不同坡面草被格局下的侵蚀产沙量及其连通性指数表征  

Erosion and sediment yield under different grass cover patterns and its characterization of connectivity index

作　　者：丁琳 许海超 秦伟[1,2] 殷哲[1,2] 焦剑 Ding Lin;Xu Haichao;Qin Wei;Yin Zhe;Jiao Jian(China Institute of Water Resources and Hydropower Research/State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,Beijing 100048,China;Research Center on Soil and Water Conservation of the Ministry of Water Resources,Beijing 100048,China)

机构地区：[1]中国水利水电科学研究院,流域水循环模拟与调控国家重点实验室,北京100048 [2]水利部水土保持生态工程技术研究中心,北京100048

出　　处：《农业工程学报》2022年第9期119-128,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(41877073)。

摘　　要：为探寻植被格局的定量表征参数,并建立其与侵蚀产沙的关系,深入揭示植被格局阻蚀减沙作用机制,该研究采用室内人工模拟降雨试验,以40%盖度的高羊茅草被坡面为研究对象,探讨了不同坡度(5°、15°和25°)和植被分布格局(裸地、带状横坡、带状顺坡、块状镶嵌、点状均匀格局)下的坡面侵蚀产沙过程变化,并分析了不同草被格局下平均汇流路径长度指数(Mean Flow Length Index,MFLI)、连通性指数(Index of Connectivity,IC)变化及其同坡度和土壤侵蚀量的关系。结果表明:带状顺坡、点状均匀、块状镶嵌和带状横坡的草被坡面平均侵蚀量分别较裸地减小42.9%、55.7%、62.4%和78.0%,带状横坡的阻蚀减沙作用最优。不同草被格局坡面间的MFLI和IC总体也与平均侵蚀量的差异关系一致,从小到大依次为:带状横坡、块状镶嵌、点状均匀、带状顺坡、裸地。MFLI和IC可分别与坡度结合用于模拟评价不同草被格局坡面的侵蚀产沙,决定系数(R^(2))达0.84以上。其中,IC与坡度的协同性更佳、依赖性更小,是表征植被格局对坡面侵蚀产沙影响的较佳参数。结果可为快速优选水土保持型植被格局、促进生态脆弱区林草植被格局优化和提质增效提供依据。Forest and grass vegetation restoration can be one of the most important measures to effectively control soil erosion at present. Four factors have posed a great impact on soil erosion and sediment yield, including the vegetation types, coverage,structure, and distribution patterns. However, the current characterization of vegetation patterns is only limited to the qualitative description. It is still lacking in the quantitative parameters reflecting the vegetation pattern and the impact on erosion and sediment yield. In this study, the quantitative characterization index of vegetation pattern was investigated to establish the quantitative relationship with the sediment yield, particularly for the greening with water, as well as the soil and water conservation function of vegetation. Meanwhile, the connectivity indexes were also proposed to consider the process of water and sediment transport. A new perspective was provided to explore the mechanism of runoff, sediment yield, and transport processes, particularly for the responses to the changes in land use landscape patterns. Taking 40% of Festuca elata grass-covered slope as the research object, an experiment of artificial simulated rainfall was conducted indoors. An investigation was made to explore the changes in the sediment yield process under different slope gradients(5°, 15°, and 25°)and vegetation patterns(bare land, cross-slope band, down-slope band, block-shaped mosaic, and uniform point-shaped pattern). Two classic connectivity indicators were preferred to characterize the hydrological connectivity of the slope,including the Mean Flow Length Index(MFLI) and the Index of Connectivity(IC). Therefore, a systematic analysis was also made to determine the changes in the MFLI and IC under different grass patterns and the quantitative relationships with the slope gradient and erosion amount. The hydrological connectivity indicators were then verified to characterize the effect of vegetation patterns on erosion and sediment yield. The results showed that th

关 键 词：土壤 侵蚀 草被格局 平均汇流路径长度指数 连通性指数 坡度 

分 类 号：S157.1[农业科学—土壤学]