Spray patterns and perceptive canopy interaction assessment of commercial airblast sprayers used in Pacific Northwest perennial specialty crop production

Quantitative assessment and pertinent adjustments of airblast sprayers can help improve spraying efficiency, reduce off-target drift and negative environmental impacts. In such pursuit, a study was conducted to characterize liquid spray delivery of four commonly used airblast sprayers in the Pacific Northwest region of the United States. Powerblast (S1), Pakblast (S2), Turbomist 30P (S3), and Columbia Accutec (S4) sprayer units were evaluated using the Smart Spray Analytical System (SSAS) and a commercial vertical spray patternator (CVSP). The spray-canopy interaction was also quantified through spray penetration potential (SPP) and spray drift potential (SDP) estimates in the specific canopy zones perceptive to cherry, apple, and grapevine crops. Spray differences between two sides were non-significant (p > 0.05) for all selected sprayers. Spray symmetry and uniformity for all four units were in very high (76–100%) and high (51–75%) ranges. All evaluated sprayers showed higher spray delivery in the bottom-middle canopy zones (fruiting zones) of selected crops. The data suggests suitability of sprayers S1, S3, and S4 for spray applications in tall tree fruit canopies (e.g. apple and cherry, SPP: 82–100%, and SDP: 0–17%), but would need adjustments for short canopies (e.g. grapevines, SPP: 43–66% and SDP: 32–56%). Sprayer S2 would suit for applications in short canopies with minor adjustments (SPP: 66–87% and SDP: 12–32%). Spray differences could be attributed to pertinent air and spray delivery component designs. Measurement differences between two patternators could be attributed to liquid collection efficiencies of each patternator. Overall, such data driven sprayer characterization could aid in timely sprayer calibration and adjustments pertinent to crop canopy specific spray requirements.