Lal R., Shukla M.K. Principles of Soil Physics
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Langmuir adsorption model, 485
Langmuir kinetic model, 487
Laplace equation, 370–372
Latitude, 524
Layered soil
calculating Darcy’s flux through, 374–375
calculating effective conductivity of, 376
calculating hydraulic and pressure heads in, 375–376
evaporation of water in, 447–448
saturated flow through, 372–376
water infiltration in, 420, 422
Leaching, 3
calculating amount of, 509
method for, 299–300
requirement for, 649–651
Least limiting water range, 294, 296–297
Least square fitting method, 503–504
Light-colored soil, albedo for, 524
Linear model, 191, 487
Liquid components, 15
Liquidity Index (LI), 239–240
Liquid ratio (σ
ρ
), 24, 25
Liquid water, 288
field moisture capacity (FC) of, 288–291
Lithosphere, 3
Log normal statistical distribution, 128
London forces, 98
Longitudinal dispersion, 472
Longitudinal strain, 192
Lower plastic limit, 238
in Casagrande test, 242
in Drop-Cone test, 242
indirect methods for measuring, 242–243
and subsoiling, 243
Lunch-time soils, 181
Lysimeters, 272–273, 274, 276
drainage, 283
for evaluating components of hydrologis cycle, 281
figures of, 278–280
under plastic shelter, 284
water-filled pillows beneath, 282
zero-tension, 508
Lysimetric analysis, 272–274, 276–281
Lysimetric measurements, 284
Macroaggregates
reduction of, 179
stabilization of, 114
Macrofauna, 224
Macropore flow, 632–637
Index 654
models of, 637
and soil management practices, 635–636
and solute transport, 636–637
and water infiltration, 636
and water-repellent soil, 654–655
Macropores. See Non-matrix pores
Macroscopic miller similarity, 658
Macroscopic mixing, 468
causes of, 479
Management of soil temperature, 457, 458
with drainage, 548–549
with irrigation, 548–549
with mulches, 545–546
with tillage methods, 546
Mariotte bottle technique, 428–429
Mass flow, 467
Mass transfer model, 487
Mass transport equation, 470–471
Mathematical signs and symbols, 668
Matric potential (Φ
m
), 325–329
measurement of, 333–337
and relative hydraulic conductivity, 383
using vapor pressure to compute, 346
Matric suction (Φ
m
), 380–382
Matrix pores, 151
Maxwell model, 191
Mean weight diameter (MWD), 126, 128
Measurements, common units for, 88–89
Mechanical analysis
dispersive agents needed to remove binding agents prior to, 38
forces in, 39
fractionation, 37–38
methods by sedimentation technique, 42
Mechanical puddling, 180
Melting, 535
Mercury intrusion method, 160
Mercury manometer tensiometers, 326–328
Mesic soils, 531
Mesopores, 155
Metabolism, 535
Metallic bonds, 59
Methane (CH
4
), 557, 567
Methanogenesis, 568
Microaggregates, 104, 105–107
formation of, 109
Microaggregate theory, 105–107
Microbial processes, 535
Micropores, 155
Microrelief, 171
Minerals, particle density of, 21
Index 655
Miscible displacement, 474
Mobile (σ
m
) water contents, 504
Modulus of rupture, 202–203
Modulus of shearing, 195
Mohr-Coulomb maximum shear strength, 200
Mohr theory, 198
Moldboard plow, 588
Molecular diffusion, 468
Mole drainage channels, 245
Monovalent cations, 64
Mounded seed beds, 460
Mulches, 453–456, 545–546
Mulching
benefit to soil water evaporation, 453–456
effect on soil temperature, 457, 458
techniques for, 221, 224
and water infiltration, 432–433
Multicolumn approach, 637
Multidivider tank, 276
Negative adsorption, 486
Nernst heat theorem, 522
net flux of, 540–541
Nernst’s potential, 61
Net radiation (R
N
), 533
Neumann’s boundary condition, 426
Neutron moisture meter, 313
Neutron moisture readings, 301–304
Neutron probe calibration, 612
Neutron thermalization, 301–304
Newtonian fluids, 266, 267
Newtonian model, 190
Newton’s first law, 534
Newton’s law of viscosity, 266, 357
Nielsen similarity analysis, 658
Nitrate reduction, 590
Nitrogen, 558
Nitrogen sorption, 160–161
Nonconservative solutes, 466
Nonequilibrium transport, 488–489
analytical solutions for equations of, 498
reduced to nondimensional equations, 496, 497
two-region model of, 489–491
two-site model of, 491–492
Nonisothermal evaporation, 452
Non-limiting water range (LLR), 294
Non-matrix pores, 151
describing by diameter size, 152
determining number of, 151
formation of, 155
Index 656
pore size distribution method for, 156
shape and continuity of, 154–155
Non-Newtonian fluids, 266–267
Nonpolar bonds, 57, 98
Non-SI units conversion factors, 678
Normal stress (τ), 192
relationship to tangential stress (τ), 198
No-till farming
with crop residue mulch, 461
effect on aggregation, 433
No-till treatment, 586, 588
