Results

• Particle drift, or the physical movement of spray particles, is

dependent on factors such as wind speed, boom height,

distance from susceptible vegetation, and spray particle size

• Spray particle size is affected by nozzle type, operating

pressure, orifice size, and tank solution

• Wind speed, wind direction, and location of susceptible

vegetation are more difficult or impossible to control

• Small droplets exit nozzles with a lower velocity and thus hang

in the air for a longer period of time than large droplets,

increasing their potential to move off-target

• In general, increasing downward droplet velocity decreases

drift potential

• Droplet movement is complex process. Therefore it is

important that all factors affecting spray particle movement are

carefully monitored

Introduction

• The objective of this study was to determine the deposition

and droplet size of spray particle drift resulting from an

application of glyphosate and 2,4-D.

Objective

• A wind tunnel drift study was conducted in 2016 at the

Pesticide Application Technology Laboratory

• Experiment Design: randomized complete 2x3x5 factorial

design with six replications

• Enlist Duo™ herbicide, a tank-mixture of glyphosate and 2,4-

D, was applied through 11004 flat-fan nozzles at 276 kPa

• Selected nozzles: Air-Induction Extended Range (AIXR) and

TurboDrop XL (TDXL)

• Selected wind speeds: 8, 16, and 21 kph

• Rate: 592 g a.e. ha-1 glyphosate and 558 g a.e. ha-1 2,4-D

Carrier volume: 140 l ha-1

• Fluorescent tracer dye (PTSA) added at 0.6 µg ml-1

• Mylar cards used to collect drift deposition rate (μg cm2)• Water sensitive cards used to volume median diameter (μm)• PROC GLIMMIX in SAS 9.4 used to conduct multiple

comparison ANOVA analysis

• Columns with same letter not statistically different at α =

0.05

Materials and Methods

a

Droplet size and deposition of glyphosate and 2,4-D drift in a wind tunnel

Matthew R. Nelson, Bruno C. Vieira, Annah M. Geyer, Greg R. Kruger

University of Nebraska-Lincoln, West Central Research and Extension Center

B

A

0

0.4

0.8

1.2

1.6

8.1 16.1 21.1

De

po

sitio

n r

ate

(ug

cm

2)

Wind speed (kph)

Deposition rate of glyphosate and 2,4-D tank-mixture

B

0

100

200

300

400

1.5 3 6 9 12Vo

lum

e m

ed

ian

dia

mete

r (µ

m)

Downwind distance (m)

Volume median diameter of spray particle drift from TDXL & AIXR nozzles

A

A

TDXL11004

AIXR11004

0

100

200

300

400

500

1.5 3 6 9 12

Vo

lum

e m

ed

ian

dia

me

ter

(µm

)

Downwind distance (m)

Droplet size of spray particle drift from tank-mixture of glyphosate and 2,4-D at 21 kph

AIXR

TDXLA

A

A

0

100

200

300

400

1.5 3 6 9 12

Vo

lum

e m

ed

ian

dia

me

ter

(µm

)

Downwind distance (m)

Volume median diameter of spray particle drift from glyphosate plus 2,4-D

8.1 16.1 21.1

kph

Figure 5. AIXR at 21 kph at different distances downwind (m)Figure 4. AIXR at 16 kph at different distances downwind (m) Figure 3. AIXR at 8 kph at different distances downwind (m)

Figure 6. TDXL at 8 kph at different distances downwind (m) Figure 7. TDXL at 16 kph at different distances downwind (m) Figure 8. TDXL at 21 kph at different distances downwind (m)

• Deposition and droplet size of the spray particle drift resulting from the application of a glyphosate and 2,4-D solution

was influenced by wind speed, as higher wind speed resulted in more deposition and larger droplets moving off-

target.

• Spraying glyphosate plus 2,4-D through the TDXL11004 nozzle at a high wind speed (21 kph) resulted in the

collection of larger spray droplets at downwind distances (1.5 and 3 m) than the AIXR11004.

• While droplet size does impact the drift potential of a herbicide application, wind speed is still the most important

factor, as even large spray droplets can move off-target.

• Factors besides spray droplet size must be considered when selecting low drift/air inclusion nozzles.

Conclusions

A

B

Figure 2. Collector setup

in low-speed wind tunnelFigure 1. AIXR11004 and

TDXL11004 nozzles

B

B

A

A

A

A

A

B

A A

A AA A

A

A

C

BA

BCC

A

BCC

A

BCC

ABC

C

1.5 1.5

1.5

1.5

1.5 1.512

12

12

12

12

1296

33

333

3

6

66

6

6

9

99

9

9

11004

1100416 218