木质素与紫云英共腐解过程中CO2释放及溶解性有机物演化特征OA

[Objective]This study aimed to investigate the response characteristics of carbon conversion to the addition of different lignin types during the decomposition of readily degradable organic materials,in order to evaluate the potential role of lignin in regulating organic carbon mineralization and promoting humus formation.[Method]Chinese milk vetch was chosen as a readily degradable organic material for the indoor simulated incu-bation experiment,which included four treatments:no lignin(CK),alkali lignin(AL),dealkali lignin(DAL),and enzymatic hydrolysis lignin(EHL).The alkali absorption method,combined with conventional measurements,and spectroscopic analysis was used to analyze CO2 release and the evolution of dissolved organic matter(DOM)during the decomposition of Chinese milk vetch.[Result]The addition of all three types of lignin reduced CO2 during the decomposition of Chinese milk vetch.After 30 days of decomposition,the cumulative CO2 release in the EHL and DAL treatments was significantly lower than that in the CK(P＜0.05),decreasing by 10.0％and 5.0％,respectively.The results of UV-Vis and three-dimensional fluorescence spectroscopy analyses indicated that the addition of alkali lignin was beneficial in increasing the aromaticity,humification degree,molecular weight,and accumulation of humus-like substances in Chinese milk vetch decomposition derived dissolved organic matter(DOM).The proportion of humus-like substances in each treatment was AL(64.5％)＞CK(63.9％)＞DAL(61.9％)＞EHL(61.5％),while the proportion of protein-like substances was EHL(38.5％)＞DAL(38.1％)＞CK(36.1％)＞AL(35.5％).Additionally,the seed germination index of AL,DAL,and EHL treatments was significantly high-er than that of CK(P＜0.05),with the increase of 20.0％,45.0％,and 16.2％,respectively.The DAL treatment was significantly higher than both the AL and EHL treatments.[Conclusion]The addition of lignin to a certain extent can reduce CO2 release during the decomposition of Chinese milk vetch and increase the seed germination index of the decomposed products.Among them,the EHL treatment performs best in reducing CO2 emissions,the DAL treatment performs best in improving the seed germination index,and the AL treatment has advantages in promoting DOM humification.These results provide a scientific theoretical basis for the application of lignin in the process of returning green manure into soil.