Author: Tom Wolf

What’s my Spray Quality, in 3 Simple Steps
The introduction of dicamba and 2,4-D tolerance traits in corn and soybeans was accompanied by an unprecedented emphasis on spray drift management by the registrants. Product label statements for 2,4-D choline and the new formulations of dicamba emphasize spray drift control to a greater degree than previous products.
In Canada, labels make prominent reference to the appropriate “spray quality”, a term referring to an internationally standardized droplet size classification (ASABE S572.2). In this standard, the droplet size spectrum produced by a nozzle is communicated using terms such as “Medium”, “Coarse”, “Very Coarse” etc., and used to describe the potential for spray coverage and spray drift. Spray qualities are colour coded for easy recognition.
An example of this label language is shown for Enlist Duo below:
“Droplet Size: Apply as a coarse to extremely coarse spray (ASABE S572 Standard). Use drift reducing nozzle tips in accordance with manufacturer directions that produce a droplet classification of coarse to extremely coarse to significantly reduce the potential for drift.”
Although spray qualities are voluntarily measured and published by most nozzle manufacturers, their appearance on the label makes their use a legal requirement. This is because the Pest Management Regulatory Agency (PMRA) conducts a risk assessment which assumes, in this case, that a Coarse spray quality supports certain calculated buffer zones (15 m in this case) to protect sensitive ecosystems from Enlist Duo damage.
The use of coarser sprays can be used to reduce this buffer zone somewhat, in accordance with an on-line “Site-Specific Buffer Zone Calculator” published by the PMRA.
The challenge for applicators will be to determine the spray quality of their current application method. Here’s a relatively simple three-step process to find out.
Step 1: Identify the nozzles currently on the sprayer.
It seems basic, but it’s surprising how many applicators can not name their spray nozzle. If unsure, closely inspect the nozzle, looking for the manufacturer’s name, the nozzle model, and its flow rate. Most nozzles will have this information printed right on them. Here are pictures of the most common nozzles. Can’t find the info? Have a look at this article for websites with pictures.
Major manufacturers include Hypro (John Deere via private label), Agrotop (marketed by Greenleaf in North America), Hardi, Lechler, TeeJet, Wilger, and Billericay Farm Systems (Air Bubble Jet). Manufacturers produce many models, but most are easily identified by a series of letters and numbers. For example, all nozzles will be offered in several fan angles (80º and 110º are most common), and flow rates (in US gpm).
To be more helpful, flow rates are colour coded according to an international standard. This table shows the colours and lists flow in US units in (gpm at 40 psi) and metric (L/min at 3 bar).
The combination of series of letters or numbers shown on nozzles follows a relatively consistent pattern: Fan angle and flow rate arranged as 11003 or 03-110. In this case, the nozzle produces a 110 degree fan and has a flow rate of 0.3 US gpm. The use of US gpm at 40 psi to designate flow rate is an international standard.
The nozzle model is frequently inserted into this stamp, and is manufacturer specific. For example, TeeJet may include “AIXR” in its stamp, and Agrotop may include “TDXL”. Hardi’s MiniDrift is abbreviated MD. Some nozzles may not list their fan angle. Others (Air Bubble Jet) are blank, creating a mystic aura of superiority. Others leave the information printed on the nozzle cap.
A bit of experience is very helpful, especially with John Deere nozzles, where the nomenclature inexplicably eliminates the first digit of the 110 or 120 degree fan angle. So the JD 11004 is labelled “1004”. That’s a bit like saying “my truck sas a 50 engine”, when you mean it has a 350. How’s a city person supposed to know you don’t mean the trusty old 250 straight 6?
Step 2: Obtain spray quality information on the nozzle.
Most manufacturers publish the recommended pressure range and the spray quality of their nozzles. This information can be found in their product catalogues, or on their websites, or in smartphone apps.
