Category: Boom Sprayers

Main category for sprayers with horizontal booms

  • Horsch Leeb sprayer gives people what they want with 6.300 VL model

    Horsch Leeb sprayer gives people what they want with 6.300 VL model

    Theodor Leeb started building self-propelled sprayers in Bavaria, Germany in 2001 and formed a partnership with Horsch LLC in 2011 (Horsch has been selling tillage and seeding equipment in North America since 2001 and has 17 dealers in the prairie provinces). The resulting company, Horsch Leeb Application Systems GmbH, is headquartered in Landau a.d. Isar, about 120 km NE of Munich. There they build pull-type and self-propelled sprayers, employ 350 staff, and had sales of approximately $80 M USD in 2019.

    This is no Johnny come lately to the sprayer scene.

    Their current flagship sprayer in North America is the Horsch Leeb 6.300 VL. I spent a day with Mike Wasylyniuk, Product Marketing Manager for Horsch, in Crossfield, Alberta to look it over.

    The Numbers

    The sprayer chassis holds a 1700 US gallon stainless steel tank and two 100 gallon clean water tanks for a total liquid capacity of 1900 gallons. A stainless steel Pentair Hypro centrifugal pump provides the flow to the boom, and a second pump is dedicated to the clean water tanks. The sprayer is powered by a familiar FPT 6.7 L producing 310 hp. The boom is 120’ wide in 5 articulated sections with 10’ nozzle spacing fitted with Raven Hawkeye Pulse Width Modulation (PWM). Top spraying speed is 20 mph, top transport is 30 mph. Horsch claims a dry weight of 32,000 lbs when fitted with Goodyear LSW 900 50R46.

    The Horsch Leeb 6.300 VL near Crossfield, AB October 2021.

    A central tubular frame creates room for four-wheel steer that has an interior turning radius of 3 m. Wheels are suspended via hydropneumatics linked to the frame with double wishbones. Track width adjusts from 120″ to 160″, independently, allowing different track widths front and rear without pinning an axle in place. Standing beside the front wheel, one has with easy access to fuel and oil filters, the radiator is on top of the machine facing up with an air-chuck outlet for cleaning.

    Four wheel steer improves maneuverability but more importantly, reduces front wheel plowing and allows use of common wheel track in headland turns.

    Plumbing

    Any loyal reader of Sprayers101 knows that we believe the biggest room for improvement in spraying is in the plumbing. Horsch Leeb seems aware of this. First, it does away with sight tubes on the tank and relies on a more accurate digital float that reads down to an empty tank. Tank slope position is considered using a gyro mounted at the rear of the sprayer. The tank can be filled with the solution pump or from the tender truck using 3” side or front fill locations. It has auto shutoff when a target amount is reached. As is common, the majority of valves are motor operated to allow automation.

    Fill station on right side of sprayer contains a 3″ fill connection as well as a 2″ drain

    The recirculating boom plumbing is standard North American 1” OD stainless steel to suit any off the shelf nozzle body clamp. It pressurizes from both ends when spraying and returns to tank from the outside of the boom when nozzles shut off or when priming or flushing. The recirculation can run during transport, allowing boom priming en-route to the field, or continuous flushing with a cleaning solution in the main tank on the way home.

    Recirculating boom feed and return lines are standard 1″ OD stainless steel.

    The second pump, an Italian Annovi Reverberi 185 BP diaphragm, powers the continuous cleaning function. It draws from the clean water tank and can push this water to the boom for overnight storage when the tank has solution left, or to the tank’s wash-down nozzles for a continuous clean at the end of a job. In continuous clean mode, the solution pump continues to supply the boom while the cleaning water washes the walls and dilutes the remainder. The tank and boom can be washed with a minimum of liquid, and the process is automated using cab or side monitor controls.

    Dedicated to the clean water tanks, this diaphragm pump can push water to the boom, to the wash-down
    Stainless tank with baffle

    The system even has a winterizing button that controls all the necessary valves to distribute antifreeze from the clean water tanks throughout the plumbing system in minutes. Remaining antifreeze in the tank can be returned to the drum at the fill station with a convenient camlock drain.

