Applied Soil Hydrology (Theory and Applications of Transport in Porous Media (32))

This state-of-the-art book clearly explains the basic principles of soil hydrology and the current knowledge in this field. It particularly highlights the estimation and application of measurements and evaluation of soil-hydrophysical characteristics using simulation models, with a focus on elucidating the basic hydrophysical characteristics of soil, such as soil water potential and hydraulic conductivity, as well as the methods of measurement. It also addresses topics such as stony soil, water repellent soils, and water movement modeling in those media. The book presents soil hydrology in a simple way, while quantitatively expressing the soil water state and movement. It clearly and precisely describes basic terms of soil hydrology with a minimum of mathematics. It also includes the latest research findings in the field as well as the basics of the mathematical modeling of water movement in the soil-plant-atmosphere system (SPAS), using original research results to illustrate these issues. This book is of interest to all scientists and professionals in soil hydrology, including beginners, as well as those interested and working in hydrology in general and soil hydrology in particular. In addition, it can also be used by specialists and students in related fields like agronomy, forestry, meteorology, hydrology, environmental engineering, environmental protection, and geography. Preface Acknowledgements Contents Symbols 1 Soil as a Part of the Soil–Plant–Atmosphere Continuum (SPAC) 1.1 Soil Hydrology 1.1.1 Conceptual Approaches in Soil Hydrology 1.2 Soil and Its Role in SPAC 1.3 Atmosphere 1.3.1 Water Vapour 1.3.2 Oxygen 1.3.3 Carbon Dioxide 1.4 Plant Canopy References 2 Basic Physical Characteristics of Soils 2.1 Porous Media, Capillary-Porous Media and Soil. Are There Differences? 2.2 Soil as a Three-Phase System 2.3 Pedogenesis 2.4 Soil Texture 2.4.1 Soil-Texture Analysis 2.5 Soil Type 2.6 Rock Fragments in Soil 2.7 Clay Minerals 2.8 Soil Structure 2.9 Chemical and Mineralogical Properties of Soil References 3 Physical Properties of Water 3.1 Soil Water and Soil Solution 3.2 Air in Water and Its Solubility 3.3 Water Density, Compressibility and Expansion 3.4 Water-Surface Tension 3.5 Viscosity of Water References 4 Soil-Water Interface Phenomena 4.1 Wetting of the Solid-Phase by Liquids 4.2 Capillarity 4.2.1 Soil as a Bundle of Capillary Tubes 4.2.2 Height of Capillary Rise 4.2.3 Decrease of Water-Vapour Pressure in Capillary Tubes Above the Menisci 4.2.4 Capillary Phenomena and Their Influence on Soil-Water Retention 4.3 Adsorption and Desorption of Water on Soil Surfaces References 5 Soil-Water Content and Its Measurement 5.1 Quantitative Expression of Soil-Water Content 5.2 Measurement of Soil-Water Content 5.2.1 Gravimetric Method for Measurement of Soil-Water Content 5.2.2 Soil-Moisture Probes 5.2.3 Neutron Method 5.2.4 Capacitance Method 5.2.5 Electrical Resistance Method 5.2.6 Time-Domain Reflectometry (TDR) Method 5.2.7 Frequency-Domain Reflectometry (FDR) Method 5.2.8 Geophysical Methods 5.2.9 Remote-Sensing Methods References 6 Soil-Water Potential and Its Measurement 6.1 Energy of Soil Water 6.2 Soil Water Potential of a Capillary Porous Medium (Soil) 6.3 Quantitative Expression of Soil-Water Potential 6.4 Components of the Total Soil-Water Potential 6.4.1 Gravitational Component of the Total Soil-Water Potential 6.4.2 