Direct and indirect drift assessment means. Part 2: wind tunnel experiments

Area of Science:

• Agricultural Engineering
• Spray Technology
• Environmental Science

Background:

• Spray drift is a significant concern in agriculture, impacting efficacy and environmental safety.
• Standardized methods are needed to accurately assess spray drift potential and reduction technologies.

Purpose of the Study:

• To quantify spray drift potential reduction percentages (DPRP) for different spray nozzles under controlled wind tunnel conditions.
• To compare the effectiveness of three distinct calculation approaches for DPRP: DPRPv1, DPRPv2, and DPRP(H).

Main Methods:

• Utilized wind tunnel measurements at Silsoe Research Institute (SRI) to record airborne and fallout spray volumes.
• Tested ten different single, static spray nozzles, including standard flat fan, low-drift, and air inclusion types.
• Calculated DPRP values based on airborne spray profiles (first moment and surface area) and fallout deposit curves.

Main Results:

• Spray deposits decreased with distance from the nozzle for fallout and with increasing height for airborne particles.
• Air inclusion nozzles generally showed higher DPRP values than low-drift and standard flat fan nozzles.
• The influence of nozzle type on DPRP was more pronounced for smaller nozzle sizes; larger ISO nozzle sizes correlated with higher DPRP.

Conclusions:

• The choice of nozzle type significantly impacts spray drift reduction, with air inclusion designs being particularly effective.
• The interpretation of wind tunnel data requires careful consideration of the chosen sampling methodology and DPRP calculation approach.
• Results highlight the importance of nozzle selection and understanding measurement techniques for effective spray drift management.