Spray drift. News articles about damage caused by spray drift seem to pop up regularly, almost as daily reminders, during the summer months. Whether it be dicamba-related issues in those states of the U.S. where dicamba-tolerant soybeans are grown, 2,4-D related issues in the Australian cotton-growing region, or any number of other events that are reported on in the news on a regular basis, spray drift seems to be omnipresent.
Spray drift, the airborne movement of chemicals as droplets, particles or vapor, can have many causes but the main ones are:
- Wrong droplet size; small droplets drift easier.
- Wrong conditions (inversion, wind too low or too high).
- Wrong formulation used; ester instead of amine formulations for example.
Chemical drift can have far reaching consequences, from not properly spraying the field that you intend to spray, to damaging a neighbor’s crop, or even creating a health hazard for humans and animals. In the long run, the consequences of repeated spray drift can mean that growers lose access to key weed control tools. Examples of this are repeated calls to ban or restrict the use of 2,4-D in Australia’s cotton growing areas, with similar dicamba issues in certain states of the U.S. This recently became even more real for many growers as the scary prospect of losing glyphosate played out as Brazil temporarily banned the use of this valuable herbicide, even though there was no scientific justification for the decision. Growers and suppliers all over the world were relieved when this initial ruling in Brazil got overturned, but it was a good reminder that it is up to us to demonstrate responsible use so that they are not taken away, leaving us with more expensive / time-consuming options.
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As shown above, there are a multitude of reasons that can cause off-target drifting, but all these reasons lead back to one common theme: Operator knowledge. Droplet size for example is a factor of pressure and nozzle type, weather factors can be measured with a weather meter and product suitability information can be found on product labels. Identifying inversions however is not that easy and it takes some practice and experience. In most areas, spray operators have to successfully complete a training course before they are allowed to operate a spray rig, but these courses only really teach the basics and operators need more experience and on-the-job training in order to become proficient.
Renowned Australian spray application expert Mary O’Brien is a passionate advocate for sustainable agriculture. She conducts workshops in spray drift risk management and assists clients with record keeping and legislative compliance among other issues. In her role as spray application expert, she encounters problems caused by spray drift on a daily basis. Mary’s comments on the operator knowledge: “I believe most operators are trying to do the right thing but they are not confident in identifying inversions and they put too much emphasis on delta T which leads to night spraying. Other issues I commonly see are applicators not reading the label, using the wrong nozzles, or using the right nozzles but the wrong way.”
Farm Management Systems (FMS) will play a key role in the future in helping growers fulfill regulatory requirements in many aspects of their operation and spraying is one of them. Growers need to keep a record of what is being sprayed on each of their fields, when their fields have been sprayed, and the climatic conditions at the time of application. Increasingly growers decide to automate this process. By linking an agronomists’ spray recommendation to a farm worker’s job list, critical information can be accessed by the spray operator, irrespective of time and place. Information such as product and rate are pre-filled in a work order already in collaborative systems, so spray operators don’t have to double-enter information.
Agworld Co-founder and Chief Strategy Officer Matt Powell remarks: “Agworld is designed around the principle of collaboration which involves everyone on or around the farm such as agronomists, growers, farm workers, custom applicators etc. Part of getting farm workers involved is making it super easy for them to record data onto the Agworld platform, but also letting them access critical information pertaining to the jobs that they are performing and the exact location they should be spraying. When your farm workers have a platform like Agworld that helps them easily record jobs on their iPad or iPhone, they are automatically encouraged to think about what they enter and whether what they are doing is correct and the app can provide extra layers of checking or warn them if something looks wrong.”
Mary adds: “I strongly encourage good spray record keeping as your records are the best way to demonstrate what you did and how you did it. Having detailed records demonstrates due diligence and will be invaluable if your practices are ever questioned. Systems that provide access to critical information and constantly remind applicators to check what they are doing will help keep best practice at the front of everyone’s mind.”
By providing spray operators with a Standard Operating Procedure (SOP) that involves accessing the work order and product labels and then entering nozzle, pressure, and weather information in an app such as Agworld that makes this information available to the grower, agronomist, and everyone else involved, a lot of issues can be prevented.
“Spray drift issues can cause friction between neighbors and are often very costly affairs when fields, vineyards, or orchards get damaged,” Powell says. “Whenever a government gets involved in recurring issues more regulation seems to be the answer, which can be even more expensive for growers in the long run. If growers use the tools that are available to them to help avoid these issues, we can avoid additional regulatory burden as much as possible as an industry.”