Matric (Moisture) Potential of Soil Water 6.4.3 Pneumatic (Pressure) Soil-Water Potential 6.5 Total Soil-Water Potential 6.6 Measurement of Soil-Water Potential Components 6.6.1 Piezometer 6.6.2 Tensiometer References 7 Soil-Water Retention Curve 7.1 Definition of the Soil-Water Retention Curve 7.2 Hysteresis of Soil-Water Retention Curves 7.2.1 Main Branches of Soil-Water Retention Curves 7.3 Soil-Water Retention Curves and Their Analytical Expression 7.4 Hydrolimits 7.5 Measurement of Soil-Water Retention Curves 7.5.1 Tension Methods 7.5.2 Pressure Methods 7.5.3 Combined Method for SWRC Estimation 7.5.4 Psychrometric Method 7.5.5 Adsorption and Desorption Methods 7.6 Estimation of Soil-Water Retention Curves from Pressure-Chamber Data References 8 Soil-Water Movement in Water-Saturated Capillary Porous Media 8.1 Two Concepts of the Quantification of Soil-Water Movement in Saturated Capillary Porous Media (Soils) 8.1.1 Darcian (Macroscopic) Approach 8.1.2 Model Porous Medium 8.2 Darcy Equation 8.3 Macroscopic (Darcian) and Porous (Real) Water-Flow Rate 8.4 Distribution of Pressure During Water Flow Through Various Measuring Devices 8.4.1 Horizontal Soil Sample 8.4.2 Vertically Positioned Soil Sample, Downward Water Flow 8.4.3 Vertically Positioned Soil Sample, Water Flows Bottom-Up 8.5 Hydraulic Conductivity of Soil Saturated with Water Measured in the Laboratory 8.5.1 Simple Laboratory Method for Measurement of Saturated-Soil Hydraulic Conductivity 8.6 Hydraulic Conductivity and Properties of Soil 8.6.1 Darcian and Non-Darcian Flow 8.6.2 Air Entrapped in Soil Pores 8.6.3 Temperature and Saturated-Soil Hydraulic Conductivity 8.6.4 Flow of Water in Layered Saturated Porous Medium 8.7 Field Measurement of Saturated-Soil Hydraulic Conductivity Above Groundwater Table in the Field 8.7.1 Measurement of Saturated-Soil Hydraulic Conductivity in the Field Above Groundwater Table at Variable Hydraulic Gradient 8.7.2 Measurement of Saturated-Soil Hydraulic Conductivity in the Field Above Groundwater Table at Constant Hydraulic Gradient 8.8 Pedotransfer Functions References 9 Water in Unsaturated Soil 9.1 The Differences Between Water Movements in Saturated and Unsaturated Soils 9.2 Basic Equations of Water Movement in Unsaturated Soil 9.2.1 Darcy–Buckingham Equation 9.2.2 Equation Describing Water Movement in Unsaturated Soil: The Richards Equation 9.3 Basic Characteristics of Water Flow in an Unsaturated Soil 9.4 Measurement and Calculation of the Unsaturated-Soil Hydraulic Conductivity Function k(hw) 9.4.1 Measurement of Unsaturated Hydraulic Conductivity of Soils 9.4.2 Unsaturated Hydraulic Conductivity of Soil, Calculated by Analysis of Soil-Water Content and Soil-Water Matric Potential Profiles 9.4.3 Calculation of the Function k = f(hw) Using Soil-Water Retention Curve and Saturated-Soil Hydraulic Conductivity 9.5 Water Movement at Low Soil-Water Content and Diffusivity of Soil 9.6 Diffusion of Water Vapour in Soil References 10 Infiltration of Water into Soil 10.1 Infiltration into Homogeneous Soil 10.1.1 The Basic Characteristics of Infiltration 10.2 Infiltration into Soil from Rain or Sprinkling Irrigation 10.3 Ponding Infiltration 10.4 The Influence of Initial Soil-Water Content and Rain Rate on Infiltration 10.5 Infiltration and Entrapped Air 10.6 Soil-Water Content Profiles During Infiltration 10.7 Infiltration Calculation According to Green and Ampt 10.7.1 Horizontal Infiltration 10.7.2 Vertical Ponding