A year has passed since Eshel Bresler, my good friend and colleague, and a member of the editorial board of the Advanced Series in Agricultural Sciences, died suddenly while on a visit to the Chinese Academy of Sciences in Beijing. We had worked together for almost 30 years at the Institute of Soils and Water, ARO, The Volcani Center at Bet Dagan. At the very beginning of our scientific careers we cooperated directly and as a result one of our first publications was coauthored (Soil Sci. 101:205-209, 1966). Thereafter, our specific research interests diver­ sified, but we continued to work together, with similar approaches to research, and to strive towards the development of Israel soil science and its integration into general worldwide scientific progress. I don't need to emphasize Eshel's contribution to the understan­ ding of the processes governing water flow and solute transport pro­ cesses in soils and unsaturated zones. The contributions to this Volume by such a body of outstanding scientists shows the apprecia­ tion of the international scientific community to his research achievements.

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The Contributions of Eshel Bresler to Soil Science.- List of Publications.- I Stochastic Modeling of Flow and Transport in Unsaturated Soil at Field Scale.- 1 The Bresler-Dagan Model of Flow and Transport: Recent Theoretical Developments.- 1.1 Introduction.- 1.2 The Assumptions and the Main Results of the Original BD Model.- 1.3 The Effect of Local Dispersion.- 1.4 Unsteady Flow (Infiltration and Redistribution) and Transport.- 1.5 Transport of Reactive Solutes in Heterogeneous Fields.- 1.6 Sensitivity Analysis of Crop Yield in a Heterogeneous Field.- 1.7 Solute Flux in Heterogeneous Soils.- 1.8 Mass Arrival of Sorptive Solute into the Groundwater.- 1.9 Validity of One-Dimensional Approximation for Infiltration in Heterogeneous Soils.- References.- 2 Field-Scale Solute Flux Through Macroporous Soils.- 2.1 Introduction.- 2.2 Transport Model.- 2.3 Travel Time PDF.- 2.4 Illustration of Results.- 2.5 Discussion and Conclusions.- References.- 3 Towards Pore-Scale Analysis of Preferential Flow and Chemical Transport.- 3.1 Scales of Preferential Flow.- 3.2 Immobile Water.- 3.3 Old Water - New Water.- 3.4 Subsurface Transport Investigations at Oak Ridge, Tennessee.- 3.5 Pathlength-Supply Hypothesis.- 3.6 Percolation Theory.- 3.7 Percolation Modeling.- 3.7.1 Hydraulic Conductivity and Dispersion Coefficient.- 3.7.2 Mass Transfer Coefficient.- 3.8 Stochastic Methods (Latin Hypercube Sampling).- 3.9 Synopsis.- References.- 4 Analysis of Solute Transport in Partially Saturated Heterogeneous Soils.- 4.1 Introduction.- 4.2 Basic Concepts and Definitions.- 4.3 Modeling of Solute Transport in Heterogeneous Porous Media.- 4.3.1 Transport in Saturated Porous Media.- 4.3.2 Transport in Unsaturated Porous Media.- 4.3.2.1 Simplified Stochastic Approach.- 4.3.2.2 Simulation of Solute Transport.- 4.3.2.3 General Stochastic Approach.- 4.4 Summary and Conclusions.- References.- 5 Solute Lifetime Correlations in Chemical Transport Through Field Soils.- 5.1 Introduction.- 5.2 Fundamental Statistical Concepts.- 5.3 Perfect Correlations Among Solute Lifetimes.- 5.4 Less Than Perfect Correlations Among Solute Lifetimes.- 5.5 Concluding Remarks.- References.- II Solutions of Flow and Transport in Unsaturated Media by Deterministic Models.- 6 HYSWASOR - Simulation Model of Hysteretic Water and Solute Transport in the Root Zone.- 6.1 Introduction.- 6.2 Governing Equations.- 6.2.1 Water Transport.- 6.2.2 Closed Scanning Loop Hysteresis Algorithm.- 6.2.3 Solute Transport.- 6.2.4 Root Water Uptake.- 6.3 Input.- 6.3.1 General Data.- 6.3.2 Soil Parameters.- 6.3.3 Boundary Conditions.- 6.3.4 Initial Conditions.- 6.4 Output.- 6.4.1 Screen Output.- 6.5 Simulations.- 6.5.1 Daily Irrigation.- 6.5.2 Six-Day-Interval Irrigation.- 6.6 Concluding Remarks.- References.- 7 Unstable Flow: A Potentially Significant Mechanism of Water and Solute Transport to Groundwater.