Пропустить навигацию.
Главная
Ученье - свет...

Геофизика

warning: Creating default object from empty value in /home/landv0/public_html/landviser.net/sites/all/modules/i18n/i18ntaxonomy/i18ntaxonomy.pages.inc on line 34.

Электрофизика почв и не только - лекция

Лопата иногда представляется неотъемлемым атрибутом практикующего почвоведа. Однако почвовед может выглядеть и по-другому.

В этом случае его инструментом становится электронный прибор и моток проводов. В своей лекции я постараюсь рассказать, какие возможности открывают перед почвоведом электрофизические методы, где-то дополняя уже ставшие классическими способы обследования почв, а где-то являющиеся и единственным методом, которым можно решить поставленные задачи.

References

Bedmar, A.P., and Araguás, L.A., 2002, Detection and prevention of leaks from dams: Taylor & Francis, Exton, PA.

Carrow, R.N., and Duncan, R.R., 2004, Soil salinity monitoring: present and future: Golf course management, no. November, p. 89-92.

Corwin, R., 1990, The self-potential method for environmental and engineering applications: Geotechnical and Environmental Geophysics, Soc. Expl. Geophysics, Tulsa, OK, p. 127-143.

Electrical potential differences in topsoil

Maps of electrical potentials in topsoil help to reveal the micro-environments for plant growth and correspond to plant biomass in natural ecosystems (Pozdnyakov, 2008).

Electrical potential differences between soil horizons

The natural electrical potentials (stationary and fluctuating) in soils were studied by our group for last 40 years and the results were summarized and presented on 17th World Congress of Soil Science (Pozdnyakov and Pozdnyakova, 2002). The largest electrical potential differences were observed between soil horizons drastically different in physical and chemical properties. In most soils topsoil has higher electrical potentials than subsoil.

Special instrumentation for soil SP method is needed

solid state Ag-AgCl electrodesLandMapper ERM-02, in addition to electrical conductivity and resistivity measurements also allows non-invasively measure natural electrical potentials in soils and plants when two special non-polarizing electrodes are connected to MN terminals (Figure 3).

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).

Ленты новостей