(213e) Field Deployable Sensor Arrays with Molecular Selectivity for Soil Health

Monitoring of soil heath is of utmost importance in agriculture. Detecting the concentration of CO₂, CH₄, N₂O, and volatile organic compounds produced during the metabolomic activities of microbiota is an efficient way to monitor soil health. The use of vapor sensors based on microfabricated cantilever arrays is a promising platform for the development of miniature, field-deployable sensors. These array-based sensors are highly sensitive, small in size, capable of multi-analyte detection, and have low power consumption, making them ideal for high-performance sensing. However, challenges such as poor molecular selectivity, especially for trace amounts of small molecules, and lack of reproducibility, have hindered the translation of this sensor platform into practical reality. Conventional methods of achieving selectivity in chemical sensing rely on immobilized receptors or chemical interfaces on sensor surfaces. However, this approach results in poor selectivity for small molecule detection when using reversible receptors. In addition, non-uniformity in the graft density of the immobilized receptor results in unacceptable levels of irreproducibility. To overcome these challenges, we have used a multi-modal, multi-physics approach for generating orthogonal sensor responses. The use of deep learning techniques to analyze multi-modal data shows significant improvements in selectivity, sensitivity, and reliability of these sensors. To deploy these sensors for field-scale studies, we have developed a long-range through-the-soil (TTS) wireless power transfer method. Energy is wirelessly distributed through conduction currents that propagate outward along and through the soil from an adjacent solar panel array. We have demonstrated power transfer within a 0.25-ha (0.6acre) area using an average input power of 6W. The combination of highly sensitive vapor sensors with improved selectivity, multi-modal data analysis, and long-range wireless power transfer offers a promising solution for the efficient and effective monitoring of soil health in agriculture.