红壤丘陵岗地区坡地产流产沙特征及影响因素研究

Characteristics of Runoff and Soil Loss and Their Influential Factors on Sloping Land in Red Soil Hilly Region

分析了2011年1月至2013年12月南方红壤坡地花生地和橘园2种土地利用方式下的产流产沙特征,并对其影响因素进行了探讨。结果表明:径流量与泥沙侵蚀量均表现为花生地极显著大于橘园(p<0.01),径流量年际变化和季节变化与降雨量变化表现基本一致,花生地泥沙侵蚀量年际变化不大,而橘园泥沙侵蚀量逐年降低,橘园的保水保土效果明显。花生地和橘园产流降雨量阈值的估算值分别为13.9mm和14.9mm,最大60min雨强(I60)阈值分别为8.0mm/h和12.0mm/h。降雨是坡面产流的主控因子,橘园产流的最大影响因子是降雨量,而花生地产流受I60的影响比降雨量大。前期土壤水势与径流系数的指数或对数关系,表明研究区产流机制主要以蓄满产流为主。多元回归分析显示,花生地泥沙侵蚀量与径流量呈极显著正相关(p<0.01),橘园泥沙侵蚀量与径流量、I60、前期土壤水势(或初始含水量)无显著相关性(p>0.1)。

Analyzed the characteristics of runoff and soil loss and their influential factors on red soil sloping land with peanut and citrus land uses.The data of runoff and soil loss were collected from four standard erosion plots（two from peanut field and the other two from citrus orchard）during the period from Jan,2011 to Dec,2013.The results showed that：The peanut field produced significantly higher runoff and soil loss than citrus orchard（p〈0.01）.The seasonal and annual variations of runoff were consistent with those of rainfall.Annual soil loss occurred in peanut field was stable from 2011 to 2013,while the soil loss production in citrus orchard gradually reduced with time.Certainly,citrus orchard was better for soil and water conversation than peanut field.The thresholds of rainfall amount to generate runoff were 13.9 mm and 14.9 mm for peanut field and citrus orchard,respectively,while the thresholds of maximum 60 min rainfall intensity were approximately 8.0mm/h and 12.0 mm/h,respectively.The rainfall was the main factor affecting runoff.The amount of rainfall was the most critical factor to runoff in citrus orchard,but the maximum 60 min rainfall intensity played a more important role than rainfall amount in peanut field.The exponential or logarithmic decay between the antecedent soil water potential and the runoff coefficient suggested that saturation excess runoff was dominant in studied area.Soil loss in peanut field had a significant positive correlation（p〈0.01）with the runoff,whereas the relationships between runoff,maximum 60 min rainfall intensity,antecedent soil water content and soil loss were poor（p〉0.1）in citrus orchard.