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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