Although the designation of Spray Quality is governed by an international standard that is designed to standardize droplet sizing among various labs, we do see some variation in results. Part of this is due to the continued evolution of the standard, requiring manufacturers to re-do some tests, or at least re-analyze their data. For example, ASABE S572.3 was released in conjunction with ISO25358 which changed the boundaries for the coarser sprays. These changes are beginning to be seen in the newer catalogues.
Another problem is that testing is done with plain water. It is well known that the use of certain formulations or adjuvants can affect spray quality. Currently, the standard does not address these effects, and data should be used with some caution.
Step 3: Identify the expected pressure for a given travel speed and water volume.
The same catalogues or websites that publish spray quality also produce charts that list the expected spray pressures at various travel speeds and water volumes.
Becoming familiar with using these charts enables the applicator to predict the spray pressure the nozzle will be operating at. For example, if an applicator intends to apply 10 gpa using a yellow (02) nozzle, this table shows the following: The nozzle will be operating at 30 psi at 5 mph, at 40 psi at 6 mph, at 60 psi at 7 mph, at 70 psi at 8 mph, and at 90 psi at 9 mph. The applicator should know the nozzle’s spray quality at each of those pressures.
Nozzle sizing follows a slightly different procedure for Pulse-Width-Modulation (PWM) systems, requiring the nozzle to be over-sized about 30% or so. Since the majority of new sprayer sales now include PWM, we’ve prepared a special article just for this system here.
Travel speed and/or spray volume should be adjusted to ensure the sprayer operates at a pressure which creates the desired spray quality. In other words, the pressure gauge should be used as a speedometer. If the nozzle model or size doesn’t produce the desired results, the applicator should consider changing nozzles. Once the right combination of factors has been determined, the spray pressures that created the label-required spray quality should be noted. From that point, the applicator can choose travel speeds that maintain the necessary pressure range.
Summary
It is up to applicators and industry representatives to ensure that herbicide products are applied according to label requirements. We expect significant scrutiny on spray drift from new products and need to ensure that proper application methods are used at all times. It’s important that everyone understands just how to do it.
Dr. Scott Bretthauer (U. Illinois) gives a nice summary in this video by Precision Labs:
December 4, 2015
Agrifac Condor: A Wake-up Call For North American Sprayer Manufacturers?
Agrifac Condor Endurance (Source: Agrifac)
I like good ideas. And at Canada’s Outdoor Farm Show in Woodstock this fall, I saw a sprayer that puts a lot of them in one place. I’m talking about the Agrifac Condor Endurance. I’ve seen European sprayers before, even operated a few. And although they are all well-engineered machines, the Netherlands-based Condor might be the first one to gain traction in North America. Why this one? Let me explain.

Size: If you thought European machines are too small for North American conditions, this one breaks the mold. Sporting an 8000 L (2100 US gal) tank, track widths up to 4.6 m (15 ft), a 320 hp Tier 4 engine, and booms up to 55 m (180 ft) wide, it’s a monster. The smaller Condor offers tank sizes of 1050 or 1300 US gal and is a smaller machine overall.
The tank sump design ensures minimal remainders.
Tank and Pump: The large tank has a molded funnel sump that feeds directly into the pump. Net result is a design that empties the tank completely, leaving a tiny remainder amount, less than 2 gallons according to Rob Blijdorp, with Agrifac North America. Because most of us clean tank remainders by diluting them with clean water, this small remainder needs less water to dilute residues to safe levels, saving time when switching products. The machine is equipped with a Hypro centrifugal pump as standard equipment in North America. A diaphragm pump is optional. This pump type is unusual for North America, but it is self-priming, can run dry, and can produce very high pressures.
Wide booms with recirculating plumbing boost productivity and minimize waste (Source: Agrifac)
Boom: The boom widths available on the Condor are astounding, and there’s no easier place to use them than the North American Great Plains. Wider booms are one of the most effective efficiency boosts in spraying, and allow slower travel speeds while creating fewer tracks. The Condor boom has a recirculating design with a pressure feed from both ends, eliminating boom ends and increasing cleanout speed. Since it uses the boom as part of its circulation system, the boom primes at filling so the new product is at the nozzles right away. Sectional control is flexible, with nozzle-by-nozzle control available.
