Optimizing Airblast Sprayers in Vineyard Canopies Using Different Nozzles and Air Assistance

Industry ImpactOptimization of airblast sprayers for use in vineyards can improvespray deposition and reduce drift. Two techniques to optimize anairblast sprayer are using different nozzle types and controlling airassistance. Using TeeJet VisiFlo® hollow cone nozzles(TJTXV12, brown) and TeeJet AI type A nozzles (AITX8002VK,yellow), with and without air assistance (fan) (Fig. 1), weevaluated canopy deposition and drift in a WA winegrapevineyard in 2018. Spray deposition was collected as described inFig. 2.The ability to optimize the airblast sprayer for grapes canultimately help improve disease control and save money.

Margaret McCoy1, Gwen Hoheisel2, Lav Khot3, and Michelle Moyer1

1Dept. of Horticulture, 2WSU Extension, 3Center for Precision & Automated Agricultural Systems; Washington State University, Irrigated Agriculture Research and Extension Center, Prosser, WA

Figure 2. Left – Tracer is added to the sprayer tank for vineyard application. Left Center -Tracer was collected from 5 zones in the canopy. Right Center - Aerial drift deposition was collected in the first 3 rows downwind of the row being sprayed. Right - Drift onto the vineyard floor was collected between the first 3 rows downwind of the row being sprayed.

Canopy Deposition

Aerial Drift

Floor Drift

AcknowledgementsAuthors would like to thank Haitham Bahlol, Rajeev Sinha, Rakesh Ranjan, Abhilash Chandel, Katherine East, Maria Mireles, and Maia Blom for their help and assistance with sampling and set up for this experiment.

Funding and SupportFunded through the Washington State Grape and Wine Research Program; funding sources include Washington State Wine Commission, Auction of Washington Wines, State Liter tax, and/or WSU Agriculture Research Center. USDA National Institute of Food and Agriculture, Hatch project #1016563.

Figure 1. A Rears Power Blast airblast sprayer appliedfluorescent tracer at 50 GPA in a Chardonnay vineyard at fullcanopy.

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Airblast – Vineyard Floor Drift AI - Air offAI - Air onVisiflo - Air offVisiflo - Air on

Results AI - air off vs. AI - air on - AI nozzles without air

assistance had greater canopy deposition. VisiFlo - air off vs. VisiFlo - air on – Air

assistance did not appear to greatly effectdeposition patterns of the VisiFlo nozzle.

AI - air off vs. VisiFlo - air off – Without airassistance, AI nozzles have greater canopydeposition than VisiFlo nozzles.

AI - air on vs. VisiFlo - air on – With airassistance, VisiFlo nozzles had higher canopydeposition than AI nozzles.

ConclusionsCanopy deposition was higher and more evenly distributedusing AI nozzles with no air assistance than othercombinations. The larger droplets produced by AI nozzles,when combined with air, likely resulted in droplets bouncingoff the leaf, decreasing deposition. Of the total (100%)deposition collected for each application canopy depositionwas 99.9% for AI - air off, 91% for AI - air on, 99.51% forVisiFlo - air off and 99.51% for VisiFlo - air on.

VisiFlo nozzles had higher deposition in the upper canopythen the fruiting zone, likely due to less foliage below thecordon which could affect the eddy (wind) patterns of thesmall droplets.

Results AI - air off vs. AI - air on – AI nozzles had greater

aerial drift with air assistance.

VisiFlo - air off vs. VisiFlo - air on – VisiFlonozzles with air assistance had more aerial drift.

AI - air off vs. VisiFlo - air off – AI and VisiFlonozzles without air assistance had low aerial drift.

AI - air on vs. VisiFlo - air on – VisiFlo nozzleswith air assistance had greater aerial drift than AInozzles with air assistance.

ConclusionsAerial drift was higher whenever air assistance was used,regardless of nozzle. The highest drift was produced by theVisiFlo nozzles with air assistance. This might be due to thesmaller droplets produced by this nozzle type, which candrift further than the larger droplets produced by AI nozzles.Of the total (100%) deposition collected for each applicationaerial drift was 0.01% for AI - air off, 1% for AI - air on,0.06% for VisiFlo - air off and 1.6% for VisiFlo - air on.

AI nozzles without air assistance produced the lowest aerialdrift followed by VisiFlo nozzles without air assistance.

ConclusionsDrift onto the vineyard floor was highest when airassistance was used; turning off the air assistance reduceddrift, regardless of nozzle type. Of the total (100%)deposition collected for each application floor drift was0.08% for AI - air off, 8% for AI - air on, 0.43% for VisiFlo -air off and 2.9% for VisiFlo - air on.

When comparing nozzles, floor drift was less with VisiFlonozzles than AI nozzles. While small droplets increaseaerial drift, they likely decrease drift onto the vineyard floor,explaining why VisiFlo nozzles had less floor drift than AInozzles.

Results AI - air off vs. AI - air on – AI nozzles had greater

floor drift with air assistance. VisiFlo - air off vs. VisiFlo - air on – VisiFlo

nozzles had greater floor drift with air assistance. AI - air off vs. VisiFlo - air off – Without air

assistance, AI and VisiFlo nozzles had very lowfloor drift.

AI - air on vs. VisiFlo - air on – With airassistance, AI nozzles had greater floor drift thanVisiFlo nozzles.

Take-Home Points AI nozzles produce large droplets, which

are less prone to aerial drift. Whencoupled with air assistance, however,they are more likely to bounce off of thecanopy and onto the vineyard floor.

Turning off air assistance on a Rears Power Blast is one way to reduce drift.

Every drop to the crop!

VisiFlo nozzles produce smaller dropletswhich are more prone to aerial drift. Thisdrift risk is increased when air assistanceis used.