不同雨强及坡度对华南红壤侵蚀过程的影响  

Effects of Rainfall Intensity and Slope Gradient on Erosion Process in Red Soil Hillslopes

作　　者：梁志权[1] 张思毅[1] 卓慕宁[1] 谢真越[1] 廖义善[1] 李定强[1,2] 

机构地区：[1]广东省生态环境与土壤研究所广东省农业环境综合治理重点实验室,广东广州510650 [2]中国科学院广州分院广东省科学院,广东广州510650

出　　处：《水土保持通报》2017年第2期1-6,共6页Bulletin of Soil and Water Conservation

基　　金：广东省省院产学研项目“南方典型小流域水土流失防灾减灾关键技术及示范研究”(2013B091500077);水利部公益性行业科研专项(201501047);省院创新平台建设专项;广东省省级科技计划项目(2015B070701017)

摘　　要：[目的]研究不同雨强及坡度对华南红壤侵蚀过程的影响,为认识红壤侵蚀过程和水土流失防治提供科学依据。[方法]通过人工模拟降雨试验,研究了不同降雨强度、不同坡度对华南红壤坡面降雨产流过程和侵蚀产沙过程的影响。[结果](1)相同坡度条件下,坡面径流量、侵蚀产沙量均随着雨强的增大而线性增大;相同雨强下,径流量随坡度的增加而减小,而产沙量随着坡度的变化比较复杂;(2)雨强和坡度共同影响着坡面产沙过程,当雨强小于等于180mm/h时,产沙量随坡度的增加而增大,在240mm/h出时呈现先增加后减小的趋势,在15°附近出现临界坡度。在降雨初期,径流率表现为波动增加过程,15min后趋于平稳,一直持续到降雨结束,其中雨强为240,180mm/h时波动较为剧烈,而产沙率呈现急剧而短暂的上升后迅速下降,在大雨强、陡斜坡条件下此现象尤为明显;(3)坡面径流平均流速与单宽流量、坡度比存在显著的幂函数关系,流速与径流量、侵蚀产沙量有着类似的变化规律。[结论]红壤侵蚀过程中雨强为主要影响因素,坡面流速可作为表征红壤坡面侵蚀特征的重要因子。[Objective] Effects of rainfall intensity and slope gradient on erosion process were studied in red soil hillslopes, to provide a scientific basis for soil and water loss control. [Methods] An simulated rainfall experiment was conducted to quantify the effects of rainfall intensity（240,180,120,60 mm/h） and slope gradients（25°,15°,5°） on runoff generation and sediment yielding on red soil slope. [Results] （1） In same slope gradient, the accumulative runoff and accumulative sediment load both significantly and linearly increased with the increase of rainfall intensity. In same rainfall intensity, slope runoff increased with slope gradient increasing, but sediment transport exhibited an elusory variaton. （2） The soil loss increased when rainfall intensity increased from 60 to 180 mm/h, while there was a critical slope at 15° in the rainfall intensity of 240 mm/h, wherein the soil loss increased at first and then decreased. Runoff rate kept a relatively stable stage after an initial fluctuated increased from 0 to 15 min, this fluctuation phenomenon was obvious under rainfall intensity of the 240 and 180 mm/h. The sediment generation rate rapidly increased and then decreased quickly. This pattern was more pronounced when there were heavy rains and steep slopes. （3） The average flow velocity of slope flow had a significant fitting relationship of power function with the unit width discharge and slope ratio. The flow rate experienced a similar regular pattern with respect to surface runoff and sediment generation. [Conclusion] Rainfall intensity is the main factor in the red soil erosion process, and velocity could be used as important indicators to assess red soil slope erosion features.

关 键 词：模拟降雨 红壤 坡面侵蚀 产流 产沙 流速 

分 类 号：S157.1[农业科学—土壤学]