Impact of uncertainty in soil texture parameters on estimation of soil moisture through radio waves transmission

Soil moisture is a key parameter which governs the soil water balance and affects hydrologic processes such as water infiltration and evapotranspiration. These processes are critical in several fields related to water resources including precision agriculture and drought management. As such, increasing attention is paid to field estimation of soil moisture. Indirect methods are generally preferred as they are non-destructive and measures can be detected almost continuously in time. Among indirect methods, here we focus on wireless underground communication networks (WUCNs) which is a promising technique based on the transmission of radio waves to a buried collector. From measurements of the electromagnetic loss, and based on either single path or two-path models, information on soil moisture can be retrieved. In this context, we perform global sensitivity analysis (GSA) to investigate how parametric uncertainty associated with soil texture, plagues soil moisture predictions. This is critical to identify which texture parameters require accurate estimation to narrow the uncertainty associated with predictions in practical applications. In particular, we study the influence of porosity and of sand and clay contents and found significantly different results for diverse soil types, thus suggesting the importance of a preliminary GSA to guide the design of measurement campaigns on field.