    Readout of tank levels and pump pressure via the external monitor. Priming, cleaning and winterizing routines are available.

    Some may gloss over plumbing paragraphs in haste, but let’s not underestimate the magnitude of these features. We are talking about a plumbing system that can prime the boom without spraying, spray the field, then spray out any remainder while rinsing the tank, air purge the boom, then rinse the boom without leaving the cab or wasting material unnecessarily. Even the system strainers have flush capability that returns any residue to a removable fine mesh filter before the liquid dumps back to the tank. Such a design saves time and money and pays in acres per hour.

    Boom

    The 120’ boom is well built and has channels for wiring harnesses that are neatly zip-tied in place. An aluminum shield covers the nozzle bodies at the front to protect them from any ground contact.  Access is relatively convenient through ports on the other side. The fitted triple nozzle bodies should be enough to suit most needs. The swing-away has a sturdy steel tube on the leading edge to absorb and deflect any sudden impact. There is no exposed plastic. The recirculating boom plumbing is stainless steel throughout except at hinges, where the rubber hose loop is protected from chafing by an additional sleeve.

    The sturdy boom is shielded where the nozzles are mounted to protect them from impact. Note the vertical hinge that permits improved contour-following.
    The break-away section has additional protection via a stainless steel pipe that absorbs and deflects impact.
    Access to the 10″ spaced nozzles and PWM solenoids is via the rear of the boom.

    The Leeb philosophy is to design sprayers that control drift at the source without reliance on extremely coarse sprays that can hamper efficiency. They’ve chosen boom height as the key variable and built the boom to make this possible. First, they needed to design a system that can reliably hold the boom low and level.

    Low, uniform boom height for drift reduction is the stated goal of the Horsch Leeb sprayer

    To that end, three pivot points are used to provide independence of the tractor unit and the boom. The first is at the centre rack from which the boom hangs but can pivot thanks to the same gyro that helps read the tank level. A sudden tractor movement due to ruts, for example, can then be compensated. The wings are the second pivot point (as it is for all sprayers), and a third point is halfway out the wings, where a hinge allows for up or down adjustments to better suit the land contour.

    A giro, visible just above the backup camera, monitors the tractor aspect relative to the boom.
    The vertical boom pivot can help prevent unnecessarily high boom ends or ground strikes.

    The height sensors have a modest look ahead slant, and the company claims that 8” boom height at 10 mph is possible. We certainly tried that in the field, and after multiple runs up and down a local field with modest knolls we did not strike ground, although the boom ends did rise significantly on occasion. The claim of such low booms will be a point of considerable testing and debate.

    Eight sensors provide boom height feedback.

    To take advantage of the low heights, narrower 10″ nozzle spacings are needed. The boom therefore has 144 nozzles instead of the usual 72, each half the flow rate. This is new territory for PWM, where the smaller tips are not as widely available. For example, a traditional 5 gpa tip at 20” and 12 mph is 03 in size, with 10” spacing this is now 015.  Smaller sizes require more attention to filtering, and they have inherently greater drift potential. This would only be a problem at the lower application rates.

    Because PWM allows for individual nozzle control, the operator can select 20” spacing, based on either of the 10” positions. This means one can spray with 20” spacing and then switch to a different nozzle simply by selecting the alternate.

    The lower boom height can offer unique advantages. The first of these is drift control. Droplets emerge from the tip at about 70 km/h, and this initial speed prevents even the small ones from drifting. The higher the boom, the more they slow down before targetting, creating drift potential. Wind speeds also tend to be lower nearer to the ground.

    Second, the beneficial effects of twin fans or angled single tips are greater with low booms. Readers will know that one of the fundamental prerequisites for successful angled sprays in Fusarium head blight (FHB), for example, are low booms. We may be in for some positive outcomes.

