| Heilongjiang Province is located in the cold region in our country,and is a big province of planting and breeding.A large number of straw and poultry manure need to be treated every year.Compost is widely used to fertilize straw and manure of livestock and poultry.Traditional aerobic compost has some problems,such as slow temperature rise,difficulty in maintaining high temperature,high energy consumption of heating equipment,long composting time,emission of a large number of greenhouse gases and malodorous gases.In this study,on the basis of exploring the nano-membrane aerobic composting process,agricultural waste chicken manure,cow manure and straw were selected for research,and the ambient temperature was about 0℃.Four treatment groups,CMJ（the ratio of chicken manure to straw）and CMN（the ratio of chicken manure to cow manure）,and CKJ（the ratio of chicken manure to straw to cow manure）and CKN（the ratio of chicken manure to straw to cow manure）,were set up to analyze the effects of different ratios of livestock manure and straw on the gas emission and nutrient changes in the compost fermentation process.In particular,the retention of nitrogen and the quality of fermentation products were evaluated,which provided support for the application and popularization of the Nano-membrane aerobic composting system in the alpine region.（1）In this experiment,the composting cycle of CMJ and CMN treatments was 33 days,which was shortened by 6 days and 4 days,respectively,compared with the corresponding treatment without membrane.In the composting process,the temperature of the composting treatment and the non-membrane treatment lasted above 50℃for 16 days and 11 days.In the composting process,compared with the non-film treatment,the temperature of the coated pile is faster,the temperature of the high temperature stage is higher,the maintenance time is longer,and the external temperature is not interfered.At the end of composting,the C/N of CMJ was 16.25%lower than that of CKJ,and the p H values were 8.03 and 7.72,respectively.The C/N of CMN was 14.45%lower than that of CKN,with p H values of 8.21 and 7.80,respectively.At the end of composting,the contents of CMJ and CMN were 34.21%and 32.76%,respectively,which were lower in the mulching group than in the non-mulching group.The conductivity of CMJ and CMN in the coated group was 2.56m S/cm and 2.82m S/cm,respectively,which was higher than that in the non-membrane group.（2）Compared with non-membrane treatment,the nano-membrane mulching system can effectively reduce nitrogen loss in aerobic compost.At the end of composting,the total nitrogen content of CMJ and CMN was 23.88%higher than that of CKJ and 17.72%higher than that of CKN.The ammonium nitrogen content of CMJ and CMN in coated group was 1890.32mg/kg and1752.46mg/kg,respectively,which were 37.63%and 47.11%higher than CKJ and CKN in non-membrane group,respectively 93%and 9.77%.It was found that compared with non-membrane treatment,the nanomembrane mulching system could effectively reduce nitrogen loss in aerobic composting.（3）During the composting process,the activities of urease,cellulase and protease in the membrane coating group were significantly increased.The urease activity of CMJ was 20.43%higher than that of CKJ and 23.30%higher than that of CMN.The cellulase activity of CMJ was25.23%higher than that of CKJ and 17.36%higher than that of CMN.The protease activity of CMJ was 27.66%higher than that of CKJ and 20.45%higher than that of CMN.（4）The cumulative emissions of NH3from CMJ and CMN were reduced by 32.18%and33.28%respectively compared with CKN.The cumulative CO2emissions of CMJ and CMN were reduced by 30.69%and 20.91%compared with CKN.The cumulative methane emissions of CMJ and CMN were reduced by 70.22%and 72.82%compared with CKN.The cumulative N2O emissions of CMJ and CMN are reduced by 81.47%and 78.50%respectively compared with CKN.These results indicate that covered Nano-membrane compost can effectively reduce the emission of greenhouse gases and odorous gases.（5）The seed germination index,total nutrient content,heavy metal content,astile egg mortality rate,fecal coliform number and other harmful risk indicators of the compost products covered with Nano-membranes all meet the requirements of Technical Specification NY/T3442-2019 and NY/T 525-2021 of Organic Fertilizer.The seed germination index of CMJ and CMN increased by 22.87%compared with CKJ and 24.85%compared with CKN.The egg mortality of ascaris in CMJ and CMN increased by 5.19%and 7.28%compared with CKJ and CKN.The number of fecal coliform in CMJ and CMN decreased by 87.45%and 83.98%compared with CKJ and CKN.The total nutrients of CMJ and CMN were 8.47%higher than CKJ and10.08%higher than CKN.The results showed that the compost products covered with nanomembrane not only had no toxic stress on crops,but also could enhance the product quality and promote seed emergence.The four groups of compost products had reached the state of decomposition,and the decomposition degree of the compost products covered with membrane was better than that of the non-membrane treatment.In summary,it is verified that the Nano-membrane covering system is a harmless,efficient and high-quality aerobic composting technology,which can provide a solution for the aerobic composting treatment of livestock and poultry manure under low temperature conditions in cold areas. |
