Characteristics Of Soil Microbial Community In The Forestland Of Camellia Oleifera

Camellia oleifera is one of the world’s four largest woody oil plants,and it is an important woody edible oil tree in southern China.It plays an important role in China’s forestry industry.The characteristics of soil microbial communities of forest land in C.oleifera have not been reported before,while researching on this fields would helpful to understand the composition and diversity of the soil microbial community.and it is helpful for their management.In this paper,the physical and chemical properties,enzyme activity,microbial biomass,carbon,nitrogen and phosphorus in the rhizosphere and non-rhizosphere soil of the forest land of C.oleifera have been measured,in order to explore the fertility characteristics of the soil.Biolog microplate method has used to analyze the functional diversity of the microbial community,and Illumina Miseq high-throughput sequencing technology has used to study the rhizosphere and non-rhizosphere soil of C.oleifera.The results show as follows:（1）The physical and chemical properties of the rhizosphere soil of C.oleifera were better than those of the non-rhizosphere soil.And the physical and chemical properties of C.oleifera’s soil in summer and in autumn were better than those of in autumn and in winter.The p H of rhizosphere soil and non-rhizosphere soil of C.oleifera were the lowest in summer,the p H range respectively was 4.94 and 5.21.The content of organic matter was the most in summer,the content of organic matter respectively was 34.24 g·kg^-1 and 15.20g·kg^-1.The content of alkali-hydrolyzed nitrogen respectively was the most in autumn,it was 129.91 mg·kg^-1and 80.39 mg·kg^-1.The content of available phosphorus respectively was the most in autumn,it was 3.97 mg·kg^-1 and 2.26 mg·kg^-1.There were significant differences among the four seasons.（2）The enzyme activity in the rhizosphere soil of C.oleifera was higher than those in the non-rhizosphere soil.And it was higher in summer and autumn than in spring and winter.And there are significant differences between the four seasons.The cellulase activity in the rhizosphere soil and non-rhizosphere soil of C.oleifera was the highest in summer,which respectively were 0.47μmol·g^-1·h^-1 and 0.28μmol·g^-1·h^-1.The urease activity was highest in autumn and the enzymatic activities of rhizosphere and non-rhizosphere soil respectively were 16.52μmol·g^-1·h^-1 and 9.14μmol·g^-1·h^-1.The acid phosphatase activity was highest in summer,and the enzymatic activities of rhizosphere and non-rhizosphere soil respectively were 0.47μmol·g^-1·h^-1 and 0.28μmol·g^-1·h^-1.（3）The contents of MBC,MBN and MBP in the rhizosphere soil of C.oleifera were significantly higher than those in the non-rhizosphere soil,and the contents were higher in summer and autumn than in spring and winter.MBC,MBN and MBP in rhizosphere soil and non-rhizosphere soil of C.oleifera showed the highest activity in summer.And there were significant differences among the four seasons.The microbial biomass carbon content in rhizosphere and non-rhizosphere soils in summer respectively was 268 mg·kg^-1 and 115mg·kg^-1.The microbial biomass nitrogen content in rhizosphere and non-rhizosphere soils in summer respectively was 52 mg·kg^-1 and 28 mg·kg^-1.The microbial biomass phosphorus content in the rhizosphere and non-rhizosphere soils in summer respectively was 3.16 mg·kg^-1 and 1.63 mg·kg^-1.（4）The number of microorganisms in the rhizosphere soil of C.oleifera was significantly higher than that in the non-rhizosphere soil,and in summer and autumn than in spring and winter.The number of microorganisms in rhizosphere soil and non-rhizosphere soil of C.oleifera was the most in summer.The seasonal dynamics of their numbers are summer>autumn>spring>winter,and the difference is significant between the four seasons.The number of bacteria in the rhizosphere and non-rhizosphere soil of C.oleifera respectively was 35.52×10⁴CFU·m L^-1 and 28.64×10⁴ CFU·m L^-1.The number of fungi respectively was 40.68×10² CFU·m L^-1 and 29.61×10² CFU·m L^-1.The number of actinomycetes respectively was 14.88×10³ CFU·m L^-1 and 10.26×10³ CFU·m L^-1.（5）The carbon source utilization ability levels of rhizosphere soil and non-rhizosphere soil are in the order of summer,autumn,spring and winter.In the same season,the carbon source utilization ability of rhizosphere soil was stronger than that of non-rhizosphere soil.The AWCD values of rhizosphere soil were in summer（1.280）,in autumn（1.123）,in spring（0.734）,and in winter（0.439）.The AWCD values of non-rhizosphere soils were in summer（0.794）,in autumn（0.623）,in spring（0.469）,and in winter（0.306）.（6）The microbial communities in the rhizosphere and non-rhizosphere soils in the four seasons were used different types of carbon sources.The soil microbial community of C.oleifera can utilize all kinds of carbon sources,but the utilization rate of soil microbial community in the rhizosphere of C.oleifera is higher.Among them,the microorganisms in the rhizosphere soil and the non-rhizosphere soil of C.oleifera make more use of ester and amino carbon sources.These two carbon sources play a major role in the functional principal component differentiation of soil microbial community of C.oleifera.The microbial dominance index,diversity index and evenness index of the rhizosphere soil of C.oleifera,were all higher than those of the non-rhizosphere soil.At the same time,there are differences among different seasons,and the diversity index of soil microorganisms is the largest in summer,indicating that the microbial community is the most abundant in summer.The C.oleifera rhizosphere and non-rhizosphere soil dominance indices were 0.983 and0.981,respectively.The rhizosphere and non-rhizosphere soil diversity indices were 4.934and 4.832,respectively.The rhizosphere and non-rhizosphere soil uniformity indices were12.409 and 6.731,respectively.（7）In the summer soil microbial communities with the most abundant microbial communities,a total of 550 species of bacteria were detected in rhizosphere and non-rhizosphere soils,belonging to 26 families,60 classes,119 orders,206 families,297genera.A total of 6 families,23 classes,71 orders,139 families,215 genera and 292species of fungi were obtained.（8）Chloroflexi,Proteobacteria,Acidobacterea,Actinobacterea,Planctomycetes,are the dominant groups of the bacterial community of C.oleifera.Ascomycota,in the fungal community,Basidiomycea,etc.are the dominant groups of the fungal community of C.oleifera.At the genus level,14 dominant genus of rhizosphere soil samples accounted for53.62%of the total abundance.The non-rhizosphere soil samples contained 14 dominant flora genera.They accounted for 76.14%of the total abundance.