旱作水稻在水分胁迫下的光合生理响应与优化灌溉策略OA

[Objective]Given the challenges of water scarcity and abundant light resources in the arid northwest region,this study aims to investigate the relationship between farmland soil moisture and crop photosynthesis to improve comprehensive resource utilization.The goal is to establish a complementary soil moisture-light mechanism,thereby promoting sustainable resource utilization.[Method]From 2019 to 2021,field experiments were conducted at three typical experimental sites in the Yellow River irrigation area of Ningxia Hui Autonomous Region.Using traditional full irrigation as the control,different drip irrigation treatments with varying water levels were established to analyze the effects of different degrees of water stress on photosynthesis,key growth indicators,and yield components during critical growth stages of rice.[Results]Water stress reduced the photosynthetic rate and the transpiration rate of rice and negatively affected yield components,but improved water use efficiency.The maximum net photosynthetic rate occurred at the booting stage,during which that under water stress treatments decreased significantly by 4.5%-26.6%compared to CK.The minimum value appeared at the milk-ripe stage,with a significant decrease of 4.2%-46.9%under water stress compared to CK.The maximum transpiration rate was observed at the booting stage,decreasing by 2.2%-16.8%under water stress relative to CK.The minimum transpiration rate occurred at the seedling stage,decreasing by 7.5%-40.7%under water stress compared to CK.Under water stress,rice plant height,straw height,straw dry weight,filled grain rate,1000-grain weight,and yield decreased by 2.2%-24.3%,0.3%-12.6%,0.8%-11.6%,0.5%-7.9%,0.3%-9.2%,and 2.3%-71.5%,respectively,compared to CK.However,water consumption decreased by 33%-46%.Under mild stress,water use efficiency at the yield level increased by 1.9%-21.5%compared to CK,while leaf-level water use efficiency decreased by 2.1%-6.8%.These results indicate that mild water stress can reduce water consumption while maintaining relatively high yield,thereby improving water resource utilization efficiency.Using the TOPSIS model combined with the information weight method and entropy weight method to evaluate different water stress treatments,it was found that maintaining the soil moisture lower limit at 90%-100%of field capacity can optimize yield,quality,and water use efficiency.[Conclusion]In arid and semi-arid regions,precisely regulated deficit irrigation strategies should be further promoted to maximize the drought resistance potential of rice.As an effective approach for water-saving agriculture,this can reduce water consumption while maintaining stable grain production.