The Priming Effect Induced By Eatrhworm Mucus In The Process Of Decomposition Of Crop Residues

China is a large agricultural country which straw yield is rich. And straw contains lots ofmineral elements, after straw application the soil fertility can be increased. At present, usingvermicomposting to degrade crop stalks has achieved good results, and earthworms showpriming effect during that pocess. It is necessary to fully understand the effect of earthworm onnutrient cycling by studying priming effect induced by earthworm mucus on strawdecomposition process. Proper understanding of the mechanism of priming effect can be usedto reduce the additive amount of mineral fertilizer by returning organic matters to the soil.In this study, maize straw, rice straw and quartz sand mixture for experimental substrate,with maize straw and Eisenia foetida mucus mix (MM), rice straw and earthworm mucus mixed(RM) for the experimental group, straw mixed with glucose and straw mixed with aminogroups for parallel group and straw with deionized water as contral group(CK). Study thechanges of physical and chemical properties of straw and the changes in relevant enzymesactivity during the decomposition process. Using high-throughput sequencing to measure M(maize straw), ME30(the30d sample of earthworm mucus mixed with maize straw), ME40(the40d sample of earthworm mucus mixed with maize straw), R(rice straw), RE30(the30d sampleof earthworm mucus mixed with rice straw) and RE40(the40d sample of earthworm mucusmixed with rice straw) to analyze the microbial composition.The results are as follows:(1) organic carbon mineralization rate reached the maximumwhich was1.16mg·(kg·d)-1at the30d of group MM; organic nitrogen mineralization ratesreached the maximum which was2.10mg1·(kg·d)-at the40d of group MM, during the maizestraw decomposition process.Organic carbon mineralization rate reached the maximum which was0.61mg·(kg·d)-1atthe20d of group RM. However, the effect of the earthworm mucus on nitrogen mineralizationwas not significant during rice straw decomposition.(2) The highest enzyme activity of endo-β-1,4-glucanase, exoglucanses, β-glucosidase,xylanase, acetylesterase, ferulic acid esterase, protease, urease, dehydrogenase, catalase enzyme in MM group was respectively at the30d,40d,30d,70d,40d,70d,30d,10d,30d and10d. Thehighest enzyme activity of endo-β-1,4-glucanase, exoglucanses, β-glucosidase, xylanase,acetylesterase, ferulic acid esterase, protease, urease, dehydrogenase, catalase enzyme in RMgroup was respectively at the50d,40d,10d,70d,10d,70d,40d,60d,20d and30d, during thedecomposition process of straw.(3) It can be found that the abundance of the experimental groups was significantly higherthan the control group in Chao and Ace, and the experimental group diversity was significantlyhigher than the control group on the diversity index of Simpson and Shannon, but the Simpsonin rice straw RE40is higher than R, by analysis of bacterial, fungal microflora communitydiversity at the97%similar levels,(4) The dominant bacteria were Sporocytophaga, Devosia, Cellulomonas, Simiduia,Chthoniobacter in group ME30, and ME40. And the dominant bacteria were Devosia,Cellulomonas, Brevundimonas, Paenibacillus, Aliihoeflea, Microbacterium, Pseudomonas ingroup RE30and RE40.The dominant community fungi were Gibberella, Fusarium, Aspergillus and Scedosporiumduring the maize straw decomposition process. And the dominant community fungi wereAspergillus, Gibberella, Emericella, Fusarium, Coprinus and Scedosporium during the ricestraw decomposition process(5) Through principal component analysis we can know that the spatial distribution ofexperimental group and control group was significant diffident in the main components, theaddition of earthworm mucus to the straw has a great influence on the microbial communitydiversity, and the length of the processing time has decided if the microorganisms couldimplement separation on the principal component.