EAGER SitS: A Multi-Sensor Probe Network for Continuous Monitoring of the Soil Health

Understanding the micro-organism community within soil is extremely important for managing the growth, health, and productivity of plants in managed and unmanaged fields. Existing sensors used to monitor the soil are not capable of measuring the micro-organism activity in a low-cost, continuous, and spatially dense manner. This project will address this issue by initiating collaborative, exploratory research between three academic institutions (Tennessee Tech University, SUNY at Buffalo, and the University of Tennessee Knoxville) on a network of multi-sensor probes that are placed across fields in multiple locations and wirelessly powered by a novel electromagnetic technology. The project will provide for continuous and uninterrupted monitoring of soil parameters at many places in the field that indicate soil microbial activity and how it changes over time. This research will produce new knowledge and engineering techniques that will enhance farmers' abilities to make better decisions about precision management of crops that could reduce amounts and costs of inputs and apply only what is needed by crops and soil to maintain soil health. This impact alone will reduce waste, improve crop yield, reduce environmental contamination, and ultimately generate greater economic income for the Nation and its farmers. <br/><br/>The objective of this project is to conduct research toward developing the next-generation of in situ, networked, multi-sensor measurement systems for continuously and uninterrupted monitoring of soil variables over wide outdoor expanses and time periods. Contemporary low-cost soil monitoring systems are discrete and are incapable of detecting soil chemical variables beyond pH. The first project goal, conducted by the State University of New York at Buffalo (SUNY at Buffalo), addresses this issue by developing a sensor system that analyzes the volatile organic compounds (VOC) produced by biological processes that characterize soil health. The sensor system utilizes an array of micro electro-mechanical system (MEMS) cantilevers as an extremely small and selective spectroscopic transducer for detecting trace gas concentrations in the mid-IR optical region. These chemically specific, extremely sensitive, and highly compact sensors will be integrated with conventional soil sensing systems that detect moisture, temperature, pH, and conductivity to create a multi-sensing probe. The second project goal, conducted by Tennessee Tech University (TTU), addresses the issue of powering the sensor probe's electronics by continuing research on a wireless power transmission technique capable of transferring energy from an electrical power source to a plurality of multi-sensing probes over wide outdoor areas. The aim is to provide the sensor systems with a stable, uninterruptable source of power to achieve a continuous sensor operation that does not require maintenance or is susceptible to interferences. The wireless transmission will be accomplished by the excitation of a non-radiating Transverse Magnetic (TM) propagation mode at radio frequencies that allow the soil/air interface to act as a waveguide. The TTU researchers will explore an original concept where a dual above/below ground excitation method is utilized in order to maximize the waveguide effect. The third project goal, conducted by the University of Tennessee Knoxville (UTK), is to analyze the data from the wirelessly powered, multi-sensor probe network in order to build predictive algorithms needed to characterize soil health and make critical growing decisions. Together, the research goals of this project will be transformative in broadening our understanding of soil health; leading to better environmental practices and enhanced agricultural production. Beyond soil health, the wireless power transmission research will achieve two very important scientific and engineering outcomes: (1) Demonstration of a completely new method of wireless electrical power transmission over a large area. Such an engineering achievement will not only have a transformative impact in soil science and agriculture, but in other fields including renewable energy, power distribution, national security, etc. (2) Advancement of our understanding of electromagnetic (EM) propagation physics by experimentally confirming the existence of the Zenneck Surface Wave over a natural earth surface.<br/><br/>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.