Regional heterogeneity in winter wheat yield responses to compound agricultural drought in the Huai River Basin

Study region Huai River Basin. Study focus Agricultural drought is a major constraint on crop production and food security, yet its definition remains inconsistent and is often based solely on soil moisture deficits, which cannot fully represent the actual process of crop damage. This study defines agricultural drought as a propagated soil-vegetation drought chain, in which soil drought precedes and is temporally linked to subsequent vegetation drought. From the integrated perspective of occurrence, propagation, recovery, and yield response, we investigate the mechanisms through which compound agricultural drought affects winter wheat yield. New hydrological insights The findings indicate that precipitation is the dominant factor controlling drought recovery characteristics. The observed mean propagation time from soil drought to vegetation drought was approximately 31 days. Propagated compound agricultural drought showed stronger yield relevance than soil drought alone. Huaibei and Luohe showed yield loss probabilities above 20%, increasing by more than 10 %age points under higher C2 exposure. The exposure threshold for a 50% probability of yield reduction varied substantially among regions, with Huaibei and Suzhou showing high sensitivity. Longer and stronger recovery processes were associated with lower yield anomalies, whereas faster recovery was linked to better yield outcomes. These findings suggest that agricultural drought in the HRB should be identified as a propagated soil-vegetation drought chain rather than by soil moisture deficit alone.