nth order model, 487
Organic bonding agents, 111
Organic bond theory, 104
Organic components, 15
in soil, 77–80
soil properties and processes affected by, 84
Organic fraction, 83–86
Organic matter
classifications of, 78–79
correlation of aggregation with, 113–114
effect on available water capacity (AWC), 293
effect on plasticity, 241
and pF curve of soils, 343
relation with soil properties, 85
role in soil fertility management, 78
Organic soils
composition of, 26
particle density of, 20
Osmotic potential (Φ
o
), 330–331
Osmotic pressure, 264, 647–648
of solutions of sucrose in water, 685
Outlet condition, 494
Overburden potential (Φ
o
), 331
Oxidation, 558
Oxidation reactions, 535–536
Oxidation reduction process, 567–569
Oxidation-reduction potential, 569
Oxygen, 558–559
Oxygen deficiency
and plant growth, 564–565
and soil properties, 565–566
Oxygen diffusion rate (ODR), 564, 565
Oxygen diffusion rate, 577–578
Packing arrangements
composite form, 76
cubic form, 74, 75
Index 657
and grade of soil material, 77
open versus closed, 76
orthorhombic configuration, 75
orthorhombic form, 74
rhombohedral configuration, 75
rhombohedral form, 74
and soil porosity, 73, 75–76
Para plow, 431
Particle density (ρ
s
), 19–20
of inorganic versus organic compo- nents, 24, 25
range of, 25
of soil minerals, 21
Particle geometry, 48–50
Particle repulsion, 172
Particles
collision efficiency of, 63–64
compression of, 206
packing arrangement of, 73–77
rearrangement of, 172–173
shapes of, 41, 48
sizes of, 48
specific surface area of, 47–52
Particle shape
angularity of, 45
elements determining, 44–45, 47
figures of, 46
indices of, 89
roundness of, 47
sphericity of, 47
Particle size
importance of, 34
uniformity of, 44
Particle size analysis, 42
Particle size distribution
assessment of particle size fractions, 37–42
defined, 34
size fractions, 34–37
Particle size fractions, 37–42
Partition coefficient, 506
Passive pool, 78–79
Pedological approach, 94
Pedosphere, 3
Pedospheric processes, 11
Pedotransfer functions, 242–243
Penetration resistance, 215–217, 218
Penetrometers, 215–217
Peptization, 63
Percent clay aggregated, 128
Percent silt plus clay aggregated, 128
Pergelic soils, 530–531
Index 658
Permanent charge, 59
Permanent wilting point (PWP), 291–292
relation between clay and volumetric water content at, 292
Persistent binding agents, 113–114
pF curves, 242–243.
See also Soil moisture characteristics
Philip equation, 434
Philip’s model
compared to other methods, 421
for predicting water infiltration, 415–418
Photons, 531
Photosynthesis, 563
Physical crusts, 166
Physical edaphology
defined, 5
role in sustaining agricultural production, 6–9
Physical nonequilibrium model, 503
Piezometer tube, 324–325
Piezometric head, 324
Piston flow, 477
Planck’s law, 532
Plant available water capacity index, 132
Plant growth
and available water capacity (AWC), 293
critical limit of air-filled porosity for, 23
effects of organic fraction on, 85
importance of pores for, 155
influence of soil air on, 564
normal range of soil physical properties in relation to, 25
and soil structure, 94–95
Plant residues, 458
Plasticity, 195–196
defined, 236
dependence on clay content, 241
effect of organic matter on, 24
impact of soil tilth, 231
index for range of, 23, 240
influence of exchangeable cations on, 241
lower plastic limit, 238
methods for measurement of, 241–243
necessary conditions for, 236
theories that explain, 236–237
upper plastic limit, 238
Plasticity Index (PI), 239, 240, 241
Plastic Range, 239, 240, 241
Plate condensation, 65–66
Plate-shaped particles, specific surface area of, 50
Platinum resistance thermometer, 518, 519
Pneumatic potential (Φ
a
), 326
Poiseuille’s equation
Index 659
for calculating water flow, 357
for finding volumetric flow rate, 389
for relationship between pore radius and laminar flow, 366–367
Poiseuille’s law, 471–472
Poisson’s ratio (v), 194
vand tensile strength, 204
Polar bond, 57
Polymers, 121
Polyvalent cations, 64
POM nucleus model, 107–108
Ponding, 424
Pore geometry, 366–370
Pores
assessing size distribution of, 155–161
classification systems of, 152–154
connectivity of, 468
estimating permeability of, 368
functional characteristics of, 154
matrix, 151
non-matrix, 151
origin and formation of, 155
proportion of textural versus structural, 199
shape and continuity of, 154–155
size classifications for, 152–154
size distribution of, 151–154
tortuosity of, 467
Pore size distribution
field methods for, 156–157
fractal analyses of, 157
laboratory methods for, 157–161
