| Environmental pollution caused by emissions of farm manure is getting worse due to the increasing of people's demand for dairy products and the amount of dairy farming. Deep litter system is a non-polluting, zero-emission organic farming technique for manure process by microbial fermentation.It can control manure pollution and achieve waste utilization at the same time and has become a hotspot in the current research field of environmental protection. In this study, ectopic deep litter fermentation technology has been used in dairy manure control, which avoids the "dead bed" problem of in situ deep litter bedding caused by the large amount of cows' urine and was of great research value.Six thermophilic strains with efficient ability of cellulose degradation and ammonia degradation have been isolated and screened according to the characteristics that cellulose is the main component of ectopic fermentation litter material and dairy waste water contains large amounts of ammonium,and the taxonomic status and biological characteristics of these strains were determined. Strains G21, G4-1 and CR-15 were identified as Bacillus subtilis, G14 was identified as Paenibacillus lactis, CR-14 was identified as B. licheniformis and CR-3 was identified as B. methylotrophicus.The agents made up of the six strains were used in ectopic deep litter fermentation. And the operation mechanism of this system was preliminarily studied through the analysis of variation of the related physical and chemical factors, small molecules, characteristic functional groups and the microbial community structure during the fermentation process. Small scale tests showed that the treatment groups with microbial agents had better fermentation effects than that of control groups,especially that with rape straw and corn stalks as the main litter material and 20% adding proportion of cow manure. Pilot-scale fermentation demonstrated that the fermentation temperature maintained above 50? for up to 18 days, the moisture content maintained at 60% to 70% and the quantity of absorbed waste water accounted for 241.7% of the litter quantity. Significant increases were observed in the contents of total and effective N, P, and K, as well as seed germination index and ascaris eggs mortality,while the valuess of organic matter, carbon-nitrogen ratio and fecal coliform significantly decreased,which achieved the national agricultural industry standard of bio-organic fertilizer. The total humic acid content was decreased and the overall decomposition rate was faster than that of synthesis. Humic acid and fulvic acid ratio showed an upward trend, indicating that the agents were conducive to the formation of humic acids and the improvement of the humus quality. Amides substances, carbohydrates(?-sugar, galactose, mannose and arabinose) and polysaccharides significantly increased based on IR(Infrared ray) and NMR (Nuclear Magnetic Resonance) analysis, which caused the mineralization and humification of the litter.According to rep-PCR and T-RFLP analysis, the quantities of bacteria increased and the microbial species were more abundant in the treatment group with the agents. Bacillus genus were found to share a greater proportion in the fermentation litter, whose abundance had a significant positive correlation with temperature, pH, nutrient contents, C/N ratio and other factors in the fermentation process. This demonstrated that the environment of litter was more conducive to the growth and reproduction of the added strains. Microbial populations were significantly different in the late period of fermentation between the treatment group and the control group, indicating that agents played an important role in the litter fermentation. Strains G21, G14, CR-15 and G4-1 were detected at different stages of the fermentation, respectively, which illustrate that these four strains had played an important role in accelerating the ectopic fermentation process and improving the fermentation result.This study preliminarily determined the parameters for the ectopic fermentation system. Main parameters are as follows: pH is about 7.50?7.75, moisture content is about 60%?70% and C/N ratio is about 45?50 before fermentation; inoculum concentration is 2 ‰, fermentation temperature maintain above 50? for more than 18 days during the process; after fermentation the pH is about 7.75?8.25, the moisture content is about 65%, C/N ratio is about 18 and the reduce amount of litter is about 65%,which achieve the effect of decomposition. The result provided foundation for the large-scale promotion of this technology. |
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