Hybrid Agricultural Monitoring System with Detachable, Biodegradable, and Printed pH Sensors with a Recyclable Wireless Sensor Network for Sustainable Sensor Systems.

Sustainable food production is one of the key challenges that humanity must overcome to combat global malnutrition and meet the projected increase in the demand for food. Digital agriculture, with the application of sensors to monitor factors such as pH, humidity, and temperature, can improve the efficiency of crop production. However, the sustainability of these devices must be considered. In this work, we report the development of impedance-based pH sensors by using biodegradable materials. It is demonstrated that impedance is an effective way to measure differences in pH using a molybdenum disulfide-based sensor. These sensors can detect agriculturally relevant compounds, as demonstrated by ethephon in this paper, where the active compound's concentration alters the solution's pH. We also demonstrate how the molybdenum disulfide pH sensors can be used with our developed wireless sensor network, which can be used for field measurements, giving good agreement compared to impedance measurements using an electrochemical workstation. Life cycle assessment analysis shows that combining a recyclable wireless sensor network with replaceable and degradable sensors leads to a small environmental footprint. As such, this is a promising approach to digital agriculture, which can contribute to more sustainable food production while minimizing the level of electronic waste generation.