Vol. 27 Núm. 1 (2021): Primavera 2021
Revisiones bibliográficas

Geofísica para la prospección agrícola y forestal: guía para interpretar imágenes del subsuelo

xml xml
  • Ulises Rodríguez-Robles,
  • J. Tulio Arredondo Moreno
Ulises Rodríguez-Robles
Universidad de Guadalajara
Biografía
J. Tulio Arredondo Moreno
Instituto Potosino de Investigación Científica y Tecnológica
Biografía
DOI: https://doi.org/10.21829/myb.2021.2712172

Publicado 2021-07-09

Palabras clave

  • mapeo de raíces,
  • métodos no-invasivos,
  • radargramas,
  • sistemas semi-áridos,
  • técnicas geofísicas,
  • tomogramas
    • ...Más
    Menos
  • root mapping,
  • non-invasive methods,
  • radargrams,
  • semi-arid systems,
  • geophysical techniques,
  • tomograms
    • ...Más
    Menos

Derechos de autor 2021

Creative Commons License

Esta obra está bajo una licencia internacional Creative Commons Atribución-NoComercial-CompartirIgual 4.0.

Resumen

La aplicación de técnicas de detección geofísica para mapear el subsuelo de campos agrícolas y forestales se ha acelerado en los últimos años. La obtención de imágenes geofísicas proporciona una alternativa o complemento a los métodos tradicionales para recopilar variables subsuperficiales a lo largo del tiempo y el espacio. Donde anteriormente el estándar era el muestreo de suelos y el análisis de laboratorio para evaluar la condición de un suelo para diversos propósitos, las técnicas de detección in situ están demostrando ser una forma muy efectiva para evaluar la variación de las propiedades del suelo / subsuelo. Este trabajo es una revisión del estado del arte relacionada con las técnicas geofísicas más aplicadas en la detección de las características y propiedades del subsuelo que influyen en la productividad y el funcionamiento de los ecosistemas forestales y sistemas agrícolas. En esta revisión se destacan las oportunidades, aplicaciones y retos que presentan las imágenes geofísicas (radargramas y tomogramas) en los campos multidisciplinarios de las biogeociencias. Las dos técnicas de investigación geofísica son muy atractivas para la comunidad científica, pues permiten mapear con precisión el subsuelo, graficar enraizamiento y monitorear contenidos de agua, identificar movimiento de sales y agroquímicos. Los agrónomos, silvicultores y la comunidad científica, podrían beneficiarse de la adopción de estas tecnologías de imágenes escalables y mínimamente invasivas para explorar el subsuelo y avanzar en nuestra investigación colectiva.

