Correct nozzle use moves to political radar

Using the right nozzle for the right product at the right water rate could some day become a legal requirement.

Tom Wolf of Agrimetrix in Saskatoon says farmers need to consider their application methods as carefully as they do their rates of product.

“Legislation is in all of our futures,” he told a farm meeting in Saskatoon last month.

“There is a new rigour for legislative requirements for spray nozzle requirements.”

However, he said producers should already be ensuring that they use their products appropriately for maximum financial benefit.

Soil-applied products can be applied with low drift, but coarse and very coarse nozzles are not so forgiving.

A highly mobile systemic product can be applied to a leaf with a spotty approach through a coarser nozzle, as long as each plant is reached. This includes modes of action such as Groups 2, 4 and 9.

However, Wolf said Groups 1, 6, 10, 14, 22 and 27 need a finer application with greater leaf coating abilities.

He said broadleaf plants can generally handle a coarser spray.

“Grasses are not very forgiving. Finer sprays and, for some of you, often higher (water rates), provide that coverage.”

Tank mixes are becoming the norm for many producers who need to defeat traditional pest plants and herbicide tolerant volunteers.

They have the additional advantage of controlling more than one type of weed and containing more than one mode of action.

“There are combinations where you are using a 9 and 6 or 9 and 14 tank mix; then the (type of) contact rules,” he said.

“If it is a grass and broadleaf, then the grass requirements rule and you need a finer approach.… If you are shorting the water (rates), then you have to make better choices (about that).”

He said some producers are looking to reduce refilling times and increase operating speeds by using finer nozzles to ensure basic coverage of leaves with lower water rates.

“You are creating problems for yourselves and potentially others,” he said.

“Group 4, dicamba and 2,4D, and the new Dow products are Group 4, you need to think about coarse to very coarse.”

Farmers can select the right nozzle using the charts that most nozzle companies provide. Other options include software applications for smartphones and tablets, such as the Saskatchewan Soil Conservations Association’s Spray Quality Finder.

Wolf said speed is always a variable, but growers can start by choosing the speed at which they would like to travel and then looking for nozzles that produce the spray fineness or coarseness re-quired for the product at the right water rate.

Their pumps’ capacity to provide the appropriate pressure will help determine either the right nozzle or the appropriate speed.

Most charts will provide four or five choices of nozzle openings at a set speed. The smaller the orifice, the higher the pressure.

Nozzles are rated for droplet size based on certain pressures. Operating outside of those parameters produces droplets that are inappropriate for the task at hand.

“These (charts) are amazingly handy,” Wolf said.

He advised farmers who find a chart for their nozzles to “laminate it, download it, put it in the cab.”

Roundup Ready Xtend soybean friendly chemistry contains dicamba and glyphosate, and BASF’s Engenia, which is used for these genetics, requires a coarse to very coarse nozzle to keep it where it is targeted.

Dow’s new 2,4-D is a choline salt formulation known as Enlist Duo that also requires coarse to very coarse.

Xtendimax is the dicamba and glyphosate product that farmers will be able to use this spring because of China’s recent approval of the technology. It is also a coarse to very coarse droplet-size product.

Maintaining good patterns and proper coverage with coarse nozzles is a product of pressure.

As a result, pressure drops when speed is reduced if low water rates are used, which can be a problem, especially when slowing for ditches and other terrestrial hazards.

Flow controls will open, bypassing product to maintain the rate per acre by cutting the pressure, but the controls don’t consider the effect on droplets or how far apart these might become.

Jason Deveau of Ontario Agriculture said producers should consider mounting inline pressure gauges on their booms to observe what the actual pressures are in their sprayer systems.

A combination of a $15 gauge with a T-fitting can provide accurate nozzle pressure readings. Those pressures are what determines nozzle rates.

Sprayers usually measure pressure only from a point near the pump, and the two can be different, especially as sprayers become wider.

Wolf said producers not only need to consider efficacy but also future regulations.

“It is coming, and it matters,” he said of pending or proposed regulations in Ontario and Manitoba.

For more information, contact Wolf at Twitter at @nozzle_guy or email at

Deveau can be reached at Twitter at @spray_guy or email at They operate an application website at

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