紫色土坡地侵蚀产沙过程的~7Be法初探  

Indicating Erosion and Sediment Yielding Processes on Purple Soil Slopes Using ~7Be Measurements

作　　者：史忠林[1,2] 文安邦[1] 严冬春[1] 巨莉[1,2] 郭进[1,2] 

机构地区：[1]中国科学院水利部成都山地灾害与环境研究所山地表生过程与生态调控重点实验室,四川成都610041 [2]中国科学院大学,北京100049

出　　处：《山地学报》2013年第1期71-76,共6页Mountain Research

基　　金：国家科技支撑计划项目课题(No.2011BAD31B03);中国科学院西部行动计划项目(No.KZCX2-XB3-09)~~

摘　　要：利用环境放射性核素示踪技术研究土壤侵蚀是传统土壤侵蚀监测技术的重要补充手段。宇宙成因核素7Be具有半衰期短和在表土分布浅等特点,能够用于指示短时间尺度的坡面侵蚀堆积过程。采用7Be技术与泥沙颗粒分析相结合,定量判读了模拟降雨下紫色土坡面侵蚀过程演变。结果表明,对于20°坡面,7Be法指示的坡面侵蚀方式转折点与侵蚀泥沙颗粒变化得到的结果基本一致。7Be在表征侵蚀过程演变时具有独特的优势,可以将坡面片蚀发育过程随降雨时间的变化明显地识别出来。这对防治坡面侵蚀,特别是细沟侵蚀的发生具有重要意义。Fallout radionuclides tracing techniques have been proven to be an important complementally means to conventional soil erosion monitoring methods. Due to its short half-time and shallow distribution in soil profile, the cosmogenic radionuclide 7 Be serves as a useful tool for indicating short-term erosion and sedimentation processes. Based on the combined use of 7 Be measurements and sediment grain size analysis, this paper investigated the ero- sion and sediment yielding processes using simulated rainfall experiments undertaken on purple soil slopes. The re- sults shown that the turning point of erosion forms estimated from 7Be measurements was similar to that of the sedi- ment grain size analysis, especially for 20°slope. 7Be approach has unique advantages when indicating the development of erosion processes and the sheet erosion can be clearly identified. This information has great significance in soil erosion prevention, especially rill erosion.

关 键 词：放射性核素 7Be 紫色土 侵蚀 三峡库区 

分 类 号：S124.2[农业科学—农业基础科学]