Tag: optical spot spray

  • Optical Spot Spraying and AI Scouting

    Optical Spot Spraying and AI Scouting

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    Site-specific treatments have long been a goal in agriculture. It makes sense to provide inputs or treatments at rates that reflect the local situation. And to a large degree, those capabilities have been available for fertility and seed inputs for some time, with input zones reflecting soil types or topography.

    Typical prescription map for nutrients (Source: Field Crop News)

    But the sprayer world has not seen as much site-specific treatment. One reason is that pest maps are time-consuming to generate and their usefulness may be short-lived. Or perhaps weeds are fairly ubiquitous, and it usually makes sense to treat an entire field. Another reason could be that sprays are relatively inexpensive compared to fertilizer or seed.

    For spraying, we need to re-define site-specific.

    While traditional zone maps (corresponding to, say soil type and/or elevation or slope position) allow unique treatments on a scale of acres, new sensors have allowed sprayers to basically leapfrog this approach and treat each square foot uniquely. These sensors identify plants directly and create an immediate treatment response.

    Optical Spot Spray(OSS) principle (adapted from WEEDit)

    The idea, and technology, has and been around agriculture since the early 1990s, with the Concord DetectSpray and later the Trimble WeedSeeker. For various reasons, these two never became widespread in North America, although a significant market formed in Australia and New Zealand.  New cutting edge technologies are about to change this.

    Green on Brown

    Two main manufacturers have occupied the traditional Green on Brown Optical Spot Spraying (OSS) space, the Trimble WeedSeeker and WEEDit. Both have been available for over 10 years and are well established and proven reliable. WeedSeeker uses the Normalized Difference Vegetation Index (NDVI) principle to detect green on a non-green background. It employs one sensor per nozzle and the nozzle is either on-or off based on what the sensor detects. The WEEDit system is manufactured in the Netherlands by Rometron (https://www.weed-it.com/), and is widely adopted for use in Australia and South America. It is now making inroads into North America. The most recent version is named Quadro.

    WEEDit spray booms contain sensors placed at 1 m intervals. These scan the ground ahead of the boom, identify the presence of plants, and trigger the nozzle in line with the plant. The newest Quadro sensor contains four channels so that its resolution is actually 25 cm (10″) wide. The boom therefore contains a nozzle every 25 cm, and this nozzle has a correspondingly narrow fan angle that treats just this space.

    Hypro even spray (banding) nozzle with 30 degree fan angle. 30 and 40 degree nozzles are currently installed on WEEDit on 10″ spacing.
    30 degree fan achieves approximately 8″ to 10″ band at target height. Boom stability is important

    The detection principle is based on the quality of light that is reflected from living plant tissue compared to everything else. A red (older generation) or blue (newest generation, Quadro) light is emitted, and chlorophyll-containing plants reflect a unique wavelength that differentiates them from ground or dead plant material.

    Older generation WEEDit sensors were placed at 1 m intervals and had five channels, each covering a 20 cm band. There were 180 nozzles on a 36 m (120′) boom.

    The response time of the system is very fast. Triggered by small solenoids, a sprayer travel speed of up to 15 mph is possible when the sensor looks 1 m ahead. Furthermore, the software allows the user two important controls: first, the sprayed distance before and after a detected plant can be buffered between 5 and 20 cm, resulting in a sprayed patch between 10 and 40 cm long. This could be useful when boom heights fluctuate and placement of the sprayed patch shifts accordingly. Second, the user can select from among four sensitivity settings. Higher sensitivity can detect smaller weeds but will also result in more false results.

    WEEDit Quadro sensor

    One reason the system has been successful in the southern hemisphere is the long growing season that may require multiple spray passes outside of the crop each year, and in which the weeds are relatively large at treatment time and therefore easier to detect.

    Water sensitive paper can be used to show whether a target has been detected (and therefore sprayed).

    In North America, the pre-seed spray window is relatively narrow and weeds may be very small or just be emerging. The risk of a miss due to non-detection is therefore greater. Fortunately, the WEEDit system has a feature that addresses this risk.

    PWM valve for WEEDit, capable of instantaneous response at 10 to 50 Hz

    The solenoids that trigger an individual nozzle are pulse-width modulated (PWM). This means that the application rate is adjusted according to travel speed via a duty cycle. And it offers an innovative capability: The entire boom can be programmed to spray a defined fraction of the full dose, to a maximum of 50%, as a background broadcast rate (called “Dual Mode” or “Bias”). The smallest weeds that escape detection are likely to be susceptible to this lower dose. Larger weeds are then detected and sprayed with an individual spot spray at the full dose. Dual Mode is typically set to about 25%; overall savings are less, but control is improved for those very early season situations.

