基于核素示踪技术和WEPP模型的侵蚀产沙评价研究
文献类型：学位论文
| 作者 | 郑进军 |
| 学位类别 | 博士 |
| 答辩日期 | 2007 |
| 授予单位 | 中国科学院水利部成都山地灾害与环境研究所 |
| 授予地点 | 成都 |
| 导师 | 贺秀斌 |
| 关键词 | 川中丘陵区 137Cs 210Pbex WEPP 泥沙平衡 侵蚀泥沙 |
| 其他题名 | Assessing Soil Erosion and Sedimentation Using Nuclear Tracing Technique and the WEPP Model |
| 学位专业 | 自然地理学 |
| 中文摘要 | 川中丘陵区是长江上游人口稠密的农业区之一，由于自然和人为因素导致该区水土流失面广、强度大、侵蚀率快，是长江上游水土流失最严重的地区之一。该区农业机械化程度比较低，精耕细作管理方式比较普遍，且本区水土流失监测数据和科研资料缺乏，急需坡耕地侵蚀强度、流域泥沙输移比的可靠资料。核素示踪技术估算侵蚀速率在国际上应用比较成熟，而WEPP模型在该区土壤侵蚀预测预报上的应用还需要进一步验证和探究，两种方法的联合评价将对WEPP模型在该区的适用性及该区传统耕作措施和管理措施对土壤空间再分布的影响提供参考。论文选择川中丘陵区内江上桥小流域为案例研究对象，主要应用核素示踪技术(137Cs和210Pbex)和WEPP模型来研究坡面尺度水蚀、传统耕作措施和管理措施对土壤在坡耕地内空间再分布的影响；并分析了该小流域的泥沙来源及泥沙平衡，查明了小流域泥沙输移比。主要结论如下： 1）利用137Cs和210Pbex核素示踪技术估算了流域内一坡度为10.5°坡耕地侵蚀速率分别为：3189.9 t •km-2 •yr-1和3011.77 t •km-2 •yr-1，平均侵蚀速率为3100.84 t•km-2•yr-1，两种核素估算的侵蚀速率在该坡耕地上呈现相同的波动变化趋势，且在总量上很接近，说明了应用核素示踪技术估算坡耕地侵蚀速率的可靠性。 2）WEPP模型预测预报的是水蚀速率，而核素示踪技术估算的是坡耕地每个点的总侵蚀速率，本研究联合使用WEPP和核素示踪技术对水蚀、传统耕作和管理措施对坡耕地内土壤空间再分布的影响进行了分析，用WEPP模型模拟的该坡地侵蚀速率为6420 t •km-2 •yr-1，且点上侵蚀速率顺坡面呈现逐渐波动增大的趋势。坡顶处137Cs估算的侵蚀速率为7820 t •km-2 •yr-1，而WEPP模型模拟的水蚀速率为794 t •km-2 •yr-1，坡脚处137Cs估算的堆积速率为3335 t •km-2 •yr-1，而WEPP模型模拟的堆积速率为868.6 t •km-2 •yr-1。这些差别主要是由传统水保措施“挑沙面土”和人工刨地耕作方式导致了两种方法计算得出坡耕地侵蚀速率及侵蚀速率顺坡面空间分布上的差异。 3) 小流域泥沙平衡及泥沙输移比通过分析小流域塘库沉积剖面137Cs深度分布，可知塘库内自1963年以来至少淤积了60 cm厚的泥沙。通过分析该小流域的泥沙平衡可知，小流域内坡耕地年均产沙量417.77 t•yr-1，林草地年均产沙量11.37 t•yr-1，水田年均淤积量264 t•yr-1，塘库年均淤积量89.54 t•yr-1，年均流出流域外泥沙75.59 t•yr-1。如果以塘库入口作为观测断面，流域泥沙输移比为0.39，如果以塘库出口作为观测断面，流域泥沙输移比为0.18。 |
| 英文摘要 | The Sichuan Hilly Basin is one of the most densely populated agricultural regions in China and the area represents one of the most severely eroded regions in the Upper Yangtze River basin because the purple soils, which are fertile soils in the Sichuan Hilly Basin, are highly susceptible to erosion. Also, it is very difficult to assess the soil and water conservation benefits of different management methods since the “Changzhi Project” and “harness of small catchment” were hold on 1998 due to lacking effective soil erosion data. And so reliable data for soil erosion rates of sloping field, sediment delivery ratio of small catchment are very important to assess the soil and water conservation benefits and establish sound policies about land use. Shangqiao Gully, a small catchment near the Shangqiao Village, was selected as the focus of the investigation. The effect of water erosion, tillage erosion and traditional soil and water conservation method to the soil redistribution in the sloping field were analyzed. In the same time, the sediment budget of the small catchment was investigated clearly and the sediment delivery ratio was estimated. Some conclusions are shown as below. 1) The soil redistribution rates for the sloping field was 3100.84 t•km-2•a-1 and present similar trend along the slope. This further confirmed the potential for 210Pbex measurement to estimate soil redistribution rates. 2) Traditional soil and water conservation methods such as “Tiaoshamiantu” and hoe tillage resulted in the difference of spatial pattern of soil redistribution rates by the radionuclide tracing methods and the WEPP model. 3) The catchment sediment output is estimated, and the sediment budget of the catchment is completed clearly through the investigation of soil erosion, deposition and land use change after 1963. In the 41 years after 1963, the sum and annual of erosion quantity of the Shangqiao Gully are 17594.56 t and 429.14 t•yr-1, respectively, the 62 % sediment came from the cultivated slopes and the 38 % came from the grass-wood slopes. The sum and annual of deposition quantity of the Shangqiao Gully are 14495.27 t and 353.54 t•yr-1, respectively. So the sediment delivery ratio for Shangqiao Gully is 0.18 regarding the outlet of pond as the outlet of the small catchment and is 0.38 regarding the inlet of the pond as the outlet of the small catchment. |
| 学科主题 | 水土保持学 |
| 语种 | 中文 |
| 公开日期 | 2010-10-20 |
| 分类号 | S15;R81 |
| 源URL | [http://ir.imde.ac.cn/handle/131551/2242]  |
| 专题 | 成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前） |
| 推荐引用方式 GB/T 7714 | 郑进军. 基于核素示踪技术和WEPP模型的侵蚀产沙评价研究[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2007. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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