| With the rapid development of agricultural production in China,the generation of a large amount of solid wastes has brought intensive potential environment pressure.Unreasonable management of these agricultural wastes will lead to serious environmental pollution.Aerobic composting is a common strategy for resource utilization of solid wastes.Conventional composting has some disadvantages such as low efficiency and long period,and inoculation of exogenous microbial agents can accelerate the temperature rising,promote the decomposition of organic material,and improve the compost quality.Additionally,in recent years,membrane-covered aerobic composting has become a new composting model,due to its features of small floor space,low cost,and less odor generation.However,the detailed effects of adding decomposing microbial inoculums on the composting efficiency and product quality of membrane-covered composting have not been well investigated.Correspondingly,in the present study,the decomposing microbial inoculums was firstly propagated by using Chinese medicine residues as the substrate,and its promotion effects on composting were also evaluated.Then,dairy manure and straw were used as raw materials to systematically study the effects of adding decomposing microbial inoculums on the fermentation efficiency of membrane-covered aerobic composting and conventional windrow composting.Finally,pot experiment was conducted to evaluate the plant growth-promoting effects of the different composting products.The main results are as follows:1.Chinese medicine residues were used as raw material for propagating the decomposing microbial inoculums and evaluating its promotion on composting efficiency.Results showed that as compared with the control pile(CK)without inoculation,addition of the inoculums significantly accelerated the temperature rising of the composting,where the temperature rose to 67.5°C on the third day while that of CK was only 61.0°C.After inoculation,the total carbon content of the compost decreased faster than that of CK,and the degradation rate of cellulose and hemicellulose was higher than that in CK.In the composting process,the contents of total nitrogen,total phosphorus,and total potassium of each treatment increased gradually,and the increase amount of the composting receiving decomposing inoculums,was higher than that of CK.During the composting progress,the germination index(GI)of the two treatments increased continuously.At the 10th day of the experiment,the GI of the treatment receiving inoculums was higher than that of the control.At the end of the propagation,the number of strains S1(Saccharomycetes),X3(Bacillus subtilis),Z5(Aspergillus)and B5(Geobacillus stearothermophilus)in the pile reached1.4×10~5CFU/g,4.7×10~4CFU/g,2.7×10~5CFU/g and 2.7×10~7CFU/g,respectively,indicating significant reproduction of these decomposing microbes.2.Using dairy manure and straw as raw materials,the effects of adding decomposing microbial inoculums on the physical and chemical properties of membrane-covered aerobic composting and conventional windrow composting was investigated.Results showed that in both composting technologies,addition of decomposing microbial inoculums can accelerate the temperature rising,increase the maximum temperature,accelerate the water loss,increase the relative contents of total nitrogen,phosphorus,and potassium,as well as promote the mineralization of organic matter in the pile.As compared with the windrow composting,membrane-covered composting can accelerate the temperature rising during the early stage that covered with membrane,where the temperature rose to 68.3°C on the11th day,while the temperature in windrow composting was only 45.7°C.Membrane-covered composting also increased the maximum temperature to 68.3°C,while the maximum temperature of windrow composting was only 64.7°C.The increase of total nitrogen content during the early stage of membrane-covered composting was larger than that of the windrow composting,but lower in the post-maturation stage.During the whole composting process,the water content of each treatment decreased gradually,and the decrease rate of membrane-covered composting was lower than that of the windro composting.There were no significant differences in p H,Electric conductivity and total phosphorus and potassium contents between the two treatmens..3.The composting maturity of membrane-covered and windrow technologies inoculated with decomposing microbial inoculums was subsequently studied.The GI of membran-covered composting at the early stage was higher than that of the windrow pile,but lower than the latter at the post-maturation stage.During the composting process,the content of water-soluble organic carbon in all treatments decreased firstly and then tended to be stable,and the highest decrease was observed in the windrow composting inoculated with decomposing agents.Cellulose and hemicellulose content showed a decreasing trend in the composting process,while lignin content showed a slow increasing trend;no significant differences were obtained among all treatments.The increase of humus and humic acid content,as well as the decrease of fulcrum acid content in the windrow composting received the inoculums,were found to be the highest in all treatments,which was 23.7 g/kg,58.7 g/kg and 35.0 g/kg,respectively.In the membrane-covered composting,the increase of humus and humic acid content,as well as the decrease of fulvic acid content in inoculated pile were all higher than that in the uninoculated treatment.These results indicated that the maturity of windrow composting was slightly better than that of the membrane-covered composting,and addition of decomposing microbial inoculums can significantly improve the maturity in both technologies.4.Chinese cabbage pot experiment was performed to evaluate the plant growth-promoting effects of organic fertilizer products made from membrane-covered composting and windrow composting that inoculated with the microbial agents.In general,the growth-promotion effects of partial replacement of chemical fertilizer by organic fertilizer,were better than that of application of chemical fertilizer with equal nutrients.Under the same application rate of organic fertilizer,the growth-promoting effect of organic fertilizer received inoculums were significantly better than those without adding of the inoculums,and There is little difference in growth promotion effect between windrow composting organic fertilizer and membrane-covered composting organic fertilizer.With regard to treatments received the same organic fertilizer,dosage of 12 g per pot was better than 6 g per pot,but no significant difference can be observed.Combined application of 12g per pot of the organic fertilizer from the inoculated windrow composting with chemical fertilizer(OF2+CF)revealed the best growth-promotion effect,and the fresh weight was74.1g.which significantly increased by 483.1%and 54.3%as compared with blank control without fertilization and treatment received chemical fertilizer of equal nutrients.In addition,the leaf area was 187.2 cm~2and chlorophyll value was 27.1 in the OF2+CF treatment,which were also the highest among all treatments.In summary,addition of decomposing microbial inoculums can accelerate the temperature rising and the process of mineralization and humification;membrane-covered aerobic composting can generally guarantee the compost quality,and also revealed the advantages of accelerating the pile heating,increasing the maximum temperature,small floor space,low cost,and less odor generation.The pot experiment of Chinese cabbage showed that the growth-promotion effects of membrane-covered composting were similar with that of windrow composting,and addition of the inoculums can enhance the growth-promotion effects of the composting.Combined application of chemical fertilizer and organic fertilizer can significantly promote plant growth and increase yield. |
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