Four wheel steer on a walking beam chassis
Chassis: The frame and suspension system looks like a walking-beam setup, and is claimed to give a smoother ride with less transfer of bumps to the boom. The system has four-wheel steer capability for less tracking in turns, and a tight turning radius. The weight of the smaller Condor machine equipped with a 120’ boom is 24,500 lbs, the Condor Endurance with the same boom is 31,000 lbs.
The HighTechAirPlus atomizer is a twin fluid design that uses air to control flow and atomization.
Nozzles: I saved the best for last. Since 1989 (yes, I remember the year!), I’ve been a fan of “twin fluid” nozzles, but have not seen them take hold anywhere. The HighTechAirPlus nozzles are Agrifac’s version. Here’s how they work: Liquid is delivered to the nozzle in the usual way, by pressure. But air is also delivered, created by a dedicated air pump that has modest volume and pressure requirements. Both air and liquid make their way through the same nozzle (a deflector style, similar to the TeeJet FloodJet).
HighTechAirPlus installed. Note the air supply and the air-activated shutoff for individual nozzle sectional control.
The advantage? Liquid flow and droplet size can be adjusted independently, with air and liquid pressure. More air results in lower liquid flow. It also reduces droplet size. More liquid pressure increases flow, and also reduces droplet size. Clever combinations of both can keep droplet size fairly constant over a wide flow rate range. Alternatively, the nozzles can change droplet size while keeping the same flow rate, depending on the drift or coverage needs at the time. The travel speed range achievable is similar to that with PWM.
Verdict. The jury’s out. As a newcomer to North America, the Agrifac faces a few challenges. Many say it needs a dealer network, inventory and parts. It needs to prove its reliability. It needs to be able to service its machines, especially if parts are non-standard. It needs field cred out here.
But I’m a bit tired of our North American sprayers adding horsepower, speed, and weight to their sprayers each year, and little else. They leave applicators to struggle alone with equally important productivity factors such as quick and thorough cleanout, drift management, nozzle selection and others.
The things that strike me with this new sprayer are Agrifac’s innovative design, and its emphasis on issues that matter to applicators: productivity and excellent control over application rate and droplet size. The company has the right priorities in my books.
November 6, 2015
Drift in the Wind – Parody
Sung to the tune of “Dust in the Wind” by Kansas
I close my eyes, only for a moment, and the spray is gone
All my drops pass before my eyes, oh no – a drift complaint
Drift in the wind
All it is is drift in the wind
Same old spray, just a tank of product in an endless field
2,4-D tumbles in the air though we refuse to see
Drift in the wind
All we do is drift in the wind
Oh, ho, ho
Now, don’t hang on, drops don’t last forever, they evaporate
They slip away, and all your money too, in drifter court
Drift in the wind
All we cause is drift in the wind
All we do is drift in the wind
Drift in the wind
Everything is drift in the wind
Everything is drift in the wind
The wind
June 24, 2015
A New Way to Purchase Sprayers
I always await a trade show with excitement. Everyone’s going to be there, showing their latest and greatest. You see old friends. And of course, trade-show food. Every year, I search for the Fiddle Sticks I learned to love in the 80s. They’ve been replaced by the Pocket Dawg, it seems. Not the same.
Touring around the sprayer and nozzle displays at this year’s Western Canada Farm Progress Show, I couldn’t help but notice that an old contrast got even more striking.
As expected, sprayers are bigger and heavier than ever. The JD r4045 is an example, weighing in at 36,000 lbs, with a list of $563 k CDN. It’s not the only one, though, I just pick on John Deere because they can take it. They know it’s outrageous.
Most sprayers are made by multinationals, with large engineering budgets, and they build complicated and sophisticated machines. They’re huge. They crush weeds. Their cost has often increased by double digits annually.