    A WEEDit Quadro boom can also be operated in “Cover Mode” for broadcast spraying where it functions as a full PWM system with turn compensation.

    Currently, several hundred WEEDit sprayers are operating in Australia, and they’ve been available in Canada and the US since 2017. in 2019, Croplands, an Australian sprayer manufacturer owned by Nufarm, started representing WEEDit in Canada. It is available as a retrofit on existing booms, and can be ordered with a WEEDit Millennium aluminum boom that contains mounting brackets and wiring harness channels. Savings compared to broadcast spraying range from 65 to 85%.

    In early 2021, John Deere announced its entry into the Green on Brown space with See & Spray Select™. This system is built around the ExactApply nozzle body and uses RGB cameras to differentiate green plants from non-green background colours. It will be in fields in 2022 according to John Deere. Similar RGB-based systems are in development by other manufacturers. Although their performance has not been compared side by side with WEEDit or WeedSeeker, initial specs suggest that the RGB systems are slower and are less able to detect small plants. Nonetheless, the future looks very promising.

    In 2021, Hardi Australia announced a new product, called GeoSelect. This system does not have boom-mounted sensors, and instead sprays according to a prescription map developed by a drone. The advantage of this system is that the amount of herbicide needed is known in advance of spraying, and the knowledge of weed distribution in the field can allow for a more efficient coverage plan to be used. This system allows for spraying under any light condition, and adjusts for boom sway to ensure accurate placement. Drone map development is the responsibility of the applicator.

    Green on Green

    Green on Green spraying, which detects weeds within a crop and differentiates them from that crop, is advancing and the earliest commercial releases are now available in Australia, offered by a partnership between Bilberry and Agrifac (WeedSmart podcast here), as well as Bilberry and Goldacres with Swarmfarm. Others, notably the SmartSprayer from Amazone in partnership with Xarvio and Bosch and Greeneye Technology are entering field testing with commercial sized units in 2021 and 2022, respectively.

    Opportunities for Optical Spot Spraying

    Taken as a whole, optical spot spraying offers a number of opportunities for weed management.

    Cost Savings: OSS has an appealing rate of return on investment. On a 5000 acre farm, a pre-seed treatment of glyphosate plus tank mix for resistance management may cost $10/acre, or $50,000 per year. At an average savings of 75%, that represents $37,500 per year. Add other non-crop uses, such as post-harvest, and savings increase. With eventual weed recognition in-crop, virtually all herbicide treatments are candidates for such savings.

    Herbicide Resistance Management: Delaying the onset of herbicide resistance requires the use of multiple effective modes of action in a tank mix. Cost is a deterrent to this practice. With OSS, these tank mixes become affordable.

    Efficiency: With 75% product savings, a tank of product will last longer. The time lost to hauling water and product, as well as filling the sprayer, will decrease. For example, WEEDit users are spraying a full day on a single load. Or they may choose to use a much smaller load, decreasing equipment weight.

    Pre- and Post-Harvest: Whether for desiccation or weed control, site-specificity of late season sprays can also be based on living tissue. Only regions in the field requiring the desiccant are treated. Perennial or late-season weeds are selectively controlled pre-harvest. Since herbicide rates in these applications are typically higher, savings are significant.

    High value crops: Row crops requiring multiple fungicide applications per season, such as potatoes, can benefit from OSS. Sprays applied prior to canopy closure can thus avoid gaps between plants, saving product.

    Producer Innovation: One user of the WEEDit system in Saskatchewan developed an innovative use. Having missed a pre-seed spray, the applicator was faced with large weeds in a 1-leaf RoundupReady canola crop. By turning down the sensitivity of the system so the canola crop did not trigger the sensors and turning on Dual Mode, he was able to broadcast spray the field at a low glyphosate dose (sufficient to control the small weeds) and then apply a full dose to the larger weeds, triggered by the sensor.

    Equipment Innovation: Since individual zones or weeds require unique doses or products, technologies like direct injection, remote nozzle switching, multiple smaller tanks and booms, and PWM will make more sense and grow. But the whole concept of detection and treatment can be moved away from pesticides to mechanical control or other techniques such as lasers, as does Carbon Robotics.

