降雨对不同坡比边坡产流产沙过程的影响

Rainfall:Impacts on the Runoff and Sediment Process Under Different Ratio Slopes

为了给侵蚀沟植被边坡防护提供理论基础,通过野外径流小区试验,观测次降雨对1:1.5和1:1.2坡比边坡7种植被配置产流产沙的过程特征。结果表明:产流量主要随降雨量变化,大于其受植被影响,产沙量主要集中于前期强降雨,15 mm雨量为阈值,高于15 mm雨量产沙量大幅度增长,植被生长后期产沙极少;不同时间段次降雨减流减沙优势植被配置不同,紫花苜蓿草种前期减流减沙效果好,无芒雀麦和早熟禾草种后期减流减沙效果好;坡度变陡,产流量随植被生长由相近逐渐提高,产沙量只在强降雨下明显升高。在侵蚀沟陡坡防护时紫花苜蓿混播比例要高,提高前期对强降雨的承受能力。

The paper aims to provide a theoretical basis for the vegetation protection of gully.We observed the characteristics of producing runoff and sediment of 7 vegetation configurations on 1:1.5 and 1:1.2 ratio slopes,through the field experiment of the runoff plots.The results showed that:the runoff mainly changed with rainfall,which was affected greater than that of vegetation;the sediment was mainly concentrated in the early heavy rainfall,and the 15 mm rainfall was the threshold;the sediment increased significantly with rainfall above 15 mm;and little sediment was produced during the late growth period;the superior vegetation configurations of reducing runoff and sediment were not the same in different time periods;the effect of reducing runoff and sediment of Medicago sativa L.was good in the early stage,and Bromus inermis Leyss.and Poa annua L.were excellent with reducing runoff and sediment in the late stage;as the slope became steeper,the sediment was gradually increased with the growth of vegetation from the similar amount,and the amount of sediment was significantly increased only under heavy rainfall.In order to improve the ability to withstand heavy rainfall in the early stage,the mixed sowing proportion of Medicago sativa L.needs to be higher in the protection of gully.