摘要
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。
Soil erosion and its eco-environmental effects are important issues among environmental topics.Quantitative estimation or measurement of soil loss is one of the main fields in soil erosion researches.As a short-time consuming and relatively simple method,^137Cs tracing technique was widely applied in quantitative estimation of soil loss caused by natural driving forces or human activities.Measurement of reference value is fundamental in estimating soil loss rate by the ^137Cs tracing method.Impacted by multi factors that intrinsically are of spatial heterogeneity,^137Cs background fallout varied across landscapes.It was enucleated here how weather,topography,soil properties and land use/cover impacted spatial distribution of ^137Cs and strengthened its spatial variation.Meanwhile,existence of soil sample sites for ^137Cs references deposition value measurement and veracity of sample site selection were discussed.Based on the above analysis,a framework subdividing target area into humongous measurement units and employing hierarchical multi-reference system and topographical rectification were suggested as solutions for handling spatial heterogeneity of ^137Cs reference value.Further studies are needed to quantify the effect of each factor on spatial variation of ^137Cs reference fallout and to eventually establish principles and methods for subdividing measurement unit.
出处
《地理研究》
CSCD
北大核心
2010年第7期1171-1181,共11页
Geographical Research
基金
国家重点基础研究发展计划项目(2009CB421104)
国家自然科学基金(40871085)
国家科技支撑计划(2006BAD09B10)
关键词
^137CS
土壤侵蚀
本底值
空间变异
修正
^137Cs
soil erosion
reference value
spatial variation
rectification
