摘要
本文指出黄土地区梁峁坡的坡角主要分布在14°—28°之间,特征坡角的上限相当于黄土的内摩擦角,下限相当于内摩擦角的0.45倍。黄土地区的坡地形态可分为直形坡、凸形坡、凹形坡、复合形坡和阶梯形坡等五种类型。土壤侵蚀主要受坡地形态和坡度的控制,侵蚀量随着坡度的增大而增加,坡度大于15°时,侵蚀量突增,坡面冲刷加剧,26°达极大值,此后冲刷作用减弱,重力侵蚀逐渐显著,至45°侵蚀达到最大值,以后又趋减弱。
In this paper the relationship between slope features and soil erosion in the loess region has been studied. Investigation shows that the angles of slopes of loess ridge and hill mostly vary from 14?to 28?The upper limit of the characteristic angles corresponds to the angle of internal friction of loess and the lower limit to half of the angle. This is coincident with the results stated by Carson (1969) .The slope forms in the loess region can be separated into five types, namely straight, convex, concave, concave-convex and step slopes. The erosion position is very different on the different kind of the slopes. It mostly occurs on the downslope of the straight slope, on the mid-down slope of the convex slope, on the mid-slope of the concave slope and on the straight segments between the convex and concave elements of concave-convex and step slope.Soil erosion is greatly controlled by slope angles. The statistical analysis of the data observed in the fields shows that 15°, 26° and 45°are very important to soil erosion. The sediment yields increase with slope angles, then over 15° the sediment yields rapidly rise and washing is greatly intensified. At 26° the way of erosion changes, from the running water wash to gravitational erosion. At 45° erosion is the most intense in the slope angles between 0 ° and 90°. This result is supported by the mathematical deduction. The study of the three slope angles is important in both theoretical research and reasonble planning for controlling the drainage basin in a comprehensive way.
出处
《地理研究》
1983年第3期19-29,共11页
Geographical Research
