Abstract:
In the context of global warming, the increasingly widespread and frequent freeze-thaw phenomenon will have far-reaching effects on the biogeochemical cycling of soil carbon, therefore, summarizing the effects of freeze-thaw on soil carbon dioxide (CO
2) emissions can provide theoretical support to scientifically reveal the mechanism of freeze-thaw effects on soil CO
2 emissions. Based on the summary of related literatures, the influence of freeze-thaw patterns (freeze-thaw temperature, cycle number and duration, etc.) on soil CO
2 emissions was systematically analyzed, and summarized the response mechanisms of soil CO
2 emissions to freeze-thaw effects in terms of soil physicochemical properties and soil microorganisms. Freeze-thaw can reduce the stability of soil aggregates, promote the release of dissolved organic carbon, and can reduce the number of microorganisms, cell rupture, and release carbon and nitrogen nutrients for use by surviving microorganisms, thus promoting the increase of soil CO
2 emissions, and is closely related to the freezing temperature and the number of freeze-thaw cycles. However, due to differences in ecosystem types, soil physicochemical properties, and freezing temperatures, freeze-thaw action may also may also promote increased stability of soil aggregates, inhibit the release of reactive carbon and microbial activity, and reduce soil CO
2 emissions. Although studies have been able to provide preliminary explanations for the effects of freeze-thaw on soil CO
2 emissions and its driving mechanisms, there are shortcomings such as the lack of in-situ experimental parameters, the lack of in-depth research on microorganisms and the difficulty in quantifying data, resulting in large differences and uncertainties in the research results, so further in-depth studies are needed.