Waterlogging severely limits wheat yields in China's Middle-Lower Yangtze River Plain. Ditch-buried straw return (DB) is a novel straw management practice that improves soil structure and water infiltration, potentially alleviating waterlogging stress. This study aimed to investigate how DB regulate soil moisture dynamic and wheat physiological responses under waterlogging. A 6-day waterlogging and non-waterlogging experiment at anthesis stage comparing DB (DB-W, DB-NW) with rotary tillage (RT-W, RT-NW) was conducted. Soil structural and hydraulic properties were determined, with an emphasis on wheat physiological responses and yield performance under soil waterlogging. Compared to the RT treatment, DB decreased soil bulk density, increased soil water holding capacity (q WHC ) and water infiltration rate (IR). Excess water drained more quickly under DB-W, facilitating soil moisture rapidly declined below q WHC and shorten waterlogging duration than RT-W. The reduced waterlogging stress by DB significantly increased root biomass, enhanced the superoxide dismutase (SOD) and catalase (CAT) activities in both roots and flag leaves, and decreased malondialdehyde (MDA) and reactive oxygen species (ROS) accumulation. The increased SPAD and net photosynthetic rate (P n ) in flag leaves collectively extended the functional photosynthetic period and enhanced the overall photosynthetic capacity. Soil structural equation model revealed that the improved soil structure enhanced soil aeration, improving wheat physiological traits and facilitating the translocation of post-anthesis assimilates to spikes, which ultimately increased grain yield. DB contributed 39.2% and 27.1% of yield increase under waterlogging and non-waterlogging conditions, respectively. Our results demonstrated that DB effectively alleviated waterlogging stress on wheat, representing as a sustainable tillage strategy to maintain wheat productivity under climate change.
Luo et al. (Thu,) studied this question.