The runoff characteristics under simulated rainfall on purple soil sloping cropland  

作　　者：XU Pei FU Bin 

机构地区：[1]Key Laboratory of Mountain Surface Process and Hazards, Chinese Academy of Sciences, Chengdu 610041, China [2]Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China

出　　处：《Chinese Journal Of Geochemistry》2011年第3期317-322,共6页中国地球化学学报

基　　金：supported by the National Natural Science Foundation of China (Grant No. 40871134);the State Key Laboratory of Earth Surface Processes and Resource Ecology

摘　　要：Rainfall runoff is a critical hydrological process related to soil erosion and agricultural non-point pollu-tion. In this study, 25 simulation experiments on rainfall were carried out in five runoff plots. Rape (Brassica campestris) was planted on the downslope of the plots. Experiments were conducted when the vegetation coverage reached 80%. Each plot was subjected to five rainfall events differing in intensity. The results showed: (1) the runoff coefficients of overland flow and subsurface flow were less than 0.6 and 0.005, respectively; (2) the discharge of overland flow was the quadratic function of time; (3) runoff coefficient was the function of slope gradient and rain-fall intensity. When the slope gradient increased from 8.7% to 46.6%, the runoff coefficient of overland flow first increased and then decreased. The runoff coefficient reached the maximum when the slope gradient was within the range of 17.6%-36.4%; and (4) the process of subsurface flow generation included the increasing phase and reces-sion phase. Discharge was a logarithm function of time in the increasing phase, and an exponential function in the recession phase. Runoff coefficient of subsurface flow decreased first and then increased when the slope gradient varied from 8.7% to 46.6% and was not correlated with rainfall intensity.Rainfall runoff is a critical hydrological process related to soil erosion and agricultural non-point pollution. In this study, 25 simulation experiments on rainfall were carried out in five runoff plots. Rape （Brassica campestris） was planted on the downslope of the plots. Experiments were conducted when the vegetation coverage reached 80%. Each plot was subjected to five rainfall events differing in intensity. The results showed： （1） the runoff coefficients of overland flow and subsurface flow were less than 0.6 and 0.005, respectively; （2） the discharge of overland flow was the quadratic function of time; （3） runoff coefficient was the function of slope gradient and rainfall intensity. When the slope gradient increased from 8.7% to 46.6%, the runoff coefficient of overland flow first increased and then decreased. The runoff coefficient reached the maximum when the slope gradient was within the range of 17.6%-36.4%; and （4） the process of subsurface flow generation included the increasing phase and recession phase. Discharge was a logarithm function of time in the increasing phase, and an exponential function in the recession phase. Runoff coefficient of subsurface flow decreased first and then increased when the slope gradient varied from 8.7% to 46.6% and was not correlated with rainfall intensity.

关 键 词：模拟降雨 径流特性 紫色土 坡耕地 农业非点源污染 径流系数 降雨强度 径流小区 

分 类 号：S157.1[农业科学—土壤学] TV121[农业科学—农业基础科学]