    The User Experience

    The Class cab has the usual creature comforts with a buddy seat, four cup holders, bluetooth radio and a phone mount. It can be fitted with any ISOBUS monitor, the one we had was equipped with the Raven Viper 4. The climb up the ladder is not as stair-like as the North American sprayers, but the treads are large and there are plenty of handholds so you can climb one-handed and bring your lunch or toddler along for the day.

    There is one native Horsch monitor that controls the chassis, wheel spacing, engine specs, speed, etc. It’s controlled using a rotary button selector like the one in many cars, a wheel that highlights items by turning, then selects them with a push. The second, an ISOBUS monitor, handles the rate control and thus creates easy compatibility with a variety of aftermarket monitors.

    The joystick is backlit and buttons can be customized. Like the Fendt stick, a push forward sets the speed and it can return to the neutral position without changing that speed. A pull back is required to slow down.  It takes a bit of getting used to. Motion can also be foot operated with a speed pedal and foot brake.  Cruise control has two preset speeds, and boom height can be raised to preset values when the master switch is shut off to facilitate a headland turn. The top two thumb buttons are Master on/off and autosteer resume.

    There is no throttle control. The sprayer decides how much throttle is needed to maintain speed, saving noise and fuel when it can. Throttling up was noticeable as we climbed hills during our test drive, returning to lower rpm as we descended while maintaining our cruise control speed.

    Some touches

    • a hand wash station at the ladder to prevent contaminating the hand-holds or cab
    • a camera focused on the centre rack nozzles that are invisible from the cab
    • cameras showing front wheel position
    • mud guards behind rear wheels to protect boom
    • Rain cover over electronics mounted on centre rack
    • A clean underbelly with good clearance and tow hooks front and back
    • Inductive (wireless) phone charging mount

    Overall Impression

    It’s clear that Horsch Leeb wants to succeed in North America. I’ve hardly ever seen a company so bent on delivering what the market wants (for familiarity and compatibility) while delivering what it knows they need (like plumbing and drift control). Spending the day with Mike I learned how quickly the engineers and fabricators implemented his suggestions at the factory. That is perhaps the most promising aspect of all, a company that listens to its customers and continually evolves its product as a result.

  • The Ideal Sprayer (an open letter to sprayer manufacturers)

    The Ideal Sprayer (an open letter to sprayer manufacturers)

    Today’s sprayer has to excel at a lot of things. It has to have capacity and low weight. It has to go fast but be comfortable. It needs wide booms that stay level over complex terrain. It has to deliver the right spray volume at the right spray quality for the job. It has to be easy to fill and easy to clean. And of course, it has to be reliable, affordable, and come with dealer support.

    We’ve definitely made progress in many of these areas. But the overall package still leaves lots of room for improvement and doesn’t address some issues that are of importance to applicators. Is it time for a reset?

    Let’s say cost is no object. Here’s where I think the industry could go.

    Focus on spray delivery

    Spraying is done to protect crops. We need to do it without harming the environment while being economical with the inputs. These three tenets make up the Application Triangle, sometimes known as the 3 Es of spraying: Efficacy, Environment, Efficiency. The triangle represents the need for balance. A gain in one or two areas often requires a loss in another. That’s why there has never been a so-called “silver bullet” in spraying.

    Priority 1: Only spray when and where required.  Site specific treatments and IPM have been slow to make their way to the spraying world partly because of the low cost of inputs, but also because of difficulties defining and mapping areas that require different rates or products. The machine learning revolution is changing that. Green on Brown or Green on Green sensing can do more than save inputs. They can generate maps that document the change of weed patches over time, identifying priority areas and threshold densities and flagging problems early.

    Priority 2: Integrate air assist. Air carries small droplets towards the target, protecting them from displacement by travel-induced or ambient winds. Once there, air can improve target interception and retention. It has to be done right, though, as improper adjustment can result in the opposite outcome. The reason it’s high on this list is because it improves efficacy and environmental protection at a modest cost.

