Effects Of Mixed Patterns On The Soil Microbial Community Of Phoebe Bournei And Cunninghamia Lanceolata

Soil microorganisms are the link between soil and plants,and are considered to be more reliable indicators of environmental change than soil organic matter.Studying soil microorganisms is of great significance for understanding soil elements,using soil scientifically,creating forest stands with optimal ecological benefits,and improving the ecological environment.This study takes Phoebe bournei and Cunninghamia lanceolate as the research objects.Through pot experiment and field experiment in 2018,Among them,the pot experiment mode is respectively the ratio of Cunninghamia lanceolate and Phoebe bournei:1:1(A),2:1(B),1:2(C),pure Cunninghamia lanceolate(D),pure Phoebe bournei(E)and control group(F)The wild experiment modes are Phoebe bournei and Cunninghamia lanceolate mixed forest(MF),pure Cunninghamia lanceolate forest(PC)and Pure Phoebe bournei forest(PP).The Illumina Miseq high-throughput sequencing platform was used to analyze the differences of soil microbial community structure and diversity of mixed patterns of Phoebe bournei and Cunninghamia lanceolata.Based on the physical and chemical properties,it finds out the main factors affecting the changes of soil microbial community structure,which provides basic data for the cultivation of mixed forest of Phoebe bournei and Cunninghamia lanceolata.The main findings are as follow:(1)The growth conditions of Cunninghamia lanceolata seedlings under different cultivation patterns indicate that its growth condition is the best when the mixed ratio of Cunninghamia lanceolata and Phoebe bournei(hereinafter referred to as mixed ratio)is 1:1,followed by mixed ratio 1:2,pure Cunninghamia lanceolata and mixed ratio 2:1.In contrast,the growth condition of Phoebe bournei seedlings is the best when the mixed ratio is 1:1,followed by mixed ratio 1:2,mixed ratio 2:1 and pure Phoebe bournei.(2)Pure Cunninghamia lanceolata soil has the strongest acidity in pot experiment.The changes of SOC,TN,and TP in each group are consistent,all showed the highest pure Cunninghamia lanceolata,followed by mixed ratio 2:1,mixed ratio 1:1,mixed ratio 1:2 and pure Phoebe bournei.In field experiment,SOC,TN and TP all showed the highest pure Phoebe bournei and the lowest pure Cunninghamia lanceolata.Compared with A,D and E of pot experiment,the change rule of soil pH in field experiment is the same with that of the pot experiment,while the change rule of SOC,TN and TP are opposite to that of the pot experiment.In the pot experiment,SOC,TN,TP are significantly correlated with the bacterial dominant group,and TN is significantly correlated with the fungal dominant group.In the field experiment,soil temperature,water content,SOC,TN,TP are significantly correlated with the dominant groups of soil bacteria and fungi.(3)The microbial community richness in the pot experiment is higher than that in the field experiment.In the pot experiment,the richness and diversity of the bacterial community were consistent,with the highest mixing ratio of 1:2 and the lowest mixing ratio of 1:1;the richness of the fungal community was the highest of pure Phoebe bournei and the lowest mixing ratio of 1:1;The diversity of communities is the highest in pure Phoebe bournei and the lowest in pure Cunninghamia lanceolata.In the field experiments,the community diversity and community richness of bacteria and fungi were the highest in pure Phoebe bournei and the lowest in pure Cunninghamia lanceolata.In the pot experiment,the microbial community composition of A,D,E and the field experiment were obviously differentiated,all of which showed that the microbial community composition of pure Cunninghamia lanceolata forest and mixed forest was similar.(4)A total of 31 bacterial phylums has been detected in the pot experiment,of which 23 are common bacterial phylums.Comparatively,a total of 28 bacterial phylums has been detected in the field experiment,of which 26 are common bacterial phylums.The dominant bacterial phylums shared by the pot experiment and the field experiment are Proteobacteria,Actinobacteria,Chloroflexi,Acidobacteria,Firmicutes and Gemmatimonadetes.The dominant bacterial phylums unique to the pot experiment include Bacteroidetes,and Saccharibacteria,while the dominant bacterial phylums unique to the field experiment are Planctomycete,Verrucomicrobia and GAL15.A total of 7 fungal phylums has been detected in the pot experiment,of which 6 phylums are common fungal phylums.In comparison,a total of 7 fungal phyla has been detected in the field test,all of which are common fungal phylums.The dominant fungal phylums are all Ascomycota,Basidiomycota,Zygomycota,and Unclassified_k_Fungi.(5)Under different mixed patterns,there are no significant differences in the functional composition and proportion of soil bacteria.In the pot experiment and field experiment,25 and 24 functional gene families are obtained respectively,thereby showing the richness of function,of which metabolic and genetic information processing are the major ones.However,the proportion of fungal functional components under different mixed patterns is quite different.Additionally,mixed vegetative fungi cover a large proportion,and most of them are saprophytic fungi.In summary,The mixed planting of Phoebe bournei and Cunninghamia lanceolata seedlings would faciltate the growth of the two plants in the early stage.When the mixed ratio is 1:1,the growth condition is the best.In the pot experiment,the content of organic matter in the soil was as follows:pure Cunninghamia lanceolata>Mixed forest>pure Phoebe bournei,but the opposite rule was shown in the field experiment;The soil microorganisms in pot and field experiments have both common dominant bacteria and their unique dominant bacteria;The soil microbial community structure is obviously affected by plant species.The community diversity is highest when the mixing ratio is 1:2 in the pot experiment,and pure Phoebe bournei is the highest in the field experiment;The correlation between environmental factors and bacterial communities in pot experiments is greater than that of fungal communities,while the correlation between environmental factors and fungal communities in field experiments is greater;The bacterial community in the soil is dominated by metabolic and genetic information processing,and the fungal community is mostly saprophytic.