汇水面积阈值对土壤侵蚀定量评价的影响  

Effect of Contributing Area Threshold on the Evaluation of Soil Erosion

作　　者：丁琳 于现举 符素华 吴思南[1] DING Lin1,YU Xianju1,FU Suhua1,2,WU Sinan1(1. Faculty of Geographical Science, Beijing Normal University, Beijing 100875 , 2. State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau,Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling, Shaanxi 71210)

机构地区：[1]北京师范大学地理科学学部,北京100875 [2]中国科学院水利部水土保持研究所,黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌712100

出　　处：《水土保持学报》2018年第3期61-67,73,共8页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41530858,41571259); 长江学者和创新团队发展计划项目(IRT_15R06); 中国科学院“西部之光”人才培养引进计划项目

摘　　要：土壤侵蚀预报模型是定量评价水土流失和评估水土保持措施效益的重要手段。通用土壤流失方程(Universal Soil Loss Equation,USLE)和中国土壤流失方程(Chinese Soil Loss Equation,CSLE)被广泛应用于土壤侵蚀定量评价。这些模型中坡长的计算受汇水面积阈值的影响较大。为揭示汇水面积阈值对土壤侵蚀定量评价的影响,选取北方土石山区、西北黄土高原区、东北黑土区、南方红壤丘陵区、西南紫色土区、西南山地区和西南岩溶区210个流域面积在0.2~3.0km^2的小流域,以1∶10 000地形图10m分辨率DEM为数据源,分别计算了1 000,1 500,2 000,2 500,3 000,5 000,7 000,9 000,11 000,13 000,15 000m^2共11个汇水面积阈值下各小流域不同坡长、土壤侵蚀强度级别以及土壤侵蚀的面积比例,分析了它们对汇水面积阈值变化的敏感性。结果表明:平均坡长、土壤侵蚀面积和轻度以上各级别的侵蚀强度面积比例都随汇水面积阈值的增加先增加而后趋于稳定。微度侵蚀面积比例随汇水面积阈值的增加逐渐减小并趋于稳定。当汇水面积阈值由1 000m^2增加到15 000m^2时,北方土石山区、西北黄土高原区、东北黑土区、南方红壤丘陵区、西南紫色土区、西南山地区和西南岩溶区的平均坡长分别增至阈值为1 000m^2时的1.53,4.16,1.95,1.90,1.69,1.57,1.47倍;土壤侵蚀面积比例分别增至阈值为1 000m^2时的1.20,1.85,1.43,1.37,1.77,1.44,1.30倍。汇水面积阈值对各分区的影响程度存在差异。从平均坡长和土壤侵蚀面积来看,东北黑土区受汇水面积阈值的影响最大。研究结果不仅为精确评价土壤侵蚀提供了数据支撑,而且对水土保持综合防治措施的评价和优化具有指导意义。Soil erosion model is a technical tool to calculate the soil loss and assess the efficiency of soil and water conservation practice.The universal soil loss equation（USLE）and Chinese soil loss equation（CSLE）were widely used to calculate the soil loss.The slope length in these models is significantly affected by the contributing area threshold.In this study,210 small watersheds which area varied from 0.2 km^2 to 3.0 km^2 were selected to investigate the effect of contributing area threshold on the slope length and then the soil loss.The small watersheds are located in Northern rocky mountain area,Northwestern loess plateau,Northeastern black soil area,Southern red soil hilly area,Southwestern purple soil area,Southwestern mountainous area and Southwestern karst area.The 1∶10 000 scale topographical map and 10 m×10 m DEM of the small watersheds were collected.11 contributing area thresholds,namely,1 000,1 500,2 000,2 500,3 000,5 000,7 000,9 000,11 000,13 000,15 000 m^2 were used to calculate the slope length and soil loss.The characteristics of slope length,soil erosion intensity and soil erosion area with the differentcontributing area thresholds were analyzed.The results showed that the average slope length and soil loss area firstly rose with the increase of contributing area threshold and then tended to keep constant.In the Northern rocky mountain area,Northwestern loess plateau,Northeastern black soil area,Southern red soil hilly area,Southwestern purple soil area,Southwestern mountainous area and Southwestern karst area,the average slope length with contributing area threshold of 15 000 m^2 was 1.53,4.16,1.95,1.90,1.69,1.57,1.47 times those of contributing area threshold with 1 000 m^2 and the soil loss area percentage with contributing area threshold of 15 000 m^2 was 1.20,1.85,1.43,1.37,1.77,1.44,1.30 times those of contributing area threshold with 1 000 m^2.The contributing area threshold had different effects in the different area.The average slope length and soil loss area in Northeastern black

关 键 词：汇水面积阈值 坡长 土壤侵蚀面积 水蚀 

分 类 号：K903[历史地理—人文地理学]