xml xml

Citas

  1. Akpan, A. E., Ilori, A. O., & Essien, N. U. (2015). Geophysical investigation of Obot Ekpo Landslide site, Cross River State, Nigeria. Journal of African Earth Sciences, 109, 154-167. doi: 10.1016/j.jafrearsci.2015.05.015
  2. Allen, C. D., Breshears, D. D., & McDowell, N. G. (2015). On underestimation of global vulnerability to tree mortality and forest die-off from hotter drought in the Anthropocene, 6(8), 1-55. doi:10.1890/es15-00203.1
  3. Allred, B. (2013). A GPR Agricultural Drainage Pipe Detection Case Study: Effects of Antenna Orientation Relative to Drainage Pipe Directional Trend. Journal of Environmental & Engineering Geophysics, 18(1), 55-69. doi: 10.2113/JEEG18.1.55
  4. Allred, B. J., Fausey, N. R., Chen, C.-C., Peters, L., Youn, H.-S., & Daniels, J. F. (2004). GPR detection of drainage pipes in farmlands, (Vol. 1). Proceedings of the Tenth International Conference on Grounds Penetrating Radar, 2004, Delft, Netherlands, 2 May 2004. Washington, USA: IEEE Corporate Communications.
  5. Allred, B., Daniels, J. J., & Ehsani, M. R. (Eds.). (2008). General Considerations for Geophysical Methods Applied to Agriculture. Handbook of Agricultural Geophysics. 14 pp. Boca Ratón. USA: CRC Press. doi: 10.1201/9781420019353
  6. Allred, B. J., Freeland, R. S., J. Farahani, H. J., & Collins, M. E. (2010). Agricultural Geophysics: Past, Present, and Future. Conference Proceedings, 23rd EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems, April 2010, cp 175-00023: European Association of Geoscientists & Engineers. doi: 10.3997/2214-4609-pdb.175.SAGEEP023
  7. Amato, M., Bitella, G., Rossi, R., Gómez, J. A., Lovelli, S., & Gomes, J. J. F. (2009). Multi-electrode 3D resistivity imaging of alfalfa root zone. European Journal of Agronomy, 31(4), 213-222. doi: 10.1016/j.eja.2009.08.005
  8. Barone, P. M., & Di Maggio, R. M. (2019). Forensic geophysics: ground penetrating radar (GPR) techniques and missing persons investigations. Forensic Sciences Research, 4(4), 337-340. doi: 10.1080/20961790.2019.1675353
  9. Barton, C. V., & Montagu, K. D. (2004). Detection of tree roots and determination of root diameters by ground penetrating radar under optimal conditions. Tree Physiol, 24(12), 1323-1331. doi: 10.1093/treephys/24.12.1323
  10. Bitella, G., Rossi, R., Loperte, A., Satriani, A., Lapenna, V., Perniola, M., & Amato, M. (2015). Geophysical Techniques for Plant, Soil, and Root Research Related to Sustainability. En A. Vastola (Ed.), The Sustainability of Agro-Food and Natural Resource Systems in the Mediterranean Basin (pp. 353-372). Cham: Springer International Publishing. doi: 10.1007/978-3-319-16357-4_23
  11. Boenecke, E., Lueck, E., Ruehlmann, J., Gruendling, R., & Franko, U. (2018). Determining the within-field yield variability from seasonally changing soil conditions. Precision Agriculture, 19(4), 750-769. doi: 10.1007/s11119-017-9556-z
  12. Brantley, S. L., Eissenstat, D. M., Marshall, J. A., Godsey, S. E., Balogh-Brunstad, Z., Karwan, D. L., Papuga, S. A., Roering, J., Dawson, T. E., Evaristo, J., Chadwick, O., McDonnell, J., & Weathers, K. C. (2017). Reviews and syntheses: on the roles trees play in building and plumbing the critical zone. Biogeosciences, 14(22), 5115-5142. doi: 10.5194/bg-14-5115-2017
  13. Brassard, B. W., Chen, H. Y. H., & Bergeron, Y. (2009). Influence of Environmental Variability on Root Dynamics in Northern Forests. Critical Reviews in Plant Sciences, 28(3), 179-197. doi: 10.1080/07352680902776572
