Aerial Application Research Update

Transcription

1 Aerial Application Research Update Click to edit Master subtitle style Andrew Hewitt

2 International Update Europe some countries restrict aerial appln heavily but very few actually ban it US working mainly on DRT scheme Canada treats aerial and ground differently Australia APVMA introducing new buffers Philippines banned aerial application for bananas..so CropLife Philippines brought in Hewitt to talk science and overturn the ban US 2,4-D Lawsuit temp. inversion/ small droplet theories

3 NZ Spray Drift Research and Modeling FRST/ MSI project through 215 developing new models for spray deposition and drift Agriculture and forestry LVL, PPCnz, Scion, Otago University, US Forest Service, AAFC

4 Aerial Research Although much of the research is for ground application systems, we are also working on improving the AGDISP model for aerial applications with canopies and on developing drift reduction technologies and field droplet size measurement systems

5 FRST/ MSI Research Signed a 3-year collaborative agreement with USDA aerial application research lab Conducting field studies in NZ for a range of crops and application scenarios

6 New Field Lasers to Measure Sprays

7 Droplet Size and Flux in Vertical Window 5 m Downwind of Sprayer PDI Compact Probe Traverse Spray Bar Remotely Piloted Vehicle or Stationary location

8 New Deposition Sampling Approach: Portable X-Ray Fluorescence In-situ (non-destructive and avoids need for artificial collectors with their own collection efficiency issues) Multiple cations allows each sprayer to be used under similar met. conditions Rapid processing (6 seconds c/w weeks) Allows sampling in the actual wind direction after application avoiding chasing the wind in study setup

9 Field Studies Vineyard studies completed Tomato psyllid studies initiated but want to now look at novel systems for providing better underleaf coverage such as aerial electrostatics plan to have a rig in NZ in late 211 for tests Kiwi fruit studies planned could include aerial if there is interest 2 months of arable studies coming up

10 Aerial Electrostatics

11 US Links MSI grant funding a workshop on US/ NZ scientific ties for research into 1) difficult-tocontrol pests/ weeds, 2) spray drift modeling and 3) extension/ education updates Lincoln University August 29-31, 211

12 University of Queensland Activities Aerial application research using wind tunnel and field studies Recently completed a Grains Research and Development Corporation project to develop an interim ground drift model Starting (this week) a new 3-year program to develop a wide range of droplet size calculators initially for ground applications but probably soon for aerial as well.

13 Droplet Size Droplet size is the main factor affecting drift Droplet size is determined by application conditions (nozzle type and use, sprayer operation, etc) AND tank mix physical properties which are determined by the entire tank mix, not the a.i. or formulation type Sensitivity to RH, temperature and some other conditions may vary among tank mixes

14 The Entire Tank Mix TANK M IX: Various Com ponents At Different Rates A.I. Product(s) Carrier Adjuvant(s) Form ulation type Product type Water Oil Surfactants Drift control adjuvants Other EC, DF, SC, WP SL, EW WSB, M EC Insecticide, Herbicide Fungicide, PGR Fertilizer

15 Adjuvants Many tank mixes include one or more adjuvants to enhance performance We need to understand what these adjuvants do to the atomization and drift potential of the product we are using when applied through the spraying system (nozzle type, pumping scenario, etc) of our application

16 Nozzle Selection Cumulative Spray Volume (%) Spinning disc Disc-core Cone Deflector Flat fan Upper Diam e ter of Droplet Size Class (µm

17 Flat Fan Roundup Invert/ Ammonium Sulfate Polymer Pumped Polymer

18 Disc- Core Roundup Invert/ AMS Polymer

19

20 Herbicide with 41 Nozzle Figu r e 2. V <141µm V alue s fo r C linch e r w ith Diffe r e nt T ank M ix Par tn e r s Sp r aye d Through an d 14 m p h A ir s tr e am s VOC, 12mph NRA1915, 12mph NuFilm, 12mph InPlace, 12mph NRA1915, 14mph VOC, 14mph NuFilm, 14mph InPlace, 14mph

21 Herbicide B with 41 Nozzle Fig u r e 1. V <141µm V alu e s fo r Ato m iz ation o f Gr az o n P+D w ith an d w ith o u t Diffe r e n t A dju van ts T 41 No z z le in 12 m p h Air s tr e am Strikezone Control In-Place Liberate Sta-Put COC No adjuvant

