| With the rapid advancement of urbanization,the output of garden waste is increasing year by year.Due to the difficulty of degradation of its main component lignin,it has become a key factor hindering the effective use of garden waste.The advantages of white rot fungus on lignin degradation,and the excellent progress of solid-state fermentation of mixed-fungi in straw agriculture provide theoretical support for the development of this experiment.Therefore,in this study,Phanerochaete chrysosporium and Trichoderma koningii were selected for compatibility experimenting,and the optimal inoculation sequence was obtained based on the degradation rate of lignin and cellulose,using single factor and response surface to obtain the best conditions for the degradation of mixed-fungi,and preliminarily proving the high efficiency of adding fungi on composting and harmlessness to plant cultivation by measuring relevant indexes of composting.The composted products were used in cultivation experiments to compare plant growth and photosynthetic indicators under different substrate ratios,clarify the possibility of replacing peat with garden waste substrates,and solve the problems of difficult disposal of garden waste and insufficient peat substrates.The specific research results are as follows:1.The plate compatibility experiment found that the two fungi have no obvious antagonistic reaction,and T.koningii had a growth advantage compared with P.chrysosporium.Compared with single fungus fermentation,mixed-fungi inoculation can significantly increase the degradation rate of lignin and cellulose,and when inoculated with P.chrysosporium for 3 d,and then inoculated with T.koningii for 10 d had the best effect,and the degradation rates were 23.13% and 25.57%,respectively.The enzyme activity of the single fungus group and the mixed-fungi group showed a trend of first increasing and then decreasing.The maximum enzyme activity appeared in the mixed-fungi group on the 8th day,which was 3.14 U/g.Looking at the mixed-fungi group as a whole,the FPase activity was higher,which was positively correlated with the degradation rate of cellulose;for Mn P enzyme activity,T.koningii showed higher activity,while Li P enzyme activity was higher under pure culture of P.chrysosporium.There was no obvious correlation between the two enzyme activities and the degradation rate of lignin.2.In the single factor experiment,when the water content was 60%,the total amount of mixed-fungi was 15%,and the ratio of mixed-fungi was 1:2(T.koningii: P.chrysosporium),the degradation rate of lignin and cellulose was the highest.On this basis,through 3-factor 3-level response surface analysis,the optimal conditions for solid-state fermentation of garden waste with P.chrysosporium and T.koningii were obtained: water content was 60.9%,the total amount of mixed-fungi was 15.4%,the ratio of mixed-fungi was 1:1.9,and the degradation rates of lignin and cellulose were 24.71% and 27.65%,respectively.The contribution of the three factors was the ratio of mixed-fungi > the total amount of mixed-fungi > water content,and the interaction between the two factors was significant.Under this process,the degradation rate of garden waste lignin can actually reach 24.68%,and the degradation rate of cellulose can reach 27.55%,which was 6.70%and 7.74% higher than before optimization.3.From the appearance of the composting substrate,the composted product of the group of mixed-fungi had smaller particles,darker color and better quality;the group of mixed-fungi can reach the high temperature composting stage after 5 d and lasted for 5 d.The highest temperature reached 52.3?,and it was close to room temperature and remained stable at 20 d.Compared with the control group,the temperature rose faster,the temperature was higher,the high temperature lasted for a long time,and the efficiency of reaching the maturity standard was high;both p H and EC increased first and then decreased slightly.At the end of composting,the p H of the mixed-fungi group and the without mixed-fungi group were 7.8 and 7.98,respectively,and the EC values were 1.36 m S/cm and 1.41 m S/cm.The decomposition of organic matter was mainly concentrated in the early and middle stages of composting.At the end of composting,the content of organic matter in the group with added mixed-fungi was significantly lower than that of the group of without mixed-fungi;both treatments can significantly reduce the piled material C/N at 30 d.When the group of mixed-fungi was 15 d,the C/N was lower than 20,and the T value was less than 0.7.It can reach the maturity standard 10 d earlier than the control group;the available nitrogen and phosphorus elements in the mixed-fungi group were significantly higher than those in the without mixed-fungi group at the end of composting,and the former was 1.07 times and 1.14 times that of the latter,respectively;the group of mixed-fungi can effectively promote the humification process of compost.The total humic acid content decreased first and then increased with the composting time.At 30 d,the content of both groups was significantly higher than that before composting.The total humic acid content of the mixed-fungi treatment was significantly higher than that of the control group.The E4/E6 trend was opposite to the total humic acid.The E4/E6 in the mixed-fungi compost decreased most significantly at 30 d;at the end of composting,the GI value of the mixed-fungi group and the without mixed-fungi group were 94.90% and86.90%,respectively,which was a significant difference,and the germination index reached 85.50% after 25 d of two-fungi composting.4.The plant height,root length,fresh weight,dry weight,chlorophyll content,Fv/Fm,ETR and other chlorophyll fluorescence parameters of Epipremnum aureum.and Cymbidium goeringii increased first and then decreased with the increase of compost products.The most suitable substrate for composting products to replace peat for plant cultivation was J1(peat: vermiculite: composted products with fungi=5:3:2).Under the same ratio,mixed-fungi composting had a better promotion effect on the growth of two kinds of plants.Porosity was the most important factor in the physical and chemical properties of the substrate that affected the growth of E.aureum and C.goeringii,which accounted for 40.8% and 23.6% of the explained amount of the cultivation substrate,respectively.In summary,this study confirmed the significant degradation effect of mixed-fungi fermentation on garden waste.When the optimal mixed-fungi system was applied to composting,it can effectively improve composting efficiency and product quality.The composted product was mixed with peat and vermiculite as a substrate for plant cultivation.Peat: vermiculite: composted product with fungi=5:3:2 was the most conducive to the growth of E.aureum and C.goeringii,and the porosity of the physical and chemical properties of the cultivation substrate was the most important factor affecting their growth. |
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