39;7be示蹤坡面土壤侵蝕過程及機理研究

1、中國科學院教育部水土保持與生態(tài)環(huán)境研究中心碩士學位論文Be示蹤坡面土壤侵蝕過程及機理研究姓名：丁晉利申請學位級別：碩士專業(yè)：土壤學指導教師：鄭粉莉20050601Application of 7Be to Quantifying Soil Erosion Process and Mechanism at Hillslope Ding Jinli (Soil Science) Directed Prof. Zheng Fenli Abs

2、tract Developing the application of 7Be to qualifying soil erosion mechanism is the principle for using 7Be to study soil erosion. It is also a hot and difficult point in this soil research field. The thesis has analyz

3、ed that soil absorbing 7Be capacity from natural rainfall during different periods, studied 7Be movement with runoff, outlined whether 7Be may be used as tracer studying soil erosion process, and evaluated the tracing pr

4、ecision under different rainfall duration, and revealed mechanism of 7Be tracing hillslope soil erosion. Using research methods of 7Be tracer, field investigation and laboratory analysis, this thesis has studied spatial

5、 distribution of soil erosion at ephemeral gully catchments and at straight slope under the individual rainfall event and rainy season. The main research results are as follows: 1. Soil absorbing 7Be capability from nat

6、ural rainfall is influenced by absorbing duration and soil texture, and 7Be volume in clay and silt particles accounts for 85% of total 7Be volume. Therefore, 7Be can be taken as a tracer to study soil erosion. But rai

7、nfall duration and soil texture must be considered when applied 7Be to study soil erosion. 2. The majority of 7Be volume mainly exists in 0-2 cm of topsoil. Soil 7Be volume decreases with the depth increase. The diffe

8、rence in 7Be distribution in soil profile is at different topographical because of different runoff and erosion intensities and different soil erosion patterns on hillslope. 3. Spatial distributed difference of 7Be conce

9、ntration in the ephemeral gully catchments is not significant before erosive rain event. But after erosive rain event, the difference becomes significant, which indicates that redistribution of topsoil happens. Spatial