Author: Jason Deveau

  • How to Properly Set Up a Crop Sprayer

    How to Properly Set Up a Crop Sprayer

    Article reprinted with kind permission from an original article written by Oliver Hill in the February, 2017 edition of Farmers Weekly. Photos ©Kathy Horniblow.

    Crop spraying is one of the most important and highly skilled jobs undertaken on any arable farm, but it is facing increased public scrutiny. This is why it is vital that the kit you use as a means to apply pesticide to crops is in prime working order and is set up correctly to deliver the product safely and accurately to its target. Optimum sprayer set up will help to maximize the efficacy of applied products, reduce spray drift and keep machinery in good condition.

    For this best practice guide to sprayer set up, Farmers Weekly teamed up with former Farm Sprayer Operator of the Year Iain Robertson. Mr. Robertson is assistant arable farm manager at David Foot Ltd, a 2,200ha mixed farm south of Dorchester in Dorset, growing wheat, barley, beans, oilseed rape and maize as forage for the farm’s three dairy herds. The machine used for this guide is a Bateman RB26 self-propelled sprayer and while most of these checks and tests are universally applicable to all sprayers, it is also important to refer to the handbook of the manufacturer of your specific machine.

    Watch the video tutorial with Mr. Robertson and then see the step-by-step guide below for more detail.

    Pre Start Checks

    Before firing up the engine, the first thing to do is your pre-start checks – that means checking your machine’s vital fluids like fuel, hydraulic oil, hydrostatic oil, engine oil and coolant levels. If yours is a self-propelled sprayer, chances are you’ll need to get up on to the back of the machine to check some of these.

    “While I’m up on the back of the sprayer I also have a quick look in the top of the tank to make sure that it is nice and clean and the tank rinse nozzles have worked properly – cleanliness is next to godliness,” says Mr. Robertson. Next, move on to the tires. Use a pressure gauge to check all tires are at the correct pressure and refer to the manufacturer’s guidelines. If you’ve got a trailed sprayer, don’t forget to check the tractor tire pressures as well.

    Aim for tires to be run at the lowest pressure recommended for the load to be carried. This will help with boom height and stability and also helps tires act like a shock absorber to ride out bumps. If using a trailed sprayer, use a spirit level to ensure that the drawbar is level. Mr. Robertson says he tries to work around the machine in a methodical, clockwise manner to ensure that he doesn’t miss anything.

    Coming to the pumps, check that they have got enough oil, check that any tool boxes have enough spare parts and any equipment needed and make sure you are carrying a spill kit with absorbent granules and a spade in case the worst happens and there is a spillage. Make sure all parts are lubricated daily and that any grease nipples are cleaned before and after use to avoid them collecting dirt and blocking.

    Check all hydraulic hoses, spray lines and air lines for any signs of wear that could result in problems while operating.

    It’s best to run the sprayer at a minimum of 5 bar to check for leaks. Also check the spray tank is fixed down securely, all straps and bolts are tight.

    Boom checks

    Once opened out, check the boom has good movement in the x- and y-axis. All machines are different so check with your manufacturer as to how the boom is set up. Mr Robertson’s Bateman has tie rods and stock bots that can be adjusted to set the boom up to ride well.

    Check the tie rod nearest the back of the machine is slightly loose when moving and that the front rod is tight. Next, check for up and down movement by gently pushing the boom down by about 50cm and letting go. The boom should return to the central position without too much bouncing around.

    “We want a little bit of movement but not excessive so that you can ride over the bumps as you go along without over- and under-dosing the crop,” says Mr. Robertson. Boom height is one of the most critical factors when spraying and the ideal height is 50cm above the crop. One of the easiest ways to work this out is by using a cable tie that is cut off at the correct length to use a visual aid from the sprayer cab.

    Don’t forget to measure from the tip of the nozzle to the crop, not the spray line.

    Good sprayer cleanliness is important, so make sure the system is rinsed through at the end of each day with clean water to make sure there’s no residue left in the boom. If your machine’s boom doesn’t have recirculation, remember to take the end caps off occasionally and flush out the whole boom.

    Nozzle checks

    Check that the nozzles are aligned both vertically and horizontally, according to the NSTS guidelines. Loosen clamps to adjust any nozzles that need realignment.

    Check the nozzle output at least twice a year by running the sprayer with clean water at 3 bar pressure. Time the output of each nozzle for 30 seconds. If nozzles have been used previously, it’s best to check their output against that of a new pair. Mr Robertson advises using a measuring cylinder rather than a jug to measure the flow rate as a jug is less accurate “because you get a bigger variation over the wider surface area”.

    With an 03 nozzle running for one minute at 3 bar pressure, the output should be 1.2 litres/minute as a rule of thumb but refer to the nozzle manufacturer’s output chart for the expected flow rate. “An easy way to remember this is: at 3 bar your nozzle size multiplied by four will give you your target litres/minute output. It works for all nozzle sizes.” If the output varies more than 4% of the average, or if the spray pattern visually doesn’t look correct, you need to change the nozzle set.

