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本文研究了四种不同方法推求土壤导水参数的差别和准确性。这四种方法是:(1)根据土壤水分的再分布过程推求土壤的导水参数;(2)水平土柱法测定土壤水分扩散率D(),由特征曲线推求导水率K( );(3)利用特征曲线,根据垂直土柱蒸发的实测水分动态过程计算土壤的导水参数;(4)瞬时剖面法测定导水率K(),由特征曲线推求扩散率D(θ)。研究结果表明:在相同的土壤含水量范围内,四种方法所获得的导水参数除方法(2)外,其他三种方法获得的值均比较接近;以水分运动基本方程为依据的推求方法(1)、(2)比以达西定律为基础的推求方法(3)、(4)有较高的准确度,其准确度分别为0.85,1.00,0.35和0.45;四种方法的最佳适用范围分别是:(1)0.17≤θ≤0.28;(2)0.20≤(?)≤0.29;(3)0.18≤θ≤0.28;(4)0.33≤θ≤0.35。
In this paper, four different methods to determine the difference and accuracy of soil water conductivity parameters. The four methods are as follows: (1) Deriving the parameters of soil hydraulic conductivity according to the process of redistribution of soil moisture; (2) Measuring the rate of soil moisture diffusivity D () by horizontal soil column method and deriving the hydraulic conductivity K () from the characteristic curve; (3) Utilizing the characteristic curve, calculating the hydraulic conductivity parameters of soil based on the measured dynamic process of soil moisture during vertical soil column evaporation; (4) Measuring the water conductivity K () by instantaneous section method and calculating the diffusivity D (θ) from the characteristic curve. The results show that in the same range of soil moisture content, the values obtained by the four methods are all close to those obtained by the other two methods except for the method (2). The method of derivation based on the basic equations of water movement (1) and (2) have higher accuracy than the estimation methods (3) and (4) based on Darcy’s law, and their accuracy is 0.85,1.00,0.35 and 0.45 respectively. The best of the four methods The applicable range is: (1) 0.17≤θ≤0.28; (2) 0.20≤ (?) ≤0.29; (3) 0.18≤θ≤0.28; (4) 0.33≤θ≤0.35.