抄録
Waterlogging assessment in wheat remains constrained by the inability of duration-based or state-based indicators to represent the cumulative environmental exposure experienced by roots and its translation into crop responses. This study asked whether dynamic root-zone water conditions can be converted into a biologically informative cumulative exposure measure and whether such a measure can unify physiological and yield responses across waterlogging scenarios. Controlled experiments spanning wheat cultivars, growth stages, and exposure durations were used to derive a soil water-based waterlogging index (WI) from time-resolved root-zone soil moisture and to evaluate its relationships with leaf Soil Plant Analysis Development (SPAD) and yield. Yield declined with increasing waterlogging duration but varied substantially across growth stages, demonstrating the limited resolution of event duration alone. WI integrated the magnitude and persistence of excess soil water, showed a consistent negative association with SPAD, and captured a nonlinear yield response characterized by a transition from relatively limited effects at lower cumulative exposure to increasingly pronounced yield loss at higher exposure levels. Cultivar-specific transition ranges further indicated that yield responses can be expressed as distinct exposure boundaries on a common WI scale. These findings establish an exposure–response framework that recasts wheat waterlogging from an event-duration problem into a cumulative process linking dynamic root-zone conditions, plant functional status, and yield-risk transitions, providing a quantitative basis for resolving cultivar-specific waterlogging response boundaries beyond conventional duration-based assessment.
