Nitrogen deposition combined with elevated precipitation is conducive to maintaining the stability of the soil fungal diversity on the Stipa baicalensis steppe

Changes in nitrogen (N) deposition and precipitation can strongly influence grassland ecology. However, the combined effects of N and water addition on soil fungal genetic diversity, and especially the underlying influencing factors, are not well understood. We investigated the response of soil fungal α diversity to experimental N and water addition in a northern Chinese steppe. We found that N addition alone exceeding N100 (100 kg N·ha−1·yr−1) significantly increased soil fungal α diversity. However, when water was added, soil fungal diversity did not significantly change following N enrichment. Structural equation modelling (SEM) results indicated that N addition increased soil fungal α diversity, while N addition combined with irrigation maintains soil fungal diversity that would otherwise be enhanced by N addition. This results from reversing the correlation between soil fungal diversity and plants\\soil physicochemical properties. Our results provide evidence that the effects of N deposition regarding soil fungal diversity might be overestimated if we ignore variations in water availability.