When floods heal or harm after drought: Three archetypes of maize photosynthetic response to drought‑to‑flood transitions across China

Drought-to-flood transitions (DTF) show regional contrasts across China’s major maize-producing regions, yet whether the flood phase mitigates or compounds drought impacts remains unresolved. 1-km observations (2000–2019) are used to identify soil-moisture-defined DTF and track canopy function with 8-day gross primary productivity (GPP) percentiles. Responses are quantified with two metrics: Compound Resistance (CR; whole-sequence GPP suppression) and Resistance Difference (RD; flood-phase effec