Effects Of Fungi On Decomposition And Transformation Of Corn Straw And Humus Formation

In view of the possibility that corn straw form humus under the action of fungal microorganisms.In order to explore the effects of fungi on the decomposition and transformation of corn straw and the formation of humus under solid-state fermentation conditions,the appearance changes(SEM),basic properties(water content,residual rate,pH),substance content(TOC,cellulose,lignin)and enzyme activities(cellulase,xylanase,?-glucosidase)were measured under four treatments: the three fungi(Trichoderma reesei,Phanerochaete chrysosporium and Trichoderma harzianum)and an uninoculated control(CK).we report the similarities and differences of the dynamic change of the humus composition of the culture product under 4 treatments,the structural characteristics(the composition of elements,DTA,TG,FTIR)of the culture product(HLS)and its alkali extract(HLA)were studied.The results show:After 25 days of fermentation in the three different fungi and CK treatments,the mechanical damages of the straw showed: T.reesei>P.chrysosporium>T.harzianum.The water contents of the remaining straw increased,the residual rates decreased,and the results under the same conditions in the triangular flask were consistent with those in the fermentation.T.reesei has the best comprehensive degradation ability of cellulose and lignin and the comprehensive enzyme activity is the strongest.Three fungi all can significantly increase the relative content of WSS in HLS,reduce the relative content of HLM,and increase the degree of humification.The effect of T.reesei is the most significant,its PQ value increases by 33.43% within 25 days.P.chrysosporium preferentially promotes the formation of FAL,while two species of Trichoderma preferentially promote the formation of HAL.The mechanism by which fungi effectively promote the conversion of corn straw into humus is consistent with the polyphenol theory.During the solid-state fermentation and humification process in the triangular flask,P.chrysosporium's ability of degrading the original aromatic substances in HLS is better than the ability of synthesizing new substances;the abilities of synthesizing new substances by two species of Trichoderma are better than P.chrysosporium.T.reesei has the best ability to increase the degree of oxidation and the proportion of aromatic substances in of HLS.Three fungi could increase the HAL with the humification time within 30 days,and the difference with the soil HA continued to decrease.T.reesei can concentrate the elemental structure of HAL in O/C=0.531 and H/C=1.330 within 30 days,and the difference between HAL and soil HA is reduced by 56.2% and 43.7%,the structural characteristics close to the HA of soil.T.reesei are extremely strong in reducing the aliphaticity of HAL,enhancing the degree of aromatization and thermal stability,and can efficiently promote the humification process of corn straw.