[Objective]In order to investigate the influence of seasonal freeze-thaw effect on soil organic carbon mineralization rate and enzyme activity in wetland,undisturbed Deyeuxia angustifolia wetland(UDDAW),disturbed Deyeuxia angustifolia wetland(DDAW),rice paddy(RP)0-20 cm and 20-40 cm soil were investigated as research objects in Sanjiang Plain Honghe National Nature Reserve.[Method]The indoor freeze-thaw simulation method was used to explore the change characteristics of soil organic carbon mineralization rate and enzyme activity under the influence of freeze-thaw action.[Results]After freeze-thaw cycle mineralization culture,the mineralization ratio of total soil carbon in the three wetlands was lower than 0.55%,and the freeze-thaw cycle reduced the total amount of soil organic carbon mineralization in different layers of the three wetlands.The total amount of soil mineralization in the three wetlands decreased,showing UDAW>DDAW>RP.The freeze-thaw cycle obviously stimulated the cumulative release of CH4,which was most obvious in the deep layer.The dissolved organic carbon(DOC)contents of the 3 kinds of wetland soil after freezing and thawing treatment were higher than those of the control(check,CK).The enzyme activity of MBC and the three soils was lower than that of CK,and UDAW˃DDAW˃RP was found in different soil types.[Conclusion]The freeze-thaw cycle decreased the total amount of organic carbon mineralization in wetland soil,but increased the mineralization rate of methane in deep soil.After freeze-thaw cycle,soil DOC content increased,but soil MBC content and three soil enzyme activities decreased.
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