22 Herbicide with AI 118 Nozzle Fig u r e 2. V <141µm V alu e s for A to m iz atio n o f Gr az on P+D w ith an d w ith o u t Diffe r e n t Adjuvan ts A.I. 118 Noz z le in 12 m p h A ir s tr e am Strikezone Control In-Place Liberate Sta-Put COC No adjuvant Activator Target Act.+Target Act.+In-Place

23 Effect of adjuvants on VMD from different nozzle types: VMD (microns) 4 3 Herbicide only Herbicide + surfactant Herbicide + modified seed oil Herbicide + surfactant+modified seed oil 2 1 CP helicopter D1-46 CP deflector 3 CP solid stre am Accu- Flo. 1 6

24 9 Effect of Adjuvants on Fine Droplets from Various Nozzle Types V<153 microns (%) 5 4 Herbicide only Herbicide + surfactant Herbicide + mso Herbicide + surfactant + mso CP helicopter D1-46 CP deflector 3 CP solid stre am Accu-Flo.16

25 Herbicide/ Modified Seed Oil Tank Mixes Chopper 48 oz/acre / Sun-It II 8 VMD (mic Sun-It II (%) Emulsifiable seed oil (%)

26 % droplets < 153 microns 3 Fine droplets (%<153 microns Sun-It II (%) Emulsifiable seed oil (%)

27 Dv.5 (µm) Solutions Emulsions Dynamic Surface Tension (mn/

28 4 Spray Volume Contained in Droplets <15 µm (%) Solutions Emulsions Dynamic Surface Tension (mn/

29 Figure 5. V<153µm Versus Dv.5 Values for Different Tank Mix Chemistry G Solutions Emulsions V<153 µm (%) Dv.5 (µm)

30 Mean Cumulative Downwind Deposition up to 1m Compared to Non- Adjuvant Treatment

31 Droplet Size Models INCLUDED IN AgDRIFT: DropKick (SDTF) USDA models INCLUDED in AGDISP: USDA models Micronair models Various website and CD ROM models

32 Nozzle Angle Angle = deg Coarser droplets Angle = 9 deg Finer droplets

33 Droplet Size Prediction Model for the Jones Air Rotating Boom Assembly C1224 Input data Predicted droplet size Air Speed (knots) 12 D[v,.1] 113 Nozzle Orifice size 4 VMD 237 Fan Angle (deg) 11 D[v,.9] 387 Nozzle Angle to Airstream (deg) Span 1.15 Results Based on Water at 3bar

34

35 AAAAs Droplet Size Calculator for 2,4-D

36 Development of Nozzle Calculator for 2,4-D Sprays AAAA sponsored development of new data, with assistance from some chemical companies Plan to update model with more products and nozzles in late 211 with Australia/ NZ funding, e.g. glyphosate, adjuvants, etc. Please provide input as to what is needed for NZ models

37 2,4-D Droplet Size Calculator for AAAA s: Methods Measure droplet size in wind tunnel for hundreds of combinations of application and tank mix parameters Nozzles: flat fan size 41, 415, 42, 43 CP with, 5 and 3º deflectors Angles of and 2º back from airstream Spray pressures between 2 and 4bar Simulated aircraft speeds of 1, 12, 14knots Water and two 2,4-D formulations at different rates Two drift control/ deposition aid adjuvants

38 Droplet Size Measurement Sympatec HELOS Vario droplet sizer measuring.5 to 35µm Vertical traverse of spray relative to laser for representative cross-section average sampling Replicate measurements

39 Modeling Multiple linear regression analysis of dependent variables (droplet size parameters Dv.1, Dv.5, Dv.9 and Fines %Vol<15µm) against independent variables speed, angle, pressure, orifice size etc for each tank mix for droplet size predictions Genstat version 7 software

40 Results Good agreement between replicate measurements Sprays became coarser with larger orifice size, slower aircraft speed, narrower nozzle angle and (for narrow angle nozzles) higher pressure Sprays coarser for higher rates of water i.e. with greater dilution Polymeric adjuvants increased the Dv.5 values but also increased the fines With this measurement system, Coarse is generally anything with fines below ~9% (actual value to be confirmed it can vary depending on measurement system, e.g. range might be 6-12%)

41 Nozzle Nozzle angle Pressure 2bar 2bar Air speed 1 knots 1 knots Product Water Water Adjuvant None None Dv.5 µm V<15µm % Cumulative distribution Q3 / % Density distribution q3* particle s ize / µm

