Comparing and contrasting the suitability of proximal soil sensors for peat characterization

Proximal soil sensors (PSS) are becoming increasingly popular to augment tedious soil sampling and laboratory analysis procedures as they become more affordable and easy to deploy. However, challenges remain in managing expectations of their suitability and limitations due to the lack of a framework, and more research is warranted. For degraded peatlands, a thorough assessment of their inventory, especially the carbon stocks, water table levels, and geological setting, is necessary to plan and initiate rewetting strategies as their restoration is crucial for slowing global warming. Here, we demonstrate a succinct overview of our experience and recommend best practices for characterizing different types of peatlands (bogs vs. fens) using on-the-go electromagnetic methods, specifically, electromagnetic induction (EMI), ground-penetrating radar (GPR), and gamma-ray spectroscopy (GR).<br/> Our results suggest that an EMI sensor proved superior in the three-dimensional characterization of fens, and GPR is promising for delineating the peat thickness in bogs. However, deploying these sensors in a peatland environment can be difficult due to the need for surveying with close contact with the ground. A GR sensor proved to be an excellent resource as it can easily be mobilized using an unmanned aerial vehicle and provided remarkable results for demarcating the spatial extent of the peatlands. All in all, the knowledge of the peatland type manifests itself to dictate the sensors’ success rate thereby holding decisive information for sensor choice. In general, we recommend performing PSS surveys following a hierarchal approach, i.e., conducting the GR surveys first, followed by EMI, and finally with a GPR. This is because EMI is also useful for assessing GPR land suitability.<br/>