Study On The Effect Of Streptomyces Griseorubens JSD-1 On The Performance Of Swine Manure And Rice Straw Co-compost And Its Microecological Effects

Agricultural waste such as livestock manure and straw is not only a source of pollution,but also a valuable resource in the agricultural ecosystem.Its comprehensive utilization is of great significance to the sustainable development of agriculture.Aerobic composting can utilize the biochemical conversion process of microorganisms to make organic solid waste recycling,reduction and stabilization.However,in the composting process,there are often problems that the high temperature period is not long enough to fully convert organic matter and effectively remove harmful substances.To improve the composting performance,Streptomyces griseorubens JSD-1 previously screened was inoculated in the co-composting of swine manure and rice straw to study the strain’s strengthening effect on the composting process and its mechanism.Moreover,reduction effect of toxic substances in composting by JSD-1 and the soil remediation mechanism of composts were also carried out.The research results can provide a scientific basis for the application of JSD-1 strain in composting enhancement.The results were summarized as follows:(1)In the co-composting inoculated with JSD-1 inoculum,the highest temperature can reach 66.8°C,while the highest temperature of the control compost without inoculum was62.5°C.In the JSD-1 compost,the thermophilic phase(above 50°C)lasted 46 days,which was twice that of the control compost.In the control compost,the period above 55°C was only 12 days,while that in the JSD-1 compost was as long as 30 days.Compared with the control compost,the inoculation with JSD-1 agent significantly increased the content of nitrogen,phosphorus,potassium and organic matter in the compost.In addition,in the JSD-1 compost,the electrical conductivity was significantly increased and the p H value was significantly reduced.There was no significant difference in the maturity degree and germination index between two compost products.In the 82-day composting period,both compost products have been completely mature.(2)The inoculation with JSD-1 agent significantly reduced the diversity of bacterial community in the co-compost of swine manure and rice straw.With the progress of composting,the differences in the composition of bacterial communities in the two composts were significantly increased.In the JSD-1 compost,the five most significant biomarker taxa were all members of the Bacteroides,including Marinilabiaceae,Bacteroidia,Bacteroidales,Ruminofilibacter and Bacteroides.In the control compost,the five most significant biomarker taxa were all members of Firmicutes,including Bacillales,Paenibacillaceae,Peptostreptococcaceae,Peptoclostridium and Thermobacillus.Inoculation with JSD-1agent can significantly increase the relative abundance of carbohydrate metabolism and membrane transport gene sequences in the compost product.The results of the network analysis showed that the key node species in two composts were different.Temperature is the primary factor affecting the composition of bacterial communities in compost.And the contents of nitrogen,phosphorus and potassium were positively correlated with temperature.(3)Metagenomics sequencing of samples in mature period showed that inoculation with JSD-1 agent can significantly reduce the abundance of genes related to 9 virulence factors in Escherichia coli,7 virulence factors in Staphylococcus aureus,3 virulence factors in Shigella and 1 virulence factors in Salmonella.But it also significantly increased the abundance of genes related to 3 virulence factors in E.coli,1 virulence factor in S.aureus and 2 virulence factors in Salmonella.In addition,JSD-1 inoculation can effectively reduce4 β-lactamase ARGs abundance,1 aminoglycoside ARG abundance and 5 peptide ARGs abundance in compost.However,the abundance of one kind of macrolide ARGs significantly increased in JSD-1 compost compared with the no-inoculated control.(4)After returning the compost product to the field,the two compost products can significantly increase the content of available phosphorus and total nitrogen in the coastal saline-alkali soil of greenhouse cultivation,and enhance the activities of soil urease and invertase.However,there was no significant effect on the content of ammonium nitrogen.Compared with the non-inoculated control compost,the application of JSD-1 compost can significantly reduce the p H value of alkaline soil and significantly increase the soil electrical conductivity and nitrate nitrogen content,but it did not cause soil salinization.Therefore,the application of JSD-1 compost product was more suitable for the improvement of coastal saline-alkaline soil.In addition,compared with the control compost product,the application of JSD-1 compost significantly increased the plant height,fresh weight and dry weight of lettuce.Compared with the non-inoculated control compost,the JSD-1compost also significantly increased the content of soluble protein and vitamin C in lettuce.(5)After the two compost products were returned to the field,they did not significantly affect the diversity of the soil bacterial community,but significantly changed the composition of the bacterial community in the soil.Compared with the unfertilized soil,in the soil with application of both composts,the significantly increased relative abundance of OTUs were concentrated in the Proteobacteria,Actinomycetes,Acidobacteria,Chloroflexi and Bacteroides.The most significant biomarker species in the soil treated with the JSD-1compost product and the control compost product were Actinomadura and SBR1031,respectively.In addition,returning the JSD-1 compost product to the field can significantly reduce the gene abundance of metabolic pathways related to toxoplasmosis infection and Shigella infection in the soil.