Advancements in the Development of Resistive-Based Method Applied to Optical Tracers for Real-Time Estimation of Spray Drift Deposition

The assessment of pesticide deposition is of key importance for the prevention of off-target area contamination, as well as to ensure the efficiency of the pesticide application. It is required by regulatory authorities also to quantify the drift potential of every possible sprayer configuration. As a matter of fact, the standard methodologies to compare sprayers' functional performance require large amounts of time, and the results are not always repeatable, due to the multitude of uncontrollable variables. This study proposes and tests an innovative approach in a laboratory wind tunnel based on resistive-based measurements applied to fluorescent tracers to address this challenge effectively. Our method utilizes screen-printed electrodes integrated into the material collector for measurement of the deposited material in real time shortly after the spray application. The estimation of the material by the standard optical method was also done along with the resistive-based method and compared with the measured weight used as a benchmark reference. Our experimental results demonstrated that both the optical and the resistive-based methods overestimated the amount of deposited material compared to weight measurement, but the overall estimation error remained below <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{2.5} \,\text{g}$</tex-math></inline-formula>. The measurements also showed that 90% of material deposition occurred at approximately <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\text{11.5} \,\text{m}$</tex-math></inline-formula>, providing valuable insights into the spatial distribution of sprayed materials. This real-time assessment leveraging resistive measurement techniques offers substantial benefits for laboratory testing of spraying machines and has also the potential for in-field resource management and monitoring. Despite the promising potential for real-time estimation of spray drift deposition, further research and testing are required to improve the method.