Growers should be aware of which chemicals pose risks and how to properly clean a sprayer’s nooks and crannies
The first step in flushing out a sprayer should actually occur when the tanks are being filled says spraying expert Tom Wolf.
“That means making sure you’re properly dissolved, making sure you’re properly mixed,” Wolf said.
He said improper mixing of chemicals can cause problems at the end of the tanks, where vigorous agitation can act as a bit of a homogenizer.
“Cleaning out that little left over becomes a challenge because it’s changed,” he said.
“That is often a problem with our emulsifier concentrates, the oil based formulations. The ones that are milky in the tank often have an oil based surfactant adjuvant in there, like Amigo, Score or Adagore. That creates the problem.”
Producers must know which products can be difficult to clean out and damage crops later on so that they can be extra careful when mixing them.
The Group 2 products that often create problems in canola have low solubility in acidic PH conditions, which is one of the reasons why ammonia works well as a cleaner. It acts as a weak base and raises the PH of the mixture, which brings difficult to dissolve products back into solution.
Wolf said Group 2 products that can cause clean-out problems include Dupont’s sulfonylureas-based products such Refine, Refine Extra, Express Pro, and Express SG. These chemistries are also in Harmony Total, which is a Horizon Plus product.
Group 2 Dow products that can be tricky to clean out include Frontline, which is in PrePass and Simplicity.
Bayer products with group 2 thiencarbazone-methyl chemistry, such as Varro and Velocity m3, are also known to cause crop damage if sprayers aren’t thoroughly cleaned after their application.
“Those are the key ones to watch out for,” Wolf said.
“If you’re using those products, or sister products, or tank mixes, be careful.”
BASF Group 2 products, called imidazolinones, including Raptor, Odyssey, Aers, and Solo, dissolve better at low PH. They tend to cause fewer problems with crop damage after a sprayer cleanout because they are soluble in plain water.
“They actually don’t even mention ammonia on their label,” he said. “They just say flush with water and you are good to go. In all the years I’ve been looking at this, I don’t remember ever seeing a problem with a BASF product in cleanout with canola. It’s very rare.”
Wolf said it’s important to clean out a sprayer immediately after spraying is completed.
“Don’t let the material (sit) overnight. Don’t let it dry on onto the tank wall,” he said.
“It just makes everything more difficult. Do it promptly.”
Do not drain tank heels onto the ground because it creates pollution.
Instead, spray the tank on the field or on a piece of land that can be sprayed until the tank is empty. Then add water from the onboard clean water tank and spray it out. Repeat, adding clean water and spraying it out three times.
“You don’t have to use a lot of water. Typically we say, if you have onboard 10 percent of your total tank volume, if you have a 1,000 gallon tank and you have 100 gallons onboard clean water, divide that into three 30 gallon batches,” he said.
“Then your residue, your liquid remainder that is in that tank, is now so dilute that it is very unlikely to create a problem.”
The Saskatchewan government’s Guide To Crop Protection suggests adding one litre of ammonia (three percent) for every 100 litres of clean water and begin agitating when performing an ammonia rinse. Allow the solution to flush through the booms until they are filled with the ammonia solution and then top up the tank with water.
Then flush the solution through the tank and pump system for 15 minutes. Flush the booms and hoses with the ammonia solution again, for at least five minutes, before emptying.
For a detergent rinse, the Crop Protection suggests filling the spray tank and adding a heavy-duty detergent at .25 litres per 100 litres of water after performing a freshwater rinse.
Then circulate the mixture for at least minutes and spray out through the sprayer nozzles.
Operators then need to clean the inside of the black rubber hose on the sprayer with a cleaner.
“Put your cleaner in there and let it sit for a little bit — just give it a chance to soak in and strip it off the walls — and then flush that out,” he said.
“There is really no sure guarantee on how long to soak it for, but I would say let it sit for a bit and flush the booms out again.”
Wolf said ammonia as a sprayer cleaner is misunderstood.
“Ammonia is not designed to get rid of an oily film; ammonia is designed to change the pH,” he said.
“Ammonia is designed to solubilize something that likes to become soluble at high PH. If you want to cut grease, you have to add a grease cutter, and that is going to be a surfactant of some sort.”
Many producers use ammonia with a commercial cleaner such as All Clear, which is best used with an antifoaming agent such as Halt.
“Some people believe ammonia can hurt your crop — it cannot. You can spray your tank clean out, don’t worry about it — it’s not going to hurt anything.”
All of the screens need to be checked once the sprayer is flushed out, including around the filter and possibly the nozzles.
The boom ends also need to be flushed, and Wolf recommended a product by Hypro that cleans the boom ends.
“The Express Nozzle Body End Cap takes care of it for you, so you never have to flush a boom end again,” he said. “It gets rid of it on its own. (It’s) on the go all the time.”
An increasing number of crop products such as micronutrients are being sold in Canada, and many of them are applied with sprayers.
However, it is unknown how they interact with other products in a tank mix, and Wolf said they could cause problems.
“Those products mixed in with the herbicide do things that you can’t right now predict,” he said.