PAM对银川城市绿地土壤水分运动及水力参数的影响

Effects of PAM on Soil Water Movement and Hydraulic Parameters of Urban Green Spaces in Yinchuan

[目的]探究不同PAM施加比例下城市绿地土壤水分运动及水力参数的变化,为城市绿地建设和合理利用水资源提供理论参考。[方法]以银川城市绿地土壤为研究对象,采用垂直一维土柱试验,选取5种聚丙烯酰胺(PAM)施加比例(质量比)0%(CK),0.02%(T_(1)),0.04%(T_(2)),0.06%(T_(3)),0.08%(T_(4)),0.1%(T_(5)),研究湿润锋进程、累积入渗量和入渗速率等入渗特征参数,比较Philip模型、Horton模型、Kostiakov模型及通用经验模型在本研究中的适用性,分析PAM施加比例对土壤水力参数的影响。[结果]入渗历时300 min时,T_(1),T_(2),T_(3),T_(4)和T_(5)较CK相比,湿润锋进程分别减少了5.2%,12.0%,13.2%,15.4%和24.2%,累积入渗量分别减少5.9%,12.8%,14.7%,21.4%和31.5%。T_(1),T_(2),T_(3),T_(4)和T_(5)稳定入渗速率较CK分别减小10.1%,22.4%,23.3%,29.2%和41.6%;4种入渗模型中Horton模型最适合描述研究区不同PAM施加比例下的城市绿地土壤水分入渗过程(R 2>0.886)。滞留含水率θ_(r)、饱和含水率θ_(s)、形状系数n随PAM施加比例增大而增大,进气吸力倒数α、饱和导水率K_(s)随PAM施加比例增大而减小。[结论]研究表明PAM可以有效改善银川城市绿地土壤水分快速渗漏、持水性能差的状况,提高土壤保水能力。

[Objective]This study explored soil water movement and hydraulic parameters of urban green space with different PAM application ratios to provide theoretical reference for building urban green space and utilizing water resources.[Methods]The soil of urban green space in Yinchuan was taken as the research sample.The vertical one-dimensional soil column test was adopted,5 PAM addition rates of 0%(CK),0.02%(T_(1)),0.04%(T_(2)),0.06%(T_(3)),0.08%(T_(4)),0.1%(T_(5))were added to urban green space soil of Yinchuan.The process of wetting front,cumulative infiltration amount,and infiltration rate were studied.The applicability of the Philip model,Horton model,Kostiakov model and general empirical formula in the soil moisture infiltration process of Yinchuan urban green space containing PAM was comparedt.The effect of PAM application on soil hydraulic parameters was analyzed.[Results]Compared with CK,the wet front processes of T_(1),T_(2),T_(3),T_(4),and T_(5)treatments decreased by 5.2%,12.0%,13.2%,15.4%and 24.2%,respectively,and the cumulative infiltration amount reduced by 5.9%,12.8%,14.7%,21.4%and 31.5%,respectively,when the infiltration lasted 300 minutes.Compared with CK,T_(1),T_(2),T_(3),T_(4),and T_(5)reduced the stable infiltration rate by 10.1%,22.4%,23.3%,29.2%and 41.6%,respectively.The comprehensive comparison results indicated that the simulated accuracies of the four infiltration models decreased in the order:Horton>Kostiakov>Philip>General Empirical Model.The retained water contentθ_(r),saturated water contentθ_(s)and shape coefficient n increased with the increase of PAM application rate,while the reciprocalαof intake suction and saturated hydraulic conductivity K_(s)decreased with the increase of PAM application rate.[Conclusion]The addition of PAM can effectively remedy the phenomenon of deep soil leakage and poor water retention in Yinchuan urban green land.