Seasonal Precipitation Drives Shifts in Arbuscular Mycorrhizal Fungal Communities and Soil Physicochemical Properties in Songnen Saline-Alkali Grassland

Abstract

: Arbuscular mycorrhizal fungi (AMF) play important roles in plant adaptation and ecosystem functioning in saline-alkali grasslands. However, the responses of AMF communities to seasonal precipitation remain poorly understood. In this study, rhizosphere soils were collected from four habitat grades in the Songnen saline-alkali grassland during the dry and rainy seasons of 2024. Floristic Quality Assessment (FQA), soil physicochemical analyses, and Illumina MiSeq sequencing were used to evaluate seasonal changes in vegetation quality, soil properties, and AMF communities. The results showed that AMF richness and diversity were significantly higher in the rainy season than in the dry season ( p < 0.01). NMDS and PERMANOVA analyses revealed significant seasonal differences in community composition, with season explaining a substantial proportion of community variation ( R 2 = 0.525, p = 0.001). LEfSe analysis identified distinct seasonal biomarkers, with Sclerocystis enriched in the dry season and Glomus enriched in the rainy season. Seasonal precipitation also altered soil physicochemical properties, particularly soil moisture and salinity. Mantel analysis indicated that soil salinity and moisture were key factors associated with AMF community structure. In addition, habitats with higher floristic quality generally supported greater AMF diversity. These findings demonstrate that seasonal precipitation and associated soil environmental changes jointly shape AMF community dynamics in the Songnen saline-alkali grassland, providing insights into plant–soil–microbe interactions and ecological restoration of saline-alkali ecosystems.