The Effect of Spray Tip Type and Pressure on Postemergence Weed Control

Transcription

1 The Effect of Spray Tip Type and Pressure on Postemergence Weed Control Roert Wolf Biological and Agricultural Engineering Dept. Dallas Peterson Department of Agronomy

2 Species Controlled: Field measure hericide efficacy comparing conventional, venturi, and variale rate spray tips.

3 Materials and Methods: Experiment: Design: Main plot: Suplots: Plot Size: Species: Visual Ratings: Hericides (2): Spray Volume: Field Plots located near Manhattan, KS 4 x 2 randomized complete lock with split plot and 3 reps. Hericide Spray tip y pressure 3 x 9 m large cragrass, ivyleaf morningglory, velvetleaf, common sunflower, sorghum, corn 14 and 28 days after treatment (DAT) Paraquat, 0.25 kg ai/ha, NIS at.25% v/v Glyphosate, 0.17 kg ae/ha, 2.0% w/w 94 l/ha Application Conditions: Date: June 28, 2006 Temp: 27 degrees C R. H.: 42% Wind: Direction degrees (180 would e perpendicular to plot). Wind Speed: 2.8 km/h, gust to 4.0 km/h

4 Materials and Methods cont.: Spray Tips: Turo Flat-fan (TT) TeeJet Air Mix (AM) Greenleaf Ultra Lo Drift (ULD) Hypro Turo Flat-fan Induction (TTI) Tee Jet VariTarget (VT) Delavan Orifice Size: TT and AM = ULD and TTI = VT = lue and yellow cap Spray Pressure: Conventional 276 kpa (40 PSI) & 483 kpa (70 PSI) VT tip at 172 kpa (25 PSI) Speed: 9.6 km/h Tractor mounted 3-point sprayer 3 meter oom with 4 tips Nozzle Spacing: 51 cm Boom Height: 51 cm

5 Materials and Methods cont.: Turo Flat-fan (TT) Air Mix (AM) Ultra lo-drift (ULD) Turo Flat-fan Induction (TTI) VariTarget (medium & coarse) VT

6 Turo/Chamer/Venturi Flat-fans: Pre-orifice Air induction Mixing Chamer Exit orifice

7 Next Generation Air Induction Tips: Next generation: More compact Larger drops Operates at lower pressures Percentage of fines do not increase with pressure Primary and secondary expansion chamers Pre-orifice Air induction Exit Orifice

8 Variale rate application tip: Speed variations from 2-20 MPH Application rates of 5-40 GPA Variale area pre orifice Variale area spray orifice Optimize spray droplet size Maintain efficacy and minimize drift. VariTarget

9 Discussion Results

10 Glyphosate y Spray Tip 40 PSI- 28 DAT 90 LSD = a a a % Control Lacg Ilmg Vele Sorg Corn Cosf tt-40 am-40 uld-40 tti-40 vt-lack

11 Glyphosate y Spray Tip 70 PSI - 28 DAT 90 LSD = 9 % Control a a a a 0 Lacg Ilmg Vele Sorg Corn Cosf tt-70 am-70 uld-70 tti-70 vt-yellow

12 Gramoxone y Spray Tip 40 PSI- 28 DAT % Control LSD = 10 a a Lacg Ilmg Vele Sorg Corn Cosf tt-40 am-40 uld-40 tti-40 vt-lack

13 Gramoxone y Spray Tip 70 PSI - 28 DAT 90 LSD = 10 % Control a a c Lacg Ilmg Vele Sorg Corn Cosf tt-70 am-70 uld-70 tti-70 vt-yellow

14 Chemical Across Spray Tip 28 DAT % Control LSD = 9 LSD = 16 NS LSD = 11 LSD = 28 a a a a NS Lacg Ilmg Vele Sorg Corn Cosf Glyphosate Paraquat

15 Spray Tip Across Chemical 40 PSI LSD = 9 % Control LSD = 11 a a a a LSD = 5 a a LSD = 7 a a a a LSD = 6 a a a a LSD = 8 a a a a a a 10 0 Lacg Ilmg Vele Sorg Corn Cosf tt-40 am-40 uld-40 tti-40 vt-lack

16 Spray Tip Across Chemical 70 PSI % Control LSD = 11 a a a a NS LSD = 7 LSD = 8 a a a a a a NS a a LSD = 9 a a a a 10 0 Lacg Ilmg Vele Sorg Corn Cosf tt-70 am-70 uld-70 tti-70 vt-yellow

17 Summary of findings glyphosate: The ULD was typically etter at 40 PSI for all species. It was significantly etter than the TT and VT for Sorg control. At 70 PSI the TT was slightly etter except for Vele, Corn, and Cosf control. It was significantly etter than the TTI for Sorg control. The only significance was found for Sorg control at oth 40 and 70 PSI.

18 Summary of findings - paraquat: The AM was typically etter control at 40 PSI except for Corn. It was significantly etter than the VT, TTI, and the ULD for Vele control. The same trend was found at 70 PSI. The AM was significantly etter than the ULD, TTI, and VT for Vele control. The only significance was found for Vele control at oth 40 and 70 PSI.

19 Summary of findings across chemical: Glyphosate had significantly etter control with Lacg, Sorg, and Corn among nozzles. Vele was controlled est with paraquat. Cosf and Ilmg control was not significantly different with either chemical.

20 Conclusions: The ULD performed est with glyphosate at the low pressure with the TT est at the high pressure. This trend is reverse of what was expected and somewhat different from last year. With paraquat, the AM did est at oth low and high pressure. The new TTI and the new variale rate (VT) did not perform as well when compared other tips with the VT eing significantly less in several comparisons.

21 Thanks