Infiltration 10.7.3 Pressure Head at the Infiltration Front 10.7.4 Ponding-Time Calculation by the Green–Ampt Approach 10.8 Infiltration Curves Expressed by Empirical Equations 10.9 Analytical Expression of Unsteady Infiltration into Homogeneous Soil 10.10 Infiltration into Nonhomogeneous Soil 10.10.1 Infiltration into Layered-Soil Profiles References 11 Redistribution of Water in Homogeneous Soil 11.1 Basic Characteristics of Water Redistribution in Soil 11.2 Water Movement in Soil During Redistribution 11.3 Quantitative Analysis of the Redistribution Process References 12 Interaction of Groundwater and Soil Water 12.1 Types of Groundwater and Soil-Water Interactions 12.2 Water-Flow Direction Between Groundwater and an Unsaturated Zone of Soil 12.3 Uptake of Water to the Soil from Groundwater 12.4 Empirical Equations to Calculate Flow of Water from Groundwater to the Soil 12.5 Flow of Soil Water to Groundwater—Internal Drainage of Soil 12.6 Groundwater Drainage 12.6.1 Drainage-Design Equation Describing Steady Groundwater Flow to Drains 12.6.2 Drainage-Design Equation of Unsteady Water Flow to Drains 12.7 Drainable and Wettable Porosity 12.8 Risk of Soil Salinization by Groundwater and Surface Irrigation References 13 Evaporation 13.1 Transport of Water in the Soil–Plant–Atmosphere Continuum (SPAC) 13.2 Evaporation as a Physical Process 13.2.1 Water Evaporation 13.2.2 The Basic Characteristics of Water Evaporation 13.2.3 Evaporation from the Water Table and Bare Soil 13.3 Water Transport in Bare Soil During Evaporation 13.3.1 Calculation of Water Movement in Bare Soil During Evaporation 13.4 Transpiration 13.4.1 Soil-Water Movement During Transpiration 13.4.2 Soil-Water Uptake Patterns by Plant Roots 13.4.3 Distribution of Root-Extraction Patterns Evaluated from Field Measurements 13.5 Methods for Evapotranspiration Estimation 13.5.1 Method of Evapotranspiration Estimation from the Energy-Balance Equation of the Evaporating Surface 13.5.2 Evaporation Calculation from a Wet Surface: The Penman Equation 13.6 Calculation of Plant-Canopy Potential Evapotranspiration 13.6.1 Evapotranspiration Calculation: The Penman–Monteith Equation 13.7 Reference Evapotranspiration and Plant-Canopy Evapotranspiration (FAO Method) 13.7.1 Reference Evapotranspiration 13.7.2 Plant-Canopy Evapotranspiration 13.8 Calculation of Actual Evapotranspiration from Potential Evapotranspiration 13.9 Structure of Potential Evapotranspiration 13.10 Daily and Annual Courses of Evapotranspiration and Its Components 13.11 Evapotranspiration Estimation by the Eddy-Correlation Method 13.12 Calculation of Potential Evapotranspiration by Empirical Equations 13.12.1 Linacre Equation 13.12.2 Ivanov Equation 13.12.3 Tichomirov Equation 13.13 Evaporation from Various Evaporating Surfaces 13.13.1 Evaporation in Slovak Territory References 14 Transport of Solutes in Soils 14.1 Basic Processes of Solute Transport in Soils 14.2 Concentration of Dissolved Compounds in Solution 14.3 Transport of Dissolved Compounds in Soils 14.3.1 Convection 14.3.2 Diffusion 14.3.3 Hydrodynamic Dispersion 14.4 Equation of Soil-Solution Transport 14.5 Péclet Number and Identification of Transport Mechanisms of Dissolved Compounds 14.6 Outflow and Breakthrough Curves 14.6.1 Outflow Curves 14.6.2 Breakthrough Curves References 15 Water and Energy Balance in the Field and Soil-Water Regimen 15.1 Soil-Water Balance 15.2 Water and Energy Balance of the Land 15.3 Soil-Water Regimen 15.4 