Halophyte Litter Decomposition Shapes Soil Microbial Community Compositional Constancy by Regulating Resource...

A key knowledge gap exists in understanding how the decomposition of litter from different halophyte species influences microbial community dynamics in soils. This study addressed this gap through a 180-day laboratory microcosm experiment investigating the effects of leaf litter decomposition from three halophytes (Kalidium cuspidatum, Nitraria tangutorum, and Reaumuria songarica) on soil biogeochemical properties, microbial dynamics, and community compositional constancy. The main research results indicate that at 180 days, the leaf mass loss (Mm) of the three halophytes reached 40.09%-42.89%, and the decomposition constants (k) were all < 0.2. Leaf total nitrogen, lignin, and carbon/nitrogen ratio directly regulated the decomposition process. Decomposition significantly increased soil nutrient pools, including total organic carbon (57.64%-100.12%), total nitrogen (51.92%-129.80%), dissolved organic carbon (44.35%-224.40%), and dissolved organic nitrogen (24.15%-238.58%), relative to bulk soil. Microbial carbon limitation increased by 21.81%-37.99%, while nitrogen limitation was alleviated, as evidenced by a 67.86%-92.28% increase in the vector angle of enzyme stoichiometry. These changes were driven by soil chemistry (explaining 45.47% of the variance) and microbial traits (42.31%-65.77%). Plant litter decomposition reshaped the structure of bacterial and fungal communities while reshaped the structure, which was linked to microbial biomass carbon, β-glucosidase, and alkaline phosphatase (p < 0.05). Furthermore, partial least squares path modeling revealed that plant litter decomposition increased soil organic resources, thereby exacerbating microbial carbon limitation; yet, along with microbial biomass, it also influenced microbial community composition. These results underscore species-specific litter effects on soil-microbe feedbacks in a controlled microcosm, emphasizing the role of resource stoichiometry and enzymatic activity in shaping microbial community in saline ecosystems.