土壤侵蚀磁性示踪剂两种布设方式下示踪效果的研究

Effects of Two Layout Methods of a New Magnetic Tracer about Soil Erosion

利用自制的新型磁性示踪剂研究了不同示踪浓度、不同示踪深度对土壤磁性的影响,以及通过自然降雨,在段面、点穴两种布设方式下示踪小区的土壤侵蚀的空间变异特征。试验结果表明：随着示踪剂浓度的增加土壤的磁化率逐渐增大,当示踪剂浓度为5%时,土壤磁化率在240（SI）左右,用SHX-2型磁化率仪测定的结果精确;在0-6 cm范围内土壤磁性随着厚度的增加而增大,土壤厚度超过6 cm时磁化率达到稳定值,当示踪深度为5 cm时,土壤厚度的增加和减小会相应的引起土壤磁化率值的升高和降低;用段面和点穴两种布设方式来布设磁性示踪剂,降雨前后土壤磁化率的变化均能指示坡面不同空间部位土壤的剥蚀和沉积,但段面式布设方式比点穴式的示踪效果更精确。

Using a new type of magnetic tracer which we made to study the effects of the tracer concentration and the tracer depth on soil magnetic susceptibility and the spatial variability of soil erosion. The plots were placed by sections and points in natural rainfall. The results showed that with the increasing of the magnetic tracer concentration, the soil susceptibility increased gradually. The soil susceptibility increased with the tracer depth from 0 to 6 cm, and when the tracer depth was over 6 cm, it reached a stable level. And the spatial variability of slope soil erosion could be reflected by the changing of soil magnetic susceptibility under the layout of sections and points, but the effects of using the new tracer by sections were more accurate than by points.