| Aerobic composting is an effective way to achieve the reduction,harmless management and resource utilization of Chinese medicine residue.However,the increasing p H value of compost after reaching the thermophilic phase induces a great gaseoμs loss of nitrogen,caμses secondary pollutionand reduces the quality of the compost products.In view of the problem of nitrogen loss during aerobic composting of Chinese medicine residue,the objective of thisresearch is to improve the quality of compost product by adding acid hydrolyzed amino acids and ammonium sulfate to the compost of traditional Chinese medicine residue.The effects of different amount of early supplemented nitrogen(ammonium sulfate)on the characteristics and nitrogen loss control of Chinese medicine compost is studied.Finally,pot experiment is perfromed to evaluate the effect of organic fertilizer.The main results are as follows:1.In order to investigate the changes of compost physicochemical properties under different amount of early supplemented nitrogen additions,three treatments were set up in the experiment of Chinese medicine residue stack composting:no nitrogen and amino acid addition(CK),1%nitrogen and 15%amino acid addition(AS1),and 3%nitrogen and 15%amino acid addition(AS3).During the composting process,the temperature was divided into three stages:warming period,high temperature period and low temperature decay period.The high temperature period(65°C)of the CK maintained 14 days,while the high temperature periods of AS1 and AS3 maintained 21 and 20 days,respectively.The p H of the initial material was about 6.5,which showed a trend of increasing,then decreasing and finally stabilizing during the fermentation process.The p H value at the end of composting was 7.44,7.18 and 7.24 in CK,AS1 and AS3,respectively.At the end of composting,the germination index of CK treatment was 98.19%,while AS1 and AS3 reached 118.3%and113.6%,respectively.All composts reached the state of maturity.Organic carbon decomposition caμsed the increase of the relative contents of total phosphorμs and total potassium in all treatments,with the highest contents of total phosphorμs and total potassium in AS1.The above results indicated that the early supplemented amount of nitrogen was optimum at 1%in the composting process of Chinese medicine residue,and its physicochemical properties were better than those of the control treatment and the 3%nitrogen addition treatment.2.The conversion of organic carbon and retention efficiency of nitrogen directly relates to the quality of compost product.In different nitrogen additions of 0%,1%and 3%,the total nitrogen contents of the three piles were 2.17%,3.29%and 4.78%,and the nitrogen retention efficiency of AS1 and AS3 were 92%and 81%,respectively.The organic nitrogen content of the three treatments in the compost products were 1.33%,2.27%,and3.42%,respectively.The relative retention efficiency of AS1 and AS3 organic nitrogen relative to organic nitrogen remaining was 76.73%and 64.81%,respectively.The organic conversion of inorganic nitrogen in AS1 and AS3 was 76.65%and 64.68%,respectively.The addition of ammonium sulfate and acidolytic amines promoted the decomposition efficiency of carbon,accelerated the humification process and improved the composting efficiency.The cellulose and hemicellulose contents gradually decreased during the composting process,in which the cellulose degradation rates of CK,AS1 and AS3 were20.32%,34%and 36.26%,respectively;the hemicellulose degradation rates were 33.29%,36.41%and 47.89%;and the lignin degradation rates were 7.99%,16.89%and 8.87%.The initial carbon to nitrogen ratios were 26.25,34.35 and 44.65 in CK,AS1 and AS3,respectively,and decreased to 14.09,9.84 and 6.31 at the end of composting due to the decrease in carbon content and increase in total nitrogen content.The nitrogen retention efficiency was higher than the CK and AS3 treatments.3.The pot experiment was conducted to investigate the effect of organic fertiliz ers produced with different amount of early supplemented nitrogen on the growth pr omotion of cabbage.A total of 13 treatments were established:no fertilizer(T1),ch emical fertilizer(T2～T4),organic fertilizer(T5～T7),organic fertilizer to replace 25%chemical fertilizer N(organic fertilizer with 0%,1%,3%nitrogen+75%NPK,T8～T10)and organic fertilizer to replace 50%chemical fertilizer N(organic fertilizer with 0%,1%,3%nitrogen+75%NPK,T11～T13).The results showed that nitrogen could increase the biomass of chard plants,and the plant biomass of the 1%suppl emented nitrogen treatment significantly higher than the other treatments.The highes t biomass was detected in the treatment of organic fertilizer to replace 25%chemica l fertilizer nitrogen(organic fertilizer with 1%nitrogen and 15%amino acid develo ped+75%NPK),in which the chlorophyll was detected to be 28.58,and was highe r than 6.95,1.54,2.15 and 0.14 in the T1,T3,T6 and T12 treatments,respectively;the number of leaves was 14,higher than 5,1,2 and 1 in the T1,T3,T6 and T12 treatments,respectively;the maximum leaf area was 186.1 cm~2,higher than 155cm~2,18 cm~2,59.2 cm~2 and 28.2 cm~2 in the T1,T3,T6 and T12 treatments,respe ctively;the yield was 69.75 g,higher than 62.08 g,21.34 g,17.73 g and 3.77 g in the T1,T3,T6 and T12 treatments,respectively.These results demonstrated that th e organic fertilizer produced with 1%nitrogen and 15%acidolyzed amino acids had the best growth-promoting effect,and the organic fertilizer with organic fertilizer ni trogen replacing 25%chemical fertilizer nitrogen was the best growth-promoting effe ct on Brassica juncea.Overall,this study investigated the effects of different amount of early supplemented nitrogen and acidolyzed amino acid combinations on the characteristics and quality of Chinese medicine residue composts The organic fertilizer product(organic fertilizer produced with 1%nitrogen and 15%amino acids+75%NPK)had the best growth promotion effect on chard.This study is important for optimizing the composting technology,improving the nitrogen retention efficiency of compost,and improving the compost quality and product efficiency. |
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