G

G. See Geometric factor (G) Galileo, 186, 194

Galvanic contact resistivity (GCR), 96-98, 295, 301

Galvanic contact systems, 99, 104

Gamma ray attenuation, 17, 24-25

Garmin WAAS products, 195-196

Gas chromatograph w/mass spectrophotometer, 242

GCR. See Galvanic contact resistivity (GCR)

GE HealthCare, 341

Generalized universal kriging models, 71 Geo-aligned data layers, 267 Geocarta SA, 98, 299 Geodetic surveys, 206

Geoelectric instruments, 295, 296-299, 299-301 Geographic coordinate system, 204 Geographic data, 201 Geographic information system (GIS) common coordinate systems, 204-206 components of, 199-200 computer software/systems, 200, 204, 207, 249 defined,386

farm equipment technology, 10-11 geo-aligned data layers, 267 geophysical data analysis, 9 and GPS, 166 introduction, 199 mapping concepts, 200-203 models and modeling, 207-208 nongeophysical spatial data, 207 sampling strategies, 35 spatial analysis, 249 spatial databases, 206-207 three-dimensional modeling of radar, 51 GeoLog, 296 Geometric factor (G), 93 Geometrics, Inc., 99 Geometry, 174-175 Geonics EM38, 19, 24, 217, 218, 222 Geonics Limited, Inc., 19, 120, 212, 235, 274, 296-298, 300

Geophones, 7, 160, 386 Geophysical data, 9, 13-14, 126-127 Geophysical measurement, 8, 9, 118-119, 124-126, 207 Geophysical methods and agriculture, 5, 199 data collection and analysis, 7 electromagnetic induction, 3, 4, 5, 13 and GPS, 195 gravity, 3

ground-penetrating radar, 3, 4, 5, 13 induced polarization, 3, 13 magnetometry, 3, 5 nuclear magnetic resonance, 3, 13 passive vs. active, 5 potential agricultural uses, 9-13 radioactivity, 3 resistivity, 3, 4, 5, 13 seismic, 3, 4, 5 self-potential, 3, 4, 5 Geophysical surveys depth of penetration, 120, 138 field procedures, 137-138 hydrological investigation, 5 interference effects, 120-121 and investigation depth of interest, 4-5

multisensor systems, 13 near-surface seismic reflection, 151 planning stages, 7 precision agriculture role, 11 station interval, 8 station spacing, 119-120 Geophysical Survey Systems, Inc., 343, 347, 348, 376 Geophysical techniques agricultural research techniques, 24 compilation of literature measuring ECa, 65 current status of, 28

EM method and equipment, 45, 113-118 future trends and needs, 34-36 geospatial measurement of EC, 59 GPR subsurface/near-surface use, 345-346 GPS mapping projects, 194, 195 hyperspectral imagery, 35 karst environments, 49 measurement of soil ECa, 62 resistivity method, 85 types of, 45

used in agricultural research, 17-18 Geophysics, 3, 4, 17, 386 Geo-referenced data, 35, 299 Geoscan's Geoplot, 149 Geosoft's Oasis Montaj, 149 Geospatial applications, 195 Geospatial ECa measurements, 28 Geospatially interpolated, 343 Geospatial measurements of ECa characterize within-field variability, 247 field measurements, 64 geophysical techniques, 59 geo-referenced yield data, 35 identify edaphic/anthropogenic properties, 34 impact of, 18 positive benefit, 32, 33 Geostatistical analysis, 13-14, 257-258 Geostatistical models, 71 Geostatistical software package, 258 Geotomo software, 299 Gf Instruments, 298 GGN. See Global GPS Network (GGN) Gilbert's discovery, 17

GIS. See Geographic information system (GIS) Global Differential GPS (IGDG), 183 Global GPS Network (GGN), 183 Global Positioning System (GPS) accuracy of, 191-192 agricultural geophysics, 166 antenna phase center location, 174 defined, 386 DGPS, 182-187

ECa-directed soil sampling, 28-29

ECa measured using EMI and, 211

Error Sources and Approximated Magnitudes, 173

farm equipment technology, 10-11

galvanic contact resistivity, 97

geographic information system, 166

geophysical methods, 195

geo-referenced measurements, 299

guidance devices, 13

how GPS works, 166-167

instrumentation, 192-194 integration with geophysical equipment, 9 intentional degradation of satellite signal, 175-176 interference and jamming, 175 introduction, 166

ionosphere and troposphere delays, 170-172 main components of, 167-168 mapping projects, 194-196 mode of sensor transport, 119 modernization/other satellite systems, 194 multipath, 172