42 Effect of Speed (1-14kn): 3-12% Fines Nozzle Nozzle angle Pressure 2bar 2bar Air speed 14 knots 14 knots Product Water Water Adjuvant None None Dv.5 µm V<15µm % Cumulative distribution Q3 / % Density distribution q3* particle s ize / µm

43 Effect of Angle (-2º): 12-21% Fines Nozzle Nozzle angle 2 2 Pressure 2bar 2bar Air speed 14 knots 14 knots Product Water Water Adjuvant None None Dv.5 µm V<15µm % Cumulative distribution Q3 / % Density distribution q3* particle s ize / µm

44 Effect of Pressure (2-4bar): 12-9% Fines Nozzle Nozzle angle Pressure 4bar 4bar Air speed 14 knots 14 knots Product Water Water Adjuvant None None Dv.5 µm V<15µm % Cumulative distribution Q3 / % Density distribution q3* particle s ize / µm

45 Solid Stream Nozzle Cumulative distribution Q3 / % Nozzle CPSS CPSS Angle Pressure 4bar 4bar Air speed 14knots 14knots Product Surpass 2.5% Surpass 2.5% Adjuvant None None Dv.5 µm V<15µm % particle s ize / µm Density distribution q3*

46 Effect of Tank Mix Rate Cumulative distribution Q3 / % Nozzle Nozzle angle Pressure 2bar 2bar 2bar Air speed 14 knots 14 knots 14 knots Product Water Surpass 5% Surpass 2.5% Adjuvant None None None Dv.5 µm V<15µm % Density distribution q3* particle s ize / µm

47 Effect of Polymer Increasing Fines Nozzle Angle Pressure 2.76bar 2.76bar 2.76bar Air speed 14knots 14knots 14knots Product Surpass 2.5% Surpass 2.5% Surpass 2.5% Adjuvant 41A 5mL/1L no pump Control 3mL/1L no pump None Dv.5 µm V<15µm % Cumulative distribution Q3 / % Density distribution q3* particle s ize / µm

48 Drift Reduction Technologies (DRTs) ISO standards cover testing procedures in wind tunnels (e.g. nozzles) and field (e.g. sprayers) Several nozzles evaluated in Europe and now encouraged as DRTs e.g. many air induction nozzle designs Some data on ground and tree crop sprayer DRTs e.g. air-assisted, shielded and shrouded systems

49 Droplet capture with vegetative barriers CPAS studies show 6-9% drift reduction. Included in state guidelines for developing barrier vegetation between urban and rural areas

50 Aerial DRTs: For Example Reverse Venturi Chamber Russ Stocker (aerial applicator) inventor Reduces effective air velocity to about half the actual aircraft speed, allowing coarser sprays at higher flight speeds ~ 5-75% drift reduction

51 Pushing the RVC to the Limit: 16kn Fines decreased from 32 to 25% Cumulative distribution Q3 / % P ro duct A djuvan t N o zzle W at er W at er W at er W at er W at er W at er A ccu-flow, p ersp ex s1 bar A ccu-flow, p ersp ex s1 bar A ccu-flow, p ersp ex s1 bar A ccu-flow, p ersp ex s1 bar A ccu-flow, p ersp ex s1 bar A ccu-flow, p ersp ex s1 bar P ressure Speed 1 8 k n 1 8 k n 1 4 k n 1 4 k n 1 6 k n 1 6 k n Dv.5 µm V<15 µm % particle size / µm Density distribution q3*

52 Drop (Lowered) Boom System Lower the aircraft boom after takeoff Drift may be reduced by up to 5%

53 Wing Tip Vortex Mitigation Technologies

54 Wing Tip Modification Devices Modelling suggests drift may be reduced by up to 75% by using wing tip sails (not AG- TIPS though)

55 µm 216 µm Wind Speed (m/s) e inte ns ity Turbulence intensity Droplet Size (VMD) (µm) Temperature (deg C) Relative Humidity (%) Boom Length (% wingspan) Aircraft Speed (m/s) Flying Height (m) AgDRIFT Sensitivity analysis - effect of application parameters on aircraft spray drift deposition at 5m downwind

56 AGDISP Developments

57

58 Three outcomes are possible on initial impact of a droplet with a leaf (fruit, stem, etc.): adhesion, bounce or shatter - (Forster, Mercer and Schou, 21) Shatter Incoming Droplet Spreading Maximum Spread Recoiling Bounce Adhere (Mercer, Sweatman and Forster, 21)

