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Title: Dynamic Air Velocity and Spray Deposition inside Dense Nursery Crops with a Multi-Jet Air Assist Sprayer

item Zhu, Heping
item Derksen, Richard
item Krause, Charles
item OZKAN, H - OSU
item Brazee, Ross
item Fox, Robert

Submitted to: ASABE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: 3/20/2006
Publication Date: 7/12/2006
Citation: Zhu, H., Derksen, R.C., Krause, C.R., Ozkan, H.E., Brazee, R.D., Fox, R.D., Losely, K. 2006. Dynamic Air Velocity and Spray Deposition inside Dense Nursery Crops with a Multi-Jet Air Assist Sprayer [abstract]. ASABE Annual International Meeting. Paper No. 061125.

Interpretive Summary:

Technical Abstract: Due to the large number of species in nursery production, commercially available sprayers have limited capacity for treating specific nursery species. An air-assist sprayer containing three five-port nozzles was developed and investigated to improve spray penetration into dense nursery canopies. Spray deposits at top, middle and bottom of canopies were quantified using a fluorescent tracer, and were compared at three nozzle heights in a commercial nursery field. Dynamic air velocities corresponding to the deposit sampling locations inside and outside the canopy were measured at the time when the sprayer passed over the canopies. The measured air jet velocity decreased from 40.1 to 19.4 m/s when the distance from the orifice increased from 0.33 to 0.79 m. The peak velocities at the top and middle elevations for both inside and outside the canopy decreased as the nozzle height above the ground increased, but the peak velocities at the bottom elevation for both situations were not significantly decreased as the nozzle height increased. The average period of time for dynamic air velocities higher than 1 m/s inside the canopy was 1.9 s at 2.5 cm, 3.8 s at 25 cm and 1.1 s at 46 cm. The mean spray deposit inside taxus canopies with leaf area index of 5.96 increased in an exponential function as the peak air velocity increased. The spray penetration capability and spray deposition uniformity inside taxus canopies were greatly improved with the five-port air-assist sprayer.