冲刷条件下黄土丘陵区浅沟侵蚀形态及产流产沙特征  

Erosion morphology and runoff generation and sediment yield on ephemeral gully in loess hilly region in field scouring experiment

作　　者：康宏亮[1] 王文龙[1,2] 薛智德[3] 郭明明[1] 史倩华 李建明[4] 郭军权[5] 

机构地区：[1]西北农林科技大学水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室,杨凌712100 [2]中国科学院水利部水土保持研究所,杨凌712100 [3]西北农林科技大学资源环境学院,杨凌712100 [4]长江科学院水土保持研究所,武汉430010 [5]延安职业技术学院,延安716000

出　　处：《农业工程学报》2016年第20期161-170,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(40771127);水利部公益性行业专项(201201048;201201047)

摘　　要：浅沟是农耕区特有的一种侵蚀沟类型,浅沟侵蚀是耕地土壤流失的主要方式之一。该文采用野外放水冲刷试验,研究黄土丘陵区典型坡耕地浅沟在不同坡度及放水流量条件下的产流产沙及侵蚀形态特征。结果表明：1）产流时间变化范围7.00~68.02 s,与坡度×放水流量交互项呈极显著负指数幂函数关系。稳定径流率变化范围3.06~23.71 L/min,与放水流量呈极显著线性函数关系,并随坡度的增大呈增大趋势。稳定流速变化范围27.35~55.59 cm/s,与坡度×放水流量交互项呈极显著幂函数关系;2）产沙率呈波动减小-稳定和增大-波动减小-稳定2种变化趋势,平均产沙率随放水流量的增加呈极显著指数函数增大,随坡度增加先增大后减小,并在26°条件下存在临界值;3）侵蚀沟槽平均宽、深变化范围分别为4.45~17.09、1.88~10.15 cm,平均宽深比变化范围1.45~2.39。平均横断面面积变化范围为11.40~197.91 cm2,是描述浅沟侵蚀产沙量的最优形态因子,二者呈极显著线性函数关系。结果可为黄土丘陵区浅沟防治及浅沟侵蚀产沙模型的建立和修正提供参考。Ephemeral gully is a kind of erosion channel formed due to alternative action of runoff scouring and tillage. It can be easily filled by normal tillage and reform again in the same location by erosive rainfall events. Ephemeral gully is not only the main channel of sediment transport, but also is the main source of eroded sediments. A field scouring experiment was conducted on a typical sloping farmland in Yan＇er watershed of Baota region（36°11′-37°09′N, 109°21′-110°03′E）, Yan＇an, Shannxi to investigate runoff characteristics and sediment yield process and morphology parameters on ephemeral gullies with different gradients under different flow discharges. Soil of the farmland was composed of 7.8% clay and 66.5% silt and 25.7% sand. With consideration of physical condition of the farmland, the gradients of ephemeral gullies were selected as 14°-29° according to preliminary field investigations. The range of flow discharge was decided as 5-25 L/min through a theoretical equation, in which rainfall intensity and runoff coefficient and some of topographic factors were given. The size of ephemeral gully plot for the experiment was designed with the length of 5 m and width of 1 m, constructed as ＂imbricated land-form＂ with 10 cm of elevation from the bottom to the edge of the channel. A set of equipment was laid out to provide evenly and stable water flow with a valve to obtain a desired and constant flow discharge. Before each test, flow discharge was calibrated repeatedly to guarantee uniformity and veracity. During the experiment, flow velocity was measured with dye tracing method and flow width and depth were measured with a thin steel rule and point gauge every 5min. Runoff sample was firstly taken once a minute within 3 minutes after runoff generation, then once 3 minutes within the rest time. After an event, morphology parameters such as width and depth of erosion gully were measured for every 5 cm of distance for transverse sections from up-slope to down-slope. The results showed that�

关 键 词：形态 径流 泥沙 浅沟 黄土丘陵区 

分 类 号：S157.1[农业科学—土壤学]