  14. Bruckshaw, J. McG. (1941). Geophysical Prospecting for Oil. Nature, 148(3745), 151-152. doi: 10.1038/148151a0
  15. Bruckshaw, J. M. (1948). The application of geophysics to geology. Proceedings of the Geologists' Association, 59(3), 113-130,IN1-IN13. doi: 10.1016/S0016-7878(48)80015-5
  16. Butnor, J. R., Doolittle, J. A., Kress, L., Cohen, S., & Johnsen, K. H. (2001). Use of ground-penetrating radar to study tree roots in the southeastern United States. Tree Physiology, 21(17), 1269-1278.
  17. Canadell, J., Jackson, R. B., Ehleringer, J. B., Mooney, H. A., Sala, O. E., & Schulze, E. D. (1996). Maximum rooting depth of vegetation types at the global scale. Oecologia, 108(4), 583-595. doi: 10.1007/bf00329030
  18. Cassiani, G., Boaga, J., Vanella, D., Perri, M. T., & Consoli, S. (2015). Monitoring and modelling of soil-plant interactions: the joint use of ERT, sap flow and eddy covariance data to characterize the volume of an orange tree root zone. Hydrology and Earth System Sciences, 19(5), 2213-2225. doi: 10.5194/hess-19-2213-2015
  19. Cermák, J., Nadezhdina, N., Trcala, M., & Simon, J. (2015). Open field-applicable instrumental methods for structural and functional assessment of whole trees and stands. Iforest-Biogeosciences and Forestry, 8(3), 226-278. doi: 10.3832/ifor1116-008
  20. Chow, T. L., & Rees, H. W. (1989). Identification of subsurface drain locations with ground-penetrating radar. Canadian Journal of Soil Science, 69(2), 223-234. doi: 10.4141/cjss89-023
  21. Cimpoiasu, M. O., Kuras, O., Pridmore, T., & Mooney, S. J. (2020). Potential of geoelectrical methods to monitor root zone processes and structure: A review. Geoderma, 365. doi: 10.1016/j.geoderma.2020.114232
  22. Collins, M. E., Doolittle, J. A., & Rourke, R. V. (1989). Mapping Depth to Bedrock on a Glaciated Landscape with Ground-Penetrating Radar. Soil Science society of America Journal, 53(6), 1806-1812. doi: 10.2136/sssaj1989.03615995005300060032x
  23. Consoli, S., Stagno, F., Vanella, D., Boaga, J., Cassiani, G., & Roccuzzo, G. (2017). Partial root-zone drying irrigation in orange orchards: Effects on water use and crop production characteristics. European Journal of Agronomy, 82(A), 190-202. doi: 10.1016/j.eja.2016.11.001
  24. Corwin, D. L., & Lesch, S. M. (2005). Apparent soil electrical conductivity measurements in agriculture. Computers and Electronics in Agriculture, 46(1-3), 11-43. doi: 10.1016/j.compag.2004.10.005
  25. Corwin, D. L., & Scudiero, E. (2019). Review of soil salinity assessment for agriculture across multiple scales using proximal and/or remote sensors. En D. L. Sparks (Ed.), Advances in Agronomy, Vol 158 (pp. 1-130). Incluir ciudad, país: editorial.
  26. Cui, X., Chen, J., Shen, J., Cao, X., Chen, X., & Zhu, X. (2011). Modeling tree root diameter and biomass by ground-penetrating radar. Science China Earth Sciences, 54(5), 711-719. doi: 10.1007/s11430-010-4103-z
  27. David, T. S., Pinto, C. A., Nadezhdina, N., Kurz-Besson, C., Henriques, M. O., Quilhó, T., Cermak, J., Chaves, M. M., Pereira. J. S., & David, J. S. (2013). Root functioning, tree water use and hydraulic redistribution in Quercus suber trees: A modeling approach based on root sap flow. Forest Ecology and Management, 307, 136-146. doi: 10.1016/j.foreco.2013.07.012
  28. Dawson, T. E., Hahm, W. J., & Crutchfield-Peters, K. (2020). Digging deeper: what the critical zone perspective adds to the study of plant ecophysiology. 226(3), 666-671. doi: 10.1111/nph.16410
