Water Volume, Tractor Speed, and Nozzle Type Effects on Spray Coverage

1. Water Volume, Tractor Speed, and Nozzle Type Effects on Spray Coverage Eric P. Prostko, Extension Weed Specialist Paul E. Sumner, Extension Ag-Engineer The University of Georgia Peanut Achievement Club - 2007

2. Factors That Influence Postemergence Herbicide Performance • weed size • rate • environment • moisture • temperature • humidity • application • water volume (GPA) • tractor speed • nozzle type

3. Current Application Trends • low water volumes • 10 GPA or less • faster tractor speeds • nozzle types • Air Induction (AI) • Turbo-Jet (TJ) • Hollow-Cone (HC) • Why?? • RR crops • More acres • Labor issues

4. U.S. Acres Planted to HerbicideResistant Varieties Includes stacked Source: NASS

7. 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

8. Examples of the nozzles used in these tests. Flat Fan Hollow Cone (Whirl-Jet)

9. RESULTS

10. Nozzle Type and GPA Effects - I3.5 MPH Tractor Speed LSD 0.10 = 3

11. Nozzle Type and GPA Effects - II5.0 MPH Tractor Speed LSD 0.10 = 3

12. Nozzle Type and GPA Effects - III7.0 MPH Tractor Speed LSD 0.10 = 3

13. 10 GPA - 7 MPH – HC (12% coverage) 20 GPA – 3.5 MPH – XR (FF) (45% coverage)

14. Summary • 3-way interaction between tractor speed, GPA, and nozzle type • HC nozzles provided less coverage than XR-FF nozzles • Tractor 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 coverage • 20 GPA > 15 GPA > 10 GPA • best coverage (45%) • 3.5 MPH/20 GPA/XR-FF • least coverage (12%) • 7.0 MPH/10 GPA/HC

15. Why is this important? • Application techniques for glyphosate (systemic) are not adequate for other types of herbicides such as paraquat (contact)!

16. Peanut Herbicides (POST)

17. www.gaweed.com