Abstract: 【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.

Key words: dryland rice, water stress, photosynthesis, physiological characteristics, TOPSIS model 

摘要： 【目的】在西北干旱地区水资源短缺与光照资源丰富的特殊地缘条件下，为解决如何提高资源综合利用的问题，探讨农田土壤水分与作物光合作用间的关系，旨在形成土壤水分-光照互补机制，从而促进资源的可持续利用。【方法】于2019−2021年，分别在宁夏引黄灌区3个典型试验点开展水稻大田试验。以传统充分灌溉为对照(CK)，设置不同水分水平的滴灌处理，分析不同程度水分胁迫对水稻关键生育阶段光合作用、关键生长指标及产量构成的影响。【结果】水分胁迫降低水稻光合速率和蒸腾速率，并对产量构成产生负面影响，但能提高水分利用效率。其中，净光合速率最大值出现在孕穗期，水分胁迫处理较CK显著下降4.5%~26.6%；最小值出现在乳熟期，水分胁迫较CK显著下降4.2%~46.9%。蒸腾速率最大值在孕穗期，水分胁迫处理较CK显著下降2.2%~16.8%；蒸腾速率最小值在苗期，水分胁迫处理较CK显著下降7.5%~40.7%，水分胁迫处理水稻株高、秸秆高度、秸秆干质量、饱籽率、千粒重、产量较CK分别下降2.2%~24.3%、0.3%~12.6%、0.8%~11.6%、0.5%~7.9%、0.3%~9.2%、2.3%~71.5%。但耗水量下降33%~46%，轻度胁迫产量水平上的水分利用效率比CK提高1.9%~21.5%，单叶水平水分利用效率较CK下降2.1%~6.8%。说明轻度水分胁迫能够在降低水分消耗的同时维持较高产量，有助于提高水资源的利用率。利用TOPSIS模型引入信息量权重法和熵权法对不同水分胁迫处理进行评价，发现水分下限占田间持水量的90%~100%可以实现产量、品质和水分利用效率的最优化。【结论】在干旱和半干旱地区，应进一步推广精准调控的非充分灌溉策略，以充分挖掘水稻的抗旱潜力。这是节水型农业的有效手段，减少水资源消耗，同时维持稳定的粮食生产。

关键词: 旱作水稻, 水分胁迫, 光合作用, 生理特性, TOPSIS模型