Advances in Microwave Sensors for Non-Destructive Monitoring of Plant Water Status

This paper presents an innovative microwave sensor designed to detect plant water stress and preliminary results from a measurement campaign conducted on olive trees' branches are also reported. The sensor's design, characterized by a dual-layer structure, has been carried out to achieve a good sensitivity obtained through a Q factor optimization procedure. Moreover, this configuration leads to compactness, enabling its use on small branches. The experiment has been conducted on 42 olive plants randomly divided into two water treatments: T0(no-irrigation) and T100 (full-irrigation). In accordance with the theoretical expectations, the study shows an upshift in the sensor resonant frequency as the irrigation water decreased. The obtained experimental results encourage future research and represent a notable advancement towards the non-destructive evaluation of plant water status, thereby improving sustainable agricultural practices.