    After checking the output, cross-reference this figure with the rate controller – you may need to adjust the flow figures to ensure that the two correlate. If a nozzle becomes blocked while spraying, Mr. Robertson says he will swap it for a new one and then clean it later using a toothbrush or airline. Never blow through a nozzle with your mouth.

    Nozzle choice

    The choice of nozzle is highly dependent on the sort of job you’re doing. “Timing is crucial but using the right nozzle at the right time will make the job so much easier, cut drift and mean that you’re getting more of the product where you want it to go. If you aim at it you will hit it,” says Mr. Robertson.

    His nozzle of choice is an 03 size and he prefers to use the Defy 3D nozzle alternated forwards and backwards across the boom for pre-emergence work and T0 applications as well as the T3 ear spray. “In less than optimum conditions I may prefer to use the Amistar/Guardian Air, a fine induction nozzle. I would use this at T1 and T2 and also in sub-optimum conditions.”  This nozzle has a 3-star Local Environmental Risk Assessment for Pesticides (LERAP) rating and is 75% drift reducing.

    A water volume of 100 litres/ha is a good rate for spring fungicide application. It provides enough coverage for good disease control and allows maximum efficiency from the sprayer.

    Forward speed

    The third and final part of reducing spray drift is forward speed. Depending on nozzle size and water volume, aim to travel at 12kph.

    Mr Robertson says he finds that this speed gives a good overall output and means you don’t get shadowing or turbulence behind the machine.

    Tips and tricks

    One of the biggest risk of contamination is at fill up. “A fantastic, cheap trick that I learned through Farm Sprayer Operator of the Year is to take a 200 litre plastic drum and cut it in half to create two drip trays to catch any spillages under the induction hopper and the tank overfill.” This eliminates point source contamination, he says.

    “Finally, there’s a plethora of information out there on the internet, loads of good apps to download. The technology is there to help us do the best job possible and make our job as safe as possible.”

  • Sprayer Loading and the Jar Test

    Sprayer Loading and the Jar Test

    The time and attention spent during sprayer loading is a worthy investment. It ensures that the products in the tank perform as intended and reduces the chance of incompatibilities.

    The label

    Pesticide labels are always the first point of reference. Labelled mixing instructions should be obeyed even if they contradict conventional practices (see Mixing order, below). Consult this article on tank mix compatibility for more information on how to quickly and easily consult labels for each of your tank mix partners.

    The carrier

    Typically, the carrier is water, and understanding its role in pesticide performance is another article (or several). We’ve provided some links here for further reading.

    • Take some time to read Les Henry’s 2016 Grainnews article called “The Coles Notes of Water Chemistry“.
    • You can also read about pH and water hardness. It should be noted that pH and the resultant hydrolysis that can affect product half-life is typically an insecticide issue (not fungicide or herbicide). The famous fungicide example is Captan, which has a half-life of 32 hours at pH 5, but only 10 minutes at pH 8. Michigan State did a great summary (in 2008 and on US product formulations) which you can find here.
    • Finally, learn how to read a water quality report, here.

    Carrier volume

    Products dissolve better in higher volumes. The sprayer tank (vat, inductor, etc.) should be at least ½ full or water before adding the first product. In the case of a fertilizer carrier, it may look like water, but it contains high levels of salts that tie up free water and reduce solubility. For fertilizers, a higher initial volume of ¾ full is required.

    Note the undissolved residue collected on these swatches of red filter material. Products dissolve faster and better in higher carrier volumes.

    The incomplete dissolution of products can leave hard-to-clean residues, plug fluid lines, and result in a non-uniform application that reduces efficacy. The risk of incompatibility is greater with low carrier volumes and high product rates (especially dry formulations). This is a common problem in regions that use low water volumes to apply multiple tank mix partners.

    Carrier and product temperature

    Both carrier and product temperature affect mixing. Imagine mixing sugar in hot tea versus iced tea – more sugar dissolves more quickly in hot liquid. Here are three common temperature-related issues:

    • Dry formulations and liquid flowables take more time to disperse (consider using a pre-mixed slurry).
    • Emulsified concentrates and oil might form gels rather than milky blooms.
    • Water soluble packages might not dissolve completely and could plug filters and nozzles – or clog the pump intake.
    Note the undissolved residue collected on these swatches of red filter material. Products dissolve faster and better when carrier and products are warmer.

    Note: Water and fertilizer are very different carriers. Beware of carrier-specific incompatibilities

    Agitation

    Keep agitation running throughout mixing and spraying. Aim for a “simmer” on the liquid surface rather than a “rolling boil.”

    Low agitation can cause products to settle, making them difficult or impossible to resuspend later. Conversely, aggressive agitation (especially in half-full tanks) can cause foaming, pump suction loss, or product separation / clumping.

    Pace

    Adding products too quickly can cause product separation / clumping or poor suspension, leading to tank mix incompatibilities. While loading quickly improves operational efficiency, complex mixes require patience; Sometimes over five minutes between additions, especially in cold water or when using dry products.

