东北黑土区冻融侵蚀研究进展与展望

摘要

[Background] Freeze-thaw erosion is one of the major types of soil erosion.Freeze-thaw cycling changes soil properties and influences the processes of runoff and erosion on slopes,resulting in severe soil and water losses.The aim of this review is to clarify the existing research results and to contribute to the future research on freeze-thaw erosion in the black soil region of Northeast China.[Methods] We collected all relevant literature and sorted them,and finally used the critical 55 references for this review.Based on these 55 references,we analyzed the mechanisms and research progresses of freeze-thaw action on soil erosion.Further we tried to analyze the issues and prospect the research on freeze-thaw erosion in the black soil region of Northeast China.[Results] 1) Freeze-thaw does not directly lead to the transport and movement of soil particles,and its action in soil erosion happens in rainfall strikes,runoff scouring,strong wind blowing or gravity.Mechanisms of freeze-thaw action on soil erosion are as follows,a) alternation of soil freeze-thaw changes the nature of soil,thus affects the sediment production process in the course of rainfall,and finally affects the degree of water and soil erosion;b) the depth change of the thawing layer directly affects the infiltration of snowmelt runoff and rainfall runoff,and subsequently the runoff and sediment yield;c) freeze-thaw cycles change erosion process of slope rill and gully and increase erosion intensity;d) the response difference from different land use of alternate freeze-thaw process leads to spatial heterogeneity of soil erosion intensified;and e) changes in the response of different underlying soil to global climate change lead to changes in regional soil erosion patterns.2) The studies of freeze-thaw soil erosion started 1960s abroad and 1980s in China,mainly focused on the influence of freeze-thaw action on soil physical and chemical properties,soil moisture temperature and soil erosion process and intensity,and most of which adopted indoor simulation experiment.3) There are 3 major issues in this research topic,a) few in-situ field studies,most were simulated ones;b) no quantitative evaluations on freeze-thaw contributions to soil erosion;and c) not considering the differences of underlying soil on the responses of freeze-thaw cycling.4) Regarding above issues and the unique interactive character in the black soil region of Northeast China,the future research should focus on the freeze-thaw cycle patterns and influence factors in the field,quantifying the contribution of freeze-thaw cycles to runoff and sediment on slopes and in watersheds,and finding reasonable evaluation methods.[Conclusions] The mechanisms of freeze-thaw action are complicated and not completely known yet,especially for the black soil region of Northeast China where there is interaction of freeze-thaw and water erosion.We need to have more in-situ field studies for better understanding it.Moreover,we should try to invent reasonable evaluation methods to quantify the contributions of freeze-thaw actions on the soil erosion in the black soil region of Northeast China.%冻融侵蚀是土壤侵蚀的主要类型之一,冻融交替通过改变土壤性质和坡面产流产沙过程,导致剧烈的水土流失.为明晰已有相关研究成果,为未来东北黑土区冻融侵蚀研究工作的开展提供参考,本文通过回顾和总结现有研究,分析了冻融作用对土壤侵蚀的影响,总结了冻融侵蚀相关影响因素和过程机制.文中指出:冻融导致土壤容重和孔隙比变化,整体上表现为冻融导致疏松的土壤变得相对紧实,而紧实的土壤变得相对疏松;冻融导致土壤团聚体稳定性降低,但当土壤处于中等含水量条件下会出现冻融后团聚体稳定性增大的现象;冻融降低土壤多种力学强度;冻融改变土壤水分特征.众多研究结果表明冻融后土壤可蚀性增大,且正融土最易受到侵蚀.在综述的基础上,笔者指出了现有研究存在的问题和不足,并提出了未来东北黑土区冻融侵蚀研究的重点方向和急需解决的关键问题.