To investigate the physicochemical properties and stability of soil aggregates and their relationships under different saline-alkali gradients in the coastal saline-alkali land of the Yellow River Delta， this study combined field sampling with laboratory analysis to determine the nutrient content， particle size distribution， and stability indicators of soil aggregates across varying gradients. The results showed that under severe saline-alkali conditions， the carbon-to-nitrogen ratio， ammonium nitrogen， and available phosphorus content in <0.25 mm aggregates significantly decreased （P<0.05）. Similarly， nitrate nitrogen and ammonium nitrogen content in 1-2 mm aggregates were also significantly lower under high salinity stress （P<0.05）. The geometric mean diameter and mean weight diameter of aggregates significantly reduced in severe saline-alkali conditions compared to moderate conditions （P<0.05）， while the proportion of 1-2 mm aggregates increased with increasing salinity. Correlation analysis revealed that salinity was significantly negatively correlated with total carbon and total nitrogen across all aggregate sizes （P<0.01）， and significantly positively correlated with the carbon-to-nitrogen ratio （P<0.01）. Under high saline-alkali conditions， available phosphorus， ammonium nitrogen， nitrate nitrogen， and aggregate stability indicators were all significantly negatively correlated with salt content （P<0.01）. In conclusion， the degree of saline-alkali stress significantly influenced the physicochemical properties and structural stability of soil aggregates， with high salinity potentially leading to nutrient loss and structural degradation.

Yellow River Delta  /  Saline-alkaline soil  /  Soil aggregates  /  Stability  /  Soil physicochemical properties