Tu Xiangjian, Struik Paul C, Sun Shixian, Wenbo Zhang, Zhang Yong, Jin Ke, Wang Zhen
Key Laboratory of National Forestry and Grassland Administration on Grassland Resources and Ecology in the Yellow River Deltar, College of Grassland Science, Qingdao Agricultural University, Qingdao, Shandong, China.
Institute of Grassland Research, Chinese Academy of Agricultural Sciences, Hohhot, Inner Mongolia, China.
PeerJ. 2025 Jan 6;13:e18791. doi: 10.7717/peerj.18791. eCollection 2025.
Grazing can alter the physicochemical properties of soil and quickly influence the composition of microbial communities. However, the effects of grazing intensity on fungal community composition in different soil depth remain unclear. On the Inner Mongolia Plateau, we studied the effects of grazing intensity treatments including no grazing (NG), light grazing (LG), moderate grazing (MG), heavy grazing (HG), and over grazing (OG) on the physicochemical properties and fungal community composition of surface (0-20 cm) and subsurface (20-40 cm) soil layers. The -diversity of fungi in subsurface soil decreased under the influence of grazing. The relative abundance of Ascomycota in the subsoil was higher than that in the topsoil, while the situation of Basidiomycota was the opposite. This was caused by the differences in the soil carbon (C) environment for the growth of oligotrophic and copiotrophic fungi. In the subsoil, grazing affected nutrient contents such as soil organic matter (SOM) and total nitrogen (TN), resulting in significantly lower relative abundance of Ortierellomycota under LG, HG, and OG than in the NG. HG showed much higher relative abundance of Glomeromycota. Results of a multiple regression tree (MRT) analysis revealed that TN and nitrate nitrogen affected the fungal -diversity in top- and subsoils, respectively; the main driving factor regulating fungal community changes was soil water content (SWC) in the topsoil, while it was ammonium nitrogen and nitrate nitrogen in the subsoil. The results of our study indicate that grazing changes the soil environment by changing TN, SWC, nitrate nitrogen, ammonium nitrogen, and affects the diversity and community structure of soil fungi. This provides empirical support for coping with the impact of grazing on soil microbiomes in desert steppes.
放牧会改变土壤的物理化学性质，并迅速影响微生物群落的组成。然而，放牧强度对不同土壤深度真菌群落组成的影响仍不清楚。在内蒙古高原，我们研究了包括不放牧（NG）、轻度放牧（LG）、中度放牧（MG）、重度放牧（HG）和过度放牧（OG）在内的放牧强度处理对表层（0 - 20厘米）和亚表层（20 - 40厘米）土壤层的物理化学性质和真菌群落组成的影响。放牧影响下，亚表层土壤中真菌的多样性降低。子囊菌门在底土中的相对丰度高于表土，而担子菌门的情况则相反。这是由贫营养型和富营养型真菌生长的土壤碳（C）环境差异造成的。在底土中，放牧影响了土壤有机质（SOM）和总氮（TN）等养分含量，导致LG、HG和OG处理下奥氏菌纲的相对丰度显著低于NG处理。HG处理下球囊菌门的相对丰度要高得多。多元回归树（MRT）分析结果表明，TN和硝态氮分别影响表土和底土中的真菌多样性；调节真菌群落变化的主要驱动因素在表土中是土壤含水量（SWC），而在底土中是铵态氮和硝态氮。我们的研究结果表明，放牧通过改变TN、SWC、硝态氮、铵态氮来改变土壤环境，并影响土壤真菌的多样性和群落结构。这为应对放牧对荒漠草原土壤微生物群落的影响提供了实证支持。