- 7.1 Nature of the Problem.- 7.2 Review of Unstable Flow.- 7.3 Instability Between Fluids Differing in Density or Viscosity.- 7.4 Instability During Infiltration into Unsaturated Soils.- 7.5 Preliminary Evidence from Field Experiments.- 7.6 Final Comment.- References.- 8 Capillary Barrier at the Interface of Two Layers.- 8.1 The Particular Physical Problem Considered.- 8.2 Conditions at the Interface.- 8.3 Basic Equations.- 8.3.1 Two-Phase Flow Background and Notations.- 8.3.2 Soil Characteristics Representation.- 8.3.2.1 Capillary Pressure.- 8.3.2.2 Relative Permeability.- 8.3.2.3 Effective Capillary Drive.- 8.3.3 Propagation Velocities of Fronts.- 8.3.4 Total Velocity Expression for Particular Problem.- 8.4 System of Equations to Be Solved.- 8.5 Solution.- 8.5.1 Procedure.- 8.5.2 Result of Integration.- 8.5.3 Numerical Procedures.- 8.5.3.1 Initialization.- 8.5.3.2 Repetitive Steps.- 8.6 Applications.- 8.6.1 Values of Parameters for Reference Run.- 8.6.2 Reference Run Results.- 8.6.3 Numerical Scheme Parameter Sensitivity.- 8.6.4 Influence of Effective Capillary Drive Magnitude.- 8.6.5 Influence of Supply Rate.- 8.7 Discussion.- 8.8 Conclusions.- References.- List of Symbols.- 9 Constant-Rainfall Infiltration on Hillslopes and Slope Crests.- 9.1 Introduction.- 9.2 Constant-Rainfall Slope-Crest Infiltration: Nonlinear Formulation.- 9.2.1 Flow Equation and Conditions.- 9.2.2 Time-to-Ponding: The Two Cases.- 9.2.2.1 Case 1: R? K1.- 9.2.2.2 Case 2: R > K1.- 9.2.3 Remark.- 9.3 Constant-Rainfall Slope-Crest Infiltration: Linearized Formulation.- 9.3.1 Flow Equation and Conditions.- 9.3.2 Dimensional Forms.- 9.3.3 Time-to-Ponding: The Two Cases.- 9.3.4 Remark.- 9.4 Long-Slope Constant-Rainfall Infiltration: - Nonlinear Formulation.- 9.4.1 Flow Equation and Conditions.- 9.4.2 Remark.- 9.5 Long-Slope Constant-Rainfall Infiltration: Linearized Formulation.- 9.5.1 Flow Equation and Conditions, Dimensionless Forms.- 9.5.2 Solution.- 9.6 Physical Implications of Long-Slope Solutions.- 9.6.1 Distribution of Potential and Moisture Content.- 9.6.2 Standard and Rotated Flow Components.- 9.6.2.1 Horizontal and Vertical Components.- 9.6.2.2 Horizontal Inslope Flow Velocity.- 9.6.2.3 Vertical Flow Velocity.- 9.6.2.4 Downslope and Normal Components.- 9.6.3 Integrated Horizontal and Downslope Components.- 9.6.3.1 Integrated Inslope Horizontal Flow.- 9.6.3.2 Integrated Downslope Flow.- 9.6.4 Time Dependence of Surface Flow Velocity Vector.- 9.6.5 Long-Slope Time-to-Ponding.- 9.7 Constant-Rainfall Slope-Crest Solution for ? = 45.- 9.8 Physical Implications of Slope-Crest Solution.- 9.8.1 Evolution of Moisture Content and Potential Distributions.- 9.8.2 The Time Course of Surface Moisture Content.- 9.8.3 Slope-Crest Time-to-Ponding.- 9.8.4 Criterion for Validity of Long-Slope Solution.- 9.8.5 Limits on Long-Slope Solution for Arbitrary ?.- 9.9 Concluding Discussion.- 9.9.1 Inslope Horizontal Flow.- 9.9.2 Downslope Flow.- 9.9.3 The Surface Flow Velocity Vector.- 9.9.3.1 Ponded Infiltration.- 9.9.3.2 Constant-Rainfall Infiltration.- 9.9.4 Comparing the Dynamics of Ponded and Constant-Rainfall Long-Slope Infiltration.- 9.9.5 The Slope-Crest Effect.- 9.9.6 The Downslope Propagation of Ponding from a Slope-Crest.- Appendix: Properties of G(X, Y).- References.- 10 The Transport of Sorbed Chemicals in Eroded Sediment.- 10.1 Introduction.- 10.1.1 Overview of Chemical Enrichment Mechanisms.- 10.2 Sediment Transport with Rainfall Impact the Dominant Erosive Agent.- 10.2.1 Deposition.- 10.2.2 Rainfall Detachment and Redetachment.- 10.2.3 Changes in Time of Sediment Settling-Velocity Distributions During Erosion in the Presence of a Water Layer.- 10.2.4 Sediment Detachment and Transport Under Rainfall with Small Water Depth on the Soil.- 10.3 Sorbed Chemical Enrichment with a Significant Water Depth.- 10.3.1 The Effect of Erosion Process and Surface Contact Cover on the Settling-Velocity Distribution of Eroded Sediment.- 10.3.2 The Effect of Erosion Pr…