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TITLE
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Influence of Tractor Speed and Boom Height on Spray Coverage
AUTHOR
Eric P. Prostko
Professor and Extension Weed Specialist
University of Georgia
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TABLE OF CONTENTS
Influence of Tractor Speed and Boom Height on Spray Coverage
The New Norm????
Is this a bad combination????
Farm vs. Research?
Herbicide Efficacy
Objective
Materials and Methods
Droplet Size - TeeJet
Spray Dimensions
Results
Influence of Tractor Speed and Boom Height on Spray Coverage (%)
Tractor Speed Effects on Spray Coverage (%) - 30" Boom Height
Tractor Speed Effects on Spray Coverage (%) - 45" Boom Height
Tractor Speed Effects on Spray Coverage (%) - 60" Boom Height
Spray Coverage - 60" Boom Height
Influence of Tractor Speed and Boom Height on Droplet Size (VMD50)
Summary - Tractor Sprayer
BackPack Sprayer Coverage Evaluation
The Influence of Nozzle Type on Spray Coverage (%) and VMD50 (microns)
11002DG
Final Thoughts
Acknowledgements
QUESTIONS?
SLIDE CONTENTS
Influence of Tractor Speed and Boom Height on Spray Coverage Eric P. Prostko1, Glen C. Rains2, and O. Wen Carter1 1Dept. Crop & Soil Sciences 2Dept. of Entomology UGA - Tifton
The New Norm????
Is this a bad combination???? 6 ft
Farm vs. Research? Concerns Tractor Speed Boom Height Coverage Quality vs. Quantity?
Herbicide Efficacy Coverage Nozzle Type GPA Pressure Boom Height Tractor Speed
Objective Evaluate the effects of tractor speed and boom height on spray quality Coverage VMD50
Materials and Methods Melroe 3430 Spra-Coupe Tractor Speeds 4.4, 6.5, and 9.5 MPH Boom Heights 30, 45, 60 in Wind = 3.0 MPH 15 GPA (water + dye) DG TeeJet Drift Guard Nozzle Tips (20” spacing) 8002DG (50 PSI) 8003DG (40 PSI) 8004DG (53 PSI) Medium Droplet Sizes 2 locations in sprayer path 8’ from tractor center (L1) 30” parallel from L1 (L0) 5 Kromekote cards (2” X 3”) 10’ apart Dropletscan (WRK of Arkansas, LLC)
Droplet Size - TeeJet
10’ 30” 8’
Results Analyzed data as 2 X 3 X 3 factorial 2 card locations 5 cards 3 speeds 3 boom heights 90 total data points Speed X Boom Height interaction for Coverage and VMD50
Influence of Tractor Speed and Boom Height on Spray Coverage (%) LSD 0.10 = 1 CV = 12.523
Tractor Speed Effects on Spray Coverage (%) – 30” Boom Height N = 30
Tractor Speed Effects on Spray Coverage (%) – 45” Boom Height N = 30
Tractor Speed Effects on Spray Coverage (%) – 60” Boom Height N = 30
Spray Coverage - 60” Boom Height 4.4 MPH 6.5 MPH 9.5 MPH
Influence of Tractor Speed and Boom Height on Droplet Size (VMD50) LSD 0.10 = 5 CV = 1.83 Medium = 236-340 VMD50
Summary – Tractor Sprayer Lowest coverage at all boom heights was at 9.5 MPH tractor speed (6-8%) For 30” and 60” boom heights, negative linear relationship between tractor speed and coverage (R2 > 0.68) ~ 1.2% loss in coverage for each MPH Boom height influenced spray coverage as follows: 4.4 MPH: 30” = 60” > 45” 6.5 MPH: 30” = 45” = 60” 9.5 MPH: 45” > 30” = 60” Generally, VMD50 increased with tractor speed 30” boom: 4.4 MPH < 6.5 MPH < 9.5 MPH 45” boom: 4.4 MPH < 6.5 MPH = 9.5 MPH 60” boom: 4.4 MPH < 9.5 MPH < 6.5 MPH 306 to 345 microns (coarse droplet size)
BackPack Sprayer Coverage Evaluation Generally, same MM as tractor study September 1, 2015 15 GPA 3 nozzle boom, 20” spacing 20” Boom Height 3.5 MPH (walking) Wind (<1 MPH) 35-40 PSI 3 nozzle types 11002DG AIXR 11002 TTI02
The Influence of Nozzle Type on Spray Coverage (%) and VMD50 (microns) 3.5 MPH - Walking 20” nozzle spacing 20” boom height 35-40 PSI 15 GPA LSD 0.10 = 1.8 CV = 18.3 LSD 0.10 = 19 CV = 6
11002DG VMD50 = 322 (C AIXR 11002 VMD50 = 402 (VC) TTI 02 VMD50 = 524 (XC)
Final Thoughts If a grower would drive 4.4-6.5 MPH, not much difference between backpack and tractor. If grower drives 9.5 MPH or greater (?), ~50% less spray coverage. Could this partially explain observed differences between research and on-farm results??? Farmer Resistance? Too big/late, too fast, too high?????
Acknowledgements Technical Support provided by Tim Richards Charlie Hilton Maryssa Davis
QUESTIONS? eprostko@uga.edu www.gaweed.com