| 西南喀斯特区土壤侵蚀研究进展 |
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| 引用本文： | 李成芳,王忠诚,李振炜,徐宪立.西南喀斯特区土壤侵蚀研究进展[J].中国岩溶,2022,41(6):962-974. |
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| 作者姓名： | 李成芳 王忠诚 李振炜 徐宪立 |
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| 作者单位： | 1.西北农林科技大学水土保持研究所, 陕西 杨凌 712100 |
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| 基金项目： | 国家自然科学基金重点项目(41730748)、面上项目( 41977073)；中国科学院青年创新促进会项目（2020359） |
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| 摘 要： | 西南喀斯特区土层浅薄、成土速率低等特点决定了其允许土壤流失量小，土壤一旦流失，极难恢复，土壤侵蚀及其造成的石漠化现象已成为制约该区可持续发展最严重的生态环境问题。文章首先明晰西南喀斯特区土壤侵蚀特征，从坡面、小流域和区域三个尺度上系统概括西南喀斯特区土壤侵蚀的相关研究进展。针对当前喀斯特区土壤侵蚀研究野外径流小区、小流域及区域空间尺度数据缺少和相关研究模型限制性强等不足，建议从不同尺度深入研究喀斯特区土壤侵蚀发生发展规律及时空演化格局，并结合高新遥感、地球物理探测技术及模型，同步监测坡面—小流域—区域土壤流失，对土壤侵蚀进行定量评估，结合不同空间尺度土壤侵蚀特征构建系统性水土保持生态恢复治理模式和监测系统评价体系。
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| 关 键 词： | 喀斯特 石漠化 土壤侵蚀 尺度 研究进展 |
| 收稿时间： | 2021-09-16 |
Research progress of soil erosion in karst areas of southwest China |
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| Abstract: | As one of the largest contiguous karst areas in the world, southwest China is characterized by shallow soil layer and low rate of soil formation. The very low tolerance of soil loss in this area may lead to the extreme difficulty in the recovery of soil layer once lost. Therefore, soil erosion and its effects such as the rocky desertification have become the most serious problem of ecological environment, restricting the sustainable development of the karst area. The purpose of this study is to review the characteristics of soil and water loss at different scales, identify the limitations of different evaluation methods for soil erosion, and to predict the future research on the soil erosion in karst areas of southwest China. Firstly, according to plenty of research data about soil erosion in karst areas at home and abroad, the characteristics of soil and water loss in karst areas are expounded at various spatial scales such as slope, small watershed, and region. Additionally, the characteristics of soil erosion in karst areas and non-karst areas are compared at these three scales. The karst area is featured by a binary three-dimensional erosion system—runoff and sediment production processes at the slope scale and the sediment transport process at the watershed scale. At the slope scale, the effect of rainfall intensity and duration, underground fissure degree, slope, and bedrock exposure rate on soil erosion are investigated at both indoor and field runoff plots. However, because of the big difference between the experimental conditions of indoor rainfall simulation and natural conditions, it is essential to investigate the soil erosion characteristics at the field runoff plots. Meanwhile, the instability of rainfall intensity and the uneven distribution of fissure degree of underground pore also pose a challenge to the accurate quantification of the correlation between rainfall intensity, fissure degree of underground pore and sediment yield in the field runoff plots. Generally, radionuclide tracing technology can quantitatively identify the spatial distribution of intensity and rate of soil erosion. However, due to the high bare rock ratio, karst slopes with high soil homogeneity and continuous soil cover must be selected to avoid the influence of bare rock on the content of radionuclide. At the small watershed scale, monitoring the discharge and sediment concentration at the outlet of watershed is a typical method to analyze the characteristics of runoff and sediment yield in small watershed, and to establish the relationship between sediment yield and runoff or its influencing factors. This method is also used to predict the average annual soil loss and soil erosion intensity in a small watershed, and to analyze the temporal and spatial variation in soil erosion for different land use patterns, altitudes and slopes. But the application of various models is still limited by some factors. For example, RMMF model is generally used within a county territory; the distributed soil erosion model has not been verified, and the influence of initial soil water content and runoff on soil erosion have not yet been considered in this model. In addition, peak-cluster depression is a special geological and geomorphic type in the karst area of southwest China, and its topographic features contribute to the depositing of most eroded sediment in the central karst depression. Radionuclide tracing technology can be applied to analyze the sediment interception rate and sediment transport ratio of different types of karst depressions, river beaches and ponds, to determine the sediment source and to establish the sediment yield model of river basins. At the regional scale, the regional differences and temporal dynamic changes of soil erosion and sediment discharge are investigated, and the dominant factors controlling the sediment discharge are also identified. The relationship between different topographic indexes and regional soil erosion is discussed, and the optimal evaluation index system of regional soil erosion is also determined. Based on the soil erosion model (RULSE), the temporal and spatial variation in soil erosion on the regional scale is investigated. In terms of research advance, it is suggested that future studies should be focused on the occurrence and development of soil erosion as well as the spatial and temporal evolution patterns in karst rocky desertification. It is necessary to explore the occurrence, development and temporal and spatial evolution patterns of soil erosion in karst areas on a larger scale, and to quantitatively evaluate the amount of soil erosion by combining high-tech remote sensing technology, geophysical exploration and different models. According to the correlation between soil loss and its influencing factors, a reasonable model for ecological restoration management of soil and water conservation and a relevant monitoring and evaluation system should be constructed. This study could provide theoretical and technical support for controlling soil erosion in the karst area of southwest China． |
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