Effects Of Grazing On Soil Fungi Of Youyu Grassland Ecosystem In Shanxi Province

The grassland area in China is about 4×10~8hm~2,accounting for 40.7%of the country's land area,making it the largest terrestrial ecosystem in China.Grazing is one of the main land use mode,which not only affects the above-ground vegetation,soil environment,etc.,but also has significant impacts on soil microbial communities.This paper studies the effects of different grazing intensities on soil fungal diversity in the Youyu grassland ecosystem in Shanxi.The experimental site is at the Youyu Field Observation and Research Station of Shanxi Agricultural University.The grazing livestock is sheep,including four grazing intensities:0 sheep/hm~2,2.35 sheep/hm~2,4.8 sheep/hm~2 and 8.75 sheep/hm~2.Soil samples were collected in September 2018and September 2019,respectively.The second-generation high-throughput sequencing method was used to analyze the soil fungal diversity and community composition under the four treatments.We also measured relvant soil physical and chemical properties.The main experimental results are as follows:(1)Grazing intensity has an effect on soil physical and chemical properties.In2018,the soil available phosphorus content in moderate grazing plots was significantly higher than other grazing intensities.The soil electrical conductivity increased with the increase of grazing intensity.The soil available nitrogen content in control plots was significantly lower than that of grazing plots,while there was no significant difference between grazing intensity in 2019.There was no significant difference in soil pH,bulk density,organic carbon,total nitrogen,and total carbon between different grazing intensities and control plots.(2)There is no significant difference in soil fungal?diversity in 2018 and 2019under different grazing intensities.The soil fungal?diversity was different in 2018,showing a significant difference between moderate and heavy grazing treatments and control,but no significant difference in 2019.(3)Grazing has a significant impact on soil fungal community structure and functional diversity.The dominant fungal phylum in the soils of the four treatments were Ascomycota,Basidiomycota,Glomeromycota,and Mortierella.The relative abundance of each dominant phylum in 2018 did not differ significantly among the four treatments.In 2019,the relative abundance of Ascomycota in light and moderate grazing plots was significantly higher than that in heavy grazing and control plots,and the relative abundance of Glomeromycota in moderate grazing plots was significantly higher than other treatments.The relative abundance of saprophytic fungi in moderate grazing in 2018 was significantly higher than that of the other three treatments;while the relative abundance of symbiotic fungi under moderate grazing in 2019 was significantly higher than that of the other three treatments.(4)The soil physical and chemical properties that mainly affect the soil fungal community structure include available phosphorus,available nitrogen and organic carbon.The fungal phylum affected mainly are Ascomycota and Basidiomycota.