Effects Of Combination Of Earthworms And Sphingobacterium On Soil Carbon,Nitrogen And Microbial Characteristics

Heavy metal pollution soil is becoming more and more serious,and bioremediation of heavy metal contaminated soil is one of the important research directions.Sphingobacterium sp.and earthworms have been found to survive in heavy metal contaminated soils.Therefore,It is important to study the effect of Sphingobacterium sp.and earthworms on the remediation of heavy metal contaminated soil.In our study,two earthworm species(Eisenia fetida and Amynthas.morrisi)and Sphingobacterium sp.were inoculated in two kinds of soil in Southern C hina for 20 days under miniature lab condition.The 12 treanent included:(1)control soil I(C);(2)Sph + soil I(CS);(3)E.fetida+ soil I(CE);(4)A.morrisi+ soil I(CA);(5)Sph+E.fetida + soil I(CSE);(6)Sph+A.morrisi + soil I(CSA);(7)control soil II(S);(8)Sph+ soil II(SS);(9)E.fetida + soil II(SE);(10)A.morrisi+ soil II(SA);(11)Sph+E.fetida + soil II(SSE);(12)Sph+A.morrisi + soil II(SSA).Each dealing with three repetitions.The main results were as follows:(1)The content of alkali-hydrolysable nitrogen was significantly increased under the influence of earthworms in non-polluted soil,the content of organic carbon was significantly lower(P <0.05),the ratio of microbial biomass N,microbial biomass C and N ratio and microbial biomass carbon / organic carbon were significantly increased under the influence of Sphingobacterium sp.,the content of organic carbon was significantly lower(P <0.05),under the combined action of earthworms and Sphingobacterium sp.,the contents of alkali-hydrolyzable nitrogen and soluble organic carbon were significantly increased,the content of organic carbon was significantly lower(P <0.05).(2)The nitrogen and microbial biomass C and N ratios of the microbial biomass were significantly increasedunder the influence of Sphingobacterium sp.(P <0.05).(3)The activity of ?-glucosidase and acid phosphatase was significantly decreased under the influence of earthworms in non-polluted soil(P <0.05);The activity of acid-base phosphatase was significantly decreased under the influence of earthworms in heavy metal contaminated soil,the activity of the protease was significantly enhanced under the influence of the Sphingobacterium sp.,and the activity of the sucrase was significantly decreased(P <0.05),urease activity was significantly reduced under the combined action of earthworms and Sphingobacterium sp(P <0.05).In summary,Earthworms are substantially reduced in carbon and nitrogen function and enzyme activity for contaminated soils and heavy metal contaminated soils,and the degree of reduction in the two soils is different,In general,the carbon and nitrogen functions and enzyme activities in non-polluted soils were higher than those in heavy metal contaminated soils.The whole Sphingobacterium sp.had little effect on soil carbon and nitrogen function and enzyme activity.However,the effects of sphingosine on soil carbon and nitrogen function and enzyme activity were different in the case of earthworms.