Soil Moisture Measurements Through a Seismic Wave-Based System: Experimental and Metrological Validation

Monitoring soil moisture is a major interest for several practical applications, and this task can be suitably performed through various methods. Although extensive literature deals with the adoptions of standard systems (many of which are commercially available), the state of the art is lacking in a rigorous validation of specific systems, such as those based on the seismic wave propagation (SWP) method. Such methods have attracted a growing interest thanks to the simultaneous combination of reliability, ease of use, low cost and, most importantly, customization possibility. In this regard, in this paper the Authors propose an experimental comparative approach for fully validating a SWP-based system through reference time domain reflectometry (TDR) measurements. To this purpose, reference TDR measurements are performed for different moisture levels, and the corresponding reference propagation velocities are compared with those directly measured through the SWP-based system. This approach provides a comprehensive assessment of the SWP-based method, from both an experimental and a metrological point of view. The ultimate goal is to provide an exhaustive performance characterization of the system, in view of practical implementation for soil moisture evaluation.