基于REE示踪对红壤细沟间侵蚀团聚体周转和泥沙迁移特征的研究  

Characteristics of Aggregate Turnover and Sediment Transport by Interrill Erosion Using Rare Earth Elements in Red Soil

作　　者：张晨阳 杨伟 汪零 彭珏 王军光[1] 蔡崇法[1] ZHANG Chenyang;YANG Wei;WANG Ling;PENG Jue;WANG Junguang;CAI Chongfa(Research Center of Soil and Water Conservation,Huazhong Agricultural University,Wuhan 430070,China;Hubei Water Resources and hydropower Research Institute,Wuhan 430070,China)

机构地区：[1]华中农业大学水土保持研究中心,武汉430070 [2]湖北省水利水电科学研究院,武汉430070

出　　处：《土壤学报》2024年第6期1492-1505,共14页Acta Pedologica Sinica

基　　金：国家自然科学基金项目(42177317);湖北省大别山区典型小流域次降雨水土流失预报模型研究项目(HBSLKY202304)资助。

摘　　要：土壤团聚体是土壤结构的基本单元,土壤表层团聚体的粒径分布变化对土壤结构和侵蚀过程发育具有重要意义。为探究细沟间侵蚀过程中土壤团聚体周转和泥沙迁移路径过程,本研究基于微型土槽,设置90 mm·h-1雨强,10°坡度的条件,进行室内模拟降雨试验。利用稀土元素示踪技术标记土壤团聚体,通过ICP-MS测定稀土元素浓度,对不同粒径土壤团聚体(5~2 mm、2~0.25 mm、0.25~0.053 mm、<0.053 mm)的破碎和形成过程进行定量分析,同时量化侵蚀泥沙的来源特征。结果表明,细沟间侵蚀过程中,侵蚀泥沙颗粒主要由同等粒径大小的团聚体受径流搬运形成,且该粒径泥沙含量随降雨时间增加而减少;残留团聚体呈明显的周转过程,<0.25 mm的团聚体更易粘结或吸附至大粒径团聚体上,而>0.25 mm团聚体倾向于发生破碎(破碎率分别为45.8%和43.3%),且破碎程度不断增加;<0.053 mm和2~0.25 mm大小的泥沙含量及相应粒径的团聚体在泥沙中的贡献率对径流系数和泥沙粒径分形维数具有重要作用。所以,细沟间侵蚀过程中土壤表土结构变化、泥沙迁移与团聚体粒径密切相关,该成果进一步为土壤侵蚀过程模型和水土保持措施提供理论依据。Soil aggregates are the basic unit of soil structure and the particle size distribution of surface aggregates play an important role in soil structure and erosion process development.【Objective】Therefore,the purpose of this study was to explores the mutual transformation of soil aggregates of different particle sizes and the sediment migration path during the interrill erosion and quantify the source characteristics of eroded sediment.【Method】In this study,a quaternary red clay was collected from Xian’ning in Hubei Province of China,and the soil aggregates were labeled by the rare earth tracer method.Under the condition of 90 mm·h-1 rainfall intensity,the laboratory simulated rainfall experiment was conducted based on a miniature soil trough with the slope set at 10°.Sediment samples were collected at an interval of 6 min after steady flow production during rainfall,and the contents of rare earth elements in the samples were determined by ICP-MS.A quantitative characterization was also performed on the transformation of soil aggregates within different particle sizes(5-2 mm,large macroaggregates;2-0.25 mm,small macroaggregates;0.25-0.053 mm,microaggregates;and<0.053 mm,silt and clay fractions)and the source characteristics of erosion sediment under the Rare Earth Element(REE)concentration.【Result】The results show that the eroded sediment particles were mainly formed by the same size aggregates transported by runoff,and the content of the sediment particles with the increase of rainfall time.The residual aggregates showed an obvious turnover process and the aggregates with size<0.25 mm were more easily adsorbed to the aggregates with large size,while the aggregates with size>0.25 mm tended to be broken(the fragmentation rate reached 45.8% and 43.3%),and the broken degree of soil aggregates increased continuously.The characteristics of sediment yield were closely related to the change in topsoil structure and sediment migration and the sediment content of<0.053 mm and 2-0.25 mm and the contribution

关 键 词：红壤 人工模拟降雨 REE示踪法 团聚体周转 细沟间侵蚀 

分 类 号：S157[农业科学—土壤学]