Real-time boom dynamics on sprayer efficacy due to boom-section or nozzle control

Many current spray controllers when coupled with GPS receivers provide automatic swath (boom-section or nozzle) control capabilities to minimize overlap and application in unwanted areas. This technology can improve application accuracy thereby reducing chemical usage and enhance environmental stewardship. However, sprayer system response from using this technology has not been investigated. Therefore, a study was conducted to develop a methodology to evaluate pressure variations on a typical agricultural sprayer equipped with a controller providing boom-section or nozzle control. To quantify boom dynamics during section/nozzle control, a testing protocol was established that included 12 simulation patterns under both compensation and noncompensation mode. Real-time pressures were recorded at 4 locations along the boom with data analyzed to quantify pressure variations and compute transition and lag times for observed pressure changes. Results indicated that pressure dynamic response was different for the boom-section and nozzle control scenarios. The boom scenario with compensation and non-compensation experienced an average pressure increase from 8.2% to 15.8% and 6.4% to15%, respectively depending on whether 1 or 2 boom sections were turned OFF. For nozzle control scenarios, the pressure increased during a simulated scenario was proportional to the number of nozzles turned OFF, a trend similar in the boom scenario. A pressure increase occurred for all tests with a maximum of 18% measured. Results indicated an increase in spray tip flow rate from 3.7% to 8.9% during the boom scenarios and 3.1% to 10.7% during nozzle scenario. Computed transition times for the boom- section scenarios were larger whereas the lag times were higher for the nozzle-control scenarios. A majority of the transition times were under 1 second. In conclusion, additional testing is needed to better understand the effect of automatic swath control on liquid applicators.