Spray drift potential of dicamba plus S ‐metolachlor formulations

Aims: Determine the droplet size spectra of agricultural sprays as affected by herbicide formulations, spray nozzle designs, and operating pressures. Place and Duration of Study: This study was conducted in April 2014 at the United States Department of Agriculture Agricultural Research Service Aerial Application Technology Research Unit Facility in College Station, Texas. Methodology: The spray droplet size spectra of six herbicide formulations as well as water alone and water with nonionic surfactant were evaluated in a low-speed wind tunnel. These spray solutions were conducted with five different flat-fan spray nozzle designs, producing a wide range of spray droplet sizes. The wind tunnel was equipped with a laser diffraction sensor to analyze spray droplet size. All combinations of spray solution and nozzle were operated at 207 and 414 kPa and replicated three times. Results: Many differences in droplet size spectra were detected among the spray solutions, nozzle designs, and pressures tested. Solutions of Liberty 280 SL exhibited the smallest median droplet size and the greatest proportion of spray volume contained in droplets 100 µm or less in size. Solutions of Enlist Duo resulted in smaller median droplet size than many of the solutions tested, but also exhibited some of the smallest production of fine spray droplets. Median droplet size was found to vary greatly among nozzle designs, with the greatest droplet size and smallest drift-prone fine droplet production observed with air-inclusion designs utilizing a pre-orifice. Increasing the operating pressure from 207 to 414 kPa resulted in a decrease in median droplet size and an increase in the production of droplets 100 µm or less in size. Conclusion: Herbicide formulations and spray nozzle designs tested varied widely in droplet size spectra and thus the potential for spray drift. Increasing operating pressure resulted in decreased droplet size and an increase in the production of drift-prone droplets. Additionally, median droplet size alone should not be used to compare spray drift potential among spray solutions but should include relative span and V100 values to better predict the potential for spray drift due to drift-prone spray droplets.

Download Full-text

Meeting droplet size specifications for aerial herbicide application to control wilding conifers

New Zealand Plant Protection ◽

10.30843/nzpp.2020.73.11712 ◽

2020 ◽

Vol 73 ◽

pp. 13-23

Author(s):

Brian Richardson ◽

Carol Rolando ◽

Andrew Hewitt ◽

Mark Kimberley

Keyword(s):

Droplet Size ◽

Field Performance ◽

The Other ◽

Spray Drift ◽

Spray Application ◽

Herbicide Application ◽

Water Control ◽

Drift Potential ◽

Droplet Sizes ◽

Air Speed

Large areas of New Zealand are being aerially sprayed with herbicides to manage ‘wilding’ conifer spread. The purpose of the study was to obtain and analyse droplet spectra produced by nozzles commonly used for wilding conifer spraying to determine whether or not operational recommendations for a target droplet size class (~350 µm) are being met. Droplet spectra were measured in a wind tunnel for 27 nozzle x 3 operating condition (nozzle angle, air speed and pressure) combinations tested for each of three spray mixes. AGDISP, an aerial spray application simulation model, was used to quantify the field performance implications of changes to droplet spectra parameters. Only one nozzle, the CP-09, 0.078, 30°, met the target droplet size specification when used at 45° but not at 0°. However, under these conditions, this nozzle produced a large driftable fraction. All but one of the other scenarios tested produced much larger droplet sizes. Operational spray mixes tended to slightly increase the potential for spray drift compared with the water control. The CP-09, 0.078, 30° nozzle used at 45° met the operational droplet size specification but is more sensitive to changes to nozzle angle (0° versus 45°) than the other nozzles tested. None of the three Accu-FloTM nozzles tested met the target droplet size specification. However, the Accu-FloTM nozzles produced very few fine droplets making them good choices for reducing spray drift potential.

