| 吴 珊.甘肃庆城县水土流失分区与防治措施[J].甘肃地质,2026,35(3):81-87 |
| 甘肃庆城县水土流失分区与防治措施 |
| SOIL EROSION AND CONTROL MEASURES IN QINGCHENG COUNTY, GANSU PROVINCE |
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| 中文关键词: 水土流失 控制因素 防治措施 庆城县 |
| 英文关键词:soil erosion control measures Qingcheng County |
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| 中文摘要: |
| 庆城县地处陇东黄土高原腹地，全县土地总面积2 692. 6 km2，其中水土流失面积达2 364. 1 km2，占县域总面积的87. 8%，严重的水土流失已成为制约当地生态安全与经济发展的关键因素。 县境内第四系黄土覆盖面广且厚度大，下覆白垩系基岩。不同地层的抗蚀性差异显著：马兰黄土结构疏松、崩解迅速（72 ～ 180 s）、湿陷性强（湿陷系数0. 107 ～ 1. 13），是产沙的主要层位；离石黄土的产沙贡献次之；午城黄土及基岩抗蚀性强。本研究以野外地质调查为基础，结合岩土样品崩解与湿陷性试验数据，综合区域地形地貌、降水、植被及人类活动等资料，采用分区评价方法，系统研究了水土流失的类型、强度及空间分布特征。 研究表明，区域侵蚀类型呈现明显的空间分异规律：自西向东，侵蚀类型由重力—沟蚀为主逐渐过渡为面蚀—潜蚀为主；年均侵蚀模数从西部6 500 ～ 7 000 t ／ （km2·a）降至河谷阶地 < 1 000 t ／ （km2·a）；地层岩性与结构是控制水土流失空间分异的基础因素，地形坡度大于12°时沟蚀显著增强，植被覆盖率低于16. 62%时侵蚀加剧。 本文系统分析该区水土流失的地质影响因素、空间分异特征，并提出针对性防治措施，建议采取“塬面梯田—沟坡林草—沟道淤地坝”立体治理模式，并重视坝后潜水位上升可能引发的土壤盐渍化，旨在为庆城县水土流失防治提供参考。 |
| 英文摘要: |
| Qingcheng County is located in the hinterland of the Longdong Loess Plateau. The county has a total land area of 2,692.6 km2 , of which the area affected by soil erosion reaches 2,364. 1 km2
, accounting for 87. 8% of the total area. Severe soil erosion has become a key factor restricting local ecological security and economic development. The Quaternary loess is widely distributed across the county with great thickness, underlain by Cretaceous bedrock. The erosion resistance of different strata varies significantly: Malan loess, characterized by loose structure, rapid disintegration （72 ~ 180 s） and strong collapsibility （collapsibility coefficient of 0. 107 ~ 1. 13）, is the main sediment -producing layer; Lishi loess contributes moderately to sediment yield; while Wucheng loess and bedrock exhibit strong erosion resistance. Based on field geological surveys, combined with disintegration and collapsibility test data of geotechnical samples, as well as integrated data on regional topography, precipitation, vegetation and human activities, this study systematically investigates the types, intensity and spatial distribution characteristics of soil erosion using a zonal evaluation method. The results show that the regional erosion types exhibit obvious spatial differentiation: from west to east, the dominant erosion type gradually transitions from gravity erosion and gully erosion to sheet erosion and suffosion erosion. The average annual erosion modulus decreases from 6,500 ～ 7,000 t ／ （km2 ·a） in the western part to less than 1,000 t ／ （km2 ·a） in river terraces. Stratigraphic lithology and structure are the fundamental factors controlling the spatial differentiation of soil erosion. Gully erosion intensifies significantly when the terrain slope exceeds 12°,and erosion accelerates when vegetation coverage falls below approximately 16. 6% . This paper systematically analyzes the geological controlling factors and spatial differentiation characteristics of soil erosion in the region, and proposes targeted control measures. A three -dimensional control model of "tableland terraces -gully slope forest and grass -gully check dams" is recommended, while attention should also be paid to soil salinization possibly induced by the rise of the groundwater level behind check dams, aiming to provide a reference for soil erosion control in Qingcheng County. |
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