| Plant extracts industry has been developed rapidly in recent years such as traditional Chinese medicine, botanical pesticides and daily chemical industry, which generated more and more extracted residues and this has become a problem need to be solved. These residues were often treated as waste and disposed by incineration or landfill which resulted in a waste of resources and environment pollution, and how to reuse these residues has become a new scientific propositions. This research has explored new ways of residue resource utilization combined with plant nutrition and crop protection. Firstly, a group of lignocellulose degradation composite strains were isolated and constructed from the nature as composting inoculant, then the Sophora flavescens extracted residues were treated with composting method which resulted in the bioorganic fertilizer. Secondly, the feasibility of making functional biofertilizer has been studied combining the compost with biocontrol agents by mixed fermentation. Furthermore, this study had explored the use of different carbon sources on the domestication of microorganisms contained in the compost teas in order to enhance its ability for prevention of certain soil-borne diseases, and the preferable carbon sources and influence factors have been got for the preparation of highly active compost tea which further expanded the application of compost in the plant protection field. The main results are as follows:(1) Two hundred and sixteen room temperature strains and 23 high temperature resistance strains were isolated from the humus soil and compost samples from Yangling, Weinan and Tianshui district which all had high cellulase activities. Detections of carboxymethyl cellulase activity, filter paper degradation and degradation ability of rice straw and Sophora flavescens residues under liquid and solid state fermentation conditions of the isolated microbes were performed, the high efficiency lignocellulose degradation composite strains were finally constructed contained 5 strains which were determined by antagonism and single strain contribution among the composite strains. The composite strains degraded 31.4% and 63.1% of the Sophora flavescens residues and rice straw, respectively, after 20 d of solid state fermentation.(2) The composite strains were inoculated into the Sophora flavescens residues composting to assess its impact on the composting fermentation process by detecting the changes of many kinds of physicochemical and biological parameters. Results showed that the inoculants treatment could significantly enhance the compost pile temperature and high temperature duration in the latter phase of composting, promote the cellulose, hemicellulose and lignin degradation of the composting materials, shorten composing period and accelerate compost maturity. The inoculant treatment has increased the degradation rate of cellulose, hemicellulose and lignin by 7.6%, 11.2% and 22.9%, respectively, after 30 days of composting. The germination index of cucumber for the treatment has reached the maximum of 133.2% after 15 days of composting while the control had reached the maximum of 125.7% after 30 days of composting. The ammonium and nitrate nitrogen ratio and C/N for the treatment and control was 0.16 and 0.20, 15.88 and 17.77, respectively, at the end of composting.(3) The combined using of the matured Sophora flavescens residues compost and two Streptomyces for enhancing pepper growth and biocontrol of pepper seedling blight were evaluated in order to investigate its feasibility of preparation of functional biofertilizer. Results showed that the combined treatment of Streptomyces and compost can significantly promote pepper growth and yield(P<0.05), significantly improve its biocontrol effects on pepper seedling blight(P<0.05); The compost and Streptomyces combination treatment significantly improved the pepper root weight, plant height, stem diameter and fresh weight by 33.2%、36.5%、40.8% and 32.8%, respectively, compared with the compost treatment, and 213.3%、89.4%、63.4% and 204.1%, respectively, compared with the Streptomyces treatment(P<0.05). The compost or Streptomyces treatments both had significantly reduced the pepper seedling blight incidence(P<0.05) in which the disease incidence was significantly lower for the treatment in the compost supplement growth media than the soil media. The compost and Streptomyces combination treatment had the best biocontrol effect of 78.7%, which improved by 49.9% and 41.0%, respectively, than the compost or Streptomyces treatment alone. The plot experiments showed that the functional biofertilizer treatment could significantly enhance the pepper plant height, stem diameter and chlorophyll content(P<0.05), significantly increase the pepper single fruit weight and yield by 11.8% and 24.7%, respectively, compared to the control. Field test results showed that the functional bio-fertilizer treatment could significantly reduce the root rot of strawberry, had a biocontrol effect of 77.4% comparing to the control. Besides, the functional bio-fertilizer treatment could significantly enhance the plant height, petiole length and root neck of strawberry(P<0.05), single plant fruit average yield increased by 20.9% comparing to the control.(4) The microorganisms contained in two kinds of compost teas(named CT1 and CT2) were domesticated with different carbon sources, and the physicochemical, biological indicators and biocontrol effect on cucumber dumping off were detected. Results showed that different carbon treatments could lead to the changes of physicochemical parameters and microbial community structure of the acclimated microbial broth, showed different biocontrol effect on the cucumber dumping off. The glucose, sucrose and starch treatments all leaded to the pH reduction of the acclimated microbial broth, especially for the glucose which reduced the pH of CT1 and CT2 to 3.34 and 3.07 respectively, from the initial 7.5. The cellulose, chitin and wheat straw treatments all caused the pH and electrical conductivity of the acclimated microbial broth increase. The glucose and chitin treatments significantly increased the cellulase and chitinase activities, respectively, of the acclimated microbial broth(P<0.05). The number of microbial species and populations showed significant difference among different treatments(P<0.05), the cellulose treatment had the most bacterial populations while the glucose treatment could significantly enhance population of yeast and fungi. The wheat straw treatment had the most number of bacterial species while the glucose treatment had the lowest. The biocontrol effect of glucose, sucrose and starch treatments on cucumber dumping off were significantly lower than the cellulose, chitin and straw treatments(P<0.05). The glucose treatment of CT1 and CT2 had the lowest biocontrol effect of 12.0% and 7.3%, respectively, while the wheat straw treatment had the highest biocontrol effect of 59.5% and 70.1%, respectively for the CT1 and CT2. Among all the parameters detected, the number of bacterial species and populations showed significantly positive correlations with their biocontrol effect which was 0.840 and 0.648, 0.764 and 0.708, respectively in the CT1 and CT2.(5) The strains primary identifications were performed for the five strains in the composite strains and two strains used in the biocontrol process. According to the morphological, physiological, biochemical, 16 S rDNA and ITS sequence alignment results, XM-3 was identified as Beijerinckia fluminensis; TS-3 was identified as Microbacterium sp. which had a high homology of 98% with Microbacterium oxydans, G-13 was identified as Bacillus sp.. The three actinomycetes all belonged to Streptomyces spp., YC-8 was belonged to the green groups while GA-5 and LS-12 were belonged to the gray brown groups. The fungus SLT-12 was identified as Chaetomium thermophlilum.In summary, the Sophora flavescens extracted residues have been made into biofertilizer successfully through the composting method. The lignocellulose degradation composite inoculants effectively accelerated the composting process, shortened the composting cycle and improved the compost maturity. The combination of compost and biocontrol agents significantly enhanced the growth of pepper and strawberry, and improved its biocontrol effect on seedling blight and root rot. The chitin, cellulose and wheat straw supplements could effectively optimize the microbial communities contained in the compost teas which could improve their biocontrol effect on cucumber dumping off when preparation of compost tea. This study has indicated that the resource utilization of plant extracted residues through biofertilizer, functional biofertilizer and compost tea are feasible, which will provide an efficient way for the plant extracted residues treatment and biocontrol of soil-borne diseases, and will give some theoretical basis for the preparation of functional fertilizer and compost tea. |
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