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Weather And Spraying; A Turbulent Relationship

Local farmer out spraying his crop. Photo Dawn Riley

Wrapping up a conversation with my neighbour two weeks ago about the difference between soil and dirt (see Issue 876) I made a statement along the lines of a ‘few quiet weeks’ in his life while the growing season took hold and progressed. His response? An extremely amused laugh. I am learning quickly that farming never has downtime.

Next on the farming calendar? Spraying, if needed. According to the Royal Society of Chemistry, crop protection chemicals can provide a cost-effective way of improving the yield and the quality of crops. They also make harvesting more straightforward and support the maintenance of consistent yields from year to year.

There are three central groups of crop protection chemicals, herbicides, insecticides and fungicides. Selective herbicides can help control the growth of weeds which grow among a crop, competing with it for water, nutrients and sunlight. Insecticides are utilized when needed to deal with harmful bugs, like flea beetles, cutworms and armyworms. Fungicides help stop the spread of fungi and their spores on plants. Without crop protection chemicals agriculture would be less efficient.

Like so many aspects of farming, weather has a direct correlation to the need for spraying a crop. It can determine the intensity of spraying, type of chemical, and amount of times a crop is sprayed in a season. Temperature and rainfall are the central weather factors of spraying possibilities in Alberta. In combination with the growth stage of the crop, these two factors can determine what chemical protection is best, and whether it is bugs or weeds that will grow and prosper in a field. Fungicide use is highly contingent on the weather, as a dry year sometimes does not require application of them. Around these parts, spraying is more often tied to weed control, as pesticides are harmful to all types of bugs, and farmers will try to preserve the habitats needed for helpful insects, such as ladybugs. Spraying of a crop can happen more than once a year, and can be for a different reason. A farmer may have to spray for weed control early in the season, then go back with an insecticide later in the growing season if an invasive bug moves in.

The third weather factor that can affect spraying is the wind. Farmers have to be aware of wind speed and direction when spraying their crops due to the possibility of spray drifting. The Alberta Government agriculture website defines spray drift as “the aerial movement and unintentional deposit of pesticides outside of the target area.” If spraying is done under less than ideal wind conditions, neighbouring crops and floral life can be destroyed. Farmers are required to spray responsibly, taking care to not endanger the areas surrounding their crops. The combination of these factors can provide a very small window of opportunity to spray a field, meaning a farmer has to be available to literally hop into the sprayer when the time is right.


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