    To save time without sacrificing quality, consider pre-hydrating dry products or using a separate nurse tank to pre-mix loads for quick transfer. Remember: even if dry products look dissolved, they may still need more time.

    Product formulation

    Product formulation is a complicated science. In the 1950s a formulation might have three active ingredients and an inert filler. See the historic formulation index card shared by Dr. M Doug Baumann (formally with Syngenta, Honeywood).

    Today, a product can include as many as 40 ingredients with formulation testing lasting two to four years! Generally, only 25% of the volume is water, 50% is active ingredients and the remaining 25% is co-formulants. This is why the more products you add to the tank, the higher the risk of antagonism. This is also why operators should carefully consider the cost benefit of generics, which may include the active ingredient, but do not tend to include the co-formulants.

    Illustration based on a slide by Dr. Samantha Francis, Formulation & Application Technology Lead at the Syngenta Honeywood Research Facility.

    Mixing order

    Tank mixing order is critical for chemical compatibility. While common acronyms like w.w.w.W.A.L.E.S., W.A.M.L.E.G.S., and A.P.P.L.E.S. serve as reliable guides 95% of the time, always defer to the pesticide label for specific instructions.

    Expanded generic mixing order:

    1. Water: Fill tank 1/2 full (or 3/4 if fertilizer carrier).
    2. Agitation
    3. Water-Soluble Bags (WSB): Allow to fully dissolve.
    4. Wettable Powders (WP)
    5. Water Dispersible Granules (WDG, WG, SG)
    6. Liquid Flowables (F, FL, SC, SE, CS, DC, EW)
    7. Emulsifiable Concentrates (EC, MEC, OD)
    8. Solutions (SN, SL, Liquid Fertilizers/Micronutrients)

    Adjuvants:

    1. Water Conditioners (e.g. anti-foamers, compatibility agents): Add before pesticides.
    2. Activator Surfactants (e.g. NIS, COC): Add after pesticides or by formulation type along with pesticides.
    3. Drift Retardants: Add last.

    Examples of mixing errors

    Micronutrients like sulfur (e.g. ATS) added to nitrogen-based formulations (e.g. UAN) can cause physical incompatibilities. This became a problem during “weed-and-feed” applications in Ontario corn in the late 2010s, and working with the registrants, we found a solution.

    What follows is not only a good example of why mixing order is critical, but why growers should get into the habit of performing jar tests. Learn more about a real-world ATS example here.

    Left: ATS and UAN premixed, followed by Primextra created curds.
    Centre: UAN, followed by low-load ATS followed by Primextra worked.
    Right: UAN followed by Primextra followed by high-load ATS worked.

    Mixing errors are just as likely in small plot work as in commercial sprayers. Watch this short video by Mike Cowbrough describing his experience with mixing order for Elevore and glyphosate.

    The jar test

    A jar test is a small-scale version of tank mixing used to check for physical incompatibility. Always wear PPE and work in a well-ventilated area away from ignition sources.

    Jar test steps:

    1. Prepare: Read all labels for formulation details, water quality requirements (pH/hardness), and mixing order. Shake liquid containers to ensure consistency.
    2. Initial Carrier: Fill a 1-litre glass jar with 250 ml of water (or 375 ml if using oil/fertilizer).
    3. Add Products in Order: Add chemicals following the standard mixing sequence, stirring constantly. Scale rates to match your tank concentration (e.g., 1 kg per 1,000 L equals 0.5 g in a 500 ml test).
    4. Wait and Observe: Allow 3–5 minutes between additions—especially for dry products—to ensure full dispersion. If testing water-soluble bags, include a small piece of the film.
    5. Final Volume & pH: Top the jar up to 500 ml with your carrier. Check the pH with a digital meter and add adjusters if required by the label.
    6. Evaluate: Let the jar stand for 15 minutes.

    The mix is likely incompatible if it generates heat, forms gels or scum, or if solids settle out (excluding wettable powders). Note: Jar tests only identify physical issues; they do not guarantee biological efficacy or crop safety.

    Compatibility kits

    When performing a jar test you must maintain the same product-to-carrier ratio as in a full-sized sprayer tank. This math is made easier with commercial compatibility kits such as the one from Precision Laboratories (below).

    Compatibility Test Kit: Five pipettes, three bottles, gloves, instructions. ~$10.00. (Photo: Precision Laboratories)

    Such kits contain a few plastic “jars” and disposable micropipettes. By following the instructions included with the kit, you can easily reduce large labelled volumes (e.g. 1 kg of product in 1,000 litres) of multiple products to small volumes at the same ratio. In this case we assume the final volume would have been 1,000 L, and so we reduce all the quantities accordingly to get 500 ml. The following mixing order is provided as an example.

