中文摘要：

通过模拟降雨试验,分别研究1.0mm/min和2.0mm/min雨强条件下,不同坡面上径流过程和土壤氮素流失特征。结果表明,在1.0mm/min雨强条件下,每个产流阶段径流变化量依次为18°〉28°〉21°,峰值出现时间依次为21°〉18°〉28°,径流峰值量依次为28°〉18°〉21°;硝态氮淋溶与土壤侵蚀同步进行;铵态氮流失量峰值的出现是坡面顶部和下部流失量的叠加结果,随后铵态氮流失量趋于降低;在2.0mm/min雨强条件下,每个产流阶段径流变化量不同,峰值出现时间依次为18°〉21°〉28°,径流峰值量依次为28°〉21°〉18°。硝态氮流失以泥沙携带为主,大坡度地表硝态氮流失量陡然增加;短时间内坡面表层土壤流失量显著增加,造成铵态氮流失量波动变化。在两种雨强条件下,累积径流流失量依次为28°〉21°〉18°;硝态氮是径流中全氮流失的主要形式;在整个降雨过程,全氮流失量表现为产流初期较低,中期增大,后期降低。各形态氮素累计流失量与径流累计流失量之间存在显著的线性关系。

英文摘要：

Based on simulating rainfall experiments,the processes of runoff and the nitrogen loss characters on the different slopes were studied under rainfall intensities 1.0 mm/min and 2.0 mm/min separately.The results show that under the conditions of low rainfall intensity,variation of runoff in every process is： 18°28°21°,the runoff peak time is： 21°18°28°,the amount of peak is： 28°18°21°,the synchronize between nitrate leaching and soil erosion,because of the superposition of ammonia nitrogen loss between the top and the lower slope,the peak of ammonia nitrogen loss is occurred,then ammonia nitrogen loss tends to reduce.Under the conditions of strong rainfall intensity,variation of runoff in every process is different,the runoff peak time is： 18°21°28°,the amount of peak is： 28°21°18°.The nitrate loss is mainly carried out by sediment,the nitrate loss on the great slope took place increase steeply,in a short of time,the amount of topsoil loss is increase significantly,which leads to fluctuate of ammonia nitrogen loss.Under the conditions of two rainfall intensities,the total amounts of runoff loss is： 28°21°18°,the nitrate loss is the main form of total nitrogen in runoff.During the course of rainfall,the amount of total nitrogen loss is lower at the preliminary stages of runoff,and which increase at the middle stages of runoff,and which reduce at the last stages of runoff.There are significant linear relationships between the total amounts of different nitrogen patterns loss and runoff.