Characteristics Of Microbial Communities In Litter And Soil Of Different Forest Stands In Helan Mountain

In this study,high-throughput sequencing methods were used to study the composition and diversity characteristics of litter and surface soil microbial communities in pure pine forests,pure spruce forests of Qinghai,and mixed forests of pines and aspens.Discussed the same and stand different floors of the same hierarchy in the different stands OTU of each sample composition,abundance at each level of the classification composition,diversity feature,the method and RDA Sperman correlation analysis redundancy,clearly the most important environmental factors affecting microbial community composition and diversity:At the phylum level and genus level in different forests,there were no significant differences in dominant fungi,genus levels were significantly different,and fungal differences were greater than bacteria.Different litter dominant species were different.The composition and diversity of litter microbial communities were not affected by the stand.soil organic carbon and total nitrogen in the falling objects are the most important factors affecting the composition and diversity of the bacterial community in the litter;the composition of the fungal community is affected by the soil organic carbon,total nitrogen,total phosphorus and total potassium;total nitrogen has obvious inhibitory effect on the growth of microorganism.The contents of soil organic carbon,total nitrogen,urease,sucrase and phosphatase in different stands were the largest in qinghai spruce forest,which provided good soil conditions for the succession of qinghai spruce forest to become the top dominant community in helan mountain.oil nutrient and enzyme activity decreased gradually with the deepening of soil layer,indicating that forest soil nutrient and enzyme activity had obvious "epigenetic effect".Soil organic carbon,total nitrogen,total phosphorus and nitrate nitrogen are the main factors affecting soil enzyme activity.There was no significant difference in the dominant phylum of soil bacteria in different stands,but there was significant difference in the genus level.The diversity of bacterial community in different stands was obviously different,and the soil of mixed coniferous and broad-leaved forest was more favorable for the formation of bacterial community diversity.Soil urease and total nitrogen are the most important environmental factors afecting the composition of bacterial community.Nitrate nitrogen and sucrase are the most important environmental factors affecting the diversity of baeterial community.A total of 15 fungal phylum were detected in the forest soil.Basidiomycetidae and ascomycetes were the dominant phylum in most soil types.The dominant phylum of fungi were greatly affected by the forest stand,mainly including the genus geodustia,the genus mortis,the genus penicillium Antarctica and the genus dipterygium.The diversity index of fungus community had no response to the change of stand and soil layer.The composition of the fungal community has a great influence on the environmental factors at the level of phylum and genus.Total phospHorus is the most influential environmental factor on the composition of the fungal community,which has an obvious inhibitory effect on the fungal activity and an obvious promoting effect on the diversity of the fungal community.Nitrate nitrogen is the most important environmental factor affecting the diversity of fungal communities.This study can enrich the information base of forest litter and soil microbial species resources in helan mountain,provide data reference for the succession law of dominant tree species in helan mountain,and provide reference for the comprehensive understanding of the interaction mechanism among forest litter,soil nutrients and microorganisms.