Air-assisted velocity profiles and perceptive canopy interactions of commercial airblast sprayers used in Pacific Northwest perennial specialty crop production

Abstract

This study aimed at providing a data-driven understanding of air velocity profiles for four commercial airblast sprayers widely used in the Pacific Northwest (PNW) region of the United States. The Rear’s Powerblast (S1) and Pakblast (S2), Turbomist 30P (S3), and Columbia Accutec (S4) were evaluated using the Smart Spray Analytical System (Bahlol et al., 2020). Air velocity contour profiles and geometrical attributes (symmetry and uniformity) were characterized on two sides as well as at three horizontal distances from the outlet (0.6, 1.5, and 2.1 m) of each sprayer. The air velocity profiles were matched to vertical canopy zones of three typical perennial specialty crops (cherry, apple, and grapevine) to identify their suitability. Air velocity differences between the two sides were majorly significant (p<0.05) for selected sprayers with magnitudes higher on the right side for S1 and S4, and on the left side for S3, but insignificant (p>0.05) for S2. Air delivery pattern symmetry was very high for sprayers S1 (95±3%, mean ± standard deviation), S2 (82±6%), and S3 (83±3%) compared to S4 (64±14%), while uniformity was high for all sprayers (left: 51–72%, right: 59–73%). Profiles suggest that the current configuration of sprayer S2 would suit for applications on modified vertical shoot position grapevine or comparable short tree fruit canopies. On the other hand, sprayers S1, S3, and S4 would be better suited for spray applications in fruiting zones of taller canopies such as central leader apple and steep leader trained cherry crop. Overall, such air delivery evaluations would aid to determine required sprayer adjustments for efficient agrochemical applications on various perennial specialty crops and canopy architectures.