Exploration of ISE Sensor Embedded in Garden Weed Block Fabric for Continuous Soil Nitrate Sensing

Wednesday, 4 October 2017
National Harbor 10 (Gaylord National Resort and Convention Center)
L. K. Burton, P. Manickam, and S. Bhansali (Florida International University)
The objective of this research was to explore novel sensing apparatus for quantifying spatial variation of leached nitrate in soil as well as serve as a method for site specific crop management. There is a need to develop sensors that can more accurately and successfully facilitate site specific soil management for monitoring nutrients and pollutants. The dominantly used sensing methods, both in field and in lab, can require lengthy time when analyzing samples and are costly. Therefore, the objective of this research was to develop a sensor on a water permeable weed barrier fabric used in garden bed soil to allow continuous monitoring of nitrate levels. An electrically conductive fabric material was prepared by applying conductive coatings onto the porous material. Nitrate doped polypyrrole (PPy(NO3-)) electrodes were used as sensing membranes and proved to have high selectivity towards nitrate ions. The electropolymerization protocols and thickness of the polymer layer were optimized (monomer concentration, deposition time, and scan rate) to synthesize the ion selective electrode (ISE) for nitrate determination. The ISE sensor provides a wide dynamic range from 0.008 mg/L to 849.9 mg/L for nitrate ions in real soil solution samples. Overall, the sensing apparatus proves to successfully detect nitrate ions in soil, sand, and solution.