GCTV Ep#11 Spray Drift Technology
Narrator: Jane Drinkwater Since the 2010 implementation of government-proposed
regulations requiring new pesticides be assessed for spray drift, and new chemical labels might
prescribe mandatory no-spray buffer zones, spray drift has been a hot topic for the agricultural
sector.
So much so a National Working Party on Pesticide Application made up of growers and industry
representatives was formed to ensure scientific accuracy underpins any decision-making process.
Peter Mailler: National Working Party on Pesticides Application, Executive member
Technology without knowledge is not an appropriate license to operate.
Narrator: As a working party member GRDC has given support
to a number of research projects, the findings and recommendations of which will assist the
NWPPA in its representations to the Australian Pesticides & Veterinary Medicines Authority.
APVMA approves chemical labels and the directions for their use.
This University of Queensland facility is conducting one such research project, examining
the variables that impact spray drift.
Peter Mailler: National Working Party on Pesticides Application, Executive member
We have known for a long-time that nozzle selection, pressure, formulations all have
an impact on spray quality and what is happening in the field.
That work actually quantifies that so that when we sit down with policy makers to talk
about how they have determined mandatory buffer zones and whether or not its even appropriate
to have mandatory buffer zones, that science is the thing that underpins it.
Narrator: By examining all aspects of the spraying process
the research team will then be able to determine which combinations give the most effective
coverage with minimal drift.
Andrew Hewitt: Centre for Pesticide Application & Safety, Uni of Qld, Gatton
We want to look at the nozzle, the pressure, the angle, the speed of the sprayer how fast
is he driving or flying if its an aircraft, the pesticide, the herbicide and the adjuvants
that they add and then the meteorology is important too so we need to look at the temperature,
humidity, wind speed, wind direction.
Narrator: Droplets with a diameter of less than 100
microns or a tenth of a millimetre known as driftable fines are the problem.
Chris O�Donnell: Centre for Pesticide Application & Safety, Uni of Qld, Gatton
They are the ones that drift in the wind and do the damage.
So farmers need to know what percentage of fines they have when they are using a particular
nozzle with a particular tank mix at a certain pressure.
Narrator: Using a diffraction laser in a wind tunnel,
the team can determine the median droplet diameter and the percentage of driftable fines
for various combinations of nozzles, spray mixtures and environmental conditions.
The challenge is getting that balance between a droplet size that is small enough to provide
good coverage, but large enough to prevent spray drift.
Andrew Hewitt: One of the key areas we are working on here
for GRDC is to build up a database of all of the different nozzles, all of the different
tank mixes that an applicator could use, to help them decide what is best for their application,
because every spray is probably going to be different.
Narrator: Information that in the short term will help
the work of the NWPPA and in the not too distant future be available to grain growers.
Chris O�Donnell: We hope to have it available as a mobile phone
app.
So the farmer if he is out in the paddock, he can just sort of put in his herbicide,
his nozzle type and the pressure he is going to use that at, and it will tell him what
his spray quality will be.
Narrator: The app is on schedule for release in the
next year or so.
Jane Drinkwater: Reporter Results from this research should produce
improved spray drift management in the future, but what should growers be thinking about
right now to reduce spray drift.
Andrew Hewitt: One way is to not spray when the wind is blowing
towards the sensitive area because drops only go where the wind takes them, so wind direction
is key.
Another key is the height of the boom, so do not take your spray boom high.
If you can, look at putting a cover over the boom if there is significant wind that could
move the droplets, the cover will effectively stop the wind.
And then another key is not to spray when there is no wind when you may have a temperature
inversion.
Narrator: Chemical spray users adopting such recommendations
and researchers being able to provide the NWPPA with quantifiable data is what is needed
to persuade policy makers to revise down the proposed increases to spray buffer zones.
Exactly the kind of data Andrew Hewitts team is providing.
Peter Mailler: So it is no longer a contest of attitude or
you know my opinion is that you do not need to do that none of that applies anymore.
We have actually got hard scientific data that the regulators can rely on as well.
Ends
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