Effects of land use, land cover and rainfall regimes on the surface runoff and soil loss on karst slopes in southwest China
Effects of land use, land cover and rainfall regimes on the surface runoff and soil loss on karst slopes in southwest China
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DOI：
10.1016/j.catena.2011.11.001
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发表时间：
2012-03-01
期刊：
影响因子：
6.2
通讯作者：
Wang, Shi-jie
中科院分区：
文献类型：
--
作者：
Peng, Tao;Wang, Shi-jie
对2007 - 2010年贵州省喀斯特丘陵坡地土地利用和降雨条件下的地表径流和土壤流失进行了分析。采用系统聚类方法，将61次亚热带季风气候条件下的降水事件按降水深度、最大30 min强度和持续时间分为5类降水型。在我们的研究中，我们首先证明，地表径流量和土壤流失量的岩溶坡地是非常小的相比，非岩溶地区，因为在岩溶地区的二元水文结构，包括地面和地下排水系统，可以影响降雨补给和产流过程。大部分的雨水通过石灰岩裂隙和裂缝被输送到地下，而很少以地表径流的形式存在。其次，土地利用管理和植被覆盖度对径流和土壤流失有影响。土壤侵蚀加剧程度依次为：草地>火烧迹地>耕地>复合植被地>幼龄林地。不同降雨条件下，径流量和土壤流失量差异显著。大的径流和土壤流失主要是由暴雨造成的，降雨深度超过40毫米，最大30分钟降雨强度超过30毫米小时（-1）。此外，前期降水量大的暴雨也会产生大量的径流和土壤流失。这些观测结果表明，石灰岩裂隙和裂缝在岩溶石灰岩坡面的地表产流中起着重要的作用，因为它们具有很大的蓄水能力和很高的入渗速率。岩溶纯灰岩坡面土壤侵蚀风险较高，尤其是过度放牧，一次暴雨造成的草地土壤流失量是年允许流失量的5倍。(C)2011 Elsevier B. V.保留所有权利。
Surface runoff and soil loss from 2007 to 2010 related to land use and rainfall regimes in karst hill slopes in Guizhou Province, southwest China, were analyzed. Using the hierarchical clustering method, sixty-one rainfall events under the subtropical monsoon climate condition were classified into 5 types of rainfall regimes according to the depth, maximum 30-min intensity, and duration of rainfall. In our study, we first demonstrated that the amounts of surface runoff and soil loss on the karst hill slopes were very small compared to the non-karst areas, because the dual hydrological structure in the karst region, including ground and underground drainage systems, could influence the processes of rainfall recharge and runoff generation. Most rainfall water was transported underground through limestone fissures and fractures, while little was in the form of surface runoff. Second, the runoff and soil loss were affected by land use management and vegetation cover. Soil loss was intensified in a descending order to five types of land uses: pastureland>burned area>cropland>combination vegetation land>young forestland. Third, the runoff and soil loss exhibited remarkable variances among different rainfall regimes. Large runoff and soil loss were mainly created by heavy rainfall storms with a rainfall depth of more than 40 mm and a maximum 30-min rainfall intensity of over 30 mm h(-1). In addition, rainfall storms with large antecedent precipitations could also produce large runoff and soil loss. These observations indicated that limestone fissures and fractures play important roles in surface runoff generation on karst limestone slopes due to their large storage capacity and high infiltration rate. Lastly, the soil erosion risk in the karst pure limestone slope is quite high and should be paid particular attention, especially in regards to over-grazing because the soil loss created by a single heavy rainstorm in pastureland was 5 times the annual soil loss tolerance. (C) 2011 Elsevier B.V. All rights reserved.