Location: Aerial Application Technology Research
Project Number: 3091-30500-001-008-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 15, 2026
End Date: Jul 14, 2028
Objective:
The objective of this cooperative research project is to evaluate herbicide efficacy and yield response, under reduced carrier volume manned aerial applications, using droplet size classifications larger than Medium while maintaining constant active ingredient rates. This project will determine whether reduced carrier volume applications <2 GPA (gallons per acre) conducted under controlled research conditions can maintain herbicide performance comparable to applications made at standard labeled carrier volumes. The study will compare herbicide efficacy of reduced carrier volume manned aerial applications to standard carrier volume applications across platforms to determine potential differences in weed control outcomes. Spray deposition characteristics associated with each treatment will be quantified using fluorometric tracer analysis and water-sensitive paper assessments to characterize droplet deposition and coverage patterns associated with each application configuration. This research will further evaluate relationships among droplet size classification, carrier volume, deposition metrics, and observed herbicide efficacy in order to better understand how spray system configuration influences biological performance. Where agronomically appropriate, crop yield measurements will also be collected to determine whether reduced carrier volume applications influence final crop productivity. Results from this research will generate data suitable for peer-reviewed publication and will contribute to development of operational guidance regarding efficient aerial application practices and spray system configuration for effective herbicide delivery.
Approach:
Field experiments will be conducted at Purdue University research locations using replicated experimental designs appropriate for herbicide efficacy evaluation. Treatments will include reduced carrier volume manned aerial applications <2 GPA (gallons per acre) with active ingredient rate held constant, standard carrier volume applications conducted at labeled carrier volumes using standard application practices, and comparator treatments using other platforms (e.g., UAV and/or ground applications) conducted at labeled carrier volumes for contextual evaluation. Applications will be performed using standard industry practices appropriate to each platform and location. Spray system configuration will target droplet size classifications larger than Medium, likely within Coarse to Extremely Coarse categories depending on nozzle selection and operating pressure. USDA will provide deposition characterization support, including fluorometric tracer sampling and laboratory analysis, to quantify spray deposition as well as water-sensitive paper assessments to characterize droplet size and coverage metrics where appropriate. Deposition samplers will be placed within treatment plots to quantify spray distribution and support interpretation of biological outcomes. Herbicide efficacy will be assessed using established visual rating protocols at standard post-treatment intervals, with remote sensing–based vegetation indices used where appropriate to supplement visual assessments. Crop yield will be measured when agronomically feasible to determine whether reduced carrier volume treatments influence final production outcomes. Statistical analyses will evaluate differences in herbicide effectiveness among treatments and examine relationships between deposition metrics and biological response as well as yield outcomes relative to application strategy. The goal of this work is to determine if reduced carrier volume aerial applications can achieve herbicide effectiveness and crop productivity comparable to conventional carrier volume applications under controlled research conditions.