  29. Dezert, T., Fargier, Y., Palma Lopes, S., & Côte, P. (2019). Geophysical and geotechnical methods for fluvial levee investigation: A review. Engineering Geology, 260, 105206. doi: 10.1016/j.enggeo.2019.105206
  30. Diallo, M. C., Cheng, L. Z., Rosa, E., Gunther, C., & Chouteau, M. (2019). Integrated GPR and ERT data interpretation for bedrock identification at Cléricy, Québec, Canada. Engineering Geology, 248, 230-241. doi: 10.1016/j.enggeo.2018.09.011
  31. Dornbush, M. E., Isenhart, T. M., & Raich, J. W. (2002). Quantifying Fine-Root Decomposition: An Alternative to Buried Litterbags. Ecology, 83(11), 2985-2990. doi: 10.2307/3071834
  32. Edlefsen, N. E., & Anderson, A. B. C. (1941). The four-electrode resistance method for measuring soilmoisture content under field conditions. Soil Science, 51(5), 367-376.
  33. Estrada-Medina, H., Tuttle, W., Graham, R. C., Allen, M. F., & Jimenez-Osornio, J. J. (2010). Identification of Underground Karst Features using Ground-Penetrating Radar in Northern Yucatan, Mexico. Vadose Zone Journal, 9(3), 653-661. doi: 10.2136/vzj2009.0116
  34. Fernández-Cirelli, A., Arumí, J. L., Rivera, D., & Boochs, P. W. (2009). Environmental Effects of Irrigation in Arid and Semi-Arid Regions. J Chilean journal of agricultural research, 69, 27-40.
  35. Freeland, R. S., Yoder, R. E., & Ammons, J. T. (1998). Mapping shallow underground features that influence site-specific agricultural production. Journal of Applied Geophysics, 40(1-3), 19-27. doi: 10.1016/s0926-9851(98)00014-7
  36. Hagrey, S. A., al (2007). Geophysical imaging of root-zone, trunk, and moisture heterogeneity. Journal of Experimental Botany, 58(4), 839-854. doi:10.1093/jxb/erl237
  37. Halvorson, A. D., & Rhoades, J. D. (1974). Assessing Soil Salinity and Identifying Potential Saline-Seep Areas with Field Soil Resistance Measurements. 38(4), 576-581. doi: 10.2136/sssaj1974.03615995003800040018x
  38. Hirano, Y., Dannoura, M., Aono, K., Igarashi, T., Ishii, M., Yamase, K., Makita, N. & Kanazawa, Y. (2008). Limiting factors in the detection of tree roots using ground-penetrating radar. Plant and Soil, 319(1), 15. doi: 10.1007/s11104-008-9845-4
  39. Jayawickreme, D. H., Jobbagy, E. G., & Jackson, R. B. (2014). Geophysical subsurface imaging for ecological applications. New Phytologist, 201(4), 1170-1175. doi: 10.1111/nph.12619
  40. Jayawickreme, D. H., Santoni, C. S., Kim, J. H., Jobbagy, E. G., & Jackson, R. B. (2011). Changes in hydrology and salinity accompanying a century of agricultural conversion in Argentina. Ecological Applications, 21(7), 2367-2379. doi: 10.1890/10-2086.1
  41. Jones, C. M. (2018). The oil and gas industry must break the paradigm of the current exploration model. Journal of Petroleum Exploration and Production Technology, 8(1), 131-142. doi: 10.1007/s13202-017-0395-2
  42. Jones, G. M., Cassidy, N. J., Thomas, P. A., Plante, S., & Pringle, J. K. (2009). Imaging and monitoring tree-induced subsidence using electrical resistivity imaging. Near Surface Geophysics, 7(3), 191-206. doi: 10.3997/1873-0604.2009017
  43. Kelly, W. E., & Mares˘, S. (1993). Geophysical Surveys for Hydrogeological Purposes. En W. E. Kelly & S. Mares (Eds.), Developments in Water Science (Vol. 44, pp. 31-99). Lincoln, NE, USA: Elsevier.
  44. Khaldaoui, F., Djeddi, M., Zagh, A., & Naa, A. Use of near-surface geophysical methods for forensic investigations. In International Conference on Engineering Geophysics, Al Ain, United Arab Emirates, 9-12 October 2017 (pp. 216-219).
