Dynamics Of Microbial Communities In Soil Decomposition Of Plant Residues In Ecological Tea Garden

The decomposition of plant residues is a necessary way for nutrient cycling.Microorganisms play an important role in the decomposition of plant residues.There are some problems in ecological tea garden,such as slow decomposition of tea pruning and its associated tree species,low nutrient turnover rate and decline of productivity.Exploring the correlation between tea and microorganisms,enzyme activities and microbial biomass of different associated tree species can accelerate the decomposition of plant residues and realize the rational management and utilization of various plants in mountain ecological tea gardens.Therefore,in this study,a total of five tree species of Camellia sinensis pruning,Cunninghamia lanceolata,Pinus massoniana,Cinnamomum bodinieri and Betula luminifera were selected as the research objects.Based on high-throughput sequencing technology,kit and chloroform fumigation technology,the microorganisms,enzyme activities and microbial biomass of tea pruning and litter of four associated tree species were measured every six months.The microbial species and community dynamics,enzyme activity and microbial biomass changes of these plant residues during the decomposition cycle were analyzed in order to realize the rational management and utilization of various configuration plants in mountain ecological tea gardens.After two years of decomposition test and determination,the main research results are as follows.(1)The enzyme activity of different plant residues varied with time.The overall trend of invertase and cellulase was consistent,showing a trend of increasing and then decreasing.The overall trend of catalase showed a trend of decreasing and then increasing.The activity of acid phosphatase changed little,showing a trend of decreasing and then increasing.The activity of polyphenol oxidase showed a trend of fluctuating and decreasing.The trend of urease in the whole decomposition period was not obvious,and the trend of protease activity increased first and then decreased.(2)The change trend of MBC and MBN in different plants was consistent with time.With the decomposition of plant residues,many easily decomposed substances were lost,resulting in a decrease in microbial substrates.The content of MBC and MBN decreased after 0.5 years of decomposition.The content of MBP decreased,increased,and then decreased with time.(3)The Shannon diversity index of microorganisms in different plant residues gradually stabilized,and the dilution curve was close to the level,indicating that the sequencing data could reflect the vast majority of microbial diversity information in the sample.The period in which fungi play a role is mainly in the early stage of plant residue decomposition,and the period in which bacteria play a role is mainly in the late stage of plant residue decomposition.There is little difference in microbial community composition between different plant residues at different decomposition stages.The dominant fungi at the phylum level were Ascomycota and Basidiomycota.The dominant bacteria at the phylum level were Proteobacteria and Actinobacteria.Ascomycota and Proteobacteria are the most abundant phylum in the early stage of plant residue decomposition,and they are also the main decomposers in the process of plant residue decomposition.Basidiomycetes have a better decomposition of refractory compounds.Oleaginomycetes play a greater role in the middle stage of plant residue decomposition.Actinobacteria play a great role in the decomposition of plant residues.The composition of dominant genera of fungi in different plant residues at different decomposition stages was different.Mortierella and Penicillium had a great effect on the decomposition of plant residues.(4)The diversity and richness of microbial communities in different plant residues were affected by various environmental factors.MBC and MBN had no effect on the diversity and richness of microbial communities.MBP was significantly negatively correlated with the diversity of bacterial communities after 2 years of decomposition(P<0.05).Microbial community diversity and richness were significantly affected by CAT,Urease and Sucrase after 0.5 years of decomposition(P<0.05).As the decomposition continued,the effect of enzymes on microbial community diversity and richness gradually decreased.(5)Urease,CAT,MBC and MBN significantly affected fungal community(P<0.05).PPO,Urease,Sucrase,MBC and MBP significantly affected the bacterial community(P<0.05).