and spatial analysis revealed significant hotspots of high efficacy clustered in the North China Plain and Yangtze River Basin, contrasting with coldspots in areas with specific soil constraints like salinity. Consequently, this study establishes a quantitative “crop–amendment–environment” matching framework, highlighting the necessity of transitioning from generic applications to regionally tailored precision strategies to sustainably manage CCOs and improve vegetable productivity in China.