    OrderIngredientQuantity for 500 ml or 500 g of product labeled for 1,000 L of final spray volume
    1Compatibility agents5 ml (1 teaspoon)
    2Water soluble packets, wettable powders and dry flowables. Include a 1cm2 cutting of PVA packaging.15 g (1 tablespoon)
    3Liquid drift retardants5 ml (1 teaspoon)
    4Liquid concentrates, micro-emulsions and suspension concentrates5 ml (1 teaspoon)
    5Emulsifiable concentrates5 ml (1 teaspoon)
    6Water-soluble concentrates or solutions5 ml (1 teaspoon)
    7Remaining adjuvants and surfactants5 ml (1 teaspoon)

    Records and delayed reactions

    Maintain detailed mixing records for traceability and to track performance. These records help you replicate successes and avoid future failures.

    Labelled jar tests are also valuable; by leaving them in the chemical shed overnight, you can see if products separate or solidify over time. This indicates whether a mix can safely sit in the sprayer or if it requires immediate rinsing. For example, one grower’s Enlist and Manzinphos mix appeared fine until it sat during a rain delay. It turned into “lard,” clogging the entire system and requiring a manual teardown. They even had to dig some of the substance out with screwdrivers (see the picture of the filter below). An overnight jar test likely would have predicted this problem.

    Some physical incompatibilities are not immediately apparent. This occurred overnight while the partially-full sprayer waited out a rain event.

    Closed transfer

    As a brief mention, an expansion of closed transfers systems for loading pesticides is on the horizon in North America. They have great potential to make loading more efficient, reduce operator exposure and reduce point-source contamination. Depending on the design, however, the operator may not be able to open pesticide containers to obtain samples for jar testing. This would be a great loss.

    For more information

    Learn more about physical and chemical incompatibility in our article on Tank mix compatibility. Be sure to download a copy of Purdue University’s 2018 “Avoid Tank Mixing Errors”. Finally, if you have questions about a specific product, contact the manufacturer, who have likely already performed the testing with common tank mix partners and can advise you.

    This article was co-written with Mike Cowbrough, OMAFA Weed Management Specialist – Field Crops

  • Angled Spray Nozzles in Wheat

    Angled Spray Nozzles in Wheat

    When T3 wheat rears its head, the first rainy day brings questions about spray angles. Let’s begin with a graphic that illustrates how angled sprays cover a vertical target like a wheat head. Assuming moderate wind and sufficiently large droplets, this is a simplified depiction of what we would expect to see.

    But is this how the nozzles actually perform? Are dual angles really better than a single fan with an aggressive angle? We hoped to answer these questions when we demonstrated a selection of dual fan nozzles at Canada’s Outdoor Farm Show in 2013. But it was a very windy few days and what we saw was that regardless of the nozzle, most of the spray tended to deposit with the wind.

    A 10 km/h wind will easily deflect Medium-and-smaller droplets and at 20 km/h all but the coarsest spray is deflected. This leads to non-uniform deposits and unacceptable levels of drift (yes, even through it’s a fungicide and you have lots of acreage.) To learn more, we turned to the literature to review studies performed in Ontario and Saskatchewan.

    Wolf and Caldwell

    In 2002, Dr. Tom Wolf and Brian Caldwell experimented with fan angles. They evaluated the impact of nozzle angle, travel speed, and droplet size on the “front” (facing the sprayer’s advance) and “back” (sprayer’s retreat) of vertical targets. They ran three laboratory experiments: spray configuration (single vs. double fan), travel speed (7.6 and 15.2 km/h) and spray quality (conventional versus air-induced droplets) using TeeJet XR’s and Billericay air bubbles at a rate of 175 L/ha. Here’s what they observed:

    • Larger, air-induced droplets produced higher average deposits than smaller, conventional droplets.
    • Twin fans improved overall average deposit compared to single fans.
    • Building on the first two points, twin air-induction fans improved overall average deposit versus conventional twin fans, and also improved deposit uniformity (i.e. coverage on the front versus the back of the vertical targets).
    • Higher travel speeds improved overall average deposit, but at the cost of reduced uniformity as the rear-facing target received reduced coverage (particularly in the case of conventional droplets).
    • Spray angle did not impact coverage from conventional tips, but increasing from 30 to 60 degrees improved coverage for AI tips.

    While the coverage data was compelling, growers were not reporting improved efficacy with the improved coverage. The authors felt there were confounding variables like crop susceptibility, disease pressure and product effectiveness. Their conclusion was that applicators should strive for improved coverage, but only after integrated pest management (IPM) criteria such as product choice, crop staging and application timing are satisfied.

