三峡山地不同坡位土壤的水分特征曲线及水力学性质  

Soil Water Retention Curve and Hydraulic Properties at Different Slope Positions in the Three Gorges Mountainous Area

作　　者：李文政 刘目兴 易军[1,2] 张海林 卢世国[1,2] 白雨诗 LI Wenzheng;LIU Muxing;YI Jun;ZHANG Hailin;LU Shiguo;BAI Yushi(Hubei Key Laboratory for Geographical Process Analyzing&Modeling,Wuhan 430079;College of Urban and Environmental Sciences,Central China Normal University,Wuhan 430079)

机构地区：[1]地理过程分析与模拟湖北省重点实验室,武汉430079 [2]华中师范大学城市与环境科学学院,武汉430079

出　　处：《水土保持学报》2021年第3期135-142,共8页Journal of Soil and Water Conservation

基　　金：国家自然科学基金项目(41771261,41601215);湖北省自然科学基金重点项目(2015CFA141)。

摘　　要：山地不同坡位的土壤水力学性质研究可为地表水文过程预测和坡地生态修复提供参考。通过采集三峡库区大老岭林区山地不同坡位的原状土样,测定饱和导水率、当量孔径、水分库容等水力学参数,利用V-G模型拟合土壤水分特征曲线,评价不同坡位土壤的渗透性能和持水能力。结果表明:坡顶土壤的入渗性能最好,平均饱和导水率为108.54 cm/d,其他坡位平均饱和导水率为34.81~47.56 cm/d。坡顶土壤的持水能力最差,吸力值从0增至100 kPa,含水量下降幅度最大(63.67%),其他坡位下降幅度在46.36%~52.07%。坡顶土壤大孔隙体积比最大可达20.95%,其他坡位在12.27%~16.58%。田间持水量库容占总库容的百分比以坡顶土壤最小(45.24%),其余在60.08%~65.33%。用V-G模型拟合土壤水分特征曲线,各样点决定系数R 2均大于0.95,拟合效果较好。饱和导水率与大孔隙体积比、砂粒含量呈正相关,与粉粒含量和黏粒含量呈负相关。V-G模型参数α与进气值相关,α值越小,持水能力越强。试验中α值与砂粒含量、大孔隙体积比呈正相关,与粉粒含量和黏粒含量呈负相关。砂粒和大孔隙越多,土壤持水性越差。参数n的取值影响拟合水分特征曲线的弯曲程度,n值越小,曲线越平缓。试验中n值与砂粒含量呈正相关,与粉粒含量呈负相关。砂粒含量越多,随吸力增大土壤排水越快。可见,山地坡面顶部土壤的持水能力最差,渗透能力最强,其他坡位差异不显著,V-G模型拟合的结果与实测结果一致。Research on soil hydraulic properties in different positions of the hillslope can provide reference for the prediction of surface hydrological process and ecological restoration in mountainous areas.In this study,undisturbed soil samples were collected from different slope positions in Dalaoling forest region,which was a typical small catchment of the Three Gorges Reservoir area,and the hydraulic parameters such as saturated water conductivity,equivalent pore diameter and water storage capacity were measured.The V-G model was used to fit the soil water characteristic curve to evaluate the soil permeability and water holding capacity of soil at different slope positions.The results showed that the soil infiltration performance of the top position was the best,and the average saturated hydraulic conductivity was 108.54 cm/d,while the average saturated hydraulic conductivity of other four slope positions was 34.81~47.56 cm/d.However,the water content of the top position decreased largely(63.67%)when the suction value increased from 0 to 100 kPa,while the average water content of other four positions decreased by 46.36%~52.07%.The macropore volume ratio of the soil at the top position was 20.95%,and that of the other four points was ranging from 12.27%~16.58%.The percentage of field water capacity in total soil water storage capacity was 45.24%in the top position,which was the smallest,and that of the other four points was 60.08%~65.33%.The V-G model was used to fit the soil water retention curve,and the determination coefficient(R 2)of each point was greater than 0.95,which indicated that the fitting effect was good.The saturated hydraulic conductivity was positively correlated with soil macropore volume ratio and sand content,and negatively correlated with silt content and clay content.The parameter α of V-G model was related to air entry values.The smallerαvalue was,the stronger the water retention capacity was.In the experiment,αvalue was positively correlated with sand content and macropore volume ratio,and n

关 键 词：山地土壤 入渗能力 持水能力 坡位 三峡库区 

分 类 号：S152.7[农业科学—土壤学]