  45. Kirkham, D., & Taylor, G. S. (1949). Some Tests of a Four-Electrode Probe for Soil Moisture Measurement. Soil Science of America Journal, 14(C), 42-46. doi: 10.2136/sssaj1950.036159950014000C0010x
  46. Kravchenko, A., Bollero, G., Omonode, R. A., & Bullock, D. (2002). Quantitative Mapping of Soil Drainage Classes Using Topographical Data and Soil Electrical Conductivity. Soil Science Society of America Journal, 66(1), 235-243. doi: 10.2136/sssaj2002.0235
  47. Leucci, G., Margiotta, S., & Negri, S. (2004). Geophysical and geological investigations in a karstic environment (Salice Salentino, Lecce, Italy). Journal of Environmental and Engineering Geophysics, 9(1), 25-34. doi: 10.4133/jeeg9.1.25
  48. Liu, X. W., Dong, X. J., & Leskovar, D. I. (2016). Ground penetrating radar for underground sensing in agriculture: a review. International Agrophysics, 30(4), 533-543. doi: 10.1515/intag-2016-0010
  49. Lorenzo, H., Perez-Gracia, V., Novo, A., & Armesto, J. (2010). Forestry applications of ground-penetrating radar. Forest Systems, 19(1), 5-17. doi: 10.5424/fs/2010191-01163
  50. Lunt, I. A., Hubbard, S. S., & Rubin, Y. (2005). Soil moisture content estimation using ground-penetrating radar reflection data. Journal of Hydrology, 307(1-4), 254-269. doi: 10.1016/j.jhydrol.2004.10.014
  51. Mares, R., Barnard, H. R., Mao, D. Q., Revil, A., & Singha, K. (2016). Examining diel patterns of soil and xylem moisture using electrical resistivity imaging. Journal of Hydrology, 536, 327-338. doi: 10.1016/j.jhydrol.2016.03.003
  52. Michot, D., Benderitter, Y., Dorigny, A., Nicoullaud, B., King, D., & Tabbagh, A. (2003). Spatial and temporal monitoring of soil water content with an irrigated corn crop cover using surface electrical resistivity tomography. Water Resources Research, 39(5), 1-20. doi: 10.1029/2002wr001581
  53. Morari, F., Castrignano, A., & Pagliarin, C. (2009). Application of multivariate geostatistics in delineating management zones within a gravelly vineyard using geo-electrical sensors. Computers and Electronics in Agriculture, 68(1), 97-107. doi: 10.1016/j.compag.2009.05.003
  54. Nadezhdina, N., & Čermák, J. (2003). Instrumental methods for studies of structure and function of root systems of large trees. Journal of Experimental Botany, 54(387), 1511-1521. doi: 10.1093/jxb/erg154
  55. Nimah, M. N., & Hanks, R. J. (1973). Model for Estimating Soil Water, Plant, and Atmospheric Interrelations: I. Description and Sensitivity. Soil Science Society of America Journal, 37(4), 522-527. doi: 10.2136/sssaj1973.03615995003700040018x
  56. Pawlik, L., & Kasprzak, M. (2018). Regolith properties under trees and the biomechanical effects caused by tree root systems as recognized by electrical resistivity tomography (ERT). Geomorphology, 300, 1-12. doi: 10.1016/j.geomorph.2017.10.002
  57. Paz, C., Alcalá, F. J., Carvalho, J. M., & Ribeiro, L. (2017). Current uses of ground penetrating radar in groundwater-dependent ecosystems research. Science of the Total Environment, 595, 868-885. doi: 10.1016/j.scitotenv.2017.03.210
  58. Piccoli, I., Furlan, L., Lazzaro, B., & Morari, F. (2019). Examining conservation agriculture soil profiles: Outcomes from northeastern Italian silty soils combining indirect geophysical and direct assessment methods. European Journal of Soil Science, 71(6), 1064-1075. doi: 10.1111/ejss.12861