    Hooker and Spieser

    In 2004, Dr. David Hooker (University of Guelph) and Helmut Spieser (OMAFRA) started exploring nozzle configuration and sprayer set-ups to optimize Folicur applications in wheat. For several years they ran field trials exploring panoramic wheat head coverage. That is, not only the front and back of the wheat head, but the sides as well. Ten different nozzle configurations were used:

    • TurboTeeJets mounted in dual swivel bodies (backwards and forwards)
    • AirMix air induction nozzles mounted in dual swivel bodies
    • Air induced Turbo TeeJets mounted in dual swivel bodies
    • Single Turbo TeeJets angled forward or angled backwards
    • Single Turbo FloodJets angled forward or angled backwards
    • TwinJets
    • Single Hollow cones
    • Turbo TeeJet’s mounted in Twincaps
    • Turbo TeeJet Duos
    • Single Turbo FloodJets alternating forward and backwards

    They explored boom height (0.5 m and 0.8 m above the crop), travel speed (10 km/h and 20 km/h) and application volume (93.5 L/ha and 187 L/ha). Here is a summary of their findings:

    • Travel speed did not appear to impact overall coverage.
    • Spraying higher volumes improved coverage.
    • Lowering the boom improved coverage.
    • Coverage from conventional flat fans and TwinJets gave ~15-18% coverage and 22-26 mg of copper was deposited per m2, but alternating Turbo FloodJets gave ~29% coverage and deposited ~37 mg copper per m2.
    • The highest percent coverage was obtained using Turbo TeeJets or the AirMix tips mounted in dual swivels (~26% coverage), or single Turbo Floodjets alternating forward and backwards (34% coverage) as long as the spray was not obstructed by the boom structure itself.

    Hooker and Schaafsma

    A few years later, Dr. Hooker and Dr. Art Schaafsma worked with OMAFRA to explore efficacy. DON is a mycotoxin that may be produced in wheat infected by Fusarium Head Blight (FHB) or scab. There is an indirect relationship between wheat head coverage of fungicide and the reduction of FHB and DON: The higher and more uniform the coverage (with the right timing) the lower FHB and DON.

    In two field experiments they performed in 2008, DON values in the untreated checks were around four parts per million. DON was reduced by an average of 22.5% using a single flat fan, 23.0% using a TwinJet and 41.5% using alternating Turbo FloodJets when averaged across two fields, two fungicides and four reps (n=16). They all reduced DON significantly. There was no statistical difference between singles and twins, but control from the alternating Turbo FloodJets was significantly better.

    The Return of Wolf and Caldwell

    Then, in 2012, Tom and Brian evaluated the new asymmetrical twin fan nozzles from TeeJet. The marketing claimed they could improve overall coverage at higher travel speeds because they decrease the contribution of the front-facing fan and increased the angle of the back. Tom and Brian’s lab-based experiments determined that:

    • Asymmetricals increased overall deposit amounts and uniformity versus single fan and symmetrical twin fans.
    • Nozzle orientation (alternating or not) seemed unimportant.
    • As suggested earlier, boom height was a big factor in coverage. Nozzle angle didn’t improve coverage when the boom was too high, but spray deposit increased significantly when the boom was lowered.
    • Coarser spray droplets have more momentum, so they can travel greater distances on their original vector. A coarser spray quality is the best choice for any angled fan.

    Water volumes and FHB

    Let’s address the notion that high water volumes might increase Fusarium Head Blight (FHB). This is a hypothesis that seems to have resonated with growers. Dr. David Hooker ran trials where he tried to favour FHB by spraying 40-50 gpa of water multiple times per day (even up to 100 gpa). There was no pathological impact (personal communication).

    Consider that 1″ of rain is the equivalent of 2,715 gpa of water. Raising your carrier volume from 15 gpa to 20 gpa is the equivalent of 0.000184″ of rain. Admittedly, it’s all aimed at the wheat head, but it’s still a tremendously small volume. While studies have shown a diminishing return in coverage at 30 or 40 gpa, spraying with 20 gpa appears to be a safe way to improve coverage significantly.

    Learn more about early morning spraying here, and a more in depth discussion of spraying when there is dew here.

    PWM

    What if you’re running a PWM system? Sizing for PWM requires the tip be sized about 20-40% more than if you were running a conventional sprayer. In other words, at expected travel speeds, the pulsing duty cycle should be approximately 60-80%. Nozzles that are permitted on PWM sprayers are limited and the angled fan selection for PWM is, at the time of writing, more so. It requires some experimenting. The following list uses the JD Exact Apply as an example system, and it is not exhaustive. We’re always looking for new ideas.

    1. 3D90 (the original 3D is arguably too misty) in the A or B positions, alternating front and back <or> in both A and B positions. This tip may not be readily available in North America.
    2. LDT (Low Drift Twin) which is two LD tips installed in a Twincap (twin 30° angles) in position A or B.
    3. LDM (Low Drift Max) which is two LDM installed in a Twincap in position A or B. This tip only goes down to an 03.
    4. The Deere 40 degree angled adaptor (developed for See and Spray) can be used to convert any PWM-compatible nozzle into an angled spray.
    5. GAT (GuardianAir Twin) is an air-induced tip, running in conventional “A” mode or in Auto Mode but sized for “B”. Avoid operating in A and B to prevent pattern interference.
    6. Wilger Wye Adaptor with SR nozzles. This does cause tips to drop below the boom frame but is a versatile option.
    7. Wilger Dual Angle Max. More compact than the wye adaptor, this asymmetrical assembly (30° fore and 50° aft) prioritizes Coarse spray.
    8. TeeJet Accupulse TwinJet.
    9. Greenleaf Blended Pulse Dual Fan Assembly.

