Changes in soil ecological stoichiometry and microbial communities related to leaf stoichiometry of different halophytes

Species differences among halophytes in arid regions, along with alterations in the physicochemical properties of understory soils induced by their litterfall, often shape distinct salt island effects. In this study, we investigated the soil physicochemical properties and leaf traits of Kalidium foliatum (KFSI), Nitraria tangutorum (NTSI), Reaumuria songarica (RSSI), and Tamarix hohenackeri (THSI) in arid salt marshes, and profiled soil bacterial and fungal communities using high-throughput sequencing. Along the salt island successional sequence from KFSI to NTSI to RSSI to THSI, soil water content, pH, electrical conductivity, and Na⁺ and K⁺ contents decreased successively. The leaf carbon content of the four halophytes was found to be negatively correlated with soil salt ions, whereas nitrogen and phosphorus contents were positively correlated with salinity indicators. THSI had the highest total carbon and soil organic carbon content, which were 117% and 280% higher than those of KFSI, respectively. The Shannon index of soil bacteria in THSI was higher, and the complexity of its microbial network (1,305 nodes, 3,929 edges) was significantly greater than that of the other salt islands. In addition, random forest analysis showed that soil physical and chemical properties (accounting for 26 -58% of the total) and plant characteristics (15 -26%) jointly regulate soil ecological stoichiometric ratios. Soil physical properties positively drove the complexity of the microbial network by influencing the chemical composition of plant leaves and microbial community composition (p < 0.01). This study delineates successional gradients in soil properties, plant leaf traits, and microbial communities across halophyte_specific salt islands and clarifies how their interplay regulates soil ecological stoichiometry, thereby shaping ecosystem structure and function in arid saline environments.