中文摘要：

细沟侵蚀是坡耕地时常发生的一种侵蚀形式。细沟侵蚀对坡面土壤侵蚀产沙有重要贡献,而且是坡面侵蚀由面蚀向沟蚀发展的过渡。本文分析了细沟侵蚀影响因素和临界条件研究取得的进展和存在的不足。影响细沟侵蚀的主要因素有降雨径流、土壤、地形、土壤表面特征和土地管理等因素,其中,前4者有多种指标来表征其效应,而土壤表面特征的影响还处于定性研究阶段。坡面需要达到特定的临界条件才可能发育细沟,细沟发生临界条件的研究主要从临界径流条件、临界土壤条件和临界地形条件等角度出发,各临界条件并非定值,而是关乎其他因素的综合指标。最后,本文对今后细沟侵蚀影响因素和临界条件研究可能的研究内容和方向进行了展望。

英文摘要：

Rill erosion plays an important role in soil erosion process in loess hillslopes.It is a quantum leap during the process of soil erosion on slopes,and also is the beginning of a qualitative change in the process of soil erosion.On the basis of studying many papers,the authors review the study of factors and critical conditions of rill erosion.Rainfall and runoff,soil,topography,soil surface characteristics and land management all have their impact on rill erosion.On the one hand,researches use a variety of parameters to represent the impact of rainfall and runoff,soil,topography and land management.On the other hand,there are two forms of soil surface characteristics,namely,surface roughness and surface soil crust.The studies on the impacts of both of them are still in a qualitative research stage,and some studies have shown they can weaken rill erosion,the other studies concluded that they would exacerbate the occurrence of rill erosion. The generation of rill on the slopes needs certain conditions,and the critical runoff,soil and terrain conditions have their corresponding research results.The critical conditions for the generation of rill are not numbers, but are related to many factors.Critical conditions for rill erosion are not fixed values,but all of them should be a comprehensive index of other factors. At the same time,the future possible research direction and contents of the influencing factors and the critical conditions of rill erosion are pointed out.More experiments and field observation data are needed.In rill erosion factors research,the following points need further works：（1）the quantitative analysis of the impact of rainfall and runoff on the joint action of rill erosion;（2）screening key indicators to represent the effect of soil,topography and land management factors;（3）an in-depth study on how the soil surface characteristics affect rill erosion,and a quantitative analysis of the impact of surface roughness and soil crust on rill erosion;（4）the interaction of various factors