    Summary

    So here’s what we can say based on all this research:

    • Higher volumes improve coverage (significantly up to ~200 L/ha or 20 gpa). Can you go to 30 gpa? Yes, and it will likely improve coverage, but it’s a diminishing return and at some point you will incur run-off.
    • When using angled sprays, coarser droplets improve vertical coverage. Compared to finer droplets, they move faster, survive longer (i.e. resist evaporation) and are less likely to be deflected by wind.
    • Maintaining the lowest operable boom height improves coverage from angled sprays. We want 100% overlap at target height, and with angled sprays that means getting pretty close. Aim for the highest wheat heads and not the tillers. If you’re 2′ away, you’re likely too high.
    • Symmetrical fans with shallow angles (e.g. 30°) improve coverage uniformity on vertical targets versus single fans, and a steeper backward-facing angle (e.g. 70°) improves coverage even more on the sprayer-retreat side.
    • Travel speed may or may not affect coverage, but slower speeds do facilitate lower booms, which do improve coverage.
    • Timing, weather and product choice are likely the most critical factors.

    Angled sprays may offer some advantage in other situations, but they are primarily intended for panoramic coverage of vertical targets.

    Short videos about dual fans

  • Tank mixing Urease and Nitrification Inhibitors in Corn Weed-and-Feed Applications

    Tank mixing Urease and Nitrification Inhibitors in Corn Weed-and-Feed Applications

    This 2023 article is based on work performed by Mike Schryver, BASF Technical Service Specialist.

    Nitrogen is an essential nutrient required throughout a plant’s lifecycle. It is commonly applied to corn in either a granular form as urea or in a liquid form as urea-ammonium nitrate (UAN). Depending on soil type and precipitation, significant amounts of nitrogen can be lost to leaching, denitrification and volatilization as N2O (a greenhouse gas). Learn more about nitrogen in soil in this excellent overview by University of Minnesota Extension.

    With the 2020 announcement of Canada’s Strengthened Climate Plan, Ontario is committed to a 30% reduction of 2020 N2O emission levels by 2030. Adding urease and nitrification inhibitors (aka stabilizers) to nitrogen fertilizer applications is an environmentally sustainable practice that reduces nitrogen losses and improves yield.

    Another essential plant nutrient, Sulphur, is applied in liquid-form as ammonium thiosulphate (ATS). Primarily used to increase corn yields, high rates (approx. >10% by volume) of ATS can also inhibit urease and nitrification, albeit not as well as other nitrogen stabilizing options.

    In the pursuit of productivity, UAN and ATS are often combined to serve as an herbicide carrier in corn weed-and-feed applications. However, liquid fertilizers are dense solutions that contain charged ions and exhibit a reduced capacity for solubilizing pesticides. This complicates the tank mixing process. When micronutrients like sulfur are added to nitrogen-based formulations, physical incompatibilities can arise that cause uneven applications and can even clog sprayers.

    Given the known compatibility issues, questions have been raised about the best way to introduce urease and nitrification inhibitors to tank mixes of UAN, ATS and herbicide. Specifically:

    1. Stabilizer Compatibility: What is the impact of adding nitrogen stabilizers to UAN carriers containing leading corn herbicides formulated as emulsifiable concentrates (EC) or suspension concentrates (SC)?
    2. Mixing Order: When UAN and ATS are premixed, does their ratio, or the addition of nitrogen stabilizer affect tank mix compatibility with herbicides?

    To answer these questions, we performed a series of jar tests.

    Method

    300 ml jars with magnetic stir bars were mixed to reflect a 10 gpa application. UAN was chilled to approx. -5°C and herbicides were added at 2x the labelled rate to simulate a worse-case scenario. Nitrogen stabilizer was added at a ratio per manufacturer’s instructions. Products were introduced at 1 minute intervals to provide sufficient time for solubilization. Jars were left to rest for at least 1 hour after mixing, and then agitated to simulate interrupted spray jobs. The solution was then poured through a 100 mesh screen to simulate a worst case scenario for sprayers that typical employ 50 mesh filters.

    HerbicidesFertilizer carriersStabilizers
    Leading EC HerbicideUAN: 28%eNtrench NXTGEN (Corteva)
    Leading SC HerbicideATS: 12-0-0-26% SUAnvol (Koch)
    Tribune (Koch)
    Agrotain (Koch)
    Neon Surface (NexusBioAg)
    SylLock plus (Sylvite)
    Excelis Maxx (Timac)
    Table 1 Herbicides, carriers and stabilizers used in the study

    Results

    Stabilizer Compatibility

    EC herbicides have active ingredients that are soluble in water and include immiscible solvents. When added at 2x label rate to chilled UAN, followed by a stabilizer, agitation created an acceptable suspension (Figure 1). The EC separated to the top of the mixture following an hour rest but was easily reintegrated. There was no appreciable residue left behind when poured through a 100 mesh screen.