network-based RTK GPS, 187-189

nongeophysical spatial data, 207

obtain positional data, 274

orbital errors, 172-173

point (absolute) positioning, 180

point vs. relative positioning, 180-182

positioning modes, 190

positioning with GPS, 179-180

precise point positioning, 189-190

processing strategies, 191

pseudorange/carrier phase observables, 176-179

real time vs. postprocessing, 190-191

receiver noise and biases, 173-174

receivers, 195-196

reference station error, 174

relative positioning, 180-182

relativistic propagation error, 172

sample-site scale analyses, 267

satellite and receiver clock errors, 172

satellites, 169

satellites and their geometry, 174-175 satellites location, 182 satellites signal data, 184 signal characteristics, 168-170 soil electrical conductivity, 166 spatial variation of yield, 248 spherical-projected GOS, 341 three-dimensional mapping of soil, 346 and underground drainage tile, 51 and Veris unit, 62-63, 282 Global Satellite Based Augmentation System (GSBAS),

182, 183 GLONASS, 186, 194 Golden Software, Inc., 151, 235 Golden Software's Surfer, 149, 151 Golf course green construction methods, 353-354 drainage system, 347, 349-350, 351 management, 345-346, 353-354 model, 289-290 studies, 50-51, 361 Golzow test site, 296, 298

GPR. See Ground-penetrating radar (GPR) methods

GPS. See Global Positioning System (GPS)

GP sentences, 186-187

Gradiometers, 6, 148

Granular fertilizer, 347-348

Gravimetric basis, 32

Gravimetric water content, 66

Gravitational field, 4

Gravity, 3

Gridded data, 122

Grid locations, 234-235, 236, 257, 347 Ground-coupled antenna, 337, 376 Ground-level measurements, 292-294 Ground-penetrating radar (GPR) methods active methods, 5 and agricultural applications, 47 agricultural drainage pipe, 373 agricultural research techniques, 17 agriculture products and management, 51 amplitude map, 370 antenna center frequency, 366 antenna frequency, 138-139 antennas, 135-137 antenna selection, 347 applications to study plants, 50 attenuation by soils with clay content, 151 cation exchange capacity, 47 compared to TDR, 26 computer-processing procedures, 361 data and analysis, 309-314 data processing, 340-343, 348 depth of penetration, 138 dielectric constant, 12 direct applications, 45-48 direct or indirect applications, 45 display processing, 142 drainage pipe mapping, surveys, 370 dye experiment, 330 electrical properties of soils, 18

electromagnetic radio energy (radar) pulse, 6, 354-355, 364

EM properties/hydrological parameters, 305-306

estimates and root biomass, 50

experimental setup, 325-326

field measurements, 319-321

field procedures, 137-138

filtering and amplification, 139

geophysical methods, 3, 4, 5, 13

golf course green issues, 356

golf course management, 345-346, 353-354

golf course studies, 50-51, 361

golf greens and, 350-351

golf greens selection, 346-347

GPR recording, 132-133

GPR surveys, 306-309

GPR technique, 324-325

indirect applications, 48-50

interpretation, 145

large physical sand tank, 326

lysimeter stand, 326

materials and methods, 354-356, 364-366, 376-378

maximum reflection amplitude, 330-332

measurements, 347-348, 355, 365

methodology, 318-319

near-surface water pathways, 337-338, 343

normalized maximum amplitude analysis (NMRA), 325

polarization, 133-134

propagation and scattering, 130-132

publications and work, 46

radargrams, migration of, 325

recording, 132-133

results and discussion, 343, 348-350, 356-361, 366-372, 378-381

sample volume, 319

saturated soil radargram characteristics, 338-339

scattering from surface roughness, 321

signal saturation correction filter, 365

site preparation prior to measurement, 347

soil mapping, 46

soil-plant systems, 35

soil surveying using, 45

soil volumetric water content, 12-13, 48, 305

soil water content, 323-324

soil water content changes, seasonal, 328-330

soil water content measurement, 317-318, 333-334

soil water content profiles, 327, 332-333

static corrections, 139

station and trace spacing, 138

subsurface drainage systems, 363-364

subsurface/near-surface use, 345-346

surface reflectivity method, 317, 322

survey protocol, 339-340

surveys, 306-309

system overview, 134-135

technology advances in, 26

temporal/spatial changes, 314

three-dimensional displays, 143-144

three-dimensional modeling of radar, 51-53

time-dependent geophysical technique, 129

time domain reflectometry, 26, 324-325, 365

time-slice amplitude maps, 9, 11

transmitter and receiver, 134-135

tree roots, 375-376, 381

two-dimensional displays, 142

uses of, 7

velocity, 134

velocity analysis and two-dimensional filtering, 139-142

water front propagation, 327-328 Ground surface trends, 5 Groundwater detection and GPR, 48 GSBAS. See Global Satellite Based Augmentation System

(GSBAS) Guidance devices, 13

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