Using TDR and Inverse Modeling to Characterize Solute Transport in a Layered Agricultural Volcanic Soil

Volcanic soils exhibit particular physical-chemical properties (i.e., strong and stable natural aggregation and high content of variable-charge minerals) that may influence solute transport. To determine if such techniques like TDR and inverse modeling are useful for analyzing solute transport in volcanic soils, we studied the governing transport processes by means of a miscible displacement experiment of Br- in a large undisturbed soil monolith. Bromide resident concentrations at several depths were monitored successfully with TDR technology, while parameters for the convective - dispersive (CDE) and mobile immobile (MIM) transport models were estimated by inverse modeling. For the relatively high soil moisture conditions, typical of high frequency-irrigation systems that we considered, Br- was found to move slowly by convection - dispersion. Simulations with the CDE and MIM transport models yielded very similar results. Although Br- is generally assumed to behave as a tracer, we found that anion in our experiment was subject to adsorption at the bottom of the monolith. This may be explained by the variable-charge nature of the minerals Fe and Al oxihydroxides) present in this volcanic soil, which exhibited anion exchange when the pH of the soil solution decreased below the zero point of charge.

[1]  Willem Bouten,et al.  Assessing temporal variations in soil water composition with time domain reflectometry , 1995 .

[2]  Y. Mori,et al.  Soft X‐ray Radiography of Drainage Patterns of Structured Soils , 1999 .

[3]  A. Sommella,et al.  Effectiveness of equilibrium and physical non-equilibrium approaches for interpreting solute transport through undisturbed soil columns. , 2001, Journal of contaminant hydrology.

[4]  Marnik Vanclooster,et al.  Analytical solutions of non-linear flow and transport equations to test numerical models for simulating flow and transport in unsaturated soils , 2002 .

[5]  W. P. Miller,et al.  Ionic tracer movement through highly weathered sediments , 1995 .

[6]  Marnik Vanclooster,et al.  Analysis of alternative measurement strategies for the inverse optimization of the hydraulic properties of a volcanic soil , 2004 .

[7]  B. Clothier,et al.  Anion Transport Involving Competitive Adsorption during Transient Water Flow in an Andisol , 1996 .

[8]  N. E. Edlefsen,et al.  A SEDIMENTATION TUBE FOR ANALYZING WATER‐STABLE SOIL AGGREGATES , 1935 .

[9]  T. Miyamoto,et al.  Applicability of multiple length TDR probes to measure water distributions in an Andisol under different tillage systems in Japan , 2001 .

[10]  Arnold Neumaier,et al.  Global Optimization by Multilevel Coordinate Search , 1999, J. Glob. Optim..

[11]  M. Vanclooster,et al.  Scale- and rate-dependent solute transport within an unsaturated sandy monolith , 2003 .

[12]  A simple approach to determine reactive solute transport using time domain reflectometry. , 2000 .

[13]  Peter J. Shouse,et al.  The Effect of Ohmic Cable Losses on Time-Domain Reflectometry Measurements of Electrical Conductivity , 2003 .

[14]  D. R. Nielsen,et al.  Miscible Displacement and Leaching Phenomenon , 1967 .

[15]  H. Olphen.  An Introduction to Clay Colloid Chemistry , 1977 .

[16]  Stephen R. Green,et al.  Characterizing Water and Solute Movement by Time Domain Reflectometry and Disk Permeametry , 1996 .

[17]  J. Feyen,et al.  Analysis of steady state chloride transport through two heterogeneous field soils , 1998 .

[18]  Y. Mualem.  A New Model for Predicting the Hydraulic Conductivity , 1976 .

[19]  T. Miyamoto,et al.  Effects of Liquid-phase Electrical Conductivity, Water Content, and Surface Conductivity on Bulk Soil Electrical Conductivity1 , 1976 .

[20]  D. Taylor,et al.  Thermodynamics of Bromide Exchange on Ferrihydrite: Implications for Bromide Transport , 1998 .

[21]  M. Celia,et al.  A General Mass-Conservative Numerical Solution for the Unsaturated Flow Equation , 1990 .

[22]  S. Dasberg,et al.  Time Domain Reflectometry Measurements of Water Content and Electrical Conductivity of Layered Soil Columns , 1991 .

[23]  Diederik Jacques,et al.  Calibration of Richards' and convection–dispersion equations to field-scale water flow and solute transport under rainfall conditions , 2002 .

[24]  Solute movement through an allophanic soil. , 2003, Journal of environmental quality.

[25]  Marnik Vanclooster,et al.  Monitoring Solute Transport in a Multi-Layered Sandy Lysimeter using Time Domain Reflectometry , 1995 .

[26]  David R. Maidment,et al.  Handbook of Hydrology , 1993 .

[27]  Van Genuchten,et al.  A closed-form equation for predicting the hydraulic conductivity of unsaturated soils , 1980 .

[28]  Albert J. Valocchi,et al.  Validity of the local equilibrium assumption for modeling sorbing solute transport through homogeneous soils , 1985 .

[29]  J. Deckers,et al.  World Reference Base for Soil Resources , 1998 .

[30]  S. Jones,et al.  A Review of Advances in Dielectric and Electrical Conductivity Measurement in Soils Using Time Domain Reflectometry , 2003 .

[31]  M. V. Genuchten,et al.  Mass transfer studies in sorbing porous media. I. Analytical solutions , 1976 .

[32]  R. Muñoz‐Carpena,et al.  Nitrogen evolution and fate in a Canary Islands (Spain) sprinkler fertigated banana plot , 2002 .

[33]  John A. Nelder,et al.  A Simplex Method for Function Minimization , 1965, Comput. J..

[34]  J. Feyen,et al.  Solute Transport for Steady‐State and Transient Flow in Soils with and without Macropores , 2000 .

[35]  Dennis E. Rolston,et al.  Gas diffusivity in undisturbed volcanic ash soils: Test of soil water characteristic based prediction models , 2003 .

[36]  Marnik Vanclooster,et al.  A global multilevel coordinate search procedure for estimating the unsaturated soil hydraulic properties , 2002 .

[37]  R. Papendick,et al.  Macropore transport of bromide as influenced by soil structure differences , 2002 .

[38]  D. Mallants,et al.  Grid lysimeter study of steady state chloride transport in two Spodosol types using TDR and wick samplers. , 2001, Journal of contaminant hydrology.

[39]  R. Kachanoski,et al.  Laboratory Measurements of Solute Transport Using Time Domain Reflectometry , 1994 .

[40]  A. R. Socorro,et al.  Time domain reflectometry models as a tool to understand the dielectric response of volcanic soils , 2003 .

[41]  K. J. Hollenbeck,et al.  RETMCL: incorporating maximum-likelihood estimation principles in the RETC soil hydraulic parameter estimation code , 2000 .

[42]  Brent Clothier,et al.  A Dielectric–Water Content Relationship for Sandy Volcanic Soils in New Zealand , 1999 .

[43]  R. Muñoz‐Carpena,et al.  TDR estimation of electrical conductivity and saline solute concentration in a volcanic soil , 2005 .

[44]  Marnik Vanclooster,et al.  Using inverse methods for estimating soil hydraulic properties from field data as an alternative to direct methods , 2003 .

[45]  M. Vanclooster,et al.  Parameter uncertainty in the mobile-immobile solute transport model , 1997 .

[46]  M. Vanclooster,et al.  Estimating solute transport in undisturbed soil columns using time-domain reflectometry , 1994 .