中文摘要：

坡面退水及其污染物负荷是研究坡地水文过程和污染物迁移机理的重要组成部分.通过室内模拟降雨试验,分析了黄土坡面退水情况及降雨因素、地形地貌和农业管理措施对退水的影响,同时从降雨-径流-土壤相互作用角度探讨了退水矿质氮的浓度和负荷量.结果表明：①黄土坡面退水以地表径流为主,退水时间、退水量和退水强度远小于降雨期地表产流;②降雨强度、地表覆盖（牧草和秸秆覆盖）和地形地貌（坡度和坡长）对坡面退水影响较大,降雨期和退水期的产流强度均与雨强呈对数增加趋势;③降雨停止后,坡面径流的流速减小,与土壤相互作用时间较长,致使退水矿质氮浓度普遍高于降雨结束时径流矿质氮浓度,坡长越长越明显;④坡面退水矿质氮流失以NO3^- -N为主,NH4＋-N流失量较低.

英文摘要：

The recession flow on loess slope and its chemicals release and transport are important for studying the sloping field hydrographic process and soil chemicals loss by runoff. Based on the artificial rainfall experiments on loess slope land, the recession flow and the influential factors, such as rainfall, topography, and physiognomy, and agricultural managements are analyzed in this paper. Meanwhile, from the interaction of rainfall, runoff and soil, the mineral nitrogen concentration and loads of recession flow are discussed. The results are as follows. First, the recession flow on loess slope mainly originates from surface runoff, and the residue time, volume and intensity of it are much less than that of surface runoff in a rain session. Second, rainfall, topography and physiognomy, as well as the surface cover greatly affect the recession flow. Runoff intensity and recession flow intensity are both increasing with the rain intensity in a form of logarithm function. Third, the recession flow＇s velocity is so slow and the interaction time with surface soil is so long that the mineral nitrogen concentration of it is usually more than that of the runoff when the rain terminates, especially for a long slope. Finally, there are much more soil nitrate than soil ammonium in the recession flow.