    Priority 3: Improve droplet size control.  Nozzle design has improved, but the overall range of spray qualities that is achievable for any specific nozzle remains narrow. Sprays can be made finer or coarser with spray pressure, but this has implications for pattern uniformity. Twin Fluid nozzles currently offer the widest range of spray qualities, allowing one nozzle to do it all. We simply need greater droplet size flexibility on the spray boom.

    Priority 4: Use nozzle-specific rate control.  At minimum, a sprayer needs a system that allows for individual nozzle rate control within a wide window, say 4:1. This allows consistent dosing over a wide speed range, turn compensation, or local adjustments to dose for specific (sensed) canopy conditions. By layering direct injection at the nozzle on top of this, the sprayer can change rate and volume independently. Being able to spray the right amount in the right spray quality at the right volume, where needed completes the opportunity created by pest and canopy sensing.

    Create better infrastructure

    The backbone of the sprayer, the frame, drivetrain, boom, tank, pump, and plumbing, are responsible for carrying and delivering the spray liquid. Poor management of these variables results in an unproductive, heavy machine.

    Priority 1: Prepare booms for future.  A limiting factor in sprayer performance is boom width and stability. Consistent and low boom heights are the cornerstone of good application, ensuring uniform distribution, reducing drift potential, and improving targeting within the canopy. But perhaps as importantly, stable booms are essential for accurate optical spot spraying and any other sensing tasks that will rise in importance. Set a standard for sway, say target height plus or minus 10 cm along the width of the boom, 90% of the time. Do the same for yaw. Accommodate brackets for sensors and wiring harnesses when designing the boom fold.

    Priority 2: Improve plumbing.  Poorly executed sprayer plumbing causes waste and decontamination headaches. Although rubber hoses attached to plastic fittings provide a very versatile and generic building block, they generate and hide countless niches in which pesticide mixtures or active ingredient residue can accumulate. A simplified design that incorporates more engineered stainless steel tubing, smooth directional and dimensional transitions, interior surfaces that don’t accumulate residues and generate more efficient flows – all these would improve many aspects of the spray operation. It needs to be goal oriented – i.e., zero waste in priming and cleaning, guaranteed decontaminated after a rinse cycle. Draining on the ground should not be necessary.

    Priority 3: Save weight. Weight causes compaction and eats fuel. Advanced materials or techniques can save weight while preserving strength. Savings can be applied to capacity. We need to explore advanced materials and trussed or exoskeletal designs (see “Aerodynamics”).

    Priority 4: Consider aerodynamics in chassis and boom design. Wind blowing past a tractor, tank or boom, or counter-rotating air from wheels creates turbulence that displaces small droplets within it, reducing uniformity. Cleaner air makes it easier to use smaller droplets, easier to implement air assist or any other drift-reducing technology. This is no small task, as air can come from any direction. But as units become larger and travel faster, this effect can’t be ignored. Monocoque designs that use aerodynamic exteriors to carry machine weight may provide an answer.

    Provide quality control

    Spraying can be a guessing game, hence the terms “Spray and Pray”. We don’t know the outcome for days or weeks, depending on the mode of action, and by the time the result is known, it is too late to do anything if it’s unsatisfactory. But we can do better in assuring some sort of standard.

    Priority 1: Confirm pressure, flow, and patterns at nozzles. The average sprayer has one flow- and one pressure-sensor. It can confirm the flow of the entire spray boom but cannot do that at the nozzle level. PWM has helped, by inferring flow from duty cycle. But actual liquid flow, and its pressure, remain unverified at the spray tip. A visual inspection of the pattern is necessary, and this is not only impractical but also wasteful and potentially hazardous.

    Priority 2: Characterize canopy. If we knew the crop canopy was dense or sparse, we could adjust the water volume or rate of the product accordingly. LiDAR (Light Detection and Ranging) can characterize the physical structure of an object that would indicate density or porosity for which a dose (or droplet size, or air) adjustment may be necessary. This is not some future technology. The iPhone 12 Pro has it. Even RGB image processing could do something very similar.

