Electromagnetic conductivity metre technology is used to measure the apparent conductivity of the ground based on the strength of a secondary magnetic field induced in the ground from a primary field emitted by the instrument. The signal is influenced by soil properties including:
- Clay type; and
- Soil moisture.
This instrument provides an integrated measure of soil conductivity to a depth of 75cm in the horizontal mode and 1.5m in the vertical mode. It provides an efficient means to stratify variations in soil properties to allow targeted sampling.
Electromagnetic conductivity technology has traditionally been used in assessment of saline land, but more recent work has obtained good correlations between EM signal and productivity in cropping and horticulture (Parkes et al., 2015).
An Electromagnetic conductivity instrument may be carried by hand for assessment of small areas, or towed behind an ATV or similar vehicle for efficient assessment of large areas.
Verterra has made extensive use of Electromagneticsuveying over many years, including assessment of a 5000-ha property near Wandoan to stratify soil variation prior to soil sampling for irrigation development, and more recently, to map site variation in species-provenance field trials established to select species suitable for production of industrial biomass on saline soils in Tanzania.
Verterra's Electromagnetic Conductivity Surveying capacity is supported by our Dualem-1H Geophysical Surveying Instrument with sensor and controller.