Then it’s off to the nozzle manufacturers, for the contrast. Small booths nestled among other family businesses, staffed by the owners. Yes, most of the nozzles we use are produced by surprisingly small family-owned companies with just a handful of employees. They make their products on-shore. They have modest research budgets. They collaborate with each other and share components. And their products are priced very low. Not bad, considering the nozzle is the most important part of the sprayer (after the operator, of course).
One can get a very good low-drift, air-induction nozzle for about $6.00. That’s close to the same price it was 10 years ago. Nozzles, engineered to remove small droplets with a two-stage venturi design offer good spray patterns between about 30 and 100+ psi. This means that a $450,000 sprayer with a 120 foot (36 m) boom requiring 72 nozzles can be outfitted with nozzles for a cost of $450 (0.1% of the sprayer cost) , or $1350 for a set of three.
A very cool cut-away view of an Airmix nozzle.
These nozzles have important tasks. They need to:
- meter the pesticide mixture out accurately (within 5% or less of the target amount);
- atomize the mixture into droplets that maximize coverage while minimizing drift and other waste
- distribute the spray uniformly across the width of the boom.
If nozzles miss on any one of these goals, producers pay with lower control, higher costs, or environmental contamination. So these little devices are important.
We do see innovation in this important area, again from small companies. Devices designed to improve rate control (pulse-width modulation or variable rate nozzles), to reduce drift (PatternMaster), or to improve canopy penetration while increasing coverage and reducing drift (Wingssprayer) are appearing. While these aren’t cheap, they cost a fraction of what the sprayer costs, are light, and reliable.
Harrie Hoeben holding a section of his Wingssprayer system.
And they’re meeting with resistance because of a very peculiar response. Over the past 15 years, when a producer has heard the cost of a new sprayer, the sticker shock has made them walk away. But not far. They’ve returned shortly after to make the purchase. Need a new sprayer, right? Need high clearance, hydrostatics, air-ride, horsepower.
But when they see the cost of even the most expensive atomization system (some as low as $4000, the most costly typically $20,000 to $40,000), they just shake their heads and walk away. Probably for good.
TeeJet’s pulse width modulation system – the DynaJet Flex 7120.
And yet it is this purchase that will probably pay the highest dividends. It’s this technology that can answer to the needs presented by heavy, fast tractor units. The $6.00 nozzle is out of its depths here. And the innovators need the sales so they can conduct proper research to give you the best value, and lower their costs.
Capstan’s new PWM solenoid for high-flow John Deere bodies.
A New Process
How about we look at it this way: Budget for a new sprayer. Say you accept that it will cost about $440,000. This is the total amount you will spend. Now budget for a great delivery or atomization system. One that either improves coverage, decreases drift, improves consistency, or makes you more productive. Let’s go for the best one, and budget $40,000.
Now don’t raise the cost of the investment by that amount, but instead make it inclusive. The sprayer’s tractor unit budget is reduced to $400,000 to accommodate the atomization system, for a total cost of $440 k, still within budget. You may need to re-evaluate the type of sprayer, or features, that you will be able to obtain with a 10% lower cost.
Or perhaps you can take advantage in the slightly more desperate market situation for big iron and score a better deal. Buy used, or invest in your old sprayer to rehabilitate it.
Either way, we need to start thinking differently. Within any given budget, let’s purchase the most important components first. Then let’s put wheels on it. And then, let’s get some Fiddle Sticks.
June 22, 2015
Spray Quality and Volume Matrix
We often write about how valuable water sensitive paper can be to visualize and assess the coverage we’re getting from a specific application method. A handy reference is this matrix that combines both factors. Print it and use it in the field to compare what your application method is doing to these relative standards. On average, you will want to see deposits similar to those in the middle of the matrix.

Download US units Matrix here (pdf)

Download Metric Matrix here (pdf)

June 13, 2015