关键词: 夏季覆盖种植, 黄河三角洲, 冬小麦, 水分利用效率, 种植模式

Abstract: Cover cropping is one of the biological amelioration strategies for saline-alkaline arable land. However, its impact on the water consumption characteristics of the succeeding winter wheat in saline-alkali fields remains unclear. We conducted a field-controlled experiment at the Yellow River Delta Saline-Alkali Agro-ecosystem Observation and Research Station, affiliated with the Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, to compare the impacts of summer planting of Sorghum bicolor ×sudanense, Sesbania cannabina, and summer maize on the water use efficiency and yield of the succeeding winter wheat. The experiment included two levels of soil salinity: light salinity (2‰) and medium salinity (4‰), and three crop rotation treatments: S. bicolor ×sudanense-winter wheat, S. cannabina-winter wheat, and summer maize-winter wheat. The results showed that, under light salinity condition, compared with the traditional summer maize-winter wheat rotation, the S. bicolor ×sudanense and S. cannabina treatments significantly increased winter wheat yield by 63.4% and 62.3%, respectively, reduced water consumption by 9.2% and 18.5%, and enhanced water use efficiency by 80.3% and 99.0%. Under medium salinity, the S. cannabina treatment did not affect winter wheat yield, but significantly reduced water consumption by 20.9% and improved water use efficiency by 46.4%. In contrast, the S. bicolor ×sudanense treatment did not affect yield, water consumption, or water use efficiency of winter wheat. Overall, from the perspective of water conservation, both the S. cannabina-winter wheat and S. bicolor ×sudanense-winter wheat rotations enhanced water use efficiency under light salinity, while the S. cannabina-winter wheat rotation also improved water use efficiency under medium salinity. In terms of yield, the S. cannabina-winter wheat and S. bicolor ×sudanense-winter wheat systems demonstrated superior performance under light salinity, but without any yield difference among the three rotations under medium salinity. These findings would provide theoretical and technical support for the efficient utilization of water resources in the saline-alkaline farmlands of the Yellow River Delta.

Key words: summer cover cropping, Yellow River Delta, winter wheat, water use efficiency, cropping pattern