    Figure 1 UAN + EC Herbicide + Stabilizer after 1 hour rest. Image A is a control with no stabilizer and image B is the same control after agitation. The arrow indicates where ECs separate at the top of each jar. All products resuspended with agitation.

    SC herbicides have active ingredients that are water insoluble, but stable in an aqueous environment. When added at 2x label rate to chilled UAN, followed by a stabilizer, agitation created an acceptable suspension (Figure 2). The SC flocculated and formed a sediment at the bottom of the mixture following an hour rest but was easily reintegrated. There was no appreciable residue left behind when poured through a 100 mesh screen.

    Figure 2 UAN + SC Herbicide + Stabilizer after 1 hour rest. Image A is control with no stabilizer and image B is the same control after agitation. The arrow indicates where SCs settled, as depicted in the inset images showing the bottoms of each jar. All products resuspended with agitation.

    Best Practices

    • Contact manufacturers and conduct a jar test to confirm compatibility
    • Ensure thorough agitation (with or without a stabilizer, and especially after tank has settled)
    • Components may separate to the top (ECs) or settle on the bottom (SCs)

    Mixing Order

    Mixing order was tested using chilled UAN, ATS, and EC herbicide. It is well known that ATS should be added last in the tank mix order, and mixes that include a higher load of ATS relative to UAN exacerbate tank mix issues.

    This is seen in the following video where we combine 203 ml of chilled UAN, 30 ml of SC corn herbicide and 68 ml of ATS. On the left, UAN, then herbicide, then ATS mixes perfectly. However, when we start with UAN, then add ATS (which represents premixed fertilizer) then the herbicide does not suspend, and prolonged agitation does not improve the situation. The video is shown at 2x speed.

    We then added a nitrogen stabilizer to the series to see if it could correct the tank mix issue arising from adding ATS immediately after UAN. This replicates the situation an operator would face when purchasing UAN and ATS premixed. We also reduced the ratio of UAN to ATS from 3:1, to 5:1 to 8:1 to establish a threshold ratio that alleviated tank mix issues (Figure 3). All solutions were poured through 100 mesh screens to capture residue (Figure 4).

    Figure 3 SC Herbicide and stabilizer added to UAN and ATS premixed at different ratios. Agitated after 1 hour and poured through 100 mesh screens (inset images).
    Figure 4 Pouring EC jar test solutions through 100 mesh screens

    Best Practices

    • Contact manufacturers and conduct a jar test to confirm compatibility
    • ATS must be added after the herbicide (EC or SC). The stabilizer can be added last, but preferably ATS is the last ingredient in the tank.
    • Adding stabilizer will not reverse a tank mix error arising from adding ATS prior to the herbicide.
    • The higher the concentration of ATS, the higher the risk of incompatibility. A 5:1 ratio of UAN to ATS failed while a ratio of 8:1 succeeded. The threshold is likely 7:1.
  • Green-on-Green in Ontario: A Custom Operator’s Experience with See & Spray Premium

    Green-on-Green in Ontario: A Custom Operator’s Experience with See & Spray Premium

    In the summer of 2025, Todd Frey of Clean Field Services (Drayton, Ontario) and I participated in the Elora Weeds Tour. We discussed his new John Deere See & Spray Premium and the practical considerations for implementing green‑on‑green spraying in Ontario (Figure 1). With that first season squarely in the rearview mirror, I reached out to Todd to ask about his experience.

    To be clear, we had a lot of questions then and we still have questions now… but we’re optimistic. This article summarizes the original topics from the Weeds Tour, Todd’s 2025 learnings, and considerations for the year ahead.

    Figure 1 – JD See and Spray Premium at the 2025 Elora Weed Tour. Todd Frey (left) and Brendan Bishop

    Challenges Identified in 2025

    Label Language and MRL Constraints

    Optical spraying introduces uncertainties when interpreting pesticide labels written for broadcast applications. For example, an operator might elect to concentrate a herbicide beyond the common broadacre rate while technically adhering to the label. Depending on the active, this risks excessive residue levels that can cause crop replant issues. A few Canadian labels already address this grey area by specifying water-to-product ratios in addition to per‑hectare limits. Most do not.

    Australia’s experience offers a possible way forward: optical systems in Australia are commonly calibrated at 100 L/ha (~10 gal/ac), and labels specify whether they permit higher concentrations for spot and patch spraying. Additionally, most labels state the operator must revert to a conventional broadcast application when fields have more than 30% weed cover.

    Tendering and Mixing Logistics

    Estimating product and water needs is, perhaps, one of the most difficult operational challenges. Traditional field scouting cannot accurately predict how much spray solution an optical sprayer will apply. This leads to logistics issues, increased risk of unnecessary leftovers, and subsequent disposal/clean out problems.

