中文摘要：

磁性示踪研究坡面土壤侵蚀已取得一定成果，但目前的磁性示踪方法不能满足次降雨后的溅蚀特征研究。因此，在无磁性的石英砂上施用不同浓度（1．5％、2．5％、3．5％）和不同粒径（20nm、200nm）的纳米磁性材料，而后进行人工模拟溅蚀试验，利用磁化率仪和3D手持微地形扫描仪研究地表磁性变化与溅蚀后地表特征变化之间的关系，研究利用纳米磁性材料表征溅蚀特征的可行性。结果表明：20nm磁性材料提高石英砂磁性背景值的幅度远高于200nm磁性材料且不同浓度的磁性差异极显著，两种纳米磁性材料均呈现出布设浓度越大，示踪时间越长的特点；溅蚀后表层磁化率随溅蚀时间的延长而逐渐衰减，二者呈现出相关性较高的x1=aln（t）＋6对数函数关系；20nm磁性材料在3．5％浓度下可有效定量表征出石英砂溅蚀量的变化（P〈O．01），二者之间的相关关系可用x2=aM^b幂函数表示；20nm磁性材料在溅蚀3min内的磁化率变化与微地形高差变化呈极显著相关关系（P〈0．01），说明20nm磁性材料可以在短时间内有效表征出溅蚀地表的侵蚀程度，可表征出的侵蚀厚度在-5～10mm内。该研究证明20nm磁性材料表征溅蚀地表特征的方法在一定程度上是可行的，可为磁性示踪法的深入研究提供新的思路和方法。

英文摘要：

Certain achievements have been made in the study on soil erosion on slopes using magnetic tracers. However, the traditional magnetic tracer method is far from effective enough to meet the requirements of the study to characterize splash erosion caused by each rainfall event. Therefore, an in-lab splash erosion simulation experiment was carried out over on a bed of non-magnetic quartz sand mixed separately with nano magnetic materials, different in particle size （20 nm or 200 nm ） , at a rate of 1.5%, 2.5% and 3.5% in this study, Magnetic susceptibility meter and Three-dimensional Laser Micro-topographical Scanner was used to monitor variation of the magnetism of the land surface and its relationship with changes in topographic characteristics of the land surface subjected to splash erosion, and hence to study feasibility of using nano magnetic materials to characterize splash erosion. Results show that the 20 nm magnetic material was more effective than the 200 nm magnetic material in raising magnetism of the quartz sand over its background value, and the effect varied sharply with concentration or incorporation rate of the magnetic materials; and the higher the concentration of the material, the more durable the tracing effect. After splash erosion, surface magnetic susceptibility declined gradually with the time going on, displaying a high logarithmic function relation expressed as X1= aln （t） ＋b; The use of 20nm magnetic material, 3.5% in concentration effectively characterized changes in splash erosion rate of the quartz sand （p 〈 0.01 ） with a power function relation expressed as x2=aMb （x2 = sediment susceptibility and M = splash erosion amount ） . The highly significant relationship between the variation of magnetic susceptibility of the 20 nm magnetic materials in the 3 minutes of splash erosion and the variation of microrelief demonstrates that the 20nm magnetic material can be used to characterize erosion degree, up to the range of -5- 10 mm, of the land surface subjected to splash e