soil fungal community in Stipa Baicalensis Steppe of northern China Metagenome. soil fungal community in Stipa Baicalensis Steppe of northern China

Soil fungi play a critical role in terrestrial ecosystem functioning. However soil fungal diversity and soil fungal community composition responds to increasing nitrogen deposition, and especially the underlying influencing factors, are not well understood. By conducting an six-year N addition experiment (0, 15, 30, 50, 100, 150, 200 and 300 kg N ha−1 yr−1), we investigated the long-term effect of simulated N deposition on soil fungal diversity and composition in a northern Chinese steppe. We found that soil nutrient concentrations (TOC, NO3—N, NH4+-N) increased, whereas soil pH and fungal diversity decreased in all the nitrogen treatments. The dominant fungal phyla were Ascomycota (26.80%~39.98%), Basidiomycota(5.57%~15.84%), Zygomycota(1.47%~3.01%), Glomeromycota (0.10%~3.47%) and Chytridiomycota (0.05%~0.73%). The relative abundance of Ascomycota increased in N30 and N50 treatments and decreased in N100, N150, N200 and N300 treatments, the relative abundance of Basidiomycota and Glomeromycota decreased in all the nitrogen treatments. Relationships between soil chemical properties and fungal communities were evaluated. Sperman correlations analysis showed that soil pH, NO3—N and available P were key environmental factors leading to the shift in the soil fungal community composition. In conclusion, nitrogen addition changed the soil chemical properties, which drove the change of soil fungal communities.