    Nozzle Availability and Performance

    Nozzle choice is central to realizing the full benefit of precision application. Ideally, operators require low‑drift, narrow‑angle nozzles with an appropriate dynamic range (i.e. travel speed vs. flow rate) to spray small weeds efficiently. Perhaps it goes without saying that a stable boom is critical in this equation, but we’ll say it anyway. Nozzle options are currently limited and we’ve written about this subject in a previous article.

    Cost–Benefit Realities

    While herbicide savings are an obvious appeal, the actual economics are more nuanced. The See & Spray Premium model adds a $6/acre CDN fee for unsprayed acres, which can diminish savings in very clean fields. A fall broadcast herbicide application improves the success of spring green‑on‑green passes, but this added cost must be figured in. Of course, there are many other benefits to a fall burndown that shouldn’t be dismissed, and you can read about them here.

    On the other hand, perhaps good agronomy should be the motivating factor. Any savings from reduced broadcast spraying may allow operators to upgrade to more effective, higher‑value tank mixes, improving weed control and contributing to long‑term seedbank reduction. Regarding the later point, there have been recent studies that suggest using low sensitivity may adversely affect the seedbank.

    New Chemistry Possibilities

    It’s a stretch, but there could be a silver lining to increasing herbicide costs and resistance pressures: chemistries once considered too expensive for broadcast use could become economically viable for spot or patch applications. This would expand chemical options.

    The 2025 Experience

    Cost savings

    To evaluate performance under Ontario conditions, Todd conducted a structured trial on his own 125‑acre corn field. In 2024 the field received a fall application targeting annual grasses and broadleaf weeds. Todd’s intention was to leave perennial sow-thistle and Canada thistle for targeted control in the spring.

    He used the See & Spray Premium to apply Lontrel + glyphosate at 13 GPA. The John Deere Operations Center map (Figure 2) shows a distinct high‑pressure zone in red. This corresponds to 2–3 acres recently reclaimed for production —significantly weedier (Figure 3) than the remaining acreage (Figure 4). This work was performed using the Deere TSL8005 nozzle, with sensitivity set to 3 (medium) and buffers set to medium in both directions.

    Figure 2 – John Deere Operations Center weed pressure map
    Figure 3 – High weed pressure in the reclaimed section of the field
    Figure 4 – Low weed pressure in the majority of the field

    Download a copy of the as‑applied data. You’ll see the See & Spray treated only 25.8% of the field. If Todd had broadcasted Lontrel at 65 mL/ac and charged his typical $14.50/ac it would have cost $4,139.36. However, even with his premium spot-spray rate of $17/ac and passing on the $6/ unsprayed acre, the total cost was $3,507.96. This represents a net savings of $631.40, and the surprise twist: he used the 100 mL rate of Lontrel and still saved money.

    So, in fields with moderate but uneven perennial pressure, See & Spray Premium can produce meaningful savings while enabling more robust chemistry.

    Scouting Limitations

    As expected, visual scouting underestimated real weed density. Figure 4 might seem clean at first blush, but the cameras see a different story hidden in the stover (Figure 5). This is why predictive tank‑mix planning is unreliable.

    Figure 5 – Weeds may hide from a scout, but not from clever optics.

    Optimizing Tendering Through Job Planning

    Todd found that the best approach to minimizing leftovers was to group farms with similar pre‑emerge programs and weed spectra. He would then book them from the smallest to the largest fields, allowing leftover spray mix from smaller jobs to feed into larger ones. His goal was to finish with <5 acres worth and broadcast it at the end of the last job.

    This kind of planning starts with the fall burndown and should be firmly in place by March. It’s already challenging to accommodate last-minute requests during spring spraying, but this approach makes it particularly difficult.

    Customer Scheduling Challenges

    There was some frustration along the learning curve. A few customers experienced delays waiting on sprayer availability and then paid the premium on a field that ended up requiring a broadcast application. Experience will help refine expectations and scheduling.

    Looking Ahead: 2026 and Beyond

    In 2025, the See & Spray machines in Ontario sprayed mostly soybean, but in Todd’s region it was predominantly corn. One reason was that most of his soybean customers weren’t quite sold on the fall application. Todd has plans to get into soybeans in 2026, but his strategy involves IP beans.

    Traditionally, IP beans get a spring application timed to catch as many weeds as possible, perhaps too late for some and too early for others. Then Todd takes his phone off the hook as customers fret over burned beans while they inevitably grow out of the visual injury. But this time, Todd will make two targeted passes with a more expensive tank mix to do a better job of controlling weeds at the right stage, while avoiding burning the IP beans. If his projections are correct, he believes he can accomplish this more economically than a single broadcast pass.

    We’ll update this article with the outcome. Be sure to check back and see if he succeeds 🙂

    Conclusion

    Ontario’s early experience with green‑on‑green optical spraying suggests that while the technology is promising, it requires substantial logistical planning, label awareness, and nozzle optimization. Under the right conditions—particularly where weed pressure is irregular but significant—operators can achieve both economic savings and precise weed control.

    As adoption increases and equipment evolves, we’ll learn more about where spot and patch spraying technology fits in changing weed management programs.

    Thanks to Todd for sharing his experience and insights.