  59. Poot, P., Hopper, S. D., & van Diggelen, J. M. (2012). Exploring rock fissures: does a specialized root morphology explain endemism on granite outcrops? Annals of Botany, 110(2), 291-300. doi: 10.1093/aob/mcr322
  60. Poot, P., & Lambers, H. (2008). Shallow-soil endemics: adaptive advantages and constraints of a specialized root-system morphology. New Phytologist, 178(2), 371-381. doi: 10.1111/j.1469-8137.2007.02370.x
  61. Proust, D., Caillaud, J., Fontaine, C., Fialin, M., Courbe, C., & Dauger, N. (2011). Fissure and mineral weathering impacts on heavy metal distribution in sludge-amended soil. Plant and Soil, 346(1-2), 29-44. doi: 10.1007/s11104-011-0791-1
  62. Querejeta, J. I., Estrada-Medina, H., Allen, M. F., Jimenez-Osornio, J. J., & Ruenes, R. (2006). Utilization of bedrock water by Brosimum alicastrum trees growing on shallow soil atop limestone in a dry tropical climate. Plant and Soil, 287(1-2), 187-197. doi: 10.1007/s11104-006-9065-8
  63. Read, D. W. L., & Cameron, D. R. (1979). Relationship between salinity and Wenner resistivity for some dryland soils. Canadian Journal of Soil Science, 59(4), 381-385. doi: 10.4141/cjss79-043
  64. Reedy, R. C., & Scanlon, B. R. (2003). Soil Water Content Monitoring Using Electromagnetic Induction. Journal of Geotechnical and Geoenvironmental Engineering, 129(11), 1028-1039. doi: 10.1061/(ASCE)1090-0241(2003)129:11(1028)
  65. Rodríguez-Robles, U., Arredondo, J. T., Huber-Sannwald, E., & Vargas, R. (2015). Geoecohydrological mechanisms couple soil and leaf water dynamics and facilitate species coexistence in shallow soils of a tropical semiarid mixed forest. New Phytologist, 207(1), 59-69. doi: 10.1111/nph.13344
  66. Rodriguez-Robles, U., Arredondo, T., Huber-Sannwald, E., Ramos-Leal, J. A., & Yepez, E. A. (2017). Technical note: Application of geophysical tools for tree root studies in forest ecosystems in complex soils. Biogeosciences, 14(23), 5343-5357. doi: 10.5194/bg-14-5343-2017
  67. Rossi, R., Amato, M., Bitella, G., Bochicchio, R., Gomes, J. J. F., Lovelli, S., Martorella, P. & Favale, P. (2011). Electrical resistivity tomography as a non-destructive method for mapping root biomass in an orchard. European Journal of Soil Science, 62(2), 206-215. doi: 10.1111/j.1365-2389.2010.01329.x
  68. Sánchez-Higueredo, L. E., Ramos-Leal, J. A., Morán-Ramírez, J., Moreno-Casasola Barceló, P., Rodríguez-Robles, U., & Hernández Alarcón, M. E. (2020). Ecohydrogeochemical functioning of coastal freshwater herbaceous wetlands in the Protected Natural Area, Ciénaga del Fuerte (American tropics): Spatiotemporal behaviour. Ecohydrology, 13(2), e2173. doi: 10.1002/eco.2173
  69. Schroth, G., & Kolbe, D. (1994). A method of processing soil core samples for root studies by subsampling. Biology and Fertility of Soils, 18(1), 60-62. doi: 10.1007/BF00336446
  70. Schwinning, S. (2010). The ecohydrology of roots in rocks. Ecohydrology, 3(2), 238-245. doi: 10.1002/eco.134
  71. Schwinning, S. (2013). Do we need new rhizosphere models for rock-dominated landscapes? Plant and Soil, 362(1-2), 25-31. doi: 10.1007/s11104-012-1482-2
  72. Senos Matias, M., Marques da Silva, M., Ferreira, P., & Ramalho, E. (1994). A geophysical and hydrogeological study of aquifers contamination by a landfill. Journal of Applied Geophysics, 32(2), 155-162. doi: 10.1016/0926-9851(94)90017-5
  73. Soge, A., Popoola, O., & Adetoyinbo, A. (2018). Detection of decay and hollows in living almond trees (Terminalia catappa L. Roxb.) using electrical resistivity method. Journal of the Indian Academy of Wood Science, 15(2), 181-189. doi: 10.1007/s13196-018-0224-3