    Priority 3: Confirm coverage and drift.  Say we’ve characterized the canopy and adjusted the atomization to suit. Is it having the intended impact? We will need a way to verify that the settings of the sprayer result in the required canopy penetration and coverage, even drift, on-the-go. We would need sprayer-mounted sensors that see spray deposits or an airborne spray cloud. The verification must be fast enough to make corrections during the spray operation. This kind of quality control provides the feedback loop to the first priority, spray delivery. It creates a perfect environment for machine learning and continuous improvement.

    Priority 4: Improve user interface.  The complexity of modern equipment monitors is great if you’re familiar with their features. But if you’re a new user or less comfortable with layers of screens and buttons and warning beepers, navigating the monitor can be a game stopper. Can we have beginner modes? Or a system where the monitor more actively engages with the user, asking questions or reminding a novice of key settings? The friendliness of the interface is a sleeper issue, it seems less important at first look but can over-ride many equipment features because of the power of a positive user experience.

    I challenge sprayer manufacturers to conceptualize and show us the ideal sprayer they’re working towards. The perfect unit may never reach us, as this proposal is rife with technological and cost barriers. But it is nonetheless important to identify priorities and identify possible ways to meet them. As we creep towards the solution with incremental improvements, recall that its not the size of the step that matters, it’s the direction.

  • End of Spraying Season Checklist

    End of Spraying Season Checklist

    It’s finally that time of year to put away the most-used piece of farm equipment, the sprayer. Winterizing is a necessary step, but also an opportunity to do a few extra things.

    Winterizing

    1. Before you do anything, walk around the sprayer and note any telltale signs of liquid leaks. Once washed, the helpful dusty surfaces are gone and slow, chronic leaks may go unnoticed.
    2. Now it’s OK to clean and rinse the sprayer tank and wash the sprayer exterior.
    3. Drain any remaining water from the product and the rinse tanks. These remainders will cause unwanted dilution of the antifreeze. After you drain filter housings, inspect and clean filters.
    4. Choose your anti-freeze. Automotive anti-freeze works, but’s it’s toxic and you can’t spray or drain it on the ground. Liquid fertilizer is sometimes used, but it’s corrosive, crystallizes when cold, and is not recommended. The best product is RV Antifreeze. It’s friendly to rubber and plastic, considered non-toxic, and can protect down to the coldest temperatures. Some dealers carry specific sprayer antifreeze. Don’t use fertilizer (e.g. 28) to winterize – especially with PWM systems.
    5. Add between 25 and 50 gallons of antifreeze to the product tank, or if you have one, to the clean water tank. Most larger sprayers need at least 25 gallons just to prime the plumbing.
    6. If you have a rinse tank, start a normal rinse procedure. Run the product pump, drawing from the rinse tank and pushing the material through the wash down nozzles into the product tank. Once the rinse introduction is complete, an automatic rinse procedure may subsequently open various lines leading to the tank as it swirls the rinse solution through the tank. Familiarize yourself with the specifics of that process.
    7. If rinsing valves are manually controlled, once the antifreeze is in the product tank, run the pump, drawing from the tank and circulating back to the tank via agitation. If you have any other bypass lines, such as sparge, make sure the valve is opened. Run for two to three minutes.
    8. If you have an on-sprayer eductor system, run the antifreeze past it and activate the eductor wash process.
    9. Now, it’s time to push the antifreeze to the boom. Treat this like a boom cleaning, making sure the antifreeze gets to each nozzle body. If you have high- and low-flow options, open them to ensure the bypass gets the antifreeze.
    10. Activate one boom section at a time and ensure all nozzles have received the antifreeze. Open nozzle end caps and allow the antifreeze the push out the water that is trapped there. It helps if you first purge the system with compressed air, then you don’t need to wait for the clear water to gradually change colour as the antifreeze arrives.
    11. For extra points, rotate the nozzles through each position. As with cleaning or servicing, a remote-control boom section controller is invaluable here.
    12. Remember to activate the fence row nozzles if you have any. These usually have their own dedicated feed line coming off the outer boom section.
    13. If you filled your anti-freeze directly into the rinse tank, briefly open the rinse and product tank fill valves to allow anti-freeze to push out any water. Don’t forget the front fill line.
    14. It’s OK to leave any leftover antifreeze in the tank. Next spring, collect it for re-use in the fall. You’ll still need more but this saves you some.
    15. Don’t forget to also winterize your spray tender and any other transfer pumps.
    16. It’s always a good idea to grease fittings after equipment is washed, to displace any water that got in, and to lubricate other moving parts that should be protected from corrosion.