    License to Farm: OSS makes intuitive sense not only to applicators, but also to the public at large. Showing and using these technologies demonstrates stewardship practices that are easy to communicate and understand.

    Artificial Intelligence Scouting

    Another approach is pioneered by several companies, for example Dronewerkers in the Netherlands (https://www.dronewerkers.nl/english/) Taranis (http://www.taranis.ag/), and Xarvio (https://www.xarvio.com). These companies have developed plant recognition algorithms that are currently able to identify over 100 different species. Each species can be divided into several growth stages. Taranis has launched a business in North America that scouts fields by high-resolution drone imagery, and then provides customers with maps that highlight potential agronomic issues such as weeds, disease, or insect damage.

    Example of information available from artificial intelligence scouting. In this case, plant and foreign material information by species, relative abundance, and growth stage.

    Resolution of the output can be species-specific (lambsquarters vs redroot pigweed), or by coarser resolution (broadleaf vs grass). The resulting output then shows the plant density at each location.

    Weeds in a soybean crop (courtesy of Taranis)

    Xarvio Scouting is a product in their Field Manager line (https://www.xarvio.com/en-CA/Scouting). App-based, the agronomist or producer takes pictures of their crops and the app is able to recognize weeds, diseases, insect feeding damage, as well as nitrogen status. The app is aware of other users in the area and basically crowd-sources emerging agronomic issues as they arise, communicating them back to the user.

    The Xarvio Scouting app can identify certain weeds, diseases, and insect feeding damage from pictures taken while scouting (Screenshot from Xarvio.com).

    The agronomic value of this information is clearly very high. Imagine knowing the distribution of weeds by species before and after treatment. Although we can already assess this when we walk fields, by conducting the task via drone we are measuring on a wide scale, permitting an accurate quantification of the treatment effect so its value can be assessed. This level of measurement intensity was not possible before. Yield loss models for time of removal of certain weeds at certain growth stages can be applied across the entire field, and economic analyses allows follow-up treatments to be tailored to specific portions of the field.

    Green-Eye Technology artificial intelligence can differentiate these ragweed plants from the pea crop. (Courtesy Green Eye Technology).

    Or imagine following specific patches of weeds over time, to monitor the effectiveness of a certain cultural practice, or be alerted to the establishment of a resistant population while it’s still feasible to contain it.

    Heat maps can be generated to document weed patches, and perhaps monitor their size over time. (Courtesy Green Eye Technology).

    When this information is converted to a prescription map, rate and tank mix composition (or cultural controls) could be varied as necessary by zone, or weeds could, in the future, be sprayed individually. Perhaps future autonomous robots could be deployed more efficiently.

    Identification of plant symptoms in canola (Courtesy of Taranis)

    Development and improvement of these technologies is ongoing rapidly. Finally, we may have all the pieces that can bring site specific weed, disease, and insect management to market.

  • How Spot Spraying will Affect Sprayer Design

    How Spot Spraying will Affect Sprayer Design

    Some years ago, a friend recommended that I read The Tipping Point by Malcolm Gladwell. In this book, Gladwell tries to understand why some things catch on, and others don’t. It’s a compelling read full of Gladwell’s trademark stories and his knack to deftly interpret scientific studies. He talks of connectors, mavens, and salesmen, as well as the “stickiness factor”, a measure of how memorable something is, as keys to success of products and ideas. I think of the book often as I ponder the many good ideas in agriculture, many of which never see widespread adoption.

    One of these good ideas is spot spraying. Green-on-brown detection was first introduced in the early 1990s. Anyone remember the Concord DetectSpray? It was great but had bad timing, as resistance wasn’t a big issue and glyphosate prices were about to slide. Green-on-brown grew to the NTech (later Trimble) WeedSeeker a few years later. Rometron’s WEEDit built on Trimble’s success and found widespread adoption in Australia in the past ten years. Spot spraying did not gain any traction in North America during this time.

    Australia is unique in many ways, not the least of which is their summer spraying practice. Summer is the hot, dry season where land is typically fallow and weeds are kept in check with herbicide sprays (aaaah, the serenity). Making several passes over a field, combined with the need to control some larger and hardy plants, is expensive, and a spot spray saves much of the cost. The savings can be put to use with more effective herbicide tank mixes that delay the onset of herbicide resistance. Spot sprays pay for themselves in short order Down Under.

