| High temperature aerobic composting is one of the effective ways to utilize the solid waste of traditional Chinese medicine residue.However,the degradation efficiency of cellulose and hemicellulose is generally very low,resulting in a low humification degree.Moreover,high temperature and pH values in the middle and later stage of composting induce the acceleration of the ammonia producing microorganisms and the loss of nitrogen as ammonia,resulting in reduced quality of composting.Therefore,the addition of liquid amino acids produced by sulfuric acid hydrolysis of animal waste protein to traditional Chinese medicine residue can not only help to reduce pH and reduce nitrogen loss,but also accelerate the process of organic carbon decomposition and humification for composting microorganisms and improve composting quality.Therefore,it is an effective method to utilize the organic solid waste and animal waste protein at the same time.In this thesis,aerobic composting of traditional Chinese medicine residue was taken as the research object.Firstly,the effects of different amounts of acid-hydrolyzed amino acids on the properties and quality of the traditional Chinese medicine residue composting.Then,the succession of microbial community during composting were studied using high-throughput sequencing method.Finally,the effects of different composting products were evaluated by pot and field experiments.The main results are as follows:1.The effect of exogenous addition of 5%,10%and 15%acid-hydrolyzed amino acids on aerobic composting of traditional Chinese medicine residue were studied.The addition of acid-hydrolyzed amino acids prolonged the duration of high temperature composting of traditional Chinese medicine dregs.The number of days without amino acids above 70℃was 14 days,and the addition of 5%,10%and 15%acid-hydrolyzed amino acids prolonged2 days,3 days and 3 days respectively compared with those without amino acids.In the control treatment,the pH value of traditional Chinese medicine residue composting gradually increased from acidic to weakly alkaline,and the addition of acid-hydrolyzed amino acids significantly reduced the pH value of the compost.The pH of 5%,10%and 15%addition decreased by 0.83,1.10 and 1.58 respectively,and the time required for composting to return to the pH value before amino acid addition was 3 days,5 days and 7 days,respectively,and the remaining nitrogen increased by 0.21%,0.41%and 0.44%,respectively.The addition of acid-hydrolyzed amino acids significantly promoted the degradation of cellulose and hemicellulose,and the degradation efficiency increased with the increase of amino acid addition.The lignin content changed little during the whole composting process,and the relative content of lignocellulose in the raw material was 65.29%.At the end of composting,the relative content of lignocellulose decreased to 51.84%,5%,10%and 15%,respectively.Compared with the lignocellulose(relative content)without amino acid treatment,the relative content of lignocellulose decreased by 3.18%,3.93%and 9.43%,respectively.Acid hydrolysis of amino acids also improves the utilization efficiency of organic carbon in raw materials,promotes the humification process of composting,reduces the nitrogen loss in composting materials,and improves the composting quality;after the addition of acid-hydrolyzed amino acids,due to the introduction of H~+,the electrical conductivity increases;the germination index of each treatment for 45 days of composting is higher than 100%,and the raw materials are mature.2.High-throughput sequencing technique was used to study the effects of different amounts of acid-hydrolyzed amino acids on the succession characteristics of microbial communities in the composting process of traditional Chinese medicine residue.With the composting process,the microbial community diversity decreased at first and then increased;the addition of acid-hydrolyzed amino acids increased the species richness,community diversity,maturity and stability of compost products.In the early stage of composting,the dominant flora were Firmicutes,Proteobacteria,Bacteroidetes.In the high temperature stage,Proteobacteria and Firmicutes were dominant.The addition of acid hydrolyzed amino acid promoted the growth of Bacteroidetes,and the community diversity increased in the later stage of composting,the main microbial groups are Firmicutes,Proteobacteria,Actinobacteria,Bacteroidetes and Chloroflexi.Dimension reduction analysis showed that the succession trend of microbial community was consistent with the trend of physicochemical change of fertilizer,indicating that microorganisms and environmental factors influence and characterize each other.Biomarkers in different treatments were analyzed.The biomarkers without acid-hydrolyzed amino acid treatment were Sinobacteraceae,SHA.31,Erythrobacteraceae et al.,the abundance is higher in 33-45 days.Compared with the treatment without adding acid-hydrolyzed amino acid,the special biomarkers were Staphylococcaceae,Acetobacteraceae,Leuconostocaceae et al.5%and 10%amino acid addition indicated that the microorganism had higher abundance on the 1st,33th and 45th day.The 15%acid-hydrolyzed amino acid treatment biomarkers were