Arid salt marsh ecosystems endure chronic water scarcity and high salinity stress, with the stability of their functions inextricably linked to the pivotal role of the rhizosphere microenvironment of halophytes. This study focused on three typical halophytes (Kalidium cuspidatum, Nitraria tangutorum, Reaumuria soongarica) in the Jiantan wetland, and deeply explore how these halophytes differently regulate the soil microenvironment through the rhizosphere effect. The results showed that the rhizosphere soil of Kalidium cuspidatum had higher pH, Na⁺, and K⁺ contents, while the rhizosphere soil of R. soongarica had higher total carbon, soil organic carbon, alkali-hydrolyzable nitrogen, and microbial biomass. Microbial community analysis revealed that rhizosphere soil of fungal diversity was significantly higher in K. cuspidatum than in R. soongarica, with distinct differences in bacterial and fungal community structures. These differences were closely associated with factors such as Na⁺, Olsen phosphorus, microbial biomass carbon and alkali-hydrolyzable nitrogen. Among the dominant phyla, Proteobacteria and Ascomycota predominate, with Desulfobacterota and Mortierellomycota exhibiting the highest explanatory power (>48%) for physicochemical property variations. The microbial network of rhizosphere soil of R. soongarica has the highest complexity (with 633 nodes and 3300 edges), but the proportion of positive correlation edges was the lowest (21.58%). Structural equation modeling indicates that soil physical properties indirectly influence network complexity by negatively regulating chemical properties and microbial biomass, while microbial diversity had a direct positive effect on dominant phylum composition and network complexity. This study elucidated the differentiated adaptive strategies of rhizosphere microenvironment-microbe interactions in halophytes, providing a theoretical basis for wetland ecological restoration.

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.