Soil and Water

Preface

Introduction

Part I: Physical Principles


1. Basic Physical Properties of Soils

A. General

B. Soil as a Disperse Three-Phase System

C. Volume and Mass Relationships of Soil Constituents

D. Soil Texture

E. Mechanical Analysis

F. Behavior of Clay

G. Specific Surface and Adsorption Phenomena

H. Soil Structure

I. Summary


2. Physical Properties of Water

A. General

B. Molecular Structure

C. Change of State

D. Density and Compressibility

E. Vapor Pressure

F. Surface Tension

G. Curvature of Water Surfaces and Hydrostatic Pressure

H. Contact Angle of Water on Solid Surfaces

I. Capillarity

J. Adsorption of Water on Solid Surfaces

K. Osmotic Pressure

L. Solubility of Gases

M. Viscosity

N. Summary


3. The State of Water in the Soil

A. Energy State of Soil Water

B. Total Soil-Water Potential

C. Thermodynamic Basis of the Potential Concept

D. Gravitational Potential

E. Pressure Potential

F. Osmotic Potential

G. Quantitative Expression of Soil-Water Potential

H. Soil-Moisture Characteristic Curve

I. Hysteresis

J. Measurement of the Soil Water Content (Wetness)

K. Measurement of Soil Moisture Potential

L. Summary


4. Flow of Water in Saturated Soil

A. Laminar Flow in Narrow Tubes

B. Darcy's Law

C. Gravitational, Pressure, and Total Hydraulic Heads

D. Flow in a Vertical Column

E. Flow in a Composite Column

F. Flux, Flow Velocity, and Tortuosity

G. Hydraulic Conductivity, Permeability, and Fluidity

H. Limitations of Darcy's Law

I. Relation of Conductivity and Permeability to Pore Geometry

J. Homogeneity and Isotropy

K. Measurement of Hydraulic Conductivity of Saturated Soils

L. Equations of Saturated Flow

M. Summary


5. Flow of Water in Unsaturated Soil

A. General

B. Comparison of Unsaturated versus Saturated Flow

C. Relation of Conductivity to Suction and Wetness

D. General Equation of Unsaturated Flow

E. Diffusivity

F. The Boltzmann Solution

G. Measurement of Unsaturated Conductivity and Diffusivity

H. Vapor Movement

I. Water Transport Associated with Thermal Gradients

J. Movement of Solutes

K. Soil Aeration

L. Summary

Part II: The Field Water Cycle


6. Infiltration-Entry of Water into Soil

A. General

B. Description of the Process

C. Profile Moisture Distribution during Infiltration

D. Horizontal Infiltration

E. Vertical Infiltration

F. Green and Ampt's Approach

G. Infiltration into Layered Soils

H. Infiltration into Crust-Topped Soils

I. Rain Infiltration

J. Surface Runoff

K. Summary


7. Redistribution of Soil Moisture following Infiltration

A. General

B. Description of the Process

C. Hysteretic Phenomena in Redistribution

D. Analysis of Redistribution Processes

E. "Field Capacity"

F. Factors Affecting Redistribution and "Field Capacity"

G. Summary


8. Groundwater Drainage

A. General

B. Groundwater Flow Phenomena

C. Flow Equations

D. Analysis of Falling Water Table

E. Flow Nets, Models, and Analogs

F. Factors Influencing Drainage

G. Drainage Design Equations

H. Summary


9. Evaporation from Bare-Surface Soils

A. General

B. Physical Conditions

C. Capillary Rise from a Water Table

D. Steady Evaporation in the Presence of a Water Table

E. Hazard of Salinization due to High Water Table

F. Evaporation in the Absence of a Water Table (Drying)

G. Non-Isothermal Evaporation

H. Simultaneous Evaporation and Redistribution

I. Reduction of Water Loss from Drying Soils

J. Summary


10. Uptake of Soil Water by Plants

A. General

B. Classical Concepts of Soil-Water Availability to Plants

C. Newer Concepts of Availability

D. Soil-Plant-Atmosphere System as a Physical Continuum

E. Flow of Water to Plant Roots

F. Water Uptake by Root Systems

G. Interaction of Soil Wetness, Suction, and Transpiration Rate

H. Transpiration in Relation to Production

I. Summary


11. Water Balance and Energy Balance in the Field

A. General

B. Water Balance of the Root Zone

C. Evaluation of the Water Balance

D. Radiation Exchange in the Field

E. Total Energy Balance

F. Transport of Heat and Vapor to the Atmosphere

G. Advection

H. Potential Evapotranspiration (The Penman Equation)

I. Summary

Appendix 1. Numerical Solution of the Flow Equation

A. General

B. The General Equation of Flow

C. Finite-Differencing Concept

D. Finite-Difference Model of Steady, Saturated Flow

E. Finite-Difference Model of Unsteady, Unsaturated Flow

F. Summary

Appendix 2. Mathematical Outline of Variables-Separable (Boltzmann) Solution of the Flow Equation

Notes

References

Author Index

Subject Index