59 Track-sprayer retention results illustrating the effect of species, formulation and volume Percent retention of 4 formulations, sprayed to wheat, canola and capsicum Species Nominal Volume (L ha -1 ) Water.1% Superspreader Formulation.25% Superspreader.1% Superspreader Wheat Canola Capsicum Note: capsicum and canola similar architecture at the age used

60 The Adhesion / Bounce Model (Mercer, Sweatman and Forster., 21) ( ) ( ) cos = dt dr sr r r Oh r r dt d dt dr r dt d θ ( ) ( ) cos 1 2 = + t = r r θ = = + = t t r We dt dr Incoming Droplet Spreading Maximum Spread Recoiling Adhere Bounce

61 The Shatter Model (Forster, Mercer and Schou, 21) Incoming Droplet Spreading Shatter Droplet shatter will occur if K exceeds a critical value, Kcrit, where: K = Oh(Re)1.25 and Oh = μ / ρσd Re = We / Oh We = ρdv2/σ K involves formulation parameters (dynamic viscosity, density and surface tension) and droplet parameters (size and velocity) No variables describing the leaf surface

62

63 Software

64

65

66

67 AGDISP Relative Humidity Effect The model evaluation paper by Bird et al. (22) struggled with the apparent inconsistency of the absence of an evaporation effect on deposition data, whereas the model appeared sensitive to relative humidity in the far field, attributing the possible problem to very small particles drifting downwind, with low collection efficiencies. What may have been missed is the behavior of relative humidity within the nozzle spray cloud. If we look only at the high humidity cases (for the 1 trials greater than 9% relative humidity), we see good agreement with data.

68 Comparison with SDTF Field Data

69 Relative Humidity Effect In AGDISP the wet-bulb temperature depression is computed once, based on the ambient temperature and relative humidity, and the assumption that the tank mix is also at ambient temperature (confirmed by SDTF). Now, in a simple laboratory experiment we measured the relative humidity inside a spray cloud and found it to be 5% higher than ambient. A correction factor was then used to generate an effective nozzle spray cloud relative humidity, and the SDTF dataset was rerun to check the effect of this correction.

70 Comparison with SDTF Field Data

71 Helicopter Model Bird et al. (22) showed that in helicopter simulations the near field deposition is over-predicted while the far field deposition is underpredicted, a behavior contrary to fixed-wing results. It was suggested that the problem was the XC/ UC droplets from the straight stream nozzles, possibly suggesting that droplet spectra from wind tunnel measurements did not account for secondary breakup. See example below for water. Most formulated tank mixes will be 1 µm less.

72 Secondary Breakup of V. Large Drops (Lane, 1951)

73 Helicopter Model Change AGDISP used a CFD model result to estimate the transition time between helicopter downwash and vortical roll-up. The estimate is that two rotor radii downstream of the helicopter, the helicopter wake looks like that of a fixed-wing aircraft. The SDTF database contains six WASP helicopter runs. A sensitivity study around the assumed transition distance permitted us to modify the helicopter model slightly to recover a more consistent downwind deposition pattern. Unfortunately, the dataset is too small to draw any significant conclusions, and the flow field is far too complicated for a simple model estimation.

74 Comparison with SDTF Field Data

75 More on Drift Management: Boom Length Shorter boom lengths can greatly reduce drift, for rotary and fixed wing aircraft Greatest benefit at <65% boom length Will not necessarily decrease swath width sufficiently to require significantly more flight passes

76 Long boom

77 Shorter boom

78 Fixed-Wing Aircraft Wakes

79 Helicopter Wakes

80

81 Release Height Height above canopy is key to distance that droplets can travel, especially at edge of application area

82

83 Application Practices: Swath Adjustment Most applicators already practice swath adjustment, a practice which can have a very large effect on reducing drift Offset varies by wind speed and droplet size

84

85 Meteorological Effects Wind speed and direction are key parameters affecting drift Temperature and relative humidity can affect evaporation rates, so may also be important Atmospheric stability important- most labels recommend not spraying under local surface temperature inversion conditions

86 Atmospheric Stability

87

88 Canopy Canopy can have significant effect on capturing droplets, reducing drift potential Downwind barriers such as hedges also can reduce drift by 6-9% Possible future addition to drift models