SITS: LOW-COST WIRELESS SMART NAIL SENSOR NETWORK FOR SOIL MICROBIAL ACTIVITY ASSESSMENT

The soil microbiome is the driving force that facilitates soil health and nutrient availability and uses efficiency in climate and conservation smart regenerative agricultural systems that seeks to maximize agronomic production and profit while minimizing environmental degradation. There is a critical need to develop in-situ sensor technology that aids farmers in real-time evaluating regenerative agriculture practices' impact on the soil microbiome and moisture reserves. Therefore, the overall goal for this project is to bridge the gap between agricultural microbiome science and material/electrical engineering by developing smart battery and electronic free nail-shaped sensors for large-area and in-situ remote soil health monitoring. The nail-shaped sensors consist of parallel plate electrodes covered with stimuli-responsive polymers that show a change in capacitance in response to the changes in soil moisture and microbial activity, which, in turn, modulates the resonant frequency information collected by the RF reader. The sensors will be inserted in the soil with an antenna panel resting above the ground and wirelessly interrogated via a portable RF reader placed onto agricultural machines (i.e., drone or tractor) to provide real-time and in situ assessment of soil conditions and accurately spread fertilizer or irrigation only where it is necessary. This will be achieved by fulfilling the following objectives: (1) Development of smart nails in a modular configuration combining an RF transmitting antenna panel with an attachable nail-shaped probe for wireless soil sensing. The wireless sensing platform will utilize backscattering RF sensing technology to communicate with the antenna panel and read information from the nail sensors inserted into the soil. (2) Develop and test functionalized smart nails for non-invasive and in-situ moisture and microbial activity assessment. The developed nail-shaped sensors will be functionalized with a polymeric coating that will enable soil moisture and microbial activity (e.g., cellulolytic activity). (3) Develop a low-power portable interrogation system. The RF interrogator will be composed of commercial-off-the-shelf components used for wireless reading of the smart nails and will be interfaced with an already established data collection and wireless transmission based on "long range" (LoRa) protocols. (4) In-field assessment of the smart nails under different regenerative agricultural management practices. The team will utilize the collected data from the sensors to assess the performance of commonly adopted regenerative agriculture practices and to improve landscape models of soil stocks, flows, and transformations that define soil health. The results will help provide the dynamic data that farmers need to sustain soil health under soil structural and health responses to changing climate.