Diffusion Processes in Water Saturated Spherical Soil Aggregates

スポンサーリンク

概要

• 論文の詳細を見る

• The release curves of D_2O, K^+, and Cl^- from saturated spherical aggregates of four soils, presaturated with a 10 mol m^<-3> KCl and 10 kg m^<-3> D_2O mixed solution, to a 10 mol m^<-3> NH_4NO_3 solution were analyzed to examine the diffusion processes in soil aggregates. Aggregates were taken from the weathering crust of a mudstone (MDR), the AB horizon of a Brown Lowland soil (BLS), the B horizon of a Brown Andosol (ADO), and the C horizon of a Volcanogenous Regosol (PUM). The apparent diffusion coefficients of the solutes for each sample were obtained by fitting the spherical diffusion model to the release curves. Although the release rates of solutes from the 2-4 mm aggregates were higher than those from the 6-8 mm aggregates, almost the same diffusion coefficients (D) were obtained for both aggregate sizes. The values of the tortuosity factor (f) which was estimated as D/D_0 for D_2O (D_0 is the diffusion coefficient in free water) ranged from 0.25 to 0.51. Higher values were found in samples with a larger porosity. The D/D_0 values for K^+ in all the samples were one hundredth to half of the f values due to the cation adsorption effect. Equilibrium coefficients for K^+ adsorption calculated from the D/D_0 of K^+ and f agreed well with those obtained independently as a product of the bulk density of aggregates and the slope of K^+ desorption isotherms. The D/D_0 values for Cl^- in ADO and PUM derived from volcanogenous materials were lower than the f values owing to the anion adsorption effect. The equilibrium coefficients for anion adsorption were estimated at 0.65 for ADO and 0.17 for PUM. On the other hand, in MDR and BLS the D/D_0 values were higher than the f values, indicating the presence of the anion exclusion effect. Anion exclusional water volume was estimated at 16% for MDR and 17% for BLS. The values could be explained by the model which determines the anion exclusional water volume as the volume of pores with a radius smaller than the anion exclusional distance from the pore wall.

• 社団法人日本土壌肥料学会の論文

著者

• Hatano Ryusuke

  Faculty Of Agriculture Hokkaido University

• Sakuma Toshio

  Faculty Of Agriculture Hokkaido University

• Tomita Atsuko

  Faculty of Agriculture, Hokkaido University

• Tomita A

  Nagoya Univ. Nagoya

関連論文

• A Toposequence of Fine-Textured Soils in the Hilly Area of Northernmost Hokkaido : IV. Hydrolitic Reaction of Aluminum in the Presence of Oxalic or Citric Acid Ligands
• A Toposequence of Fine-Textured Soils in the Hilly Area of the Northernmost Part of Hokkaido : III. Importance of Chelating Low Molecular Organic Acids in the Migration Process of Aluminum and Iron
• A Toposequence of Fine-Textured Soils in the Hilly Area of the Northernmost Part of Hokkaido : II. Mineralogical and Micro-Analytical Studies
• A Toposequence of Fine-Textured Soils in the Hilly Area of the Northernmost Part of Hokkaido : I. Morphological and Physico-Chemical Properties
• EVAPOTRANSPIRATION IN CRACKED CLAY FIELD SOIL
• RELATIONSHIP BETWEEN THE DISTRIBUTION OF SOIL MACROPORES AND ROOT ELONGATION
• THE SOURCE-SINK EFFECT OF CLAYEY SOIL PEDS ON SOLUTE TRANSPORT
• Canopy Modification of Precipitation Chemistry in Deciduous and Coniferous Forests Affected by Acidic Deposition
• Effect of Nb Content on Martensitic Transformation Temperatures and Mechanical Properties of Ti-Ni-Nb Shape Memory Alloys for Pipe Joint Applications
• Effects of Pre-Strain and Heat Treatment Temperature on Phase Transformation Temperature and Shape Recovery Stress of Ti-Ni-Nb Shape Memory Alloys for Pipe Joint Applications
• HYSTERESIS IN THE PHOSPHORUS SORPTION AND DESORPTION PROCESSES OF SOILS
• 1-13 Use of resin capsule for in situ assessment of variability and availability of soil nutrients
• A Morphological Approach to Describe Solute Movement Influenced by Bypass Flow in a Structured Clay Soil
• Diffusion Processes in Water Saturated Spherical Soil Aggregates

もっと見る 閉じる

スポンサーリンク