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геофизическое оборудование

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Measuring Electrical Potentials with LandMapper ERM-02

Electrical geophysical methods are classified as methods measuring natural electrical potentials of the ground without introducing additional electrical field and methods utilizing artificial electrical or electromagnetic fields to measure soil electrical parameters. Method of self-potential (SP) measures the naturally existing electrical potentials in soils and “bio-potentials” in plant, which are important in agriculture. Despite growing popularity of electrical resistivity/conductivity methods in agriculture, method of self-potential is rarely used.

Seven-step approach for complete near-surface resistivity survey of farmland with LandMapper

Despite numerous EC-mapping case studies conducted in many countries, only a few studies have demonstrated a complex approach to electrical geophysical site survey. In most studies only one technique of EC-mapping, either EM, GPR or four-electrode method was employed. This is understandable since most commercially available EC/ER measuring equipment operate in limited range of resistivities and depths (1-2 manufacturer-set depths are typical).

Locations

Protvino, MOS
Russia
55° 44' 34.0548" N, 37° 36' 55.4436" E
United States
42° 52' 48.8676" N, 104° 45' 56.25" W

Table 2. Technical Specifications of LandMapper ERM-02

Table 2. Technical Specifications of LandMapper ERM-02

Range of measurements   ……………………………………….……..    ER= 0.1-1 106 Ohm m

Table 1. Compare LandMapper ERM-01 and ERM-02

Table 1.  Compare LandMapper ERM-01 and ERM-02

Feature

LandMapper ERM-01

LandMapper ERM-02

Electrical Resistivity, Ohm m

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).

Introducing LandMapper ERM-01

To address those applications Landviser, LLC has developed and commercialized first model of LandMapper ERM-01 in 2004, which was able to measure electrical resistivity with central-symmetric four-electrode probes of Shlumberger and Wenner configurations to the depth of five meters. Device became popular among agricultural researchers in USA and Europe, and was tested for fast mapping and monitoring of agricultural and horticultural lands (Pozdnyakova et al., 2004; Paillet et al., 2010; Duncan et al., 2008; Carrow and Duncan, 2004).

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.

Electrical Fields and Soil Properties (17th World Congress of Soil Science)

The most downloadable PDF publication on Landviser, LLC website is our proceedings paper on 2002 World Congress of Soil Science. So we decided to publish it on our site as our first interactive eBook. It a short synopsis of our research on application of electrical geophysical methods to study soil genesis and provides theoretical background to all applied case studies. To cite this presentation use:

Pozdnyakov, Anatoly, and Larisa Pozdnyakova. “Electrical Fields and Soil Properties.” In 17 World Congress of Soil Science, Symp. 53:Paper #1558. Bangcock, Tailand, 2002. http://www.landviser.net/webfm_send/1.
Registered users can download PDF of full text of proceedings paper from our website. Or browse online version below and leave your comments. You might also like to go to IUSS website to get PDFs of other publications on World Congress of Soil Science.

 Abstract

The electrical fields in the surface of soils appear as many different kinds. Methods of self- potential (SP), electrical profiling (EP), vertical electrical sounding (VES), and non-contact electromagnetic profiling (NEP) was used to measure the electrical properties of basic soil types, such as Spodosols, Alfisols, Histosols, Mollisols, and Aridisols (USA Soil Classification) of Russia in situ. The density of mobile electrical changes, reflected in measured electrical properties, was related to many soil physical and chemical properties. Soil chemical properties (humus content, base saturation, cation exchange capacity (CEC), soil mineral composition, and amount of soluble salts) are related to the total amount of charges in soils. Soil physical properties, such as water content and temperature, influence the mobility of electrical charges in soils. The electrical parameters were related with soil properties influencing the density of mobile electrical charges in soils by exponential relationships based on Boltzmann's distribution law of statistical thermodynamics (r=0.657-0.990). Generally, the electrical methods can be used for in situ soil mapping and monitoring when the studied property lone highly influences the distribution of mobile electrical charges in the soil. The electrical properties were used to improve soil characterization for soil morphology and genesis studies; to develop accurate soil maps for precise agriculture practices; and to evaluate soil pollution, disturbance, and physical properties for engineering, forensic, and environmental applications.

