Influence Of Transformation Promoter On Vermicomposting Of Rural Garbage

In China, about 70 million tons of straw are annually produced in rural areas, and about 70 percent of straw are burning in situ as life energy or direct application, causing serious resource waste and air pollution. At the same time, the amount of animal manure of the whole country is increasing year after year. Manure as organic fertilizer in agriculture without any preliminary treatment can lead to a considerable emission of harmful gases released into atmosphere, and contamination of soil with pathogens is possible. Composting is an effective and safe way for reduction of the manure's mass and volume, for destruction of pathogens and stabilization of nutrients and organic matter in it. Organic waste vermicomposting combines traditional composting with biological treatment, it's a biooxidation and stabilization of organic material involving the joint action of earthworms and microorganisms, it has been an important approach on the transformation of organic solid wastes into useful resources.The Eisenia foetida, transformation promoter such as EM solution(Effective microorgnism) and organic materials compost promoter, wheat or corn stalks, cattle manure and so on are used as the experimental materials, pre-composting by adding transformation promoter and vermicomposting are applied as the experimental method. In the research of the best material ratio suitable for earthworm survival under the condition of adding the same amount of EM solution, the effect of pre-composting production with different amount of transformation promoter on vermicompoting and earthworm growth and reproduction. In the experiment, physical, chemical and microorganism enzyme index have been determined. Experimental process parameters obtained can be used to guide the field experiments and provide scientific basic. The main results have been obtained as follows:(1) The best material ratio of raising earthworm with pre-composting production was investigated, by the effect of different eight ratio pre-composting production (dung manure: corn stalks: garbage = 1:2:1, 1:3:1, 2:3:1, 0:2:3 and dung manure: wheat stalks: garbage = 2:1:2, 3:1:2, 4:1:3, 0:1:10)on earthworm survival ratio under the same adding amount of EM solution. The C/N value of piles containing corn straw is higher than the piles containing wheat straw at the beginning and end of the pre-composting. At the end of pre-composting, the C/N value of different eight piles is 17-26, NH₄⁺-N concentration basically maintains about 200mg/Kg, and cattle manure: corn straw: rabbish(vegetable leaves: paper = 4:1 by dry weight. ) 1:3:1 has the highest earthworm survival ratio of 87.50%.(2)The effect of different adding amount of transformation promoter on pre-composting is studied according to the ratio of dung manure: corn stalks: rabbish 1:3:1, under the different adding amount of EM solution (wet ratio) and organic materials compost promoter (dry ratio). Based on the results of study, it was concluded that the pH is 7.60-7.90, C/N is 28-35, NH₄⁺-N concentration is 270mg/Kg-440mg/Kg, cellulose, sucrase and urease stabled at low levels in every compost pile at the end of pre-composting, meeting the condition of earthworm grow and reproduction with the pH value of 6.00-8.50 and C/N value of 25-35. At the same time, the C/N value of 5‰EM is the lowest of 28.02, NO₃^--N/NH₄⁺-N value is the highest of 10.25, which illustrate the amount of 5‰EM solution is more conducive to mineralization.(3) Different pre-composting production is used in vermicomposting. The effect of different pre-composting production on earthworm growth and reproduction is investigated. It concludes that organic carbon content of the piles adding EM solution is lower than adding organic materials compost promoter in the course of vermicomposting, the C/N value of 5‰EM group is the lowest and NH₄⁺-N concentration is about 350mg/Kg of every pile at the end of vermicomposting. In the group of the 5‰EM, at the end of vermicomposting, NH₄⁺-N concentration is 314.52mg/Kg, which is the lowest; the NO₃^--N concentration is 10857.36mg/Kg, which is the highest; and NO₃^--N/NH₄⁺-N value is aslo the highest; the activity of cellulose and sucrose are the lowest. Earthworm grown steadily in the group of 5‰EM, and has the highest reproduction ratio of 1.55, which indicates that the 5‰ adding amount of EM solution not only obtains pre-composting production suitable for vermicomposting, but also the interactions of the earthworms and microorganisms promotes the maturity, mineralization and stability of the organic materials.(4) Based on the PCR-DGGE and phylogenetic analysis of bacteria and fungi of 4‰FU, 5‰EM and CK at the start and end of vermicomposting, it was concluded that the dominant bacterial species of 4‰FU and 5‰EM was Luteimonas and Clostridium, the dominant fungal species of 5‰EM and CK was Verticillium and Aspergillus.