The Effect of Spray Tip Type and Pressure on Postemergence ...
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The Effect of Spray Tip Type and Pressure on Postemergence Weed Control Robert Wolf Biological and Agricultural Engineering Dept. Dallas Peterson Department of Agronomy
Transcript of The Effect of Spray Tip Type and Pressure on Postemergence ...
The Effect of Spray Tip Type and Pressure on
Postemergence Weed Control
Robert WolfBiological and Agricultural Engineering Dept.
Dallas PetersonDepartment of Agronomy
Species Controlled:
Field measure herbicide efficacy comparing conventional, venturi, and variable rate spray tips.
Materials and Methods:Experiment: Field Plots located near Manhattan, KSDesign: 4 x 2 randomized complete block with split plot and 3 reps.Main plot: HerbicideSubplots: Spray tip by pressurePlot Size: 3 x 9 mSpecies: large crabgrass, ivyleaf morningglory, velvetleaf, common
sunflower, sorghum, cornVisual Ratings: 14 and 28 days after treatment (DAT)Herbicides (2): Paraquat, 0.25 kg ai/ha, NIS at .25% v/v
Glyphosate, 0.17 kg ae/ha, AMS @ 2.0% w/wSpray Volume: 94 l/ha
Application Conditions:Date: June 28, 2006Temp: 27 degrees CR. H.: 42%Wind: Direction - 203 degrees(180 would be perpendicular to plot).Wind Speed: 2.8 km/h, gust to 4.0 km/h
Materials and Methods cont.:Spray Tips: Turbo Flat-fan (TT) TeeJet
Air Mix (AM) GreenleafUltra Lo Drift (ULD) HyproTurbo Flat-fan Induction (TTI) Tee JetVariTarget (VT) Delavan
Orifice Size: TT and AM = 11002ULD and TTI = 110015VT = blue and yellow cap
Spray Pressure: Conventional Tips @ 276 kPa (40 PSI) & 483 kPa (70 PSI)VT tip at 172 kPa (25 PSI)
Speed: 9.6 km/h
Tractor mounted 3-point sprayer3 meter boom with 4 tipsNozzle Spacing: 51 cmBoom Height: 51 cm
Turbo Flat-fan (TT)Air Mix (AM)Ultra lo-drift (ULD)Turbo Flat-fan Induction (TTI)VariTarget (medium & coarse) VT
Materials and Methods cont.:
Turbo/Chamber/Venturi Flat-fans:Pre-orifice
Exit orifice
Air induction
Mixing Chamber
Next Generation Air Induction Tips:• Next generation:
– More compact– Larger drops– Operates at lower
pressures– Percentage of fines do not
increase with pressure
Pre-orifice
Air induction
Primary and secondary expansion chambers
Exit Orifice
Variable rate application tip:• Speed variations from 2-20 MPH• Application rates of 5-40 GPA• Variable area pre orifice• Variable area spray orifice• Optimize spray droplet size• Maintain efficacy and minimize drift.
VariTarget
Discussion
Results
Glyphosate by Spray Tip40 PSI- 28 DAT
0
10
20
30
40
50
60
70
80
90
Lacg Ilmg Vele Sorg Corn Cosf
% C
ontr
ol
tt-40 am-40 uld-40 tti-40 vt-black
LSD = 9
a aa
b b
0
10
20
30
40
50
60
70
80
90
Lacg Ilmg Vele Sorg Corn Cosf
% C
ontr
ol
tt-70 am-70 uld-70 tti-70 vt-yellow
Glyphosate by Spray Tip70 PSI - 28 DAT
a a
a ba
LSD = 9
0
10
20
30
40
50
60
70
80
90
100
Lacg Ilmg Vele Sorg Corn Cosf
% C
ontro
l
tt-40 am-40 uld-40 tti-40 vt-black
Gramoxone by Spray Tip40 PSI- 28 DAT
LSD = 10
aa
bb b
0
10
20
30
40
50
60
70
80
90
Lacg Ilmg Vele Sorg Corn Cosf
% C
ontro
l
tt-70 am-70 uld-70 tti-70 vt-yellow
Gramoxone by Spray Tip70 PSI - 28 DAT
a a
c
bb
LSD = 10
0
10
20
30
40
50
60
70
80
90
Lacg Ilmg Vele Sorg Corn Cosf
% C
ontro
l
Glyphosate Paraquat
Chemical Across Spray Tip – 28 DAT
a
aa
bb
LSD = 28
b
a
b
LSD = 11LSD = 9 LSD = 16
NS
NS
0
10
20
30
40
50
60
70
80
90
Lacg Ilmg Vele Sorg Corn Cosf
% C
ontro
l
tt-40 am-40 uld-40 tti-40 vt-black
Spray Tip Across Chemical – 40 PSI
a a a
b
b
a a
LSD = 11
LSD = 5
LSD = 7
LSD = 6
LSD = 8
LSD = 9
b
a a
aa ab
b
aa
aa
a aa
bb
ba
aa
b
0
10
20
30
40
50
60
70
80
Lacg Ilmg Vele Sorg Corn Cosf
% C
ontro
l
tt-70 am-70 uld-70 tti-70 vt-yellow
Spray Tip Across Chemical – 70 PSI
a a a
bba
a a a a
a a a a
b
b
a aa aNS
NS
LSD = 11 LSD = 7 LSD = 8
LSD = 9
Summary of findings – glyphosate:
• The ULD was typically better at 40 PSI for all species. It was significantly better than the TT and VT for Sorg control.
• At 70 PSI the TT was slightly better except for Vele, Corn, and Cosf control. It was significantly better than the TTI for Sorgcontrol.
• The only significance was found for Sorgcontrol at both 40 and 70 PSI.
Summary of findings - paraquat:
• The AM was typically better control at 40 PSI except for Corn. It was significantly better than the VT, TTI, and the ULD for Vele control.
• The same trend was found at 70 PSI. The AM was significantly better than the ULD, TTI, and VT for Vele control.
• The only significance was found for Velecontrol at both 40 and 70 PSI.
Summary of findings across chemical:
• Glyphosate had significantly better control with Lacg, Sorg, and Corn among nozzles.
• Vele was controlled best with paraquat.• Cosf and Ilmg control was not significantly
different with either chemical.
Conclusions:
• The ULD performed best with glyphosate at the low pressure with the TT best at the high pressure. This trend is reverse of what was expected and somewhat different from last year.
• With paraquat, the AM did best at both low and high pressure.
• The new TTI and the new variable rate (VT) did not perform as well when compared other tips with the VT being significantly less in several comparisons.
Thanks