Locations

Bangcock 13° 45' 7.9992" N, 100° 29' 38.0004" E
59° 44' 53.8008" N, 41° 23' 47.3424" E

ЛандМэппер ERM-02 - недорогой портативный прибор широкого профиля

Landmapper - field EC meter with lab accuracy

Пожалейте свою спину - уменьшите количество отбираемых почвенных образцов! Меньше образцов - меньше времени и денег будет затрачено при последующем лабораторном анализе!.....

Don’t break your back collecting soil samples. Reduce amount of samples sent for laboratory analysis and save money. And still make detail soil map of your fields, which will be more accurate than conventional soil surveys. Impossible? Not at all with LandMapper ERM-02.
This device measures three important electrical properties of soil: electrical resistivity (ER), conductivity (EC), and potential (EP). Utilizing the most accurate four-electrode principle LandMapper measures ER or EC and helps delineate areas with contrasting soil properties within the fields quickly, non-destructively and cost-efficiently.

In a typical setting, a four-electrode probe is placed on the soil surface and an electrical resistivity or conductivity value is read from the digital display. Using the device prior to soil sampling you can significantly reduce the amount of samples required and precisely design a sampling plan based on the site spatial variability.
Bulk soil EC was correlated with salinity, texture, stone content, bulk density, total available nutrients, water holding capacity, and filtration rates. Guided by detailed soil EC map obtained with LandMapper, only minimal amount of soil samples is needed to invert EC map into correlated soil properties. Also, LandMapper can be used to measure EC in soil pastes, suspensions and solutions and quickly estimate total dissolved salts (TDS) in solid and liquid samples.

Разработка Метода Оценки Состояния Растений на Основе Определения Сопротивления в Системе Почва-Растение

измерение сопротивления древесины ЛандМэпперУДК 504.064: 631.413

РАЗРАБОТКА МЕТОДА ОЦЕНКИ СОСТОЯНИЯ РАСТЕНИЙ НА ОСНОВЕ ОПРЕДЕЛЕНИЯ СОПРОТИВЛЕНИЯ В СИСТЕМЕ ПОЧВА-РАСТЕНИЕ*

Н.В. Терехова1, Г.Н. Федотов1, А.И. Поздняков2

1Московский Государственный Университет леса

2Факультет Почвоведения МГУ им. М.В. Ломоносова, antpozd@bk.ru

При мониторинге молодых посадок в условиях города чрезвычайно важно правильно оценить состояние растений. В настоящее время, для определения состояния молодых посадок используют визуальный метод обследования. Однако,  данный метод позволяет обнаружить ухудшение состояния растений только после появления внешних признаков, которые зачастую начинают наблюдаться через несколько месяцев, а иногда и через несколько лет. Поэтому,  разработка метода оценки  ослабления деревьев на ранних стадиях их проявления, представляет собой весьма важную задачу.

Можно предположить, что при рассмотрении системы почва-растение, у растений, имеющих большую листовую поверхность, будет   более высокая транспирация и, следовательно, больше площадь активной корневой системы,  а  электрическое сопротивление меньше. Отсюда,  цель исследования состояла в разработке способа оценки  активноcти корневой системы растений,   на  основании  измерений электрического сопротивления между корневой системой растений и почвой.

Для измерения электрического сопротивления использовали 4-х электродный метод, суть которого заключается в пропускании слабого электрического тока между задающими электродами, размещенными, в нашем случае, один в растении, а другой в почве и фиксации разности потенциалов между измерительными электродами, расположенными между задающими электродами один в растении, а другой в почве.

При проведении измерения подобным образом величина сопротивления является суммой сопротивлений: растения, почвы и границы раздела почва-растение. Причем первые два сопротивления необходимо минимизировать, так как они вносят ошибку в определение величины сопротивления границы раздела почва-растение, характеризующей состояние растений. Предварительно проведенные эксперименты показали, что измерения лучше проводить на постоянном токе при разности потенциалов на задающих электродах в несколько вольт.

Поэтому в качестве измерительного прибора использовали «LANDMAPPER – 02», разработанный фирмой LANDVISER (США) с участием фирмы ASTRO GROUP (Россия). В этом случае влияние сопротивления предварительно увлажненной почвы и самого растения становится минимальным.

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