Structural Differences Of Humic-Like Substance Formed From Corn Stover Decomposition By Microorganism Inoculation In Different Period Of Time

The purpose of this study was to investigate the effects of mixed micsoorganisms on humic-like substances（HLS）composition and the structure of humic-like acid（HLA）under the condition of inoculation corn stover in different period of time（different inoculation time and sequence）.In this study,Bacillus subtilis,Trichoderma reesei,Phanerochaete chrysosporium,and Trichoderma harzianum were selected on pairwise combinations and used antagonism experiments to screen the combination.Then,corn stover was used as the base material for 30 days for different single strain culture test and mixed strains culture experiment.The changes of HLA structure（by FTIR,TG-DTA,the composition of element,and Fluorescence spectra）and HLS composition were analyzed,and the best inoculation method for each mixed micsoorganisms combination was determined.The results showed as below:（1）Both T.reesei,T.harzianum and P.chrysosporium showed superiority in corn stover degradation in different single strain culture experiments,while B.subtilis had no obvious superiority.Moreover,in the analysis of HLA structures under B.subtilis and natural inoculation treatments,the HLA structure of B.subtilis treatment have no obvious change.Due to the insufficient ability phenomenon of single strain inoculation,the study of mixed strains inoculation on corn stover was reasonable.After antagonistic experiments,4 groups without antagonistic microoganisms were selected:T.reesei and T.harzianum group,P.chrysosporium and T.harzianum group,P.chrysosporium and B.subtilis group,and T.harzianum and B.subtilis group.（2）The contents of TOC and HLM-C in the 4 mixed strains combinations with different inoculation sequence and time were lower than that in single strain treatments of each main strain.And the FLA-C contents in the mixed strains treatments were all lower than that in the single strain treatments,and the HLA-C contents in the mixed strains treatments were basically higher than that in the single strain treatments.The best inoculation scheme for T.reesei and T.harzianum group,P.chrysosporium and T.harzianum group,P.chrysosporium and B.subtilis group,and T.harzianum and B.subtilis group were LH₇,BH₄,BK₁₇,and HK₁₂ respectively.Their relative HLA contents were 17.3%,18.9%,18.3%and 16.3%respectively;the PQ value were 63%,58.6%,61.9%,and 61.9%respectively;and the heat loss ratios were32.47,22.0,4.5 and 17.4,respectively.T.reesei and T.harzianum group and P.chrysosporium and T.harzianum group were beneficial to the production of both complex structural HLA and simple structural HLA.P.chrysosporium and B.subtilis group and T.harzianum and B.subtilis group were only beneficial to the production of complex structural HLA.