    It’s more of a challenge in the northern plains of North America, where the fallow season involves snow cover and burnoff occurs in a short window before seeding and sometimes after harvest. But nonetheless, spot sprays have a fit for many of the same reasons.

    WEEDit is the first system to make serious inroads in North America, with several dozen systems having been retrofitted to high-clearance sprayers. High detection accuracy and hardware reliability is proven in three seasons.

    On March 2, 2021, John Deere entered the Green-on-brown spot spray area with See & Spray Select. This not to be mistaken as competition. Instead, the entry of a major brand provides validation of the concept like only a large manufacturer can. Yes, we’ve reached a tipping point.

    While the first Green-on-brown units are becoming established, Green-on-green, the ability to detect weeds within a crop, continues to be developed around the world. French startup Bilberry has made enough gains in Australia to bring its product to market with Agrifac, where it’s called AIC Plus. In farmer field trials, they have achieved 90 per cent detection accuracy of wild radish in Western Australia, and claim that they are ready for broadleaf weed identification in wheat, barley and oats. Bilberry’s technology will also be seen on Australia’s Goldacres and France’s Berthoud. Other startups, notably Israel’s Greeneye Technology, plan to introduce a Green-on-green system in the U.S. in the near future. Amazone, the German farm equipment giant, partnering with Xarvio and Bosch, announced plans at Agritechnica to have a commercial unit for sale by 2021.

    This technology will have significant impact on sprayer design philosophy. At present, productivity is synonymous with capacity, and large tanks with commensurate heavy and powerful tractor units dominate. Spot spraying savings will depend on weed density and hardware resolution, but 50 per cent to 90 per cent reductions in spray volume can be expected. A 1,600-gallon tank would no longer be necessary. The savings in frame weight and horsepower would be significant, as would the time savings from less intense tendering demands. These savings would offset the lower driving speeds that accompany sensing technologies, and, overall, provide a lower bar for autonomous operation. We may see lighter specialty spot sprayers.

    The savings in brute size will be countered by increased sophistication. Better boom height management is essential for spot spraying, not just for the sensor to properly see the target and estimate the time needed for the boom to reach that spot, but also for the spot spray itself to deliver the right dose. In any fan spray, band width at ground level changes with height, and that, of course, is related to dose. Trailed booms can address this issue easily.

    But not everyone wants a specialty spot sprayer that would require an extra pass over the field. With growing utility of soil residual herbicides, dual tank sprayers—small tank for the spot spray, large tank for the broadcast residual—make sense. Large sprayer frames can accommodate an additional smaller tank, second pump, and plumbed boom easily.

    Plant detection and identification bring other opportunities. Adjusting dose for plant size is one of the first, or for harder to control weed species.

    Spot sprays rely on fast, precise response of the nozzle, and this provided by fast-reacting solenoids that are part of pulse-width modulation (PWM) systems. On a broadcast sprayer, these solenoids can change the emitted dose instantly, within a certain envelope, by altering the duty cycle of the pulse. This, however, works best in the context of a boom with overlapping spray patterns. A single band spray would not change dose with duty cycle as easily.

    Higher dosing would be an opportunity for multiple nozzle bodies that are able to spray one, two or more nozzles in the same spot simultaneously. These are already widely available and popular in Europe.

    This also brings direct injection into play. Current systems introduce the active ingredient into the boom upstream of the nozzles, affording it time to mix into the water. For true spot spray utility, though, direct injection ought to be at the nozzle. Only then can custom mixes and rates be applied on a spot basis. It’s been done before, if only to show how difficult it would be to deliver uniform doses to a spot spray machine.

    Spot spray sensors have agronomic benefits. By recording the location sprayed, weed patches can be mapped. As plant identification becomes possible, it’s conceivable to obtain plant species and stage distribution maps from the spray pass That would turn the sprayer into a high-resolution crop scouting tool. As machine learning and sensor sophistication grows, other plant and soil parameters can be mapped. The agronomic value of such maps, especially if created over the course of the growing season, is immense. Of course, data density, handling, storage, and analysis will constrain this.

    If the past has taught us anything, it’s that there seems to be a appetite for investment in farm equipment. Sprayers have been the most-used implement on the farm for some time, and their popularity continues despite sharp price increases. These new capabilities will only add value to these implements. Prepare for sticker shock, followed by acceptance and adoption.