Alteromonadaceae,Nocardiopsaceae,Alcaligenaceae et al.The abundance was higher in the 1st,5th,33rd and45th,indicating that the key microorganisms without acid-hydrolyzed amino acid treatment were mainly involved in the function of humization in the later stage,while the biomarkers treated with acid-hydrolyzed amino acid not only participated in the decomposition of substances in the early stage,but also participated in the formation of humification in the later stage.The correlation between marker microorganisms and environmental factors was analyzed,which may be related to the carbon and nitrogen cycle during composting,such as cellulose,hemicellulose degradation or nitrate production.The addition of acid-hydrolyzed amino acids can improve the activity of microorganisms and promote the humification of compost.3.The bio-organic fertilizer was made by adding Bacillus amyloliquefaciens SQR9 to the organic fertilizer product of traditional Chinese medicine residue.The pot experiment was conducted to compare the growth-promoting effect of organic fertilizer and bio-organic fertilizer products with different amount of acid-hydrolyzed amino acids on pepper.Compared with the non-fertilization treatment,organic fertilizer/bio-organic fertilizer could increase the plant height,stem diameter and chlorophyll content of pepper by 19.5%-35.3%,13.8%-25.5%and 17.6%-34.7%,respectively.The plant fresh weight of the organic fertilizer treatment increased by 40.3%to 59.9%compared with the unfertilized treatment and 5.4%to 20.6%compared with the chemical fertilizer treatment,and the plant fresh weight of the bio-organic fertilizer treatment increased by 37.8%to 58.6%compared with the unfertilized treatment.compared with chemical fertilizer treatment,it increased by 3.5%and 19.1%.Organic fertilizer and bio-organic fertilizer could increase the yield of pepper pot,among which the organic fertilizer and bio-organic fertilizer with 10%acid-hydrolyzed amino acids had the best yield-increasing effect.The bio-organic fertilizer products of acid-hydrolyzed amino acids increased by 146.8%and 79.3%respectively compared with non-fertilization and chemical fertilizer treatment,which increased by 125.5%and 64.1%,respectively.After drying,the dry weight of pepper treated with 10%acid-hydrolyzed amino acid added organic fertilizer was 222.8%and 94.1%higher than that of non-fertilization treatment and chemical fertilizer treatment,respectively.The bio-organic fertilizer with 10%acid-hydrolyzed amino acids increased by 197.8%and 79.1%compared with non-fertilization treatment and chemical fertilizer treatment,respectively.The above results show that the addition of 10%acid-hydrolyzed amino acids is the best addition of traditional Chinese medicine residue composting.4.The effect of fertilizer was further evaluated and verified by field experiment.The experiment of promoting the growth of pepper and eggplant was carried out by applying 10%amino acid organic fertilizer/bio-organic fertilizer.The experiment set up no fertilizer treatment,chemical fertilizer treatment,organic fertilizer treatment,organic fertilizer plus chemical fertilizer treatment,bio-organic fertilizer treatment and bio-organic fertilizer plus chemical fertilizer treatment.Compared with chemical fertilizer,organic fertilizer/bio-organic fertilizer improved the nutrient absorption efficiency of crops and increased the physiological index and yield of crops,in which bio-organic fertilizer plus chemical fertilizer treatment was the best treatment of pepper,which increased the yield by 25.4%compared with chemical fertilizer treatment.the yield of eggplant yield of optimal treatment(bio-organic fertilizer treatment)increased by 8.5%compared with chemical fertilizer treatment.According to the radar map analysis of plant indexes of two kinds of crops,bio-organic fertilizer plus chemical fertilizer was the best treatment of pepper in the field,and bio-organic fertilizer was the best treatment of eggplant in the field.Overall,the addition of acid-hydrolyzed amino acids can decrease the pH value and reduce the nitrogen loss in the composting process.In addition,the acid-hydrolyzed amino acids contain organic nitrogen nutrition for the microorganisms,which will promote the of cellulose and hemicellulose decomposition,prolong the duration of the high temperature period of the composting process,promote the humification process and improve the mineral nutrient accumulation of composting products.Amino acids can improve the diversity of bacterial community in the compost,increase the relative abundance of carbon and nitrogen cycling microorganisms,and promote the maturation of the compost.The bio-organic fertilizer produced by composting with acid-hydrolyzed amino acids and functional strains showed great advantages in improving crop growth in pot and field experiments.Compared with the chemical fertilization,bio-organic fertilizer could significantly increase the crop yield.This study provides theoretical guidance for improving composting efficiency and quality,and provides a practical basis for adopting reasonable fertilization methods to improve nutrient use efficiency and crop yield. |
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