中文摘要：

以2011-2012年汛期野外降雨资料为基础,分析陕南后沟小流域泥沙和总氮（TN）随径流流失特征。研究结果表明,坡耕地、退耕地、菜地泥沙流失通量与径流量拟合方程采用S形曲线方程表达较为合适;果园采用线性函数反映两者之间的关系。坡耕地和菜地径流量与TN浓度采用倒数曲线表达,而果园和退耕地采用线性函数表达;汛期不同土地利用类型土壤流失通量顺序为：菜地（4 011.7kg/hm2）〉坡耕地（1 720.0kg/hm2）〉退耕地（1 606.3kg/hm2）〉果园（776.3kg/hm2）;径流中TN流失通量顺序为：菜地（15.29kg/hm2）〉退耕地（7.20kg/hm2）〉坡耕地（4.92kg/hm2）〉果园（1.37kg/hm2）。2011-2012年汛期后沟小流域出口径流动能与泥沙量流失量采用线性函数和幂函数描述两者之间关系,而TN流失量与径流动能采用对数函数和幂函数表示。汛期末期阶段泥沙和TN流失风险最大。

英文摘要：

To study the loss characteristics of sediment and total nitrogen（TN）by runoff in a typical watershed of the Southern Shaanxi area under natural rainfall events,Hougou agricultural watershed was selected to examine runoff,sediment and TN in natural rainfall events of rainy seasons during 2011 to 2012.The results showed that the best regression equation was S curve equation between sediment loss flux and runoff of slope land,returning farmland,garden field,and linear functional relation was the best regression equation for orchard field.The reciprocal equation model could describe the relation of TN concentration and runoff in slope land and garden field,linear functional relation could express the relationship of TN concentration and runoff in returning farmland and orchard field.The order of sediment and TN loss flux in different land use in rainy season was：Garden field（4 011.7kg/hm2）slope land（1 720.0kg/hm2）returning farmland（1 606.3kg/hm2）orchard field（776.3kg/hm2）,garden field（15.29kg/hm2）returning farmland（7.20kg/hm2）slope land（4.92kg/hm2）orchard field（1.37kg/hm2）.The linear equation and power function equation could show the relation of runoff kinetic energy and sediment loss,and the logarithmic function curve and power function equation could explain the relation of runoff kinetic energy and TN loss.The risk of the loss of sediment and TN was the highest at the later stage of rainy season in the Southern Shaanxi area.