    What will a future spot sprayer look like? Although it will have tanks and booms, the level of electronic sophistication will make it so much more versatile we can’t yet imagine all the ways in which it might be used. But it seems to me the situation has tipped and we’re already accelerating toward that future.

  • John Deere See & Spray Select

    John Deere See & Spray Select

    On March 2, 2021, John Deere entered the optical spot spray (OSS) market with its first product, See & Spray Select™. This “Green on Brown” system identifies green material on a non-green background and is thus suited for pre-seed burnoff, chem fallow, or post harvest. It is competing for the same market space as Cropland’s WEEDit and Trimble’s WeedSeeker, but uses a slightly different approach.

    At the heart of the See & Spray system is a relatively simple RGB camera that is mounted directly to the boom and looks about 1.5 m ahead.  When this camera detects a spot of green colour, it assumes that this is a plant and activates a nozzle in line with that plant. John Deere says the weed size threshold is about ¼” (6 mm), and is evaluating its experimental data to identify exceptions to that rule of thumb.

    See & Spray Select uses an RGB camera to detect weeds (Image courtesy John Deere)

    In 2017, John Deere conducted a highly publicized acquisition of Blue River Technologies, a start up that pioneered artificial intelligence (AI) plant identification and coined the term “See & Spray”. However, the technology John Deere announced this time originated with the University of Southern Queensland near Toowoomba, Australia. The university’s Centre for Agricultural Engineering had received some initial seed financing from Sugar Research Australia, Cotton Research and Development Corporation, and Hort Innovation, and eventually partnered with John Deere. This is yet another example of the value of farmer investments in research.

    Blue River contributed to this project but remains committed to its path of developing Green on Green OSS through machine learning. John Deere says this first product is part of an evolution of spraying with ever-increasing precision that will culminate in spot spraying weeds within a canopy.

    The pixels in the See & Spray camera chip are mapped during its initial calibration, allowing the processor to know which nozzle to turn on. There are two user-selected modes. In “Single Nozzle” Mode, the system turns on as few nozzles as possible. If the weed is directly under a nozzle, just that nozzle is turned on. Should the weed be in between two nozzles, both will be turned on. In “Overlapping” Mode, a detection will turn on at least three, and up to six adjacent nozzles. This mode is intended for herbicides that contain specific nozzle recommendations on the label, such as dicamba. By fitting these tips on the spot spray location, the required overlap and subsequent coverage can be guaranteed to be compliant with that label, a unique feature of See & Spray.

    The number of nozzles activated by a weed detection depends on the location of the weed relative to the nozzles, and the mode selected by the user (Image courtesy John Deere)

    In all modes, the user can specify the distance before and after the detected plant that the nozzle will spray. This feature is useful when boom height varies or when travelling faster to provide extra assurance that the target will be covered by the spray. The boom height range for See & Spray is 26 to 47” (66 to 120 cm), and the maximum travel speed with nozzles pointed down is 12 mph.

    Installation of a 40 degree angled adaptor allows sprays tom be emitted backwards, and increases the spray speeds to 16 mph due to the extra distance and time afforded the sensors andoin processors to make a decision.

    See & Spray has a built in contingency for suboptimal conditions, for example when the boom falls outside its height range, or the nozzle speed (not tractor) exceeds the 12 or 16 mph maximum in a turn, or a light or sensor or processor fault occurs. Called “Fallback Mode”, the boom can be configured to shut off, or to go into broadcast mode (using the spot spray nozzles) at that time. These types of insurance are a necessary part of an OSS on the market today.

    To prevent fallback mode from occuring unecessarily, operators often choose to reduce their tractor speed one or two mph to allow for yaw without triggering all the nozzles.

    No OSS system is perfect. Tiny weeds, or those obscured from camera view by crop residue, may be missed. The contingency for WEEDit is “Combined Mode”, where the entire boom emits a broadcast spray at a user-determined fraction of the full dose, while still maintaining spot spray capability at the full dose when a detection occurs. The reduced dose is sufficient to control the smallest weeds, whereas the spot spray is emitted at the full label rate for the larger ones. This capability is made possible through Pulse-Width Modulation (PWM) control of each nozzle.

