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137Cs示踪法因能快速、相对简便地估算土壤侵蚀量而在土壤侵蚀定量研究中得到广泛应用。本底值获取是137Cs示踪法的关键和基础。在具有空间异质性多因素综合作用下,本底值呈现高度的空间异质性。针对本底值空间变异性,从气候气象要素、地形、土壤属性、土地利用/覆被四个方面阐明各因素与本底值空间变异的作用机理。分析了当前137Cs示踪法应用中在本底值获取时参考点存在性及选点的准确性、单个或几个本底值对研究区本底值的代表性和参考点采样设计。提出划分侵蚀测定单元、建立多本底值体系和进行地形校正解决当前137Cs示踪法中本底值存在问题的对策。侵蚀测定计算单元的划分原则和方法、根据已有参考点的137Cs本底值推算各单元137Cs本底值的技术方法、定量化研究各因素对137Cs的作用是今后需要深入的工作。
The 137Cs tracer method is widely used in the quantitative study of soil erosion because it can estimate soil erosion quickly and relatively easily. Background value acquisition is the key and foundation of 137Cs tracer method. Under the combined effect of spatial heterogeneity and multiple factors, the background value shows a high degree of spatial heterogeneity. In view of the spatial variability of the background value, the mechanism of the spatial variability of each factor and the background value is clarified from the aspects of climatic and meteorological elements, topography, soil attributes and land use / cover. The accuracy and accuracy of the reference point selection and background selection of the 137Cs tracer are analyzed. The representativeness of the background value of the study area and the sample design of the reference point are analyzed. The countermeasures to solve the problem of the background value in the current 137Cs tracing method are put forward by dividing the unit of erosion measurement, establishing the multi-basement value system and performing the terrain correction. According to the 137Cs background of existing reference points, 137Cs background values of each unit are calculated. It is necessary to study the effects of various factors on 137Cs in the future.