| In view of the problems of slow degradation and high loss rate of carbon and nitrogen in the process of straw composting,this study used corn stover experimental material to construct cellulose-degrading bacteria by using laboratory cellulose-degrading bacteria Based on the optimization of enzyme production conditions,the effects of cellulose-degrading bacteria,cellulose-degrading enzyme preparation and bacteria-enzyme combination on the physicochemical properties and maturity of corn straw compost were determined.The main conclusions are as follows:(1)Through the antagonistic test of strains and the determination of cellulose-degrading enzyme activity,the Luteimonas sp.X11-1,Trichoderma longibrachiatum Z8-2,Aspergillus flavus Z5-3 strain could be compounded,and the enzyme activity of the bacterial community is higher than that of each single strain.Therefore,the cellulose-degrading bacteria in this experiment consisted of these three strains.The results of the optimization of the enzyme production conditions of the cellulose-degrading bacteria group were:corn stalk powder as the sole carbon source,the carbon source mass fraction was 2.50%,the nitrogen source was sodium nitrate,the C/N ratio was 26:1,and the initial pH 7.00,the cultivation temperature is 30℃,the inoculation amount is 9%,and the ratio of the number of cells(or spores)of the X11-1,Z8-2 and Z5-3 strains is 20:1:1.Under this condition,the carbo xymethylcellulase(CMCase)activity and filter paper enzyme(FPase)activity of the flora were 0.694 U·mL-1 and 0.157 U·mL-1,respectively.(2)Corn straw compost with different inoculation amount of cellulose degradation agents can promote compost maturity,shorten the composting time and improve the quality of compost products,but there are differences among different treatments.The results show that the stack temperature of the material can be increased by adding bacteria,and the material can enter the high temperature period 1-2 days in advance.Among them,the addition of 15%of the volume fraction of fungicide treatment 2 days ahead of the control entered the high temperature period.Compared with the carbon and nitrogen losses of 37.97%and 42.47%,the carbon and nitrogen losses of materials treated with cellulose degrading bacteria were 21.18%-28.51%and 17.55%-30.85%,respectively,which were significantly reduced.Among them,the loss of carbon and nitrogen in the treatment of adding 15%bacteria was the lowest,21.18%and 17.55%respectively,which indicated that the appropriate amount of bacteria was more conducive to the reduction of carbon and nitrogen loss.Adding bacteria to compost can promote nutrient transformation of materials.The total P and total K content of the treatment with bacteria increased by 13.22%-26.45%and 40.54%-62.16%respectively compared with the treatment without bacteria;the content of available P and available K increased by 3.87%-13.56%and 9.31%-19.86%respectively compared with the treatment without bacteria,of which 15%bacteria was the best.The activities of cellulase,sucrase and catalase in corn straw compost were higher than those in the control.Among them,adding 15%fungicide was the shortest,23 days,6-10 days earlier than other treatments.Therefore,15%by volume is the best inoculum for corn straw composting..(3)Adding enzyme preparation with different mass fraction to corn straw compost material can promote compost maturity and improve the quality of compost products.Compared with no enzyme treatment,the enzyme preparation with different mass fraction can enter the high temperature period 2 days in advance.Compared with the loss of 38.18%and 41.85%of carbon and nitrogen without enzyme treatment,the loss of carbon and nitrogen with enzyme treatment was 23.96%-38.18%and 18.18%-24.59%respectively,which could significantly reduce the loss of carbon and nitrogen.Among them,the loss of carbon and nitrogen was the lowest when 0.8%enzyme was added,which was 23.96%and 18.18%respectively,significantly lower than that of other enzyme treatments,indicating that adding appropriate enzyme was more conducive to the reduction of carbon and nitrogen loss.The content of total P and total K in compost increased by 12.71%-37.52%,45.39%-96.76%respectively,and the content of available P and available K increased by 4.84%-10.65%,5.28%-17.32%respectively,of which 0.8%enzyme was the best.The activity of cellulase,sucrase,urease,dehydrogenase and catalase could be increased by adding enzyme.When 0.8%enzyme was added to the compost,the time needed for the compost to mature was the shortest,17 days,2-16 days earlier than other treatments.Therefore,0.8%is the best dosage of corn straw composting enzyme.(4)Adding bacteria(15%by volume),enzyme(0.8%by mass)and microbial enzyme(15%by volume+0.8%by mass)to corn straw aerobic compost can promote composting maturity,shorten composting cycle and improve the quality of compost products.Compared with the control,each treatment of compost material can promote the material to enter the high temperature period ahead of time.Among them,when the control entered the high temperature period 2 days in advance,the carbon and nitrogen losses of the materials were the lowest,18.91%-15.51%respectively,16.28%-50.34%,19.43%-63.09%lower than those of other treatments,indicating that the enzyme-linked bacteria was more conducive to carbon and nitrogen conservation of materials.By the end of compost fermentation,compared with the control,the total P and total K content increased by 34.48%-62.93%,71.43%-117.14%,and the mass content of available P and available K increased by 13.69%-15.65%,17.10%-23.23%,respectively.Among them,enzyme-linked bacterial treatment of the materials of total nutrient concentration and transformation effect is the best.The activities of cellulase,urease,sucrase,dehydrogenase and catalase were the highest.The ripening time was the shortest,only 15 days.Therefore,15%by volume and 0.8%by mass were the best treatments.In summary,in the corn stalk compost,the addition of 15%volume fraction of complex bacteria agent and 0.8%mass fraction of enzyme preparation,the material carbon and nitrogen loss is lower than other treatments,the effect of nutrient transformation and concentration was the best,and the ripening time was the shortest,which is the best treatment plan. |
