| Composting is an effective way to deal with organic solid waste,and also an important way of agricultural solid waste treatment and utilization in the future.It will play a positive and effective role in promoting the sustainable development of agriculture and the pollution prevention in China.In order to provide theoretical guidance and help for agricultural waste composting,the community evolution of bacteria and fungi in different raw materials were compared and the main factors leading to the differences were discussed.Pig manure and tea waste were used as the main raw materials of composting respectively.The physical and chemical parameters such as temperature,moisture content,p H,electrical conductance（EC）,total organic carbon（TOC）,total nitrogen（TN）and carbon nitrogen ratio（C/N）were monitored during the composting process.The evolution of bacterial and fungal communities was characterized by PCR-DGGE and gene sequencing technology.The relationship between the change of chemical parameters and the evolution of bacterial and fungal communities was analyzed by constructing phylogenetic tree and redundancy analysis.The changes of physical and chemical parameters reflect the typical aerobic composting process.Different raw materials will lead to different physical and chemical parameters in the composting process.The high temperature maintenance time of each reactor meets the requirements of harmless treatment.Tea waste（TW）is more conducive to the ventilation and oxygen supply of the reactor,making the temperature of the heating period higher and faster into the thermophilic period.Pig manure（PM）contains more nutrients,which makes the thermophilic period last longer.The p H values of PM and TW compost products were7.86 and 8.56,respectively,and EC was 243.5 ms·m-1and 73.6 ms·m-1,respectively,which were in the suitable range of mature compost products and suitable for application in soil.The dominant populations of bacteria and fungi exist in different stages of composting,and their community succession is different.Their composition will change with the change of substrate environment.Because of the different raw materials in PM and TW compost,the composition of pig manure is more complex than that of tea waste.Compared with TW,the DGGE fingerprint of fungi in PM has many bands,complex structure and strong signal.The PM showed more complex and intense fungal community succession,while the TW was more single and stable.Twenty-six dominant species of bacteria and eighteen dominant species of fungi were detected from DGGE.Bacteria are mainly divided into five phyla:Firmicutes,Proteobacteria,acidobacteria and Bacteroidetes.Fungi are mainly divided into Ascomycota,Basidiomycota and mucoromycotina.The dominant populations were distributed in different composting environments of different raw materials and different time periods,and there were significant differences in bacterial and fungal community structure among different raw materials.In the same fermentation stage,most of the dominant populations have more close relationship.Through redundancy analysis,TN,EC,p H and TOC are significant factors that affect the change of bacterial community structure.19.3%（F=2.9,P=0.002）,12.8%（F=3.6,P=0.020）,7.7%（F=2.1,P=0.032）and7.1%（F=2.0,P=0.048）of the changes in bacterial community structure were explained respectively.TN,EC,moisture and TOC are the significant factors affecting the change of fungal community structure.37.2%（F=8.3,P=0.002）,9.3%（F=2.3,P=0.048）,10.6%（F=3.0,P=0.022）and 7.2%（F=2.7,P=0.02）of the changes in fungal community structure were explained respectively.In conclusion,TN,TOC and EC are the most important environmental physical and chemical factors that affect the evolution of bacterial and fungal communities in the process of agricultural waste composting.These parameters are important factors affecting the succession of bacterial and fungal communities,and may be the most sensitive factors of bacterial and fungal communities. |