mercury intrusion method for, 160
microscopic measurements for, 157
nitrogen sorption for, 160–161
water desorption method for, 158–160
Pore volumes, 476
Pore water velocity, 467, 501
calculating, 509
relation to dispersion coefficient, 481
Porosity (f
t
), 22
air-filled porosity (f
a
), 23
air ratio (a), 23
assessment of, 155–161
defined, 22, 149–150
expressing degree of soil compaction in, 205
of gravelly soil, 606–608
indices for measuring, 129
methods of expression of, 151–155
and packing arrangements of soil, 73, 75–76
pore size distribution, 156–161
range of, 25
Index 660
structural, 150
textural, 150
total porosity (f
t
), 22, 155
void ratio (e)
,
23, 155
Porous blocks, 300
Porous material sensors, 334
limitations of, 336–337
measurements of, 336, 337
Potential evaporation, 441–442
Power model, 487
Precipitation, measurement of, 272, 273, 275
Precipitation infiltration, 424–425
Preferential flow paths. See Macropore flow
Pressure potential (Φ
t
), 324–325
Proctor compaction test, 209–210, 242
Profile-controlled infiltration, 408
Pseudoplastic fluids, 266
Psychrometers
figure of, 336
limitations of, 334, 335
measurements of, 335
types of, 335
Puddlability (P), 179
Puddling, 179–181
Pulse application, 495–496
Push-in electrodes, 307
Quanta, 531
Quasi crystals, 105
Quasi-crystal theory, 104
Radiation, 531–533
emitted by the Sun, 532
net, 536–537
Radiation methods, 213–215
pros and cons of, 217
Radiation techniques
gamma ray attenuation, 304–305
measuring soil moisture content with, 300–305
neutron thermalization, 301–304
Rainfall, transmission of water after, 290
Rainfall simulators, 431
Rain gauge, 273
Reactive solutes, 466
Recalcitrant pool, 78–79
Redox potential, 569
Reduction reactions, 535–536
Red water, 255
Regression analysis, 657
Index 661
Relative diffusion coefficient, 573
Relative hydraulic conductivity (K
s
)
model for predicting, 397–399
Relative solute concentration, 474, 475
Remote sensing, 309–310
Remote sensing method, 313
Remote Sensing Thermometer, 519–520
Representative elementary volume (REV), 637
Repulsion, 477, 478
Resident concentration, 467–468
Residual pores, 152, 154
formation of, 155
Residual shrinkage, 247–248, 249
Resistance blocks, 336
Respiration, 563
Respiration rate (R
T
), 525–526
Respiratory coefficient, 566
Retardation factor (R), 500–501
Retention pores
formation of, 155
increasing, 180
Reversible potential, 61
Reversible process, 522
Reynolds number (N
Re
), 360
Rheology
defined, 189, 231
determining soil elasticity, 194
models of, 189–191
stress-strain relationship in, 192–193
Rheopectic fluids, 267
Richards’ equation, 386–389
for calculating decrease of moisture content with respect to time, 428
capacitance form of, 425
diffusivity form of, 425, 451
Rock fragment classifications, 604
Root channels, 221, 223
Root growth, 619–620
Roots, as binding agents, 111–112
Rothmund-Kornfeld ion exchange model, 487
Roundness, 47
Runoff, 272, 276–278
example for calculation of, 281
Russell’s theory of crumb formation, 100–101
St. Vincent model, 190
Saline soils, 644
Saline-alkali soils, 644
Salinity, 645–646
effects on water movement, 648–649
Index 662
Salinization, 644
Salt-affected soils, 644–651
Salt sieving, 356
Sand, 34–35, 36
Sandy soils, strength of, 200
Saturated flow.
See also Saturated hydraulic conductivity
calculating with Laplace equation, 370–372
importance of knowing, 355
through layered soil, 372–376
versus unsaturated flow, 381
Saturated hydraulic conductivity (K
s
), 358, 580
alternative system for determining, 363–364
calculating with Darcy’s law, 361–362
and constant head method, 362–363
defined, 361
ensuring saturation of soil for, 363–364
and errors in volumetric flow rate measurement, 364
estimating from pore geometry, 366–370
estimating with Kozeny-Carman equation, 368–369
and falling head method, 365–366
homogeneity and heterogeneity of, 372
and intrinsic permeability, 362
in layered soil, 372–376
schematic of apparatus for, 363
Saturated uncompressible soils, 371
Saturated vapor pressure, 268
Saturation deficit, 269
Scalding, 565
Scale factors, 658
Scaling methods in soil physics, 656–659
Second atmosphere, 557
Second law of thermodynamics, 522–523
Second-order irreversible model, 487
Sedimentation, 9, 38
Settling equation, 40, 41
Settling velocity, 41–42
Shearing stress, 192
elastic relation for, 195
Shear strain (γ), 193
Shear strength, 197, 243, 244
Shear stress (τ), 266
Shear tests
cylindrical, 202
direct, 201
triaxial, 201–202
Vane, 203
Shrinkage characteristic, 640
Shrinkage limit, 237–238
defined, 246
Index 663