Download Full-text

Phase Doppler technology for infield assessment of drift potential

New Zealand Plant Protection ◽

10.30843/nzpp.2013.66.5690 ◽

2013 ◽

Vol 66 ◽

pp. 381-381

Author(s):

R.L. Roten ◽

R.J. Connell ◽

A.J. Hewitt

Keyword(s):

Particle Size ◽

Particle Size Distribution ◽

Spray Drift ◽

Model Output ◽

Agricultural Equipment ◽

Spray System ◽

Drift Potential ◽

Close Proximity ◽

Drift Models ◽

The Given

Laserbased technologies for droplet analysis have existed for decades but most of these devices are not suitable to be moved once calibrated PhaseDoppler interferometer (PDI) technology has enabled the capture of live infield spray particle data such as the particle size distribution velocity and flux which are essential to accurately measure and model the drift of agricultural equipment The objective of this study was to develop and implement methods to determine if drift could be detected and if so to use the data obtained to crossreference its validity with spray drift models AGDISP and WTDISP The spray apparatus consisted of a 12V trailertype sprayer outfitted with a 50 cm high fournozzle boom with 110SG02 nozzles delivering 238 litres/ha at 34 bar This setup was selected to maximise the output of the sprayer and produce the worstcase drift scenario for the given spray system It was observed that driftable particles of a passing and a static sprayer could be detected within close proximity of 8400 cm2 These results also agreed with the model output generated

Download Full-text

DROPLET SIZE SPECTRA, DRIFT POTENTIAL, AND GROUND DEPOSITION PATTERN OF HERBICIDE SPRAYS

Canadian Journal of Plant Science ◽

10.4141/cjps74-091 ◽

1974 ◽

Vol 54 (3) ◽

pp. 541-546 ◽

Cited By ~ 13

Author(s):

J. MAYBANK ◽

K. YOSHIDA ◽

R. GROVER

Keyword(s):

Droplet Size ◽

Field Experiments ◽

Control Technique ◽

Hydraulic Pressure ◽

Spray Drift ◽

Reduced Pressure ◽

Size Spectra ◽

Nozzle Height ◽

Drift Potential ◽

Ground Deposition

Droplet size spectra and quantity of spray drift were studied for two types of flat-fan nozzles. The large orifice flat-fan nozzles operated at reduced pressure produced less drift potential; however, the spectrum of droplets was coarse. The properties of the whirl jet cone nozzles suggest that these would also produce less drift-prone material. The spray fraction likely to drift was calculated to be approximately 3–8% of the total volume of spray with the flat-fan nozzles. This was confirmed in field experiments using labelled herbicides and a liquid scintillation counting technique. A realistic pattern of the distribution of ground deposition density over a swath (obtained by field experiments), and a factor of three in density fluctuation suggest that the generally accepted concept of uniformity of spray distribution in experimental plots should be modified. Recommendations of spray drift control technique were proposed regarding the hydraulic pressure, nozzle height and orientation, travelling speed/pressure, and the size of orifice.

Download Full-text

Spray Drift from Dicamba and Glyphosate Applications in a Wind Tunnel

Weed Technology ◽

10.1017/wet.2017.15 ◽

2017 ◽

Vol 31 (3) ◽

pp. 387-395 ◽

Cited By ~ 11

Author(s):

Guilherme Sousa Alves ◽

Greg R. Kruger ◽

João Paulo A. R. da Cunha ◽

Bruno C. Vieira ◽

Ryan S. Henry ◽

...

Keyword(s):

Wind Speed ◽

Wind Tunnel ◽

Laser Diffraction ◽

Spray Drift ◽

Downwind Distance ◽

Fluorescent Tracer ◽

Drift Potential ◽

Herbicide Treatments ◽

Low Speed Wind Tunnel ◽

Nozzle Type

With the recent introductions of glyphosate- and dicamba-tolerant crops, such as soybean and cotton, there will be an increase in POST-applied tank-mixtures of these two herbicides. However, few studies have been conducted to evaluate drift from dicamba applications. This study aimed to evaluate the effects of dicamba with and without glyphosate sprayed through standard and air induction flat-fan nozzles on droplet spectrum and drift potential in a low-speed wind tunnel. Two standard (XR and TT) and two air induction (AIXR and TTI) 110015 nozzles were used. The applications were made at 276 kPa pressure in a 2.2 ms−1 wind speed. Herbicide treatments evaluated included dicamba alone at 560 gaeha−1 and dicamba+glyphosate at 560+1,260 gaeha−1. The droplet spectrum was measured using a laser diffraction system. Artificial targets were used as drift collectors, positioned in a wind tunnel from 2 to 12 m downwind from the nozzle. Drift potential was determined using a fluorescent tracer added to solutions, quantified by fluorimetry. Dicamba droplet spectrum and drift depended on the association between herbicide solution and nozzle type. Dicamba alone produced coarser droplets than dicamba+glyphosate when sprayed through air induction nozzles. Drift decreased exponentially as downwind distance increased and it was reduced using air induction nozzles for both herbicide solutions.

