黔东北喀斯特坡面产流产沙及土壤含水量特征

Characteristics of Runoff and Sediment Yield and Soil Water Content on Slope in Karst Area of Northeast Guizhou

为了解不同因素对喀斯特地区坡面产流产沙的影响、给喀斯特地区石漠化综合治理和水土流失防治提供理论指导,基于贵州省浒洋水水土保持监测站径流小区的降雨、产流产沙、土壤水分、植被盖度等资料,采用ORIGIN2017及SPSS22软件进行数据处理及相关性分析,探讨了降雨量、坡度、土地利用类型、前期土壤含水量对喀斯特坡面产流产沙的影响及植被盖度对土壤含水量动态变化的影响。结果表明:①坡面径流小区的产流产沙量与降雨量、降雨侵蚀力均成正相关关系,在相同的侵蚀性降雨条件下,不同类型径流小区的侵蚀敏感度存在较大的差异,撂荒地侵蚀敏感度最大、坡耕地侵蚀敏感度最小;②随着地面坡度从13°增大到25°再增大到30°,撂荒地径流小区单位面积产沙量呈现先增大后减小的趋势,25°可以作为撂荒地单位面积产沙量的参考临界坡度;③在相同的侵蚀性降雨条件下,喀斯特坡耕地单位面积产沙量最大,原因是坡耕地生态环境较差、人类活动强烈,土壤侵蚀量大且动态变化不稳定;④径流深及土壤流失量与前期土壤含水量均成显著的正相关关系,植被盖度的变化对土壤含水量具有一定的影响,植被盖度>15%时,随着植被盖度的提高土壤含水量呈现抛物线增大趋势。

In order to understand the influence of different factorsto the runoff and sediment yield on slopes in the Karst area to provide theo⁃retical guidance for comprehensive control of rocky desertification and prevention of soil erosion,effects of rainfall,slope,land use type and previous soil water content on runoff and sediment yield and vegetation cover on dynamic change of soil water content were discussed based on slope monitoring data of rainfall,runoff and sediment yield,soil water content and vegetation cover from Huyangshui Water and Soil Conser⁃vation Monitoring Station in Zunyi City,Guizhou Province and data and their relative relationship were analyzed by ORIGIN2017 and SPSS22.The results show that a)for slope runoff plots,runoff and sediment yield has a positive correlation with the amount of rainfall and rainfall erosivity and under the same erosive rainfall conditions,the erosive sensitivity of different types of land use is significantly different,the erosive sensitivity of old fields is the biggest and the erosive sensitivity of crops of sloping cultivated land is the smallest;b)25°can be used as a reference of critical slope of sediment yield for per unit area in abandoned land.Between 13°and 25°,with slope increase,the a⁃mount of sediment yield for per unit area is firstly increased and then decreased;c)under the same erosive rainfall conditions,sediment yield for crops of sloping cultivated land is the most severe because of poor ecological environment,severe human disturbance and large and unstable dynamic changes of soil erosion and;d)previous soil water content has a significant positive correlation with runoff depth and soil loss amount,the change of vegetation coverage has a certain impact on soil water content.When the vegetation cover exceeds 15%,with the increase of vegetation coverage,the soil water content shows a significant parabolic increasing trend.