Partitioning the Contributions of Sheet and Rill Erosion Using Beryllium‐7 and Cesium‐137
Partitioning the Contributions of Sheet and Rill Erosion Using Beryllium‐7 and Cesium‐137
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DOI：
10.2136/sssaj2005.0295
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发表时间：
2006-09
影响因子：
2.9
通讯作者：
Mingyi Yang;D. Walling;J. Tian;Pu-ling Liu
中科院分区：
文献类型：
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作者：
Mingyi Yang;D. Walling;J. Tian;Pu-ling Liu
了解片蚀和细沟侵蚀对与单个事件相关的总土壤流失的相对贡献以及事件期间它们相对重要性的变化对于开发更有效的土壤侵蚀预测模型以及预测与原位土壤相关的侵蚀沉积物的物理和地球化学特性非常重要。使用传统监测技术很难获得事件期间片蚀和细沟侵蚀相对重要性变化的信息。使用环境放射性核素，特别是铍 7 (Be-7) 和铯 137 (Cs-137) 作为沉积物示踪剂，为获取此信息提供了另一种方法。由于其不同的深度分布，这两种放射性核素提供了一种区分从土壤表面通过片状或细沟侵蚀而侵蚀的沉积物和通过细沟侵蚀从更深处侵蚀的沉积物的方法。该方法通过在中国陕西省伊川县的两个小侵蚀地块上进行的模拟降雨实验进行了测试，这些侵蚀地块代表了耕地和以前被森林覆盖的未开垦土地。结果证实，耕地中侵蚀的沉积物中 Be-7 活性的变化以及未耕地中侵蚀的沉积物中 Be-7 和 Cs-137 活性的变化明显地表明了地块内小溪的发育。通过将侵蚀土壤的 Be-7 和 Cs-137 活性变化与两个地块土壤中两种放射性核素的深度分布信息以及侵蚀土壤质量相关联，可以估计两个侵蚀过程对总土壤流失及其通过事件的变化的相对贡献。该信息为研究事件期间片蚀和细沟侵蚀的相对贡献的时间变化对该事件期间从该地块侵蚀的沉积物的物理和地球化学性质的变化的影响提供了基础。
An understanding of the relative contributions of sheet and rill erosion to the total soil loss associated with individual events and of changes in their relative importance during an event is important for developing more effective soil erosion prediction models and for predicting the physical and geochemical properties of the eroded sediment in relation to those of the in situ soil. It is difficult to obtain information on variations in the relative importance of sheet and rill erosion during an event using traditional monitoring techniques. The use of environmental radionuclides, particularly beryllium-7 (Be-7) and cesium-137 (Cs-137), as sediment tracers offers an alternative approach to obtaining this information. Because of their contrasting depth distributions, the two radionuclides provide a means of distinguishing sediment eroded from the soil surface by sheet or interrill erosion and that eroded from greater depths by rill erosion. The approach was tested using simulated rainfall experiments undertaken on two small erosion plots located in Yichuan County, Shaanxi Province, China, representative of cultivated land and uncultivated land previously under forest. The results confirmed that the development of rills within the plots was clearly marked by changes in the Be-7 activity of the sediment eroded from the cultivated plot and changes in the Be-7 and Cs-137 activity of the sediment eroded from the uncultivated plot. By relating the changes in the Be-7 and Cs-137 activity of the eroded soil to information on the depth distribution of the two radionuclides in the soils of the two plots and the mass of soil eroded, it was possible to estimate the relative contributions of the two erosion processes to the total soil loss and their changes through an event. This information provided a basis for investigating the influence of temporal variations in the relative contributions of sheet and rill erosion during an event on variations in the physical and geochemical properties of the sediment eroded from the plot during the event.