Discriminating stratigraphic layers of cultivated organic soils using proximal sensors

Raphaël Deragon is a Ph.D. candidate at Université Laval (Canada), working under the supervision of Drs. Jean Caron and Budiman Minasny. His work focuses on detecting and mapping peaty, limnic and mineral layers found within the first metre of soil in drained and cultivated peatlands. To survey thousands of hectares more efficiently, the use of automated and proximal sensors has the potential to reduce manual sampling efforts and eliminate the need for laboratory measurements. Few studies have attempted to specifically detect limnic layers in an agricultural context, and even fewer have discussed appropriate sensors for detecting them. To gain a better understanding of the physical and chemical properties of the three soil materials, Raphaël characterized around 900 10 cm soil profiles from nine fields. He hypothesized that there were at least two discriminant properties that could be easily evaluated in situ with proximal sensors to classify each soil material. In his first field experiment, he found that soil volumetric water content, electrical conductivity, and penetration resistance exhibited statistically significant differences between the soil materials and with depth. With this new information, he selected a time-domain reflectometry probe and a soil penetrometer to replace manual sampling and intersected these measurements with those of commonly used proximal sensors, such as the EM38-MK2, Veris Q2800, and the MS-700 gamma-ray spectrometer. Data from this new experiment is currently being processed and results are expected soon. A detailed chemical characterization of limnic layers will be performed to assess the long-term use of degraded soils. This work will allow farmers to delineate priority management zones for applying soil conservation practices at the field-scaley.

Raphaël Deragon won the ISHS Young Minds Award for the best poster presentation at the I International Symposium on Growing Media, Compost Utilization and Substrate Analysis for Soilless Cultivation in Canada in June 2023.

Raphaël Deragon, Soil Science and Agrifood Engineering Department, Université Laval, G1V 0A6 Québec, Canada, e-mail: raphael.deragon.1@ulaval.ca

The article is available in Chronica Horticulturae