MEASUREMENT OF MOLECULAR DIFFUSION OF SALT IN UNSATURATED SOILS
MEASUREMENT OF MOLECULAR DIFFUSION OF SALT IN UNSATURATED SOILS
复制标题
不饱和土壤中盐分子扩散的测量
DOI：
10.1097/00010694-199502000-00006
复制
发表时间：
1995
期刊：
影响因子：
--
通讯作者：
S. Shiozawa
中科院分区：
文献类型：
--
作者：
B. Mehta;S. Shiozawa
采用瞬态法测定了小内沙丘砂和关东壤土在大含水率范围内盐的分子扩散系数。相对扩散系数Dr（盐在土壤中的扩散系数与水在土壤中的扩散系数之比）在0.31 ~ 2.98 × 10-3之间变化，体积含水量从31.74% （0.00215 MPa）下降到2.13% （5 MPa）。关东壤土含水率从60.89% （0.0021 MPa）下降到20.22% (3.11 MPa)，吸水率在0.17 ~ 6.25 × 10-3之间变化。两种土壤在较高含水量时，Dr与土壤含水量在对数对数尺度上呈线性关系。然而，它显示了在含水量处的断点，对应于两种土壤的基质吸力约为0.09 MPa。在高含水量（>断点）条件下，山内沙丘砂和关东壤土的Dr（θ）斜率分别为0.75和1.25，低含水量条件下，Dr（θ）斜率分别为3.99和4.1。发现Dr与基质吸力的关系较少依赖于土壤质地。
The molecular diffusion coefficients of salt were measured in Shonai sand dune sand and Kanto loam soils over a wide range of water contents using a transient state method. The measured relative diffusion coefficient, Dr, the ratio of diffusivity of salt in soil to the diffusivity in bulk water, varies from 0.31 to 2.98 × 10-3 for Shonai dune sand as volumetric water content decreases from 31.74% (0.00215 MPa) to 2.13% (5 MPa). For Kanto loam soil it varies from 0.17 to 6.25 × 10-3 as water content decreases from 60.89% (0.0021 MPa) to 20.22% (3.11 MPa suction). The relationship of Dr with water content in soil shows a linear relationship on log-log scale at higher water contents for both soils. However, it shows a break point at the water content that corresponds to a matric suction of about 0.09 MPa for both soils. The respective slopes of Dr(&thetas;) for Shonai dune sand and Kanto loam are 0.75 and 1.25 at higher water contents (> break point) and 3.99 and 4.1 at lower water contents. The relationship of Dr with matric suction is found to be less dependent on the soil texture.