    John Deere has developed a mode of its ExactApply system to create the same outcome. Called “A & B Mode”, the rear nozzle (B location on the ExactApply nozzle body) is being activated by See & Spray. The front nozzle (A location) can be asked to spray simultaneously over the entire boom width. By choosing a smaller nozzle, a fraction of the label rate can be applied as a broadcast while maintaining spot spray capability. The broadcast boom is pulse-width modulated and retains the swath control and turn compensation of ExactApply. This mode also makes it easier to ensure coverage of these smaller weeds by selecting a finer, wider (110 degree) angles spray on the broadcast boom, and retaining a coarser, narrower fan angle banding nozzle for the spot application. The spot spray does not use PWM, relying on conventional speed and pressure to ensure the correct rate.

    If planning to use A & B Mode, a user would first need to decide if they will calculate the spot spray dosing on a single or a multiple activated nozzle system. If priorizing the single nozzle actiation, one would first determine the band width of that nozzle, and size the nozzle accordingly. The band width should be ar close to the nozzle spacing as possible to maximize savings. Say the sprayer has 15″ spacing, and the nozzle’s band width is 20″. Now, whenever multiple nozzles are activated, they would operate as a 15″ spacing and would over-apply 20/15 = 1.33, or 33%. Say you want to apply 15 gpa (you may need to boost the spot spray volume to allow you to cut that with the broadcast feature). You can do it with the band (and overdose when using multiple nozzles, or apply 15 gpa with the multiple nozzles, underdosing by 28% when a single nozzle is activated. Or split the difference.

    The next step is to select the application rate of the broadcast. If you want to apply 30% of the spot spray rate using the broadcast nozzles, size these accrodingly to apply 5 gpa.

    For band- and spot-sprays, the width of the spray pattern at the target height determines the dose, therefore careful selection is advised. A worksheet that shows boom heights at various fan angles and nozzle spacings is downloadable here. TeeJet and Hypro offer a selection of narrower flat fan tips, but none yet in a low-drift design. Other nozzles are in development. Agrotop has already developed a low-drift “Spot Fan”, and MagnoJet, a Brazilian ceramic nozzle supplier, has 30 and 40 degree low drift tips for sale. Wilger has develped the DX series ComboJet tips in 20, 40, and 60 degree fan angles, in a low drift (pre-orifice design that works with PWM.

    The camera sensing threshold can be adjusted to optimize a specific target. For example, to specify a certain weed size, that weed can be held in view of the sensor and the user can adjust the sensitivity until the weed is properly detected. As with any higher sensitivity, this runs the risk of more false detections, resulting in over-application. But it gives the user some knowledge that an important weed stage is being targeted properly.

    The See & Spray camera relies on ambient light conditions, and John Deere recommends it not be used within 30 minutes of dawn or dusk. Both WEEDit and WeedSeeker, in contrast, can operate under any light conditions.

    One of the challenges of running a OSS boom is the unpredictable fluctuation in flow requirement, which can theoretically range from just a few nozzles spraying to the whole boom activated in less than one second. While this extreme example is rare, a sophisticated and fast-responding pressure-based flow capability is nonetheless required. WEEDit uses a Ramsay Valve into their units to handle this challenge, whereas John Deere is relying on its existing plumbing design.

    As a factory install, the See & Spray is fully integrated into the Series 4 display and is tied into JD Link. As a result, it can generate a high resolution map that shows each spot spray activation, by nozzle. The agronomic utility of this capability is significant, as it provides a very high resolution plant density map. This capability is also inherent in WEEDit and most green on Green systems available..

    See & Spray Select is a factory option and comes integrated into the 4600 series monitor (Image courtesy John Deere)

    It’s no secret that I believe optical spot sprays represent the future of pesticide application (see here). And it’s great news to see John Deere enter the OSS area with a factory installed option. As an influential force in ag, it lends credence to the concept and will benefit all other companies vying for this space. As they say, a rising tide raises all ships.

  • The Most Important Developments in Spraying

    The Most Important Developments in Spraying

    Some things have improved a lot. Others have lost ground.

    Some years ago, a few of us weed scientists sat around a table and debated the most important developments in agriculture in our lifetimes. It was a great discussion, and we arrived at a few that included direct seeding (for its soil and moisture conservation as well as improved fertilizer placement), GMO crops (for slowing Group 1 and 2 herbicide resistance), and the abandonment of summer fallow in much of western Canada. Let’s apply this exercise to spray application to see what we come up with.

    What follows are my version of the most important spray technology developments in the last 50 years.

