Soil Micoorganisim Diversity And Soil Quality Assessment In Different Mixed Forests Of Dalbergia Odorifera

Dalbergia odorifera T.Chen is one of China’s endangered species.It is also an endemic species that mainly distributes in Hainan.Dalbergia odorifera has great values in medicine,economics and ecology.This study investigated soil microorganisms’ community and diversity in four different mixed forests of Dalbergia odorifera plantation,i.e.Dalbergia odorifera mixed with Dalbergia oliveri,Pterocarpus macarocarpus,Santalum album L.and Homalium hainanense Gagnep.,respectively.,in Chengmai County,Hainan Province in China by using a high-throughput sequencing technique.Analyses of variance(ANOVA),redundancy analysis(RDA)were used to analysis the relationship among soil physical-chemical characteristics,soil enzyme activities,soil bacteria and soil fungi.Finally,we evaluated the soil quality of these four mixed forests by using principal component analysis(PCA)in order to find a way that could improve soil fertility of Dalbergia odorifera plantation.The main research results were as follow:(1)Soil physical-chemical characteristics and soil enzyme activities in the four mixed forest.The results showed that soil physical-chemical characteristics and soil enzyme activities were different in the four mixed forest.Especially,the Dalbergia odorifera and Santalum album L.mixed forests has the best soil structure with higher moisture content,organic matter,total N,available K and ureas,5.24%、1.65 g/cm3,36.18%,5.24%、39.42 g/kg、0.85 mg/g、37.46 mg/kg and 0.32 mg/kg,respectively.Dalbergia odorifera and Pterocarpus macarocarpus mixed forests with higher pH,available P and polyphenol oxidase,4.48、6.04 mg/kg and 4.19 mg/kg,respectively.(2)Soil bacterial community and diversity in different mixed forests of Dalbergia odorifera.①We got 293,677 sequences with an average length of 434.17bp,about 99.98%of the high quality sequence by using high-throughput sequencing;②The dominant bacteria taxa in the four mixed forests were Proteobacteria,Acidobacteria,Actinobacteria,Chloroflexi and Firmicutes.The results of RDA showed that pH,organic matter,polyphenol oxidase and ureas were the main factors that had significant effect on the structure and diversity of soil bacterial community in this four mixed forests.③The soil bacteria diversity of these four mixed models were:Dalbergia odorifera x Pterocarpus macarocarpus>Dalbergia odorifera × Dalbergia oliveri>Dalbergia odorifera × Santalum album L.>Dalbergia odorifera ×Homalium hainanense Gagnep.,and the correlation analysis results showed that the main factors which had effect on soil bacterial diversity were pH,available P,organic matter,ureas,polyphenol oxidase and sucrase.(3)Soil fungal community and diversity in different mixed forests of Dalbergia odorifera.①We got 328,670 sequences with an average length of 401.58bp,about 82.62%of the high quality sequence by using high-throughput sequencing;②The dominant fungal taxa in the four mixed forests were Ascomycota(73%)and Basidiomycota(20%)at the taxonomic level of phylum,and at the taxonomic level of class,Sordariomycetes,Eurotiomycetes,Agaricomycetes,Tremellomycetes,Dothideomycetes and Chytridiomycetes were the main fungal taxa.The results of RDA showed that sucrase,ureas,cellulase and pH were the main factors that had significant effect on the structure and diversity of soil fungal community in this four mixed forests.③The soil fungal diversity of these four mixed models were:Dalbergia odorifera ×Pterocarpus macarocarpus>Dalbergia odorifera × Santalum album L.>Dalbergia odorifera × Dalbergia oliveri>Dalbergia odorifera × Homalium hainanense Gagnep.,and the correlation analysis results showed that the main factors which had effect on soil fungal diversity were pH,organic matter,available P and ureas.(3)Soil quality assessment of Dalbergia odorifera mixed forests.We chose 25 factors containing soil physical-chemical characteristics,enzyme activities,different bacteria and fungus to assess these four mixed forests by using principal component analysis,the results showed that the SQAV of four plots were:Dalbergia odorifera × Santalum album L.(2.128)>Dalbergia odorifera × Dalbergia oliveri(1.204)>Dalbergia odorifera × Homalium hainanense Gagnep.(-0.327)>Dalbergia odorifera x Pterocarpus macarocarpus(-3.005).In a word,Dalbergia odorifera x Santalum album L.is the optimum mixed model of Dalbergia odorifera among these four mixed forests,and Chloroflexi,Acidobacteria,Actinobacteria,Elusimicrobia,Sordariomycetes and Pezizomycetes could be as the indicator micoorganisms of soil quality.