    Inspecting and Reflecting

    You’re going to be looking closely at a clean sprayer, and this is a good time to spend a few extra moments to ponder the big picture. But first:

    1. Inspect the full length of all hoses. Look for kinks, rubbing, small leaks, loose or defective clamps, valves, nozzle bodies. Tighten what’s loose, replace what’s worn.
    2. Check cabin air filter service interval. Most new sprayers have activated carbon filtration that requires regular replacement. Activated carbon starts deteriorating with any air contact, so if you get a new one, leave it wrapped in its plastic until you need it.
    3. Download or record sprayer performance data. How many engine and spraying hours? How many acres? How much water? A typical sprayer may calculate your acres per hour, but uses spraying hours only which paints a rosy picture. Do the calculation using gross engine hours to get a better idea of time lost to idling, transporting. Compare to previous year, perhaps set some goals.
    4. Check with the dealer to make sure you’ve got the latest controller software version. Many systems get an upgrade during the off-season, so check back in the spring.
    5. Remove the flow meter from the system and ensure it runs free. Do not use compressed air to run the impeller, this can ruin it. Simply blow on it and ensure it runs freely. This is an important part of the sprayer, so some people store it separately over winter. Did it provide accurate information?
    6. Top up the fuel tank to prevent condensation.
    7. Don’t forget to mouse-and bird-proof.

    Now:

    1. Think back on the season. What went well? What went poorly? What repairs were needed? Which ones did you put off? Are you happy with your procedures for filling and cleaning? Did you hear or read about improvements that seem interesting? Reminisce by reading the notes you wrote on your cab windows.
    2. Make a list of the improvements that would address the main issues you came up with during your reflection. Is it time for a better filling setup? Do you need a whole tender system, or just an upgraded fill pump or a better inductor? Is it time to add a continuous rinse system?

    Replacements and Improvements

    1. Some sprayer components simply wear out and need regular replacement. A rule of thumb for sprayer nozzles is about 30,000 acres for an average sprayer speed and boom width. But before you buy, make sure you know what you need. Were you happy with the spray performance? Did you have more drift than you wanted, or poor coverage? As our cropping systems change, we may need different nozzles to suit the purpose. Now is the time to think about that very coarse low-drift nozzle that would have allowed you to get the spray on before the rain that delayed you for 3 days. Or the higher volume spray that would have done a better job with desiccating the tall canola crop, speeding up harvest. Or the finer spray that works better with the contact products you need to manage resistance.
    2. Pumps can also wear. An impeller replacement can revitalize a centrifugal pump and give back more pressure and flow. Or a new pump with run-dry seals can avoid downtime from a pump failure in the middle of a good stretch of weather.
    3. We still see plastic boom lines on some sprayers. Replacing them with stainless steel eliminates warped lines and makes spray patterns more accurate, improves cleanout, and adds sparkle.
    4. A wider boom can dramatically increase productivity. After-market booms are available in 135′ and larger widths. Aluminum construction keeps them light, and corrosion-free.
    5. Pulse Width Modulation (PWM) can be retrofitted on any sprayer. This will offer improved sectional control resolution, turn compensation, and better droplet size control.
    6. Spot spraying can be added to any sprayer, and this will save 50 to 75% of pre-seed product use. In the case of WEEDit Quadro, these systems now come with stand-alone PWM that will work for general broadcast spraying in crop, with all the features mentioned above. Trimble offers the WeedSeeker II, it’s also feature rich but doesn’t offer PWM.
    7. Become part of a mesonet. Most crop imaging services and some agronomic service providers offer weather stations, and obtaining one can make you part of a large, high resolution network. Local monitoring of temperature, rainfall, and wind conditions improves spray decisions as well, and may even give you the ability to identify temperature inversions.

