Study On The Changes Of Microorganisms And Its Degradation Effect In The Process Of Rape Straw Stacking In Alpine Region

Within the cold northern locales of China,farmers and herders usually burn rape straw directly as fuel,resulting in a waste of resources and environmental pollution,which seriously restricts the utilize and industrialization of rape straw in northern areas.Based on this,Qinghai Province with typical northern climatic characteristics was used as the study area and local oilseed rape was used as the study material in this study.Using microbial degradation techniques(multi-enzyme system flora),we carried out pile rotting on different substrates of piles(straw,straw + pig manure mixture),which was to determine physicochemical and straw degradation related indicators,microbial community structure,etc.,during the rotting process.Changes in cellulose and degradation rates,microbial community structure and its response to environmental factors were analysed,while the degradation effects of rape straw were explored during the decay of different piles,which clarified the main functions of the microbial community in the degradation process,laying the theoretical and experimental basis for the selection of biodegradation techniques on rape straw in alpine regions.The main research results are as follows:(1)The results of the physicochemical properties of the piles and the cellulose degradation of rape straw showed that piles with different substrates(rape straw,rape straw + pig manure mixture)were treated with a multi-enzyme system flora(2.4d +2.6b + 310b)which significantly shortened(P < 0.05)the fermentation cycle of the piles;After the pile process,the nitrogen content of the treatment group with rape straw as the substrate was always higher than control group(treatment: 0.68%,control:0.62%),However,the piles with a mixture of rape straw and pig manure as substrate showed the nitrogen content of the control group was higher than treatment group(treatment: 1.83%;control: 2.07%),indicating that there is a significant antagonistic effect between the original microorganisms and multi-enzymes in pig manure with bacterial flora.In terms of the degradation rate of rape straw,the addition of multi-enzyme bacterial flora can significantly accelerate the degradation of rape straw,after the degradation cycle,the cellulose,hemicellulose and lignin contents in each treatment of the rape straw pile were shown that control: 40.43%,5.04%,18.31% and treatment: 39.62%,2.50%,6.59%,and for rape straw and pig manure mixture pile was shown that control: 30.20%,8.47%,4.74% and treatment: 28.76%,7.28%,3.26%.(2)The results of high-throughput sequencing showed that the addition of a multi-enzyme lineage to the pile significantly reshaped the community structure and species composition of its microorganisms.During the decomposition of the heap pile,the main phylum levels(relative abundance >1%)of bacteria during pile decay are Proteobacteria,Bacteroidetes,Actinobacteria,Firmicutes,Verrucomicrobia and Chloroflexi;the main groups of fungi: Ascomycota and Basidiomycota.Bacteria degrade oilseed rape straw which are mainly(relative abundance >0.1%): the genera Pseudomonas,Flavobacterium and Clostridium sensu stricto;while fungi are mainly:Chaetomium,Aspergillus,Fusarium and Penicillium at the genus level.(3)A comparison of the different substrate piles showed that Environmental factors influenced the structure of the microbial community in the piles.The environmental factors of temperature and electrical conductivity had the strongest effect on the bacterial and fungal communities in the piles which multi-enzyme flora were added to the straw as a substrate.The environmental factors of conductivity had the strongest effect on the bacterial community,and the strongest environmental factors for the fungal community were moisture,p H and conductivity in the case of the multi-enzyme flora added to the straw+pig manure mixture as substrate.In summary,the addition of multi-enzyme flora to piles with different substrates(rape straw,rape straw + pig manure mixtures)increased the rate of cellulose degradation,shortened the pile decay cycle and significantly reshaped the microbial community structure in piles with different substrates.Therefore,our study reveals an important role played by microorganisms with multi-enzyme lineages being added to different substrate piles in the decay process,and providing new options for rape straw biodegradation technology in alpine regions.