Biological Systems Engineering


Date of this Version



(Forney, 2016)


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Agricultural and Biological Systems Engineering, Under the Supervision of Professor Joe D. Luck. Lincoln, Nebraska: August, 2016

Copyright (c) 2016 Shane H. Forney


Pesticide application is an integral part of crop production and ground-based agricultural boom sprayers are used extensively to apply pesticides to the crop canopy or soil surface across millions of acres in the United States. Efficient application is necessary to minimize costs and limit adverse environmental impacts. Errors in flow rate and system pressure measurements may cause as-applied maps to incorrectly indicate application rates and could negatively affect downstream data processing or analysis. The goals of this study were to provide quantified measurements on the effects of nozzle setup errors on spray pattern uniformity and evaluate how laboratory patternator data would compare to measurements on a full spray boom. More specific objectives were to: 1) determine the effects from factors such as nozzle lateral angle, nozzle spacing, nozzle replacement and nozzle pitch angle on spray pattern distribution, 2) evaluate a simulation approach to predict the effects of single nozzle boom setup errors on full boom system pattern uniformity, and 3) assess full boom operational measurements (e.g., flow, pressure, and spray pattern) to assess sensitivity for predicting boom distribution errors. Laboratory and field-based tests were devised to quantify the impact of nozzle setup and operational errors on spray pattern uniformity, boom pressure, and nozzle flow rates. Results indicated that small variations in boom setup or nozzle operation (i.e., pressure or flow) can cause significant errors in spray nozzle distribution which may not be completely detectable by measuring spray pattern alone. Simulations using laboratory data from setup or operational errors reflected similar changes in spray pattern CV as full boom data with similar setup errors. These findings were significant in that it may be possible to model full boom spray distributions based on smaller laboratory-collected datasets. Finally, full boom system-based pressure and flow measurements were compared with similar values at the boom subsection level. Results indicated that localized issues with nozzles or boom subsections may not be readily detected with system-based measurements. Those relying on system-based readings (e.g., pressure or flow) should expect errors exceeding 10% compared to localized measurements across the spray boom.

Advisor: Joe D. Luck