    The sprayer will often be the first piece of equipment used in the spring. Preparing it for its next job starts now.

  • Spray and Soil Fumigant Buffer Zones in Canada

    Spray and Soil Fumigant Buffer Zones in Canada

    Spray buffer zones are no-spray areas required at the time of application between the area being treated and the closest downwind edge of a sensitive terrestrial or aquatic habitat. Spray buffer zones reduce the amount of spray drift that enters downwind, non-target areas.

    Sensitive Terrestrial Habitats

    Sensitive terrestrial habitats can include hedgerows, grasslands, shelterbelts, windbreaks, forested areas and woodlots. Crops and private properties adjacent to treated areas are not considered to be sensitive terrestrial habitats and do not require spray buffer zones. However, labelled spray buffer zones are a good indicator of potential damage to adjacent vegetation. Applicators are responsible for ensuring their spraying programs do not adversely affect neighbouring properties.

    Sensitive Aquatic Habitats

    Sensitive aquatic habitats can include lakes, rivers, streams (channelized or natural), creeks, reservoirs, marshes, wetlands and ponds. Temporary bodies of water resulting from flooding or drainage to low-lying areas are not considered sensitive aquatic habitats. Nor are aquatic drainage ditches or seasonal water courses that are dry at the time of application. Water body depth will determine the buffer zone distance, as indicated on the pesticide label. Downslope open water may also require a vegetative filter strip .

    The pesticide label will indicate when a spray buffer zone is required. The distance will depend on the product used, the method of application and the crop being sprayed. In some cases, the buffer zone may be modified using Health Canada’s Spray Buffer Zone Calculator . When provincial and label restrictions differ, or label restrictions differ between tank mix partners, use the greatest distance.

    Buffer zones or No-Spray zones physically separate the end of the spray swath for the nearest downwind sensitive area.
    Buffer zones or No-Spray zones physically separate the end of the spray swath for the nearest downwind sensitive area.

    Spray Buffer Zone Calculator

    Unless forbidden by the pesticide label, Health Canada’s Spray Buffer Zone Calculator may permit applicators to reduce the size of the spray buffer zone specified on a pesticide label. To be eligible, the product label must specify a field or aerial spray quality coarser than “Very Fine” and finer than “Very Coarse”. All airblast spray qualities are applicable.

    Modifications are based on meteorological conditions, sprayer configuration and the application method at the time of application. If modified spray buffer zone distances are less than provincial or municipal distances, use the greater distance.

    Applicators that choose to use the calculator must retain a copy of the summary page for at least one year following the application to demonstrate compliance with label directions.

    Vegetative Filter Strips

    A vegetative filter strip is a permanently vegetated strip of land that sits between an agricultural field and downslope surface waters. Vegetative filter strips reduce the amount of pesticide entering surface waters from runoff by slowing runoff water and filtering out pesticides carried with the runoff.

    Pesticide labels may require a vegetative filter strip, or recommend one, as a best management practice. They must be at least 10 metres wide from edge of field to the surface water body and be composed primarily, but not exclusively, of grasses.

    Spray buffer zones do not apply to vegetative filter strips unless there is a pre-existing sensitive terrestrial habitat within them. Therefore, vegetative filter strips may overlap spray buffer zones when open water is both downslope and downwind (see illustration). In this case, the minimum 10 metres vegetative filter strip distance must be observed, but the set-back can be larger based on spray buffer zone, provincial or municipal restrictions.

    Soil Fumigant Buffer Zones

    Soil Fumigant Buffer Zones are mandatory, untreated perimeters surrounding the treated field. They limit user exposure and increase the protection of workers, bystanders and the environment. The distance will depend on the application method, product rate and field size, as indicated on the pesticide label. An Emergency Response Plan is required when residences or businesses are located within 90 metres of the buffer zone perimeter.

