Effect Of Fertilization And Simulated Grazing On Soil Microbial Composition And Abundance In Area Infested By Pedicularis Kansuensis

Plant community and productivity were strongly influenced by Pedicularis kansuensis which widespreaded of Bayinbuluk alpine grassland in Xinjiang.Previous studies have shown that fertilization and grazing have a significant impact on the growth of root hemiparasitic plants and other plant community composition and productivity.However,the previous research mainly focused on the ecological process of the above-ground,and the understanding of the related underground process was very limited.It is necessary to understand the change rules of soil microorganisms in the process of fertilization and grazing in Pedicularis kansuensis invaded plant community,and to understand regulation process and mechanism,then to provide scientific guidance for the reasonable prevention and control of P.kansuensis.In this study,three years of continuous fertilization experiments and simulated grazing samples were carried out in the research group,and the abundance of arbuscular mycorrhizal?AM?fungi was determined by using the traditional methods to analyze root colonization,soil spore abundance and hyphae length density,the composition and diversity of AM fungi,bacteria and fungi were analyzed by 18S rRNA,16S rRNA and ITS sequencing method,respectively.The effects of fertilization and simulated grazing on the composition and abundance of soil microbial were explored in P.kansuensis invaded places.The results are as follows:?1?Soil available N and organic matter content in 0-10 cm were significantly higher than other depths in fertilization and simulated grazing treatment;The biomass of Pedicularis kansuensis significantly declined in high N and P fertilization,when applied with high N and P,the biomass reduced by 95.61%,52.63%,respectively.Root biomass in 0-10 cm was significantly higher than other soil layers regardless of treatments.?2?In total,fungi OTU belonging to 6 phylum,relative abundance of Ascomycota was high,they were 64.28%and 60.92%,respectively.Fungi diversity was significantly reduced in deep soil under these two treatments.?3?The total and vesicle colonization of N₉ and P fertilization groups in 0-10 cm were significantly higher than other soil layers.Soil spore abundance and hyphae length density of AM fungi increased gradually under the fertilization gradient,especially in P treatment group,they increased by 67.24%,66.86%and 74.82%;Root total colonization and spore colonization were significantly increased under grazing treatment,they increased by 66.7%and 70.2%,but soil spore abundance and hyphae length density were not changed.?4?A total of AMF OTUs were detected in the study belonging to 7 genera within 6families,the Glomus was the most abundant,57.66%and 60.9%in two treatments.There were no significant effects of fertilization and simulated grazing to AMF diversity.?5?For bacteria,the detected OTU belonging to 15 phylum,the relative abundance of Actinobacteria was high,40.67%and 37.94%under these two treatments.The bacteria diversity was high in 0-10 cm,and gradually reduced with soil depth under these two treatments.