Download Full-text

Drift Evaluation of a Quadrotor Unmanned Aerial Vehicle (UAV) Sprayer: Effect of Liquid Pressure and Wind Speed on Drift Potential Based on Wind Tunnel Test

Applied Sciences ◽

10.3390/app11167258 ◽

2021 ◽

Vol 11 (16) ◽

pp. 7258

Author(s):

Qi Liu ◽

Shengde Chen ◽

Guobin Wang ◽

Yubin Lan

Keyword(s):

Wind Speed ◽

Wind Tunnel ◽

High Efficiency ◽

Plant Protection ◽

Spray Drift ◽

Liquid Pressure ◽

Agricultural Plant ◽

Wind Speeds ◽

Drift Potential ◽

Test Platform

Background: Unmanned Aerial Vehicles (UAVs) applied to agricultural plant protection is widely used, and the field of operation is expanding due to their high efficiency and pesticide application reduction. However, the work on pesticide drift lags behind the development of the UAV spraying device. Methods: We compared the spray drift potential at four liquid pressures of 2, 3, 4, and 5 bar ejected from the hydraulic nozzles mounted on a UAV test platform exposed to different wind speeds of 2, 4, and 6 m/s produced by a wind tunnel. The combination of the wind tunnel and the UAV test platform was used to obtain strict test conditions. The droplet size distribution under spray drift pressures was measured by a laser diffraction instrument. Results: Increasing the pressure leads to smaller droplet volume diameters and produced fine droplets of less than 100 µm. The deposition in the drift area was elevated at most of the sampling locations by setting higher pressure and faster wind speed. The deposition ratios were all higher than the flow ratios under three wind speeds after the adjustment of pressures. For most samples within a short drift distance (2–8 m), the drift with the rotor motor off was more than an order of magnitude higher than that with the rotor motor on at a pressure of 3 bar. Conclusions: In this study, the wind speed and liquid pressure all had a significant effect on the UAV spray drift, and the rotor wind significantly inhibited a large number of droplets from drifting further.

Download Full-text

Drift measurements for conditions of hydrogen cyanamide spraying in kiwifruit

New Zealand Plant Protection ◽

10.30843/nzpp.2018.71.186 ◽

2018 ◽

Vol 71 ◽

pp. 19-24

Author(s):

Robert Connell ◽

Scott Post ◽

Mark Ledebuhr ◽

Brian Moorhead ◽

Andrew Hewitt

Keyword(s):

Spray Deposition ◽

Late Winter ◽

Spray Drift ◽

Bud Burst ◽

Spray Application ◽

Hydrogen Cyanamide ◽

Adjuvant System ◽

Drift Potential ◽

Downwind Side ◽

Time Of Year

Kiwifruit are sprayed in late winter with hydrogen cyanamide to enhance with bud burst. The trellis layout of kiwifruit vines in combination with the canopy dormancy at that time of year means that a higher portion of the spray is able to drift away from the canopy. A spray application field study was conducted in a kiwifruit orchard to investigate spray drift potential, with particular focus for conditions relevant to hydrogen cyanamide applications. Spray application with conventional airblast-sprayer hollow-cone nozzles/adjuvant was compared with air-induction (AI) nozzles/drift-reducing adjuvant. Spray was applied every second row in the orchard with spray drift sampling conducted by measuring vertical distribution of spray deposition on both sides of the downwind shelterbelt. The trial showed that airborne drift carried to a height of at least 15 m to the downwind edge of the orchard, which was the height of the vertical sampling towers. The air-induction nozzle/drift-reducing adjuvant system reduced the drift intercepted at 15 m height on the downwind side of the shelterbelt by approximately 78% compared to the standard nozzle/adjuvant system.

Download Full-text