Could it Get any Worse?

Helmut Spieser - Agricultural Engineer/OMAFRA Ridgetown
23 May 2008

The spring of 2008 will be remembered by many farmers but not necessarily in a good way. It has been cool, lots of rain, enough frost risks to forget, some sun, some warm days, more rain and wind. The calendar marches on and spraying needs to be done. With farm equipment spending more time in the shed than in the field, farmers' patience is wearing thin. As trying a time as this may be, there is no excuse for making bad choices.

Case Study

A farmer is out spraying. The picture really tells it all. No, the field was not dusty, rain the three previous days pretty much eliminates that. Everything you see that is not sky, bush, bare field, green field or equipment is likely airborne spray. I don't know the wind speed or wind direction at this location since I did not take this picture. If the individual spraying would like, I could send them copies of the pictures.

This is not a pretty picture. People driving down a public road should not be able to take a picture like this. Even if nobody was there with a camera, this should not happen. Farmers pride themselves in using and applying crop protectants in an environmentally conscience manner. When one sees spray lingering this far behind the sprayer and being carried aloft to such a height, it's hard to stand up and say "Trust me - I know what I'm doing".

So what could have been done to prevent this situation?

1. Check the wind speed.
2. Check the wind direction.
3. Check your surroundings, there's a tree row or small bush nearby.
4. Look back once in a while, the spray is getting away.
5. Re-evaluate your nozzles; consider upgrading to designs with less drift, now!
6. Stop spraying.

Whenever discussions come up involving spray drift, people want to know what the maximum wind speed is safe for spraying. There is not a standard answer to this question. The product label may state the maximum allowable wind speeds for spraying. Having said that, if you are spraying at wind speeds well below the allowable wind speed on the label and you cause drift - you are in violation of the Pesticides Act.

Figure 1. Operating a sprayer and causing thismuch drift is irresponsible
and requires changes immediately or STOP SPRAYING!

A number of factors may have contributed to the amount of spray being carried by the wind in this picture. If the wind was passing over the tree row at an angle it may have rolled, carried small spray droplets up and back in an ever growing vortex. The result - spray droplets further behind the sprayer and higher in the air than one could imagine.
Sprayer operators should constantly evaluate environmental conditions in the field you are spraying and make adjustments as required to prevent drift. In some cases, your only option may well be to stop spraying. This likely does not sit well with some farmers. You should do whatever it takes to do a good spray job all the time not just when it's convenient. Whether you realize it or not - people are watching what you're doing and how well you're doing it. Society is fickle in that no one congratulates you when you do a good job of spraying but they do notice a poor spray job and sometimes they tell others.