Sensor system for water stress detection using in-plant transmitted signal amplitude evaluation

Environmental sustainability has become a significant topic, especially in recent years. Extreme natural phenomena and food insecurity related to the rising world population have highlighted the need for a new approach to agriculture. Smart Agriculture solutions may represent a viable answer to boost productivity, reduce emissions, and optimize human labor through the utilization of several new technologies and techniques in the climate-change scenario. From this perspective, the following paper proposes a sensor system capable of evaluating the plant’s health status based on stem electrical impedance from a local and global point of view. In particular, the receiving system is able to sense the global stem impedance, monitoring the amplitude of a signal transmitted inside the plant itself. The system injects a square wave into the plant, and thanks to the proposed sensor, it is possible to read a frequency proportional to the amplitude of this signal collected from another point of the stem. The developed system has been tested on a tobacco plant, showing correlations of 0.94 and -0.97, respectively, for the local sensor and global sensor with respect to the soil water potential.