Debunking Sprayer Myths

Transcription

1 Debunking Sprayer Myths Tom Wolf AgriMetrix Research and Training Saskatoon,

2 Challenge: Controlling pests without harming your neighbours crops or the environment

3 Trends for 2014 more fungicides more stainless steel wider booms faster speed capability bigger tanks more pulse width modulation more auto boom height more complex monitors twin fan nozzles

4 Myth #1 More pressure forces spray into canopy

5 Pressure affects: Flow rate Spray quality Pattern uniformity Droplet velocity

6 Velocity (m/s) Droplet Velocity Distributions High Pressure Low Pressure Droplet diameter (µm)

7 Droplet Speed At tip: all droplets: 70 km/h 50 cm below tip: Large droplets: 28 km/h Small droplets: 7 km/h

8 Droplet Direction Large droplets: combination of nozzle and travel direction e.g. 30 km/h, 10 km/h Small droplets: whichever way the wind is blowing

9 Velocity rapidly dissipates with height

10 Myth #2 Higher water volumes lead to runoff

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12 Foxtail spray retention (µl/g dw) Spray Retention on Foxtail y = x R² = Water volume (L/ha)

13 Myth #3 Spray drift is no issue for fungicides & insecticides

14 New Buffer Zone Label Language Untreated (Buffer Zone) Conventional application 20 m untreated Low-drift application 15 m untreated Very low-drift application 5 m

15 Aquatic Organisms are Sensitive

16 Typical Herbicide Buffer Statements Do not apply with spray droplets smaller than ASAE medium classification When using a shroud, BZ can be reduced by 70%...

17 Caramba

18 Astound

19 Prosaro

20 Lorsban

21 Myth #4 Faster travel speed saves time and boosts productivity

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24 Areas Vortices of unequal become pressure more create vortices pronounced which at remove faster travel small droplets from speeds the spray cloud

25 Productivity (not counting turns) Drive Faster Fill Faster Spray Wider Scenario 1 Scenario 2 Scenario 3 Scenario gal tank 80 boom 12 mph 10 gpa 50 gpm fill 800 gal tank 80 boom 18 mph 10 gpa 50 gpm fill 800 gal tank 80 boom 12 mph 10 gpa 300 gpm fill 800 gal tank 120 boom 12 mph 10 gpa 50 gpm fill 84 acres/h 110 acres/h 110 acres/h 111 acres/h

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27 Fill Efficiency

28 Myth #5 Double nozzles produce more droplets and improve coverage.

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30 Droplet Number Droplet Number ER11006, 40 psi SR11006, 40 psi MR11006, 40 psi DR11006, 40 psi

31 Myth #6 Calm early mornings have the lowest drift risk

32 Wind speed at 1 m height (m/s) Daily Wind Pattern Time of day (h)

33 Thermal Turbulence

34 Unstable (Desirable normal daytime conditions) Dispersion Warm Soil Spray cloud disperses, moving upward and downwind Inversion Conditions Stable (inversion) Warm, still air Cold air - dense, still Cold soil Spray cloud hangs over treated area in high concentration

35 Height Height Unstable Stable (Inversion) Temperature Temperature

36 Height 3 pm 11 pm 3 am 5 am 7 am 8 am 9 am 3 pm Sunset 10 pm Sunrise 5 am Temperature Inverted layer No dispersion Inversion cap

37 3 pm 11 pm 3 am 5 am 7 am 8 am 9 am 3 pm Sunset 10 pm Sunrise 5 am

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39 Myth #7 A rate controller calibrates the sprayer

40 Best Practices Sprayer Setup Metering / Calibrating Pressure Drop Screens

41 Myth #8 If I mess up agronomic decisions, I can correct that with a good spray application

42 Grain Yield (kg/ha) Effect of Time of Removal bu/acre days 17 days Untreated XR 8001 (Fine) Air Mix (Coarse) TurboDrop XL/TT (Extr. Coarse)

43 Myth #9 Ammonia is a good general purpose tank cleaner

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45 Myth #10 There is an optimal nozzle that does it all

46 Weed Control Grassy Targets, Contact Products Medium Coarse Very Coarse Extra Coarse Droplet Size

47 Pest Control Broadleaf Targets, Systemic Products Medium Coarse Very Coarse Extra Coarse Droplet Size

48 Water Volume and Canopies

49 Win some, Lose some Drift Rebound Most Useful Nozzle %<200 %>600 % Conv LD LD LD

50 Spray Quality

51 Spray Quality Volume Median Droplet Diameter Min. Volume Comments Extremely Coarse >550 µm 15 gpa Not usually recommended Very Coarse µm 10 gpa Broadleaf plants only Coarse µm 5-7 gpa Grasses and broadleaves Medium µm 3-5 gpa Grasses and broadleaves Fine µm 3 gpa Not recommended Very Fine <150 µm 3 gpa Not recommended

52 Summary Use a Coarse spray Calibrate all nozzles Operate in middle of pressure range Keep booms and travel speed low if possible Fill faster Add water to improve canopy penetration Spray on time Understand inversions and avoid them Respect buffer zones Be thorough when cleaning sprayer