Vertical Soil Profiling Using a Galvanic Contact Resistivity Scanning Approach

Abstract

Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep) soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument.

Soil Moisture Mapping Using Multi-Frequency and Multi-Coil Electromagnetic Induction Sensors on Managed Podzols

“…Khan et al [43] reported a low EC a , between 2.1 and 35.5 mS m −1 , on an orthic Humo-ferric podzol while Pan et al [59] indicated a low EC a between 1.36 and 3.29 mS m −1 in a sandy soil. Martini et al [60] also observed a low EC a , between 0 and 24 mS m −1 , with a very small range of spatial variation which was predominantly attributed to the low heterogeneity of soil texture (Sand = 6%-28%, Silt = 55%-79%, Clay = 13%-25%).…”

Electrical Conductivity Measurements in Agriculture: The Assessment of Soil Salinity

“…Besides, the newest Veris models (V2000XA, V3100, V3150) present two pairs of potential measurement electrodes instead of just one, which jointly enable a simple soil profiling of EC a with two depths. The coulter electrodes are also sold individually and therefore users can build their own craft ER sensor systems [47].…”

“…EC a measurements have been widely used to characterize soil salinity at field scale. Modern mobile ER measurement systems based on a four-point array along with the use of GPS allow to elaborate 3D maps of EC a in agricultural fields, giving rise to ER Imaging (ERI) in soil studies and agriculture [47,62]. Good contact between the electrodes and the soil is maybe the most important constraint to have reliable EC a measurements using ER.…”

Real-Time Electrical Resistivity Measurement and Mapping Platform of the Soils with an Autonomous Robot for Precision Farming Applications

“…Moreover, real-time soil resistivity measurement is important to map spatial farmland heterogeneity for precision farming applications. A useful approach for soil-property investigations is to use proximal soil measurements that combine soil sensors and data analysis methods to obtain high resolution soil data of the huge farmland [18]. Two portable systems are used to measure real time soil resistivity or conductivity of soil in agricultural studies-electrode-soil contact based system and noncontact electromagnetic induction (EM) system.…”