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Sign up for webinar "Application of Geophysical Methods to Agriculture: Methods Employed"

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

28° 8' 11.7564" N, 90° 50' 5.8596" W

AEMP-14 - Multi-frequency Electro-Magnetic Induction Sounding

Landviser, LLC is offering advanced equipment for multi-frequency electromagnetic sounding and profiling - AEMP-14 - manufactured by KB Electrometry Ltd in Novosibirsk, Russia.

Price of the system ordered through us is the same as listed on Nemfis.ru. Registered website users can view price of for the complete AEMP-14 system including field hand-held PDA, GPS, laptop with pre-loaded EM interpretation software and training videos in current catalog 

Please, request your personalized quotation from us: info@landviser.com or call 1-609-412-0555 / 1-888-306-LAND. The system is shipped worldwide from Russia, shipping costs will vary. See specification table at the bottom of this page on estimated weight of the system and components.

LandMapper ERM-02 – three parameter geophysical instrument

The newest model, LandMapper ERM-02, can automatically output EC or ER, accepts four-electrode probes of any configuration, including dipole-dipole and rectangular probes, reaches down to 10 m depth in most soils and stores up to 999 resistivity values in non-volatile memory. Also, ERM-02 model can be used to measure natural electrical potentials in soils, plants and other media with two non-polarizing electrodes (Figs. 2&3).

LandMapper ERM-02: handheld meter for near-surface electrical geophysical surveys

published in December, 2010 issue of FastTIMES, online peer-reviewed journal of EEGS. To cite this publication use:FastTIMES dec 2010 Agriculture: A budding field in Geophysics

Golovko, Larisa, Anatoly Pozdnyakov, and Antonina Pozdnyakova. “LandMapper ERM-02: Handheld Meter for Near-Surface Electrical Geophysical Surveys.” FastTIMES (EEGS) 15, no. 4 - Agriculture: A Budding Field in Geophysics (December 2010): 85–93. http://www.landviser.net/webfm_send/69

Abstract

On-the-go sensors, designed to measure soil electrical resistivity (ER) or electrical conductivity (EC) are vital for faster non-destructive soil mapping in precision agriculture, civil and environmental engineering, archaeology and other near-surface applications. Compared with electromagnetic methods and ground penetrating radar, methods of EC/ER measured with direct current and four-electrode probe have fewer limitations and were successfully applied on clayish and saline soils as well as on highly resistive sandy soils, such as Alfisols and Spodosols. However, commercially available contact devices, which utilize a four-electrode principle, are bulky, very expensive, and can be used only on fallow fields. Multi-electrode ER-imaging systems applied in deep geophysical explorations are heavy, cumbersome and their use is usually cost-prohibited in many near-surface applications, such as forestry, archaeology, environmental site assessment and cleanup, and in agricultural surveys on farms growing perennial horticultural crops, vegetables, or turf-grass. In such applications there is a need for accurate, portable, low-cost device to quickly check resistivity of the ground on-a-spot, especially on the sites non-accessible with heavy machinery.

Quick Estimation of Salinity in Field Soils and Irrigation Water with LandMapper ERM-02

ec mapping with Landmapper on dead rice field after hurracaine IkeSoil salinity is routinely evaluated in the labs from electrical conductivity of liquid soil saturation extract (ECe). The resulted total salinity is reported either directly in conductivity units (dS/m) or converted to TDS (total dissolved solids) concentration in ppm (parts per million) using formula: 1 dS/m = 1 mS/cm = 1 mmho/cm = 640 ppm = 640 mg/L= 0.64 g/L=0.064%

But now EC of soil and waters can be measured directly in the field using highly accurate method of four-electrode probe and Landmapper ERM-02 measuring device. Best of all, probes can be build to sense different soil layers down to 30 ft! Probes are simple and inexpensive to make from common materials available at any hardware store.

For irrigation water and soil solutions: To measure ECw just put 4-electrode probe of Landmapper used for mapping into a ditch, canal, or other water source. Make sure that all 4-electrodes are in contact with water. Take a reading in EC (conductivity) mode. Display will read (example):  
K0*C= 150m  - which indicates milli Siemens (mS/m)
To convert to dS/m, divide display number by 100, i.e. 150 mS/m=1.5 dS/m.

Vertical Electrical Sounding and Self-Potential Methods to Survey for Placement of Potable Water Wells

Science of Geophysics vs Art of DowsingWater is a precious commodity  in most urban and rural areas. Luck of local  potable  water sources threatens not only thriving but a mere survival of rural communities all over the world.  Establishing potable water wells requires a lot of fundings and resources and often cost prohibitive for local governments in South America and Africa.

Searching for shallow groundwater require knowledge of subsurface layers and locating intensity and directions of water fluxes, which can be accomplished with geophysical methods of vertical electrical sounding (VES) and self-potential (SP).  A method of VES can distinguish differences in electrical resistivity or conductivity at the multiple (10+) layers in soil profiles. These differences reveal the changes in soil texture and structure  between water-bearing and waterproof  layers,  which form a framework for  the subsurface water fluxes. 

The directions and intensities of the fluxes  can then be evaluated with the self-potential method. However, conventional equipment for VES and SP is very expensive, bulky and complicated to operate. We tested a simple low-cost handheld device, LandMapper ERM-02, to evaluate layers in the ground with VES method and results were well  correlated with drilled profiles in Central TX.  Information is provided for the VES array assembly, field measuring procedure and interpretation of sounding results. Previously, device was used in Astrakhan area, Russia for estimation of the groundwater table and salinity layers in the soil profiles. The method of self-potential was used to estimate subsurface water flux directions and intensities through the measured variation in electrical potential on the soil surface and direct potable wells placement in Kiev, Urkaine and Dmitrov, Russia.

Cite this presentation:SAGEEP 25 - 2012 - Tucson, AZ
 
Golovko, Larisa, Anatoly Pozdnyakov, and Terry Waller. “A Vertical Electrical Sounding and Self-Potential Methods to Survey for Placement of Potable Water Wells.” In Making Waves: Geophysical Innovations for a Thirsty World. Tucson  AZ: Environmental and Engineering Geophysical Society, 2012. http://www.landviser.net/webfm_send/89

Locations

Water For All International San Angelo, TX 31° 27' 49.5792" N, 100° 26' 13.3368" W
SAGEEP 2012 Tucson, AZ 32° 13' 18.2748" N, 110° 55' 35.3244" W
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