Effects Of Black Soldier Fly Vermicompost On Soil Physicochemical And Microbial Community Structure

In recent years,the use of black solider fly(Hermetia illucens L.BSF)bioconversion technology to treat food waste has attracted more and more attention due to its advantages in harmlessness,resource utilization and reduction.After BSF larvae were harvested,the separated residual biomass was further composted to obtain stable BSF vermicompost,which would be a valuable biofertilizer.However,at present,the physical and chemical and biochemical characteristics of the fertilized farmland soil have not been fully understood,which is not conducive to the market promotion of BSF vermicompost,and also will affect the implementation and service of the whole industry chain technology project of food waste BSF bioconversion.Therefore,in this paper,loquat(Eriobotrya japonica(Thunb.)Lindl.)and luffa(Luffa cylindrica(L.)Roem.),two local characteristic crops in Yuhang District of Hangzhou City,were selected to carry out field experiments on the application of BSF vericompost.The changes of soil physical and chemical indexes,nutrient composition and microbial community caused by BSF vermicompost were analyzed and discussed to reveal the ecological environment effect of BSF vermicompost application in farmland.(1)After the application of BSF vermicompost,the electrical conductivity of loquat soil and luffa soil increased by 68.5% and 30.3% respectively,and the acid soil(loquat group)was improved to neutral,but the improvement effect of alkaline soil(luffa group)was not significant.In loquat soil,the contents of dissolved organic matter(DOM),water-soluble nitrogen(SN),ammonium nitrogen,available phosphorus,available potassium,total sulfur and available sulfur increased by 43.6%,92.4%,-27.7%,23.0%,91.8%and 33.9% in loquat soil.Meanwhile,total carbon,DOM,total nitrogen,ammonium nitrogen,total phosphorus,available phosphorus,available potassium,total sulfur and available sulfur in luffa soil were increased by 149%,114%,126%,57.0%,419%,283%,78.8%,48.3% and 113% respectively.(2)The application of BSF vermicompost increased the activity of soil enzymes.The results showed that the activities of soil sucrase,urease and catalase in loquat group increased by 14.6%,13.8% and 17.4%,respectively,and that of luffa increased by4.61%,58.3% and 16.6%,respectively.The enhancement of these soil enzymes is beneficial to the turnover of soil carbon pool and nitrogen.(3)The analysis of UV-Vis absorption spectrum showed that application of BSF vermicompost could improve the aromatization and humification of DOM in soil.In loquat soil,the intensity of E254 and E280 in loquat soil increased by 24.8% and 27.0%,and the intensity of E250 / 365 decreased by 6.80%;similarly,the intensity of E254 and E280 in luffa soil increased by 51.9% and 55.6%,and the intensity of E250 / 365 decreased by 5.69%.(4)We use the 16 Sr DNA high-throughput sequencing technology was used to analyze the microbial community structure of crop soil.? diversity analysis showed that the diversity of crop soil decreased and the evenness increased after treatment with fly manure organic fertilizer;while the results of ? diversity analysis showed that the effect of fly manure organic fertilizer on microbial composition of Luffa soil was more significant than that of loquat soil.The results of redundancy analysis showed that in loquat soil,the variation of DOM was positively correlated with the variation of Verrucomicrobia,while in Luffa soil,the variation of DOM was positively correlated with the variation of Firmicuest.