冻融循环对五台山典型植被土壤微团聚体的影响  

Effects of Freeze-thaw Cycles on Soil Micro-aggregates in Typical Vegetations of Wutai Mountain

作　　者：李杨波 刘楠[1] 韩进斌 郭勇强 李变华 申彦科[3] LI Yangbo;LIU Nan;HAN Jinbin;GUO Yongqiang;LI Bianhua;SHEN Yanke(College of Water Resources Science and Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Shanxi Provincial Department of Forestry,Shanxi Wutai Mountain Arboretum,Xinzhou,Shanxi 035500,China;Beifang Investigation,Design&Research Co.Ltd,Tianjin,300222,China)

机构地区：[1]太原理工大学水利科学与工程学院,山西太原030024 [2]山西省林业厅,山西省五台山树木园,山西忻州035500 [3]中水北方勘测设计研究有限责任公司,天津300220

出　　处：《水土保持通报》2018年第5期21-27,共7页Bulletin of Soil and Water Conservation

基　　金：国家自然科学基金项目“基于水文过程和冻融循环的高山植被土壤氮动态研究”(31400618);国家留学基金管理委员会资助(201708140203,留金法[2017]5087号);国家自然科学基金项目(41572239,41502243)。

摘　　要：[目的]研究气候变化背景下季节性冻融对土壤微团聚体的作用,为影响林线附近土壤地球生物化学过程的相关研究提供参考。[方法]选择五台山林线附近3种典型植被:草甸、华北落叶松(Larix principis-rupprechtii)和云杉(Picea meyeri)覆盖下的土壤,通过土柱野外原位培养,测定不同时期土壤各粒径微团聚体含量以及土壤分形维数(D)。[结果]在培养期内,3个样地的2～0.25mm和0.25～0.05mm团聚体含量变化趋势各不相同;0.05~0.02mm(先降后增再降),0.02～0.002mm(先降后增,华北落叶松样地除外),<0.002mm(先增后降)团聚体含量变化趋势基本一致。在初冻期和融化期,季节性冻融导致3个样地土壤微团聚体含量发生显著变化(p<0.05),深冻期无显著变化(p>0.05)。生长季同样发生了土壤微团聚体含量的显著变化(p<0.05)。不同样地植被组成的差别造成了土壤微团聚体含量差异显著(p<0.05),体现在初冻期和融化期。季节性冻融期间,土壤微团聚体分形维数逐渐增加,而此时云杉样地土壤微团聚体分形维数最低;生长季期间,微团聚体分形维数逐渐降低,草甸样地土壤微团聚体分形维数最低,但在生长季末期,则是华北落叶松样地最低;但3个样地土壤微团聚体分形维数仅在生长季末期存在显著差异(p<0.05),且培养期结束时的土壤分形维数与开始时无显著差异(p>0.05)。[结论]季节性冻融对3个样地土壤微团聚体含量都具有显著影响,且3种植被下土壤结构对季节性冻融的响应也明显不同,主要发生在初冻期和融化期;在培养期内,虽在冻融作用下土壤微团聚体分形维数增加,但进入生长季后都逐渐减少至培养前水平,3个样地土壤结构性和团聚能力均呈周期性变化,具有一定的自我恢复能力。[Objective]The effect of seasonal freeze-thaw on soil micro-aggregates in the context of climate change was studied in order to provide references for the reserch of soil biochemical processes near the timberline.[Methods]Soil samples from three typical vegetation types(meadow,Larix principis-rupprechtii and Picea meyeri)near the timberline of Wutai Mountain were collected for soil column in situ experiment.Soil micro-aggregates contents and fractal dimensions(D)were measured.[Results]The variations of 2~0.25 mm and 0.25~0.05 mm aggregate contents were different among the three plots.The content of 0.05~0.02 mm aggregate reduced initially,then increased and finally reduced.The content of 0.02~0.002 mm aggregate reduced initially and then increased(except in Larix principis-rupprechtii plot),and the content of<0.002 mm micro-aggregates increased firstly and then reduced.The content of micro-aggregates changed significantly(p<0.05)due to seasonal freeze-thaw events in initial freezing and thawing periods,while there was no significant change in deep freezing period(p>0.05).Soil micro-aggregate contents also changed significantly(p<0.05)in the growing season.Different vegetation compositions caused significant differences(p<0.05)among micro-aggregate contents in three plots,especially,in initial freezing and thawing periods.During the freezing-thawing period,D values were increased,and that of Picea meyeri plots was the lowest.In growing season,D values were decreased,and that of meadou plots was the lowest.Significant differences(p<0.05)of D values among three researched plots were only observed in the late growing season,and the least D value is obtained in H.principis-rupprechtii.[Conclusion]Freeze-thaw cycles have great impacts on soil micro-aggregate contents.The responses of soil structures to seasonal freeze-thaw events are significantly different,and mainly occur in initial freezing period and thawing period.The D values of all plots are increased by freeze-thaw cycles.Although the D value of soil microaggre

关 键 词：冻融循环 林线 土壤微团聚体 分形 五台山 

分 类 号：S714[农业科学—林学] S718.5