    Soil fumigant buffer zones have a time component. This Buffer Zone Period begins at the start of the application and ends a minimum 48 hours following the application. Respiratory protection and stop-work triggers, as specified on the pesticide label, will apply to anyone present in the buffer zone area during the buffer zone period.

    Buildings and residential areas within the soil fumigant buffer zone must be unoccupied during this period. Unless in transit, non-handlers (including field workers) must be excluded from the soil fumigant buffer zone during this period. Entry is permitted for fumigant handlers with appropriate certification, emergency personnel and local, provincial, or federal officials performing inspection, sampling, or other similar duties.

    Image from www.onspecialitycrops.ca

    Soil fumigant buffer zone signage must be posted within 24 hours prior to the application and remain posted until the buffer zone period expires. Signage must include, but is not limited to, the date and time the buffer zone period ends and the name, address, and telephone number of the applicator. Soil fumigant buffer zone signage must be located at the outer perimeter of the buffer zone, at all entrances to the field, and along likely routes where people not under the owner’s control may approach. Soil fumigant buffer zone signs are in addition to, and do not replace, fumigant application block signage .

    Applicators must develop a written Fumigation Management Plan prior to the start of any application. The plan outlines key steps to ensure a safe and effective fumigation, including site conditions, buffer zones and emergency response planning. Both the owner/operator of the fumigated area and the fumigant applicator must retain signed fumigant management plans as well as a summary of Post-Application Procedures for two years following the application.

  • Three Manageable Factors that Affect Spray Drift

    Three Manageable Factors that Affect Spray Drift

    In 2014 one of our OMAFRA summer students designed a short-and-gritty demonstration using a backpack sprayer, a variable-speed fan and some water-sensitive paper positioned downwind at 1.5 metre intervals. The intent was to illustrate how sprayer operators could reduce the potential for off-target drift by recognizing and accounting for three factors:

    • Apparent wind speed (i.e. the sum of wind speed and travel speed)
    • Boom height (i.e. release height)
    • Droplet size (i.e. nozzle spray quality)

    Apparent Wind Speed

    Spray operators know they should not spray when the air is calm or when the wind is too high, but they often forget that the nozzles experience “apparent wind speed” which means driving 10 km/h into a 10 km/h headwind is essentially spraying in a 20 km/h wind.

    The result of spraying with a Medium spray quality in 10 km/h and 15 km/h wind: water-sensitive papers indicated that there is more downwind drift in higher winds.

    Boom Height

    Spray operators raise their booms to ensure their nozzles clear the crops, but this contributes to off target drift and greatly reduces coverage – particularly when using twin-fan style tips. Dr. Tom Wolf explains how to set your boom height here, or you could watch one of our Exploding Sprayer Myths videos on the subject.

    The result of spraying with a Medium spray quality in a 10 km/h wind at 50 cm and 100 cm from the ground: water-sensitive papers indicated that downwind drift increases as the boom gets higher.

    Droplet Size

    The coarser the spray quality, the less likely the spray will drift off target. Remember, for a given volume, shifting to larger droplets means fewer droplets. Application volumes may have to increase to compensate for potentially reduced coverage.

    The result of spraying with a Medium spray quality versus spraying with an Extremely Coarse spray quality: water-sensitive papers indicated that there is more downwind drift from smaller droplets.

    Take-Home

    This demo used percent coverage as a metric, which is convenient but greatly underestimates drift. So even when the spray window is small and the spray has to go on, take a moment to drop the boom, use a coarser droplet size and if it’s too windy, just don’t spray.

    WUR Drift Calculator

    There are many drift calculators available for home use. Some require more expertise than others to get a reliable result. This free downloadable calculator from Wageningen University & Research was made available in 2021. It can quantify spray drift deposits onto surface waters and non-target terrestrial areas near a sprayed field or orchard

    The calculator uses statistically obtained regression curves to calculate spray deposition next to the sprayed field. The spray drift curves are based on the latest experimental data for field crops, fruit orchards and avenue tree nurseries.

    Download your copy here.