Study On The Humification Of Wheat Straw And Pig Manure Aerobic Compost Promoted By Gloeophyllum Trabeum Pretreatment

Aerobic composting is one of the most effective methods to recycle livestock manure and crop straw.Shortening compost maturity period and increasing compost humification degree are important directions to improve compost efficiency and product quality.In this study,Gloeophyllum trabeum was used to pretreat wheat straw,and the optimal conditions of producing phenolic compounds and the process of regulating lignocellulose degradation were found out.The effect on promoting the humification of wheat straw and pig manure mixed aerobic compost and the fertilizer efficiency of compost products were clarified,which provided strong technical support for improving the humification level of agricultural waste aerobic composting.The main results are as follows:(1)The effects of pretreatment conditions on total phenol yield and lignocellulose structure of wheat straw were studied in solid-state fermentation experiments.According to the three factors including inoculation amount,fermentation time and water content,the orthogonal experiment was designed.The results showed that the best pretreatment condition was 30%inoculation amount,5 days of fermentation time and 80%water content,and the total phenol production was increased by 60%compared with the control.The primary and secondary relations of the three factors were:water content>fermentation time>inoculum amount,in which water content and fermentation time had significant effects on the total phenol yield of wheat straw pretreated by Gloeophyllum trabeum(P<0.05).The surface structure,crystallinity and polymerization degree of wheat straw before and after pretreatment were also characterized.It was found that after 5 days of pretreatment the surface morphology and structure of wheat straw were obviously destroyed.And the crystallinity and polymerization degree of cellulose were reduced by 6.7%and 29%,respectively,which contributed to the decomposition and utilization of wheat straw by microorganisms during the subsequent composting process.In addition,14 phenolic compounds were identified by liquid chromatography-mass spectrometry(LC-MS).The content of 10 phenolic compounds increased significantly(P<0.05).The results showed that pretreatment of wheat straw by Gloeophyllum trabeum promoted the production of humus precursor and was beneficial to the subsequent composting towards the direction of humus synthesis.(2)Through aerobic composting of mixed wheat straw and pig manure,the effect of pretreatment of wheat straw by Gloeophyllum trabeum on the physical and chemical properties and humification parameters of compost was studied.The results showed that the pretreatment group reached the thermophilic phase 4 days earlier and the composting period was shortened by 4 days.The carbon conversion efficiency of the pretreatment group was significantly higher than those in the inoculation group and the control group.Compared with the control group,the degradation rates of cellulose,hemicellulose and lignin were increased by 27%,15%and 13%in the pretreatment group,respectively,and compared with the inoculation group,they were increased by 19%,24%and 12%in the pretreatment group,respectively.After composting,humic substance(HS)and humic acid(HA)in the pretreatment group increased by 75%and 69%,respectively,and humification parameters were significantly higher than those in the inoculation group and the control group(P<0.05).These results indicate that the pretreatment of wheat straw with Gloeophyllum trabeum can shorten the composting period,improve the composting efficiency and promote the degree of composting humification.(3)The effects of compost products of different treatment groups on the yield and quality of Chinese cabbage(Brassica campestris)and soil nutrient content were studied in indoor pot experiments.The results showed that under the condition of equal nitrogen amount,the effects of application of different fertilizers on the yield and quality of Chinese cabbage as well as soil quality were:pretreatment group>inoculation group>control group>chemical fertilizer>no fertilizer control.Compared with the control group,the fresh weight,dry weight,soluble protein content and soluble sugar content of Chinese cabbage in pretreatment group was increased by 15,10,46 and 13%,respectively.The content of alkali hydrolyzed nitrogen,available phosphorus and available potassium in the soil of the pretreatment group was increased by 6.6,12 and 7.3%,respectively.Compared with the application of organic fertilizer alone,the combination of organic fertilizer in the three treatment groups and chemical fertilizer lowered the quality of Chinese cabbage and reduced the soil nutrient content or had no significant impact.Correlation analysis showed that humification index and HS content were the important factors affecting the yield and quality of Chinese cabbage,they were significantly positively correlated with the yield and quality of Chinese cabbage(P<0.05),while HS content,HA content,humification rate,degree of polymerization and percentage of HA were significantly positively correlated with the soil nutrient content(P<0.05).Considering plant yield,quality and soil nutrient content,the effect of applying organic fertilizer in the pretreatment groupwith higher humification degree was better.