The influence of uniaxial compression upon pore size distribution in bi-modal soils
The influence of uniaxial compression upon pore size distribution in bi-modal soils
复制标题
DOI：
10.1016/j.still.2005.02.001
复制
发表时间：
2006-03-01
影响因子：
6.5
通讯作者：
Panayiotopoulos, KP
中科院分区：
文献类型：
--
作者：
Kutílek, M;Jendele, L;Panayiotopoulos, KP
水的输送、溶解和非溶解化学物质的输送、气体的输送、植物的生根以及所有土壤生物群的条件都受到土壤孔隙系统和土壤孔隙大小分布的影响。我们分析了在0 ~ 300 kPa范围内短时间压缩对Entisols、Alfisols和Verfisols土壤孔隙系统的影响。该方法是基于对土壤保水曲线的评价。采用双模态土的对数正态孔径分布方程进行分析。得到的物性参数描述了土壤孔隙系统及其在压缩作用下的变化。两个孔径分布峰之间的最小压头h(A)代表了土壤孔隙系统结构域和基质域的边界。h(A)的取值范围从h(A) = - 136到h(A) = -585 cm。压力头对应于从r = 10.9到r = 2.5 μ m的等效孔隙半径。在所有测试的土壤中，由于施加压缩而导致的h(A)变化率并不相同。h(A)随压缩应力的增大，部分土壤类群的h(A)减小，部分土壤类群的h(A)略有增加。由此可见，对于所有的土壤和所有的压缩应力，不能将土壤孔隙类别之间的边界作为一个固定值。压缩应力的增大导致总孔隙度的减小，但结构孔隙度的减小更为明显。压缩对结构孔隙度的影响比在0.91 ~ 0.48之间。基质孔隙度的变化趋势在所有土壤中并不相同。随着压应力的增大，两种土壤的压应力随压应力的增大而略有减小。孔径分布特征也没有均匀变化。由于构造域中的压缩作用，孔隙尺寸分布曲线更平坦，分布范围更广。在矩阵域则相反。压缩作用下孔隙大小分布变化的一般规律并不适用于所有土壤类群。在团聚体稳定性较低的土壤中，这两个区域的变化都很大。在结构发育良好的土壤中，这种变化相对较小，与结构域的关系更大。对数正态模型并不是在所有情况下都适合于结构域的孔径分布。深入研究土壤微观形态有助于更好地描述土壤孔隙系统及其压缩过程中的内部变化。(c) 2005 Elsevier B.V.版权所有
Transport of water, of dissolved and non-dissolvedchemicals, of gas, the rooting of plants and the conditions for all soil biota are influenced by the soil porous system and by the soil pore size distribution. We have analyzed the change of the soil porous system due to the short time compression in ranges from 0 to 300 kPa in Entisols, Alfisols, and Verfisols. The procedure was based upon the evaluation of the soil water retention curves. The equation of log-normal pore size distribution in bi-modal soils was applied for the analysis. The obtained physical parameters describe the soil porous system and its change due to the compression. The minimum pressure head h(A) between two peaks of pore size distribution represents the boundary between the structural and matrix domains of the soil porous system. The value of h(A) was in broad ranges from h(A) = - 136 up to h(A) = -585 cm. Pressure head corresponds to equivalent pore radius from r = 10.9 to r = 2.5 mu m. The rate of change of h(A) due to the applied compression was not the same in all examined soils. h(A) decreased in some soil taxons and in other soils it slightly increased when the compression stress rose. It follows that the boundaries between the soil pore categories cannot be taken as a fixed value for all soils and for all compression stresses. The increase of the compression stress caused a decrease of the total porosity, but the decrease of the structural porosity was much more expressed. The ratio of the decrease of structural porosity due to compression was in ranges between 0.91 and 0.48. The change of the matrix porosity has not the same tendency in all soils. In majority of instances it was increasing, but in two soils it was slightly decreasing with the increase of compression stress. The characteristics of the pore size distribution did not change in a uniform way either. The pores size distribution curve is more flat and more broadly distributed due to compression in the structural domain. The tendency is opposite in the matrix domain. A generally valid rule on the change of the pore size distribution due to compression does not exist for all soil taxons. The change was great in both domains of soils with a low stability of aggregates. The change was relatively small in soils with a well-developed structure where it was more related to the structural domain. The log-normal model does not fit in all instances to pore size distribution in the structural domain. A profound study of the soil micromorphology may result in a better description of the soil porous system and its internal change during compression. (c) 2005 Elsevier B.V. All rights reserved.