地表粗糙度对黄土坡面产流机制的影响  

Effects of soil surface roughness on runoff generation mechanism on loess slope

作　　者：王林华 汪亚峰[1] 王健[2] 林青涛[3] 吴发启[2] 

机构地区：[1]中国科学院生态环境研究中心城市与区域生态国家重点实验室,北京100085 [2]西北农林科技大学资源环境学院,杨凌712100 [3]西北农林科技大学水土保持研究所,杨凌712100

出　　处：《农业工程学报》2018年第5期120-128,共9页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目"黄土坡耕地地表粗糙度对产汇流的影响研究"(41271288)

摘　　要：为探明地表粗糙度对坡面产流机制的影响,该研究通过室内与室外径流小区模拟降雨试验相结合,分析在3种雨强(60、90、120 mm/h)下粗糙坡面与平整坡面(坡度5°、10°、15°、20°)产流点位空间分布和坡面产流时间特征,阐明地表粗糙度对坡面产流机制的影响。结果表明:粗糙坡面与平整坡面产流点位沿径流方向的变异系数分别为34.4%~52.9%、15.5%~31.1%,即粗糙坡面产流点位较平整坡面更为分散。相较于平整坡面,地表粗糙度具有推迟坡面产流效应,且推迟效应随坡度、雨强增大而逐渐减弱。表明地表粗糙度在小坡度、小雨强条件下具有较强延迟坡面产流能力。地表粗糙度影响坡面产流一方面通过地表填洼的直接作用;另一方面通过增加降水入渗水头,增强坡面入渗能力的间接作用。通过坡面地表填洼量预测的初始产流时间与实测坡面产流时间比值范围为2.2%~36.2%,表明地表粗糙度间接作用为延迟坡面产流的主导作用。因此,该研究结果阐明了粗糙坡面的点状产流与坡面产流特征,进一步为粗糙坡面产流机制的揭示及地表粗糙度对坡面土壤侵蚀机理的影响提供了科学依据。Soil surface roughness(SSR) is used to describe the surface spatial variation of elevation on rough slope and it plays a critical role in runoff generation and erosion process. Due to the presence of mounds and depressions distributed on rough slope, these micro-reliefs modify the surface depression storage capacity and extended rainwater retention time on slope. Consequently, it regulates the runoff generation and soil erosion process. Most of studies on SSR are focused on its measurement methods(Pin meter, Chain method, Laser scanner and Photogrammetry) and quantification index(Random Roughness, Mean Upslope Depression, Limiting Elevation Difference and Limiting Slope, etc.). And they also investigate SSR impacts on runoff and soil loss and how it evolves in soil erosion process. However, little information is available on the effect of soil surface roughness on runoff generation mechanism. Therefore, the aim of this study is to clarify how soil surface roughness impacts on runoff generation and investigate dominant impact on runoff generation process in sloping land under simulated rainfall. To achieve this purpose, the following specific objectives were addressed: 1) comparing the distribution of runoff generation points on rough and smooth slope; 2) analyzing the depression storage capacity, runoff generation time and process features during the simulated rainfall-runoff event for separating the direct and indirect impacts of roughness on runoff generation. Experiments were conducted on indoor soil box and outdoor runoff plots with four slope gradients(5?, 10?, 15?, 20?) under rainfall simulation condition. Five soil surface conditions were treated, included artificial digging(AD), artificial hoeing(AH), contour plough(CP), traditional plow(TP) and smooth surface(SS), by applied simulated at rainfall intensity of 60, 90, 120 mm/h. These results showed that the runoff generation point distance along the runoff downward direction on the rough and smooth surface was 12-181 cm, 40-180 cm, respectively. The coeff

关 键 词：土壤 粗糙度 侵蚀 产流点位 地表填洼量 产流机制 

分 类 号：S157.1[农业科学—土壤学]