砂箱不同剩餘水分之土壤水分特性曲線推估

The Estimation of Soil Water Characteristic Curve on Sandbox Using Different Residual Water Contents

10.29995/JSHR.201106.0005

曹舜評(Shun-Ping Tsao)；張圖杰(Tu-Je Chang)

土壤水分特性曲線 ； 砂箱試驗 ； 基質勢能 ； Soil water characteristic curve ； Sandbox experiment ； Matric potential

坡地防災學報

10卷1期（2011 / 06 / 01）

50 - 58

繁體中文

本文利用砂箱進行土壤水分特性曲線之研究，研究中以三種砂土裝填入砂箱中，砂箱內設置量測土壤水分及張力之儀器，加水至飽和後以自然排水之方式量測得到低張力狀態之土壤水分特性曲線，再利用Brooks and Corey、van Genuchten、McKee and Bumb-Boltzmann與McKee and Bumb-Fermi等四種土壤水分特性曲線模式擬合。擬合時剩餘水分含量以兩種方式處理，一是將剩餘水分含量以風乾土水分含量代入；另一是將剩餘水分含量視為待定的擬合參數，在擬合時與其他參數一齊產生。研究結果顯示，就整體而言以McKee and Bumb-Fermi模式及van Genuchten模式最適於本研究之土樣水分特性曲線模擬。另分析發現是否將剩餘水分含量視為已知數值或待定參數，對McKee and Bumb-Fermi模式並無影響；但對其他模式而言，不管何種土樣，均是將剩餘水分含量視為待定參數時，會有較佳之模擬效果。由研究結果可見，以風乾土之水分含量作為剩餘水分含量，並不適宜。

The soil water characteristic curve describes the relationship between the soil matric potential and water content. Residual water contents value is one of basic parameters for soil water characteristic curve estimating. In this study, sandbox experiments were used to investigate soil water characteristic curve for experiment normal sand and Ottawa sandy soils. The mathematic estimating models, included Brooks and Corey method, van Genuchten method, Mckee and Bumb-Boltzmann method and Mckee and Bumb-Fermi method, were used to compare the experimental results. Two different types of residual water were used, one was air dry water contents, and the other was to treat as fitting parameter. The experimental results showed that Mckee and Bumb-Fermi method and van Genuchten method were the best-fit models. Residual water contents treat as fitting parameter were better than air dry water contents.