摘要
本文根据地质地貌特征,对正宁县的水土流失的形式、类型以及成因作了较详细的论述和分析。认为该县水土流失的形式主要有水力侵蚀和重力侵蚀,其中以水力侵蚀为主。侵蚀类型与山坡坡度、植被密度、侵蚀模数的高低以及地形的变化有关,得出本县侵蚀强度和水流输沙量自东向西有规律地递增,年侵蚀模数由东部林区的低于500吨/平方公里向西部的6,000吨/平方公里增加。由此推断了水土流失的原因是:支离破碎、千沟万壑和梁峁起伏的特殊地形;软硬相间的地层结构和集中的降水;活跃的新构造运动以及人类不合理的开发利用等。
According to the geological and geomorphical characters, this paperexpounds and analyses the forms, types and causes of soil and water lossof Zhengning county in Gansu province in detail. It thinks that themain forms of soil and water loss in this county are hydraulic and gravi-tational erosions,hydraulic erosion is the leading one.The types of erosionrelates to the angle of hill slope, vegetation density, erosion modulus,strength and the sand discharge carried by water current keeping increasingfrom east to west in this county, the modulus of erosion increases fromless than 500t/km^2·y in the east forest area to 600t/km^2·y in the west.Based on above analysing, the authors deduce that the causes of soil andwater loss are the special landform with the deep cut gullies, the strati-graphic structure with soft rocks accompanied with hard rocks, the con-centrated rainfall, the active new tectonic movement and unreasonableexploring and utilizing by mankind, etc.
出处
《水土保持通报》
CSCD
北大核心
1989年第6期45-49,共5页
Bulletin of Soil and Water Conservation