Soil-Water Regimen and Its Diagnostics 15.4.1 Soil-Water Regimen Classification 15.4.2 Hydrological Classification of the Soil-Water Regimen 15.5 Soil-Water Regimen Diagnostics and Biomass Production References 16 Swelling and Shrinking Soils 16.1 Cracks Porosity and Soil-Water Content 16.2 Specific Volume and Specific Surface of Soil Cracks 16.3 Formation and Kinetics of Soil Cracks 16.4 Soil Characteristics Influenced by Soil Swelling and Shrinking 16.5 Infiltration of Water into Soils with Cracks References 17 Stony Soils 17.1 Specific Features of Stony Soils 17.2 Stony Soils Classification 17.3 Stony Soils Occurrence 17.4 Representative Elementary Volume of Stony Soils 17.5 Sampling of Undisturbed Stony Soils 17.6 Physical Characteristics of Stony Soils 17.6.1 Stoniness of Stony Soils 17.6.2 Stony Soils’ Bulk Density 17.6.3 Stony Soils’ Porosity 17.7 Hydrophysical Characteristics of Stony Soils 17.7.1 Stony Soils’ Volumetric Water Content 17.7.2 Stony Soils’ Water Retention 17.7.3 Hydraulic Conductivity of Stony Soils 17.7.4 Effective Hydrophysical Characteristics of Stony Soils 17.7.5 Soil-Water Content of Stony Soils Measurement 17.8 Water Flow in Stony Soils 17.8.1 Modelling of Water Flow in Stony Soils 17.8.2 More Complex Modelling Approach to Water Flow in Stony Soils 17.8.3 An Example of Measured Characteristics of the Stony Soil and Estimation of Input Data for a Deterministic Simulation Model (a Case Study) References 18 Water Repellent Soils 18.1 Water Repellency of Soils and Its Identification 18.2 Characteristics of Soil-Water Repellency 18.2.1 Severity of Soil-Water Repellency 18.2.2 Persistence of Soil-Water Repellency 18.2.3 The Repellency Index 18.3 Water Repellent Compounds in Soils 18.4 Water Repellency and Soil-Water Characteristics 18.5 The Effects of Soil-Water Repellency on Soil-Water Movement References 19 Soil Air and Its Dynamics 19.1 Soil Aeration and Plant Respiration 19.2 Composition of Soil Air 19.3 Transport of Soil Air 19.3.1 Convective Flow of Soil Air 19.3.2 Diffusion of Soil Air 19.4 Movement of Oxygen from Soil to Plant Roots References 20 Soil Temperature and Heat Transport in Soils 20.1 Soil Temperature 20.1.1 Soil-Temperature Regimen 20.2 Soil-Heat Transport 20.2.1 Transport of Heat in Soil by Conduction 20.3 Soil-Heat Capacity 20.4 Thermal Diffusivity of Soil 20.5 Soil-Water Transport Under Non-isothermal Conditions 20.6 Temperature and Water Properties 20.6.1 Water Density and Temperature 20.6.2 Water Viscosity and Temperature 20.6.3 Surface Tension of Water and Temperature 20.7 Hydrophysical Characteristics of Soil and Temperature 20.7.1 Hydraulic Conductivity of Saturated Soil and Temperature 20.7.2 Soil-Water Retention Curves and Temperature 20.8 Soil-Water Movement Under Non-isothermal Conditions References 21 Modelling of Water Flow and Solute Transport in Soil 21.1 Modelling in Soil Hydrology 21.2 Governing Equations of Water and Solute Transport in Soil 21.3 Characteristics of the Soil-Plant-Atmosphere Continuum: Model Inputs 21.4 Main Model Outputs 21.5 Governing Equations and Their Solutions 21.5.1 Initial and Boundary Conditions 21.6 Water Flow Modelling in Heterogeneous Soils 21.6.1 Dual-Porosity Model 21.6.2 Dual-Permeability Model 21.7 Calibration, Verification and Validation of Soil-Water Flow Models 21.8 Overview of Some Soil-Water Flow Models 21.9 Current Trends and Future Challenges Concerning Water-Flow Modelling in the Unsaturated Soil Zone References Index