Agricultural Geophysics Outlook

New developments in the overall discipline of geophysics are ongoing, with innovative methods, equipment, and field procedures continuing to be introduced. The same is particularly true for agricultural geophysics. Many concepts being tested and initiated at present will eventually become commonplace for agricultural geophysics. In this regard, the following is a list summarizing the probable future trends (some previously mentioned) for agricultural geophysics.

1. New agricultural applications will continue to be discovered for the geophysical methods already used in agriculture (resistivity, electromagnetic induction, and GPR).

2. Geophysical methods not traditionally employed in the past for agricultural purposes will find significant use in the future. The geophysical methods likely to make inroads into agriculture include magnetometry, self-potential, and seismic. Agricultural opportunities for other geophysical methods, such as nuclear magnetic resonance, induced polarization, and seismoelectric, may also exist.

3. The incorporation of GPS receivers will become the norm, especially with regard to realtime kinematic (RTK) GPS, which will allow geophysical measurement positions to be determined with horizontal and vertical accuracies of a few centimeters or less. Guidance devices, video display tracking systems, or even simple on-the-go guesstimates of the spacing distance between transects, when used with an accurate GPS, can provide the capability of efficiently conducting geophysical surveys over large agricultural field areas without the need to mark out a well-defined grid at the ground surface. For some geophysical methods, the computer processing procedures used for horizontal mapping of measurements may require some modification for input of data collected along a set of transects with somewhat irregular orientations and spacing distances.

4. Geophysical surveying with more than one sensor will become a standard approach because of the variety of field information required to make correct agricultural management decisions. Multisensor systems based on a single geophysical technique have already been produced, and these systems are certainly beneficial to agriculture. Examples include GPR systems having more than one transmitter and receiver antenna pair (the individual transmitter and receiver antenna pairs can have the same frequency or different frequencies), or continuously pulled resistivity electrode arrangements containing more than one four-electrode array. However, multisensor systems based on more than one geophysical technique still need to be developed for agricultural purposes, something likely to happen in the near future. For reference, the physical properties responded to by the different geophysical methods are reviewed in Table 1.2.

5. Multiple geophysical data sets integrated and analyzed together along with other geospa-tial information can provide agricultural insight not available when analyzing each geophysical data set separately. Geostatistical analysis techniques can be especially useful in this regard. GISs are particularly well adapted for integration and geostatistical analysis of

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