Concentrated chemical residue | Failing to wash sprayer and booms inside and out is ‘a good way to reduce your yield’
WOODSTOCK, Ont. — New herbicide formulations, registrations and blends are mixing up trouble in boom land.
It isn’t what farmers are intentionally spraying that is causing the problems. Instead, it’s what is coming out of the nozzles that farmers don’t know about.
“There was a time not too many years ago that if you did a half-assed job of cleaning out (the sprayer), you could sleep pretty easy. That’s over,” said Helmut Spieser, an Ontario provincial agricultural engineer.
Spieser said a quick rinse and boom wash became “a little too popular” when applications were limited to a lot of Roundup or Liberty and a few easy-going Group 2 or 4 chemistries.
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“Even then you had damage but might not have noticed, or you blamed it on something else,” he told farmers during field demonstrations at Canada’s Outdoor Farm Show in Woodstock last week.
Producers in the 1970s and 1980s avoided leaving chemicals in their tanks overnight.
Some of the formulations used during those years were prone to forming glutinous masses in undisturbed tanks.
As well, some molecules in a few of the products’ active ingredients formed temporary bonds with the insides of tanks and booms and re-leased as soon as they came into contact with a sudsy adjuvant mixed with another chemical.
The resulting, unregistered combination killed or damaged every plant it hit.
Farmers learned those lessons quickly and cleaned out every night. This usually involved a partial fill, a boom flush and a repeat process.
Glyphosate changed all that.
The farmer friendly product with its built-in adjuvant is a great form of tank cleaner, capable of freeing residue and delivering it to non-tolerant crops.
The need for tank mixed products to control herbicide tolerant crop volunteers and resistant weeds and to improve burn-off of older and fall annual weeds has added compounds that once again like to lurk.
Jason Deveau, an application technology specialist with the Ontario agriculture ministry, said the amounts of most chemistries hiding at boom ends or lightly bonded to interior surfaces are often enough to do a lot of damage to the wrong crop.
“And we are getting some new formulations of some old and more volatile and aggressive products,” he said.
“Dicamba and 2,4-D have been reformulated (recently) to be less prone to drift, but if they come into contact with some other chemistries in the form of residues, it results in the salt (that has been chelated onto them) stripping off and products like dicamba returning (to)their roots, only worse. You end up with very unstable products that can end up off-target.”
Spieser said “it gets to be very expensive if the “off target” is a neighbour’s crop.
“The (American Society of Agricultural and Biotechnical Engineers) did a sprayer study back many years ago, for those, more insidious products in the 1970s and ’80s,” he said.
“They found that just cleaning out the machines overnight and a single, water rinse removed 95 percent of the residue. Leaving these products in the machines overnight today is going to give you old-school problems out in the field.”
The advice is to clean out the machines every day by emptying and partially refilling with the tank spinner engaged and then draining out again, including dumping the ends of the booms.
Specialists say this is more effective than leaving machines loaded overnight and then cleaning with tank cleansers later on.
The advice is based on a recent Colorado study of farmers and commercial applicators that found that only 22 percent of operators clean out completely at the end of each day or before each new chemistry.
Fifty-nine percent will clean out the machine when changing pesticides and 31 percent will clean out when changing locations or crops.
The study found that 78 percent of operators washed both the inside and the outside when sprayers were fully cleaned out.
“You have to wash both,” Spieser said. “That machine is covered in products and often concentrated levels of them. Don’t worry if you don’t, you can use your next crop to wipe them off. It’s a good way to reduce your yield.”
The study found that 34 percent of operators used water for a full machine clean out.
Tank cleanser was used in two rinses in 14 percent of cases and 50 percent used it three times.
Six percent used another combination or method.
Ammonia was used where called for and some operators used chlorine. The study found that a single respondent used fuel oil.
Some cleansers use active ingredient neutralizers.
Deveau reminded producers that those products need to be rinsed out.
“They can neutralize your next application very quickly,” he said.
Triple rinsing with water can be effective, except where cleaning solutions are required or preferred. Machines should be filled to 10 percent capacity and run for 10 minutes. This is repeated two more times.
