碳(C)、氮(N)、磷(P)是湿地土壤养分的重要组成部分，其生态化学计量特征可以反映土壤的供肥能力和质量状况，对湿地生态系统养分循环具有重要意义。水盐条件是控制河口湿地养分循环的重要因子，但其对C、N、P生态化学计量特征的影响仍不十分明晰。本文以黄河口淡水湿地为研究对象，采用模拟培养法，基于水位(地表淹水，+10 cm；地表落干，−10 cm；干湿交替，−10 cm~+10 cm)和盐分(空白对照、5‰、10‰和15‰)正交设计实验，研究水盐条件对湿地土壤C、N、P生态化学计量特征的影响，并探讨其作用机制。研究结果表明，模拟培养16周后，地表淹水、地表落干和干湿交替下不同盐度处理土壤C、N、P含量分别为2.67~9.14 g/kg、0.43~0.72 g/kg、0.54~0.67 g/kg，表现为对照高于其他盐度处理，淹水条件下土壤C和N含量较高，而水位条件对土壤P含量影响较弱。地表淹水、地表落干和干湿交替下不同盐度处理土壤C∶N、C∶P和N∶P分别为5.67~16.85、12.21~36.68和1.65~2.78，盐度升高降低了土壤C∶N、C∶P和N∶P，在高盐度(15‰)处理下分别下降了14.3%、23.2%和10.5%；土壤C∶N、C∶P和N∶P均在淹水水位中较高，在落干水位和干湿交替水位中较低。土壤C、N、P及其生态化学计量比与土壤含水量、pH和植物生物量呈正相关关系，与电导率呈负相关关系；盐度是控制黄河口淡水湿地土壤C∶N和C∶P变化的主导因素，而N∶P变化则更多受到水分条件的制约。结果表明，在气候变化背景下，河口湿地水位下降和盐度升高可能会改变土壤C、N、P生态化学计量学特征，进而影响土壤养分循环过程。

Carbon (C), nitrogen (N), and phosphorus (P) are fundamental components of soil nutrients in wetlands. Their ecological stoichiometric characteristics serve as critical indicators that reflect the soil fertility supply capacity and quality, which is of great significance to nutrient cycling in wetland ecosystems. Water and salt conditions are recognized as key environmental factors governing nutrient cycling in estuarine wetlands. However, their specific impacts on the ecological stoichiometric characteristics of soil C, N, and P remain poorly understood. In this study, the freshwater wetland of the Yellow River Estuary were selected as the research object. A simulated incubation experiment was conducted using an interactive design with three water levels (surface flooding at +10 cm, surface drainage at −10 cm, and dry-wet alternation from −10 cm to +10 cm) and four salinity gradients (blank control, 5‰, 10‰ and 15‰) to investigate the effects of water-salt conditions on the stoichiometric characteristics of C, N and P. The results showed that soil C, N, and P contents over 16-weeks incubation period under different water-salt conditions ranged from 2.67 g/kg to 9.14 g/kg, 0.43 g/kg to 0.72 g/kg, and 0.54 g/kg to 0.67 g/kg, respectively. Nutrient concentrations in the control treatment were consistently higher than those in the salinity treatments. Specifically, soil C and N contents were higher under flooding conditions, whereas the water level exhibited a relatively weaker influence on soil P content. Under different water-salt conditions, the soil C:N, C:P, and N:P ratios ranged from 5.67 to 16.85, 12.21 to 36.68, and 1.65 to 2.78, respectively. Elevated salinity exerted a suppressive effect on these ratios, compared to the control, the C:N, C:P and N:P ratios in the high-salinity treatment (15‰) decreased by 14.3%, 23.2% and 10.5%, respectively. Furthermore, these stoichiometric ratios were consistently highest in the flooding treatment and lower in the drainage and dry-wet alternation treatments. Correlation analysis indicated that soil C, N, and P contents and their ecological stoichiometric ratios were positively correlated with soil water content, pH, and plant biomass, but presented negative correlations with electrical conductivity. Salinity was identified as the dominant factor controlling the variations of soil C:N and C:P in the freshwater wetlands of the Yellow River Estuary, while the variation of N:P was more strongly influenced by hydrological conditions. These findings suggest that in the context of global climate change, the declining water levels and increasing salinity in estuarine wetlands may alter the ecological stoichiometric characteristics of soil C, N and P, thereby affecting soil nutrient cycling processes.