Stabilization Of Peanut Shells By The Vermicomposting

At present,the area of growing peanut in the world is about 2521 Mhm~2,and the total production is about 4184.86 Mt.In 2013,the planting area of peanuts in China reached 471 Mhm~2,and the total yield was about 1700 Mt.The produced peanut shells were about 1.8 Mt each year.In addition to a small amount of the shells is used as fuel and coarse fodder,most of the shells were discarded.This causes not only great waste of resources,but also great pollution to the environment.The biological methods developed in recent years have the advantages of no pollution,high efficiency and high yield etc..It makes waste profitable,saves the field and improves the economic benefit.The study took the natural dried peanut shell and decomposed cattle-manure as substrates,mixed the two substances according to a certain proportion,the Eisenia fetida was vaccinated at the appropriate temperature and humidity.The total weight of the material in the experimental group is 800 g,four groups of A,B,C and D were set up according to the proportion of peanut shell and cattle-manure,the specific grouping is that(A)is composed of 60%peanut shell and 40%cattle-manure,(B)is composed of 80%peanut shell and 20%cattle-manure,(C)is composed of 100%peanut shell,(D)is composed of 60%composed of and 40%cattle-manure inoculated on the Trichoderma reesei.Each proportion was set into four experimental groups,namely,A1,A2,A3,A4,B1,B2,B3,B4,C1,C2,C3,C4,D1,D2,D3 and D4.The number of Eisenia fetida vaccinated in the four experimental groups were 0,60,120and 180,and the composting experiment lasting for 60d was performed.The sampling process was performed every twelve days,the physicochemical properties,enzyme activity and lignocellulose content of the sample was tested.The sequencing of the initial substrates,that is,the A1 group on 0 d,A1 and A3 groups on the 12 d,24 d,36d,and 48 d were sequenced by high throughput sequencing technology,the changes of microbial community was analyzed.The results are showed as follows:(1)In the Vermicomposting process of herbal residues,we compared experimental group for vaccinating earthworms and control group without earthworms,there was a significant change in pH from the beginning of the Vermicomposting to the end of the Vermicomposting.The pH value of experimental groups for vaccinating earthworms were decreased significantly from the 0 d to the12d,increased significantly in the 12 d to the 36 d,decreased significantly from the36 d to the 60 d,and tended to be stable.The conductivity of experimental group was higher than control group,and the more the number of earthworms inoculated,the greater the conductivity,indicating that vaccinating earthworms could accelerate the mineralization of organic matter.The organic carbon content of experimental was lower than control group,but the total nitrogen content increased,the carbon-nitrogen ratio of the composting material was dropped below 20 at the end of composting.The content of available nitrogen,available phosphorus and available potassium were all increased after vermicomposting,and the A3 group was higher than the other groups.(2)The enzyme activity of carboxymethyl cellulose,microcrystalline cellulose and?-glucosidase of A,B,C,D group were all showing the first increase and then reduce.The enzyme activity of vaccinating earthworms experimental groups were significantly higher than control group,and the A3 group was higher than other group.The activity of xylanase,lignin peroxidase,dehydrogenase,protease and urease present the same trend that first increase and then reduce.The enzyme activity gradually rise from 0 d to 36 d,and gradually decrease from 36 d to 60 d.(3)The degradation rates of cellulose,hemicellulose and lignin of A,B,C,D group were all showing the first increase and then reduce.The degradation ratesof the vaccinating earthworm group was significantly higher than the experimental group without vaccinating earthworm,and the degradation rate of D group was the highest of all the group.(4)At the level of bacteria,the High-throughput pyrosequencing sequence statistical data showed that the total number of mircoorganisms in the bacterial community diversity of A3 in the 36 d was the highest and the total number of mircoorganisms in the fungal community diversity of A3 in the 48 d was the highest.The bacterial community diversity of A3 in the 36 d was the highest and the fungal community diversity of A3 in the 48 d was the highest.In bacteria,Proteobacteria and Actinobacteria were dominant bacterial community.In fungal,Ascomycota was dominant bacterial community.In different composting conditions,the relative abundance increased first and then decreased with the extension of time.In the first batch of 36 d,the relative abundance of the dominant bacteria was the largest.