Objective Tall fescue (Festuca elata ‘crossfire II’) was used as the test material to study the effects of different levels of saline-alkali treatment on the diversity, composition and network complexity of bacterial and fungal communities in the rhizosphere soil of tall fescue.

Method Four salts (NaCl, Na₂SO₄, NaHCO₃, and Na₂CO₃) were mixed in a 9∶1∶1∶9 M ratio, and four treatments of 0 (S₀), 200 (S₁), 400 (S₂) and 600 mmol/L (S₃) were set. Illumina MiSeq high-throughput sequencing was used to measure soil microbial community.

Result S₁ and S₂ saline-alkali treatments had no significant effect on soil fungal diversity and network complexity compared with S₀ treatment, while S₃ treatment significantly reduced soil fungal diversity and network complexity. Saline-alkali treatment also shifted fungal community composition, with increased relative abundances of dominant phyla Ascomycota and decreased relative abundances of Chytridiomycota. Compared with fungal community, saline-alkali treatment had less effect on soil bacterial community. S₃ saline-alkali treatment reduced the complexity of soil bacterial network, but had no significant effect on bacterial diversity and community composition. SEM showed that the saline-alkali effects on soil fungal community composition were primarily mediated by soil organic carbon and soil available phosphorus).

Conclusion High concentration saline-alkali treatment reduced the diversity and network complexity of fungi in rhizosphere soil of tall fescue, and changed the composition of fungal community, but had little effect on bacterial community.