摘要
黄土丘陵沟壑区降雨集中且多为暴雨,暴雨所形成的坡面径流是造成黄土丘陵严重水土流失的主要原因,而草地植被对坡面径流有良好的抑制作用,草地植被能够通过改变坡面下垫面条件、土壤入渗率来阻延坡面径流的产生,因此揭示草地植被对坡面产流过程的作用及调控机理对于控制该地区的水土流失具有重大意义。该研究以黄土丘陵沟壑区典型草地坡面为研究对象,通过野外人工降雨,探究坡面降雨-产流过程对不同草被覆盖度的响应规律。结果表明,(1)坡面流达到稳定产流时间随着草地植被覆盖度的增大所需时间更长;稳定产流时间随着降雨强度的增大而减小。(2)在60 mm·h^−1的降雨强度时,草地植被覆盖度的阈值为75.38%;在90 mm·h^−1的降雨强度时,草地植被覆盖度的阈值为90.54%;而对于120 mm·h^−1的特大降雨强度时,草地植被覆盖对于径流的影响不显著。(3)坡面流的雷诺数和弗劳德数分别为40.07-695.22和0.33-1.56,阻力系数为1.42-43.53。降雨强度越大,草地植被覆盖度对这些参数的影响逐渐减弱。黄土丘陵的降雨特点多为暴雨,草被对坡面径流的调控作用在强暴雨下不是特别显著,应当辅以林木、灌木措施,才能更有效地控制水土流失。若是只考虑草地植被对坡面的调控作用,90%左右的草地植被覆盖度能够最大效率的应对黄土丘陵沟壑区的降雨状况。
The rainfall in the loess hilly and gully area is concentrated and mostly rainstorm.The runoff on the slope caused by rainstorm is the main cause of serious soil and water loss in the loess hilly area,and the grassland vegetation has a good inhibitory effect on the runoff on the slope.The grassland vegetation can delay the runoff on the slope by changing the underlying surface conditions and soil infiltration rate,therefore,it is of great significance to reveal the role of grassland vegetation in the process of runoff generation and control mechanism for controlling soil erosion in this area.In this study,typical grassland slopes in hilly and gully regions of the loess plateau were taken as research objects.Through artificial rainfall in the field,the response rules of slope rainfall-runoff process to different grass coverage were explored.The results show that:(1)The time for slope flow to reach stable flow generation is longer with the increase of grassland vegetation coverage.The stable flow time decreases with the increase of rainfall intensity.(2)At 60 mm·h−1 rainfall intensity,the threshold of grassland vegetation coverage is 75.38%;at 90 mm·h−1 rainfall intensity,the threshold of grassland vegetation coverage is 90.54%;at 120 mm·h−1 rainfall intensity,the impact of grassland vegetation coverage on runoff is not significant enough.And(3)the Reynolds number and Froude number of slope flow are 40.07‒695.22 and 0.33‒1.56 respectively,and the drag coefficient is 1.42‒43.53.The greater the rainfall intensity,the weaker the impact of grassland vegetation coverage on these parameters.Rainfall in the loess hilly area is characterized by intense rain.The regulating effect of grass cover on slope runoff is not particularly significant under intense rain.Forest and shrub measures should be supplemented in order to control soil erosion more effectively.If only considering the regulation of grassland vegetation on slopes,about 90%of grassland vegetation coverage can cope with the climatic conditions of loess hilly and gully region most efficiently.
作者
陈戎欣
吕锡芝
倪用鑫
魏义长
CHEN Rongxin;LU Xizhi*;NI Yongxin;WEI Yichang(North China University of Water Resources and Electric Power,Zhengzhou 450003,China;Yellow River Conservancy Commission,Yellow River Conservancy Research Institute/Key Laboratory of Soil Erosion Process and Control on Loess Plateau,Ministry of Water Resources,Zhengzhou 450003,China)
出处
《生态环境学报》
CSCD
北大核心
2020年第1期122-128,共7页
Ecology and Environmental Sciences
基金
国家自然科学基金项目（41601301
51979118）
中央级公益性科研院所基本科研业务费专项资金项目（HFY-JBYW-2019-01）
关键词
草被覆盖度
坡面
野外人工降雨
径流过程
水力学参数
grass coverage
slope
field artificial rainfall
runoff process
hydraulic parameter
作者简介
陈戎欣(1994年生),男,硕士研究生,主要从事水土保持研究。E-mail:crx940322@163.com;通信作者:吕锡芝(1986年生),男,博士,高级工程师,主要从事水土保持、生态水文方面研究。E-mail:nihulvxizhi@163.com。
