Dr. Larisa Golovko (President of Landviser, LLC) will be presenting "Geophysical Methods of Electrical Resistivity and Self-Potential in Agriculture" in first of 

Agricultural Geophysics Webinar Series: "Application of Geophysical Methods to Agriculture: Methods Employed"

A live webinar on the application of geophysics to agriculture will be offered on:

Tuesday, February 18, 2014, from 3pm - 4:30pm EST
(2:00 - 3:30 CST, 1:00 - 2:30 MST, 12:00 - 1:30 PST)

This first in a series of agricultural geophysics webinars will focus on the near-surface geophysical methods presently being used for agricultural purposes, which include resistivity, self-potential, electromagnetic induction, ground penetrating radar, dielectric sensors, VIS/NIR/MIR spectrometry, gamma ray spectrometry, mechanical soil compaction sensors, and ion selective potentiometry. Five presenters will provide a short overview of agricultural geophysical methods during the first 30 minutes of the webinar. The last hour of the webinar will be devoted to a panel discussion with the presenters, who will answer questions from the audience.

Location

1. Install Google Earth from http://earth.google.com . Open Google Earth and go to Tools\Options

Location

Guest post by Dr. Leonid Anisimov, Principal Scientist of Lukoil-Engineering, Volgograd, Russia. VolgogradNIPImorneft – scientific center of the LUKOIL Oil Company for the South Volga, Caspian Region and Middle East.

Shalow gas accumulations in shale deposits are unconventional energy resources. However those are hazardous objects for drilling especially in the offshore areas.
Seismic is a principal instrument to detect shallow gas pockets but electromagnetic methods may have advantage. The presentation below shows principal geography and techniques for detection and development of shale gas fields. A pilot project of Landviser LLC in using VES for monitoring accumulation and release of methan in peat bogs of Eastern Siberia is attached.

Locations

Example of electrodes arrangement and measurement sequence that can be used for a 2-D electrical imaging survey is shown on the left. Many different multi-electrode systems have been developed over the past 15 years using different arrangements of the cables and measurement strategies (Loke, 2011). This program is designed to invert large data sets (with about 200 to 100000 data points) collected with a system with a large number of electrodes (about 25 to 16000 electrodes). The survey is usually carried out with a system where the electrodes are arranged along a line with a constant spacing between adjacent electrodes. However, the program can also handle data sets with a non-uniform electrode spacing. RES2DINV program can be used for surveys using the Wenner, pole-pole, dipole-dipole, pole-dipole, Wenner-Schlumberger, gradient and equatorial dipole-dipole (rectangular) arrays. In addition to these common arrays, the program even supports non-conventional arrays with an almost unlimited number of possible electrode configurations (Loke et al. 2010). You can process pseudo sections with up to 16000 electrode positions and 70000 data points at a single time on a computer with 4 gigabytes (GB) of RAM. Besides normal surveys carried out with the electrodes on the ground surface, the program also supports aquatic and cross-borehole surveys.

Locations

The technique and procedure described here can be performed with LandMapper ERM-01 or ERM-02 (set in resistivity mode). The electrode spacings provided in this example are identical to Landviser's supplied "big manual VES" cable set made to measure 16 layers of topsoil down to approximately 9 m. The worksheet for pre-set electrode spacings in such cable re-calculating measured resistivities to 1D VES profile can be downloaded as Manual 1D VES workbook (MS Excel format).

Other electrode spacings are possible for custom-made cable arrays to reach deeper profiles. For example, we developed and tested with LandMapper a 60m-long cable, measuring down to ~ 20 m for one custom hydrology project. 

This manual VES technique is most convenient to use with three people. Follow step-by-step instructions below. If you need further help, do not hesitate to contact Landviser, LLC @ +1-609-412-0555 or info@landviser.com. Register on our site and download 7 related publications and software!

Locations

Zotero [zoh-TAIR-oh] is a free, easy-to-use tool to help you collect, organize, cite, and share your research sources. It lives right where you do your research — in the web browser itself. You can use it to quickly grab and re-use citation from our public library “Soil Electrical Geophysics”.

RES3DINV software -Create 3D models of subsurface resistivity or IP!
For Windows XP/Vista/7  (available for 32- and 64-bit PCs.)

3D surveys for pole-pole, pole-dipole, dipole-dipole, rectangular, trapezoid, Wenner, Wenner-Schlumberger,and non-conventional arrays.

Now available as a combined package together with RES2DINV, the 2D Resistivity & IP inversion program.
Supports exact and approximate least-squares optimisation methods
Supports smooth and sharp constrasts inversions
Supports up to 5041 electrodes and 67500 data points on computers with 1GB RAM
Supports trapezoidal survey grids
Supports parallel calculations on Pentium 4 (and compatible) based computers
Multi-core support with RES3DINVx32, 128GB memory support with RES3DINVx64

Task on hand: estimate salinity level on fields planned for rice next year. Six fields with total area of 322 acres were selected by farmer.

Equipment on hand: two LandMappers with different size probes attached (measuring electrical conductivity (EC) down to ~ 8” and 18”), Columbus GPS data-logger, all-road vehicle or “Mule”. Three people: farmer driving a '”mule” and recording data on paper, one person measuring with Landmapper at 18” depth, other person measuring EC with LandMapper to 8” depth and recording POI or way points with GPS. Results: 30 points recorded in less than 1.5 hour (including about 45 min break to wait out the rain). EC in the field varied from 5 mS/m to 106 mS/m on surface; and from 19 mS/m to 400 mS/m in deeper layer.

Location

Download DEMO 32-bit version of RES2DINV and RES3DINV from attached files below this post or download DEMO versions of RES2DINV and RES3DINV. Supplemental publications and other versions of software (legacy or 64-bit) are available for registered users from the respective folders (RES2DINV and RES3DINV) under SUPPORT/Downloads section of this website. You have to login before you can acces the Downloads repository (see more here)

Note, that you can use RES2DINV without RES3DINV, but not other way around - RES2DINV have to be installed first. This demo software has decreased functionality, but it might be enough for your research and the DEMO versions never expire.
However, if you decide to purchase software, please request a formal quote from us ASAP before contacting GEOTOMO directly, as we will meet or beat price of other dealers, but we cannot guarantee it unless you secure order from us first.