    1. Low-drift Nozzles. Spray drift is the biggest time management challenge and also perhaps the biggest public relations battle. These nozzles reduce drift, making more time available for spraying and doing it safely and effectively.
    2. Rate Controllers. I both love and hate these things. On the one hand, a rate controller matches sprayer output to travel speed. On the other, it has allowed spray pressures to go wherever they need, even beyond the optimum, to match travel speed, and that can lead to nozzle performance issues.
    3. Pulse Width Modulation. The pulsing nozzle fixes the rate controller problem mentioned above. Now, travel speed and pressure are independent. Plus, of course, a whole host of other flow management options, such as turn compensation and rate boosting, become available.
    4. Optical Spot Spraying. Once you see these in action, you can’t go back. Why would you spray a whole field when weeds only cover 10% of it? Products like WEEDit and WeedSeeker are proven green-on-brown performers after years of field success around the world.
    5. GPS Guidance. Some of us grew up with foam or disk markers, others learned to aim for brave family members perched on headlands. Achieving accuracy was stressful, overlap was insurance, and misses were common. The importance of this development is probably under-estimated.
    6. Sectional Control. The ability to adjust the spray width in individual nozzle steps makes sense, and this can come with or without PWM. In fact, that alone can save 5% of an annual chemical bill compared to conventional sections measuring about 10 to 15 feet. And it’s definitely better than the left boom or right boom options from the 70 and 80s.
    7. Operator Comfort and Safety. The refuge of the cab makes longer days bearable for all equipment, but for spraying it dramatically improves safety as well.

    But we’re far from done. We still need work in these areas.

    1. Cleaning and Waste Management. I can’t imagine another industry where managing potentially hazardous leftover materials are left to the discretion and circumstances of the applicator. Let’s make it easy and fast to thoroughly clean the sprayer and safely dispose of leftovers. Step 1 is smarter and simpler plumbing.
    2. Boom Stability. Booms are too high, resulting in more drift and poorer nozzle performance, and adding to operator stress. The sole reason is unsatisfactory levelling. It’s possible to solve this, but it seems to not be a priority.
    3. Weight. The road to productivity seems to be paved with larger, heavier machines. The side effects are fuel consumption, compaction, getting stuck. Let’s get smarter with frame design and logistics and talk acres/h rather than tank capacity and power.
    4. Cost. All farm equipment has seen cost increases that far outstrip inflation or any reasonable accounting of productivity and features. Sprayers lead the way. Yes, it’s possible to spins this as a value proposition. But it shouldn’t be necessary.
    5. Drift Management. Sprayer design continues to ignore drift management. We need sprayers that produce less drift by design, and this requires consideration of tractor unit, wheel, and boom aerodynamics. It’s more than a droplet size issue.
    6. Direct Injection. Although very handy for single product application, the plethora of product formulations and mixes has limited the success of direct injection systems. The complexity of injecting at the nozzle, and the resulting lack of available systems, has stymied some very attractive options, such as site-specific rate or product use.
    7. Ergonomics. If you need training, or to call someone before using your new sprayer for the first time, something’s wrong. Interfaces need to be intuitive and simple. The golden age of spray monitors was the 1980s. Those featured a main power toggle switch, a pump power switch, boom section switches, an agitation switch, and a simple way to enter the important information which was basically desired application volume. The screen can still be pretty, and you can still paint and monitor or tweak all the functions if you like that. But let’s at least have different tiers so beginners can also use the machine. Make interfaces using the philosophy Steve Jobs instilled in his trusted designer Jony Ive with the first iPod: no more than three clicks to achieve any desired outcome.

    A few areas show promise and may suit certain niches.

    1. In-Crop Weed Sensing. The green-on-green sensing that has been made possible by machine learning has shown some encouraging early success. Continuing improvements will eventually bring its reliability to within commercially acceptable standards. There is significant activity below the radar in this area, as all players recognize the enormous upside of a breakthrough.
    2. Autonomy. While dispensing a pesticide adjacent to sensitive areas isn’t exactly the low-hanging fruit of autonomy, such field sprayers will have a fit in the temperate plains of North and South America, Australia, and Asia and may help solve the cost and weight problem.
    3. Drone Application. The rapid pace of advancement in remotely piloted aerial systems, along with a seemingly low barrier to entry of new companies, will put pressure on the industry to make a decision on this alternate application method. If it can be done safely, it will have a dramatic impact.

    If you want to improve your sprayer, don’t ignore the small things you can do in your operation. Although we’re conditioned to look for game-changing technology, the most sustained improvements don’t come from a single innovation, but from a period of persistent evolution. A lot of small improvements add up. Spray application is no different.