Chemicals can build up in the sprayer and cause problems for later operations if they are not properly cleaned out
A spray day doesn’t end when the farmer parks the rig.
Producers who use Group 2 products that are formulated as a dry fine ground powder have one more important task when they park the sprayer: cleanup.
The issue is compounded if they mix Group 2 dry products with other products that have an oily adjunct, says Clark Brenzil, weed specialist with Saskatchewan Agriculture.
“That’s the concern because a lot of glyphosates have an adjuvant called tallowamine,” said Brenzil.
Tallow is synonymous with fat, and while tallowamines are not technically classified as oils, they do have the same properties as oils when they’re inside a sprayer.
“They don’t make the glyphosate itself stick badly enough to the insides of your sprayer to be a problem, but they do allow a buildup of Group 2 products,” he said.
These Group 2 chemicals are active at such low concentrations that they’ll cause crop damage later if not completely purged from the spraying system.
Proper clean out is also important during preseeding burnoff.
“There’s no crop involved, so farmers feel they can spray lots of acres with some of these combinations of products and not clean their tanks out through the whole burn-off season. That’s a wrong assumption.”
Brenzil said a daily clean out during the glyphosate season is every bit important as the daily clean out during the growing season.
He said a common crop damage situation occurs when the weather and soil temperature become conducive to seeding near the end of burn-off spraying. The sprayer is quickly parked while all human resources are channeled into putting a crop in the ground.
However, residual burn-off chemicals in the sprayer are strong enough to do considerable damage when it comes time to do in-crop spraying, despite a quick, but incomplete, clean out.
“The longer the sprayer sits, the more opportunity there is for deposits to form in the tank and the plumbing. Then it’s time to spray again, so they’ll top up the tank and go spraying,” he said.
“Over time, you get a pretty significant buildup. Your glyphosate adjuvants are not extremely oily, but they are oily enough to form a residue.”
There’s evidence that the residues bond to plastic and rubber surfaces, but Brenzil said there’s no way to completely eliminate plastic and rubber from the sprayer.
“You’ll often hear stainless steel tanks promoted by sprayer manufacturers because it reduces the amount of adherence to the tank,” he said.
“That’s fine, but it doesn’t address the bigger problem, which is the plumbing of the sprayer.”
Stainless steel cleans faster and more thoroughly than poly products, so it should be installed when replacing components.
However, stainless does not eliminate the necessity of doing a total clean out, especially the boom components.
Brenzil said the entire tank and plumbing system should be thoroughly cleaned every time the machine is shut down longer than it takes for a normal fill for water or fuel.
“You should clean your sprayer as often as you clean yourself. If you clean the sprayer daily, it’s not such a major task,” he said.
“There are some herbicides that actually recommend you clean the sprayer after every 1,000 acres or so. Group 1 herbicides are an example of that because they have fairly oily adjuvants that go with them.”
He said an effective way to get good results is to let the sprayer soak overnight. Empty the tank and then run clean water through the sprayer to rinse out any loose residues.
Some producers who have been running glyphosate mixed with Group 2 herbicides think they can run more glyphosate through the tank for clean out, but Brenzil said it doesn’t work that way.
“Take the tank to about one-third full, then add the appropriate cleaning substance that’s specific to whatever herbicide you’ve been spraying,” he said.
“If you have that oily film, ammonia has a good reputation in the kitchen as a grease cutter, but the oily film adhering to the tank and plumbing may be more than ammonia can handle. In that case, a soapy detergent might also be a good option to include in the tank as well. Some of the commercial tank cleaners like Clean Out or All Clear have the ammonia to cut the oily film and raise the pH.”
The detergent mix should be circulated through the plumbing. Run some of it out through the boom and through the nozzles and then let it set overnight to work away at the residual buildups in the system. Drain it out the next morning, and put a fresh rinse through the plumbing, booms and nozzles. The farmer is then set to go with clean equipment.
Brenzil said it’s important to prevent a product from settling and sticking to the bottom of the tank.
Changing from one product to another is the time to do a thorough clean out. Remove all screens, nozzles and the main screen from the bottom.
Put it all in a five gallon bucket with hot soapy water and scrub it well until it’s perfectly clean.
He said the main screen at the bottom of the tank should be checked every few days, but producers often ignore it because it’s in an awkward location.
As well, some products require a larger screen size in the main screen and nozzle screens.
Brenzil said obvious functional problems will occur if a sprayer reaches the point where there’s so much residual buildup that normal cleaning won’t do the trick. This happens when owners rely only on ammonia to take care of the oily buildup.
“That’s why it’s so important to have the entire system sitting overnight with ammonia and the correct detergent soaking all components,” he said.
DuPont agronomist Doug Fehr said the tank is relatively easy to keep clean, but the boom has more nooks and crannies, which allow deposits to take hold.
“Some people refer to it simply as tank clean out,” he said.
“I prefer to call it sprayer clean out, just to emphasize that we’ve got to include the boom and all the screens, filters, nozzles and fittings.”
Fehr encouraged producers to charge the entire system with detergent and ammonia and run it through the boom for a few minutes before letting it sit overnight. This gives the detergents a chance to work away at the deposits.
“To do a really good job of cleaning the boom, the other thing you need is to install the Hypro’s Express Nozzle Body End Caps at the ends of each boom section,” he said.
“These end caps let you flush all the product residues from those dead spaces at the end of each section. The other side benefit is these end caps bleed air from the lines on the go as you’re spraying.”
Fehr knows that seeding sometimes interrupts spraying and the sprayer might sit for a week or longer as the residues inside grow harder. It’s a bad situation nobody likes to face.
“When that happens, you need all the regular products like ammonia plus the detergents that are designed for those specific herbicides, but that doesn’t always do the job,” he said.
“So we flush it out and let it soak in detergent a couple times, plus add laundry or dish detergents to cut into the oil and residue.
“With the older herbicides we had years ago, we’d also use things like vinegar and bleach, but those cleaning agents won’t do anything to touch the new generations of herbicides we have today. I’d say probably three quarters of the liquid-based herbicides we have today are oily based products.”
Agrimetrix spray specialist Tom Wolf said ammonia is required to raise the pH, which improves the detergents’ cleaning ability.
For example, tank mixing a burn-off concoction of glyphosate and Sulfonylurea (SU) Group 2 automatically creates a cleaning challenge. The acidic glyphosate lowers the pH to about five, and the SU Group 2 chemicals don’t easily dissolve in water with such low pH.
Ammonia solves the problem by raising the pH enough to make the SU products soluble.
For more information, contact Clark Brenzil at 306-787-4673 or 306-533-9301 and Doug Fehr at 306-441-7781.