Water Volume, Tractor Speed, Water Volume, Tractor Speed, and Nozzle Type Effects on and Nozzle Type Effects on
Spray CoverageSpray Coverage
Eric P. Prostko, Extension Weed SpecialistEric P. Prostko, Extension Weed Specialist
Paul E. Sumner, Extension Ag-EngineerPaul E. Sumner, Extension Ag-Engineer
The University of GeorgiaThe University of Georgia
Peanut Achievement Club - 2007Peanut Achievement Club - 2007
Factors That Influence Postemergence Factors That Influence Postemergence Herbicide PerformanceHerbicide Performance
weed sizeweed size raterate environmentenvironment
– moisturemoisture– temperaturetemperature– humidityhumidity
applicationapplication– water volume (GPA)water volume (GPA)– tractor speedtractor speed– nozzle typenozzle type
Current Application TrendsCurrent Application Trends low water volumeslow water volumes
– 10 GPA or less
faster tractor speedsfaster tractor speeds
nozzle typesnozzle types– Air Induction (AI)– Turbo-Jet (TJ)– Hollow-Cone (HC)
Why??Why??– RR crops– More acres– Labor issues
U.S. Acres Planted to HerbicideU.S. Acres Planted to HerbicideResistant VarietiesResistant Varieties
0102030405060708090100
2000 2001 2002 2003 2004 2005 2006
Crop
% o
f Ac
res
Corn Cotton Soybean
Source: NASS Includes stacked
3.5, 5.0, 7.0 MPH
10, 15, 20 GPA
XR-Flat Fan (XR-FF) and Hollow Cone (HC) Nozzles
9 replications
Kromekote water sensitive cards
Examples of the nozzles used in these tests.
Flat Fan Hollow Cone (Whirl-Jet)
RESULTSRESULTS
Nozzle Type and GPA Effects - INozzle Type and GPA Effects - I3.5 MPH Tractor Speed3.5 MPH Tractor Speed
34
45
18 2024
0
10
20
30
40
50
10 15 20
GPA
Cov
erag
e -
%
FF HC
LSD 0.10 = 3
Nozzle Type and GPA Effects - IINozzle Type and GPA Effects - II5.0 MPH Tractor Speed5.0 MPH Tractor Speed
21
31
38
1418
24
0
10
20
30
40
50
10 15 20
GPA
Cov
erag
e -
%
FF HC
LSD 0.10 = 3
Nozzle Type and GPA Effects - IIINozzle Type and GPA Effects - III7.0 MPH Tractor Speed7.0 MPH Tractor Speed
22
3236
1215
21
0
10
20
30
40
50
10 15 20
GPA
Cov
erag
e -
%
FF HC
LSD 0.10 = 3
10 GPA - 7 MPH – HC(12% coverage)
20 GPA – 3.5 MPH – XR (FF)(45% coverage)
SummarySummary 3-way interaction between tractor speed, GPA, and nozzle type3-way interaction between tractor speed, GPA, and nozzle type
HC nozzles provided less coverage than XR-FF nozzlesHC nozzles provided less coverage than XR-FF nozzles
Tractor speedTractor speed– FF and 20 GPA = 3.5 mph > 5.0 mph = 7.0 mph– HC and 10 GPA = 3.5 mph > 5.0 mph = 7.0 mph– HC and 15 GPA = 3.5 mph > 7.0 mph
increases in GPA improved coverageincreases in GPA improved coverage– 20 GPA > 15 GPA > 10 GPA
best coverage (45%)best coverage (45%)– 3.5 MPH/20 GPA/XR-FF
least coverage (12%)least coverage (12%)– 7.0 MPH/10 GPA/HC
Why is this important?Why is this important?
Application techniques for glyphosate Application techniques for glyphosate (systemic) are not adequate for other (systemic) are not adequate for other types of herbicides such as paraquat types of herbicides such as paraquat (contact)!(contact)!
Peanut Herbicides (POST)Peanut Herbicides (POST)
HerbicideHerbicide ActivityActivity
2,4-DB2,4-DB systemicsystemic
BasagranBasagran contactcontact
CadreCadre systemicsystemic
ClassicClassic systemicsystemic
CobraCobra contactcontact
GramoxoneGramoxone contactcontact
PoastPoast systemicsystemic
PursuitPursuit systemicsystemic
SelectSelect systemicsystemic
StormStorm contactcontact
Ultra BlazerUltra Blazer contactcontact
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