^(210)Pb_(ex)示踪法应用于非耕作土壤侵蚀的研究探讨

Study on ^(210)Pb_(ex) Tracer Method Applied in Uncultivated Soil Erosion

[目的]为更好地使用210Pbex示踪法测定土壤侵蚀速率提供依据。[方法]叙述210Pbex的来源、示踪原理与土壤中210Pbex的计算方法,探讨210Pbex在非耕作土壤中的深度分布及土壤侵蚀模型中的应用。[结果]210Pbex在非耕作土壤剖面中存在于0~16 cm处。从土壤表层自上而下,非耕作土壤和矮树林土壤中的210Pbex含量随土层深度增加呈指数降低。利用环境放射性核素210Pbex来研究土壤侵蚀和沉积具有很大的应用价值和潜力,当核素随大气沉降到地表时,迅速被土壤颗粒吸附,通过其在土壤间的移动和有规律的分布模式可以示踪100年尺度上的土壤侵蚀速率。[结论]210Pbex示踪技术可以研究近100年的土壤再分配状况,在时间尺度上很好的弥补了示踪短周期的土壤再分配速率。

[ Objective] The aim was to provide the basis for applying ^210Pbex tracer method to detect the soil erosion rote better. [ Method ] The origin and tracing theory of ^210Pbex and its calculation method in soil were narrated, and the depth distribution of ^210Pbex in uncultivated soil and its application in soil erosion model were discussed. [ Result ] ^210Pbex existed in uncultivated soil profile at 0 - 16 cm. The ^210Pbex content in uncultivated soil and in shrub soil was decreased with the increase of the soil depth from the soil surface. Using environmental radionuclide ^210Pbex to study the soil erosion and sediment had great application value and potential. When the nuclide was settled on the surface with atmosphere, it was absorbed by the soil particle quickly. The soil erosion rate on the scale of 100 years was traced through the remotion of nuclide in soil and its regular distribution mode. [ Conclusion] ^210Pbex tracer method could investigate the soil redistribution status in recent 100 years and remedied the soil redistribution rate in short period of trace.