Abstract: [Objective] This study aimed to reveal the community structure and diversity of soil fungi and their impact factors in four habitats in Hulun Buir sandy land, and explore the influence of different habitats on soil fungi.[Method]The soil fungi in four habitats, including bare sandy land, grassland, Pinus sylvestris var. mongolica plantation and natural forest were selected as the research objects. The community structure characteristics of soil fungi were compared and analyzed by using field investigation, ITS high-throughput sequencing and RDA analysis.[Result]The results showed that 5 phyla, 22 classes, 73 orders, 28 families and 257 genera were detected in the soil samples of Hulun Buir sandy land. Among them, Ascomycota was the dominant fungal phyla in bare sand and grassland soil, and Basidiomycota was the dominant fungi in soils from P. sylvestris var. mongolica plantation and natural forest. There were 31 dominant genera in these areas. The dominant genera in soil from bare sandy land and P. sylvestris var. mongolica plantation were Mortierella and Cortinarius, and the dominant genera in grassland and P. sylvestris var. mongolica natural forest soil were Mortierella and Archaehorizomuses, Russula and Geminibasidium, respectively. The evolutionary branches of soil fungi from bare sandy land and grassland were more similar, while those from P. sylvestris var. mongolica plantation and natural forest soil were closer. The species richness and individual number of fungi from grassland were the highest and the distribution was the most uniform, followed by those in bare sandy land. The species richness, individual number and diversity index of soil fungi from natural and planted P. sylvestris var. mongolica forests were lower, and the distribution was more concentrated. Soil water content was the main impact factor affecting the distribution of soil fungal community. The distribution of dominant fungi was influenced by some environment factors. Soil porosity, soil water content, and soil organic matter were the dominant influencing factors of Mortierella, Archaeorhizomyces and Cortinarius, respectively, while total phosphorus was the dominant influencing factor of Russula and Geminibasidium.[Conclusion]The soil fungi in four habitats in Hulun Buir sandy land were mainly composed of Ascomycetes and Basidiomycetes. The evolutionary branch of soil fungi community structure from bare sand land was similar to that from grassland, while the evolutionary branch of P. sylvestris var. mongolica plantation and natural forest was similar. Various kinds of herbaceous plants increased the number of fungi and resulted in more even distribution of fungi. However, P. sylvestris var. mongolica reduced the number and variety of fungi to a certain extent, and made their distribution more concentrated. Different vegetation in different habitats influenced soil properties, and environmental factors such as soil moisture, nutrients and porosity directly affected the metabolic process and functional characteristics of dominant fungi in four habitats, resulting in variation in soil fungal community structure and diversity characteristics in the four different habitats.

Key words: soil fungi, community structure, diversity, habitats, Hulun Buir sandy land