Halophyte Litter Decomposition Shapes Soil Microbial Community Compositional Constancy by Regulating Resource Stoichiometry and Enzymatic Activity in a Microcosm Study

ABSTRACT

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.