Calibrating soil-moisture probes for organic tundra horizons

Dielectric soil-moisture probes convert a material-dependent electrical response into a water-content estimate. This methods note synthesises organic-soil calibration experiments, freeze–thaw dielectric research, and uncertainty guidance to examine transfer from mineral to organic horizons. A fictional core calculation separates gravimetric and volumetric content and shows how drying shrinkage can alter the reference value before a sensor equation is fitted. The discussion considers calibration domains, independent validation, sensing support, saturation, installation, raw-output preservation, and the difference between liquid-water response and total water during freezing. It recommends no universal equation, drying procedure, or ecological threshold. The practical implication is to match calibration and phase-state interpretation to the intended inference, and to report a narrower relative signal when absolute water content remains insufficiently constrained.