Analysis of Plant Tissues Dielectric Response at Various Frequencies by Measuring Stem Capacitance

To optimize output and minimize waste, agricultural practices have incorporated sensing technologies capable of identifying initial indicators of plant stress. In this work, we investigate and propose a method to analyze plant tissue’s dielectric response at various frequencies by measuring stem capacitance. We hypothesize that frequencies over 1 MHz provide a more comprehensive understanding of plant health than fixed lower frequencies. To investigate this, we conducted experiments that involved inducing water stress in a Coleus specimen, using parallel plate aluminum electrodes, and using plastic film to both electrically insulate and secure the electrodes in place. Measurements were performed with a Nano Vector Network Analyzer (NanoVNA). Results show significant capacitance variability with frequency, presenting a noticeable capacitance dispersion through frequency, suggesting different factors influence measurements at varying frequencies. Thus, the findings presented in this paper highlight the importance of investigating monitoring frequencies and the potential of higher frequencies analysis to provide more insights into plant development.