  74. Steeples, D. (2001). Engineering and environmental geophysics at the millennium. Geophysics, 66, 31-35. doi: 10.1190/1.1444910
  75. Tardieu, F. (1988). Analysis of the spatial variability of maize root density. Plant and Soil, 107(2), 267-272. doi: 10.1007/BF02370556
  76. Tennant, D. (1975). A Test of a Modified Line Intersect Method of Estimating Root Length. Journal of Ecology, 63(3), 995-1001. doi: 10.2307/2258617
  77. Tinker, P. B. (1976). Transport of Water to Plant Roots in Soil. Philosophical Transactions of the Royal Society of London-Series B, Biological Sciences, 273(927), 445-461.
  78. Tosti, F., Patriarca, C., Slob, E., Benedetto, A., & Lambot, S. (2013). Clay content evaluation in soils through GPR signal processing. Journal of Applied Geophysics, 97, 69-80. doi: 10.1016/j.jappgeo.2013.04.006
  79. Triantafilis, J., & Monteiro Santos, F. A. (2013). Electromagnetic conductivity imaging (EMCI) of soil using a DUALEM-421 and inversion modelling software (EM4Soil). Geoderma, 211-212, 28-38. doi: doi.org/10.1016/j.geoderma.2013.06.001
  80. Vanderborght, J., Huisman, J. A., van der Kruk, J., & Vereecken, H. (2013). Geophysical Methods for Field-Scale Imaging of Root Zone Properties and Processes. En S. H. Anderson & J. W. Hopmans (Eds.), Soil-Water-Root Processes: Advances in Tomography and Imaging (Vol. 61, pp. 247-282). Madison, WI, USA: Soil Science Society of America, Inc.
  81. von Hebel, C., Rudolph, S., Mester, A., Huisman, J. A., Kumbhar, P., Vereecken, H., & van der Kruk, J. (2014). Three-dimensional imaging of subsurface structural patterns using quantitative large-scale multiconfiguration electromagnetic induction data. Water Resources Research, 50(3), 2732-2748. doi: 10.1002/2013wr014864
  82. Walter, J., Luck, E., Heller, C., Bauriegel, A., & Zeitz, J. (2019). Relationship between electrical conductivity and water content of peat and gyttja: implications for electrical surveys of drained peatlands. Near Surface Geophysics, 17(2), 169-179. doi: 10.1002/nsg.12030
  83. Ward, S. H. (1987). Electrical Methods in Geophysical Prospecting. En C. G. Sammis & T. L. Henyey (Eds.), Methods in Experimental Physics (Vol. 24, pp. 265-375). Los Angeles, CA, USA: Academic Press.
  84. Welbank, P. J., & Williams, E. D. (1968). Root Growth of a Barley Crop Estimated by Sampling with Portable Powered Soil-Coring Equipment. Journal of Applied Ecology, 5(2), 477-481. doi: 10.2307/2401574
  85. Wu, K., Rodriguez, G. A., Zajc, M., Jacquemin, E., Clement, M., De Coster, A., & Lambot, S. (2019). A new drone-borne GPR for soil moisture mapping. Remote Sensing of Environment, 235, 111456. doi: 10.1016/j.rse.2019.111456
  86. Yoder, R. E., Freeland, R. S., Ammons, J. T., & Leonard, L. L. (2001). Mapping agricultural fields with GPR and EMI to identify offsite movement of agrochemicals. Journal of Applied Geophysics, 47(3-4), 251-259. doi: 10.1016/s0926-9851(01)00069-6
  87. Yuan, Z. Y., & Chen, H. Y. H. (2013). Effects of Disturbance on Fine Root Dynamics in the Boreal Forests of Northern Ontario, Canada. Ecosystems, 16(3), 467-477. doi: 10.2307/23501472
  88. Zenone, T., Morelli, G., Teobaldelli, M., Fischanger, F., Matteucci, M., Sordini, M., Armani, A., Ferre, C., Chiti, T. & Seufert, G. (2008). Preliminary use of ground-penetrating radar and electrical resistivity tomography to study tree roots in pine forests and poplar plantations. Functional Plant Biology, 35(9-10), 1047-1058. doi: 10.1071/fp08062