For most of the time farmers have been running self-propelled and pull-type sprayers, the rate the machine put down was tied to how fast it was driving, because the rate controller adjusted flow by changing pressure, and pressure was the only lever it had. Speed up and the controller raised pressure to keep gallons per acre on target; slow down and it dropped pressure. That works on paper and it has run a lot of acres, but it carries a problem that every operator who has sprayed a curving field or a terraced hillside knows in their bones - when the pressure changes to chase the rate, the droplet size changes with it, and the spray pattern you carefully selected at the nozzle is no longer the pattern coming out. Push pressure up and the droplets get finer and drift more; let it fall and the droplets get coarse and the pattern collapses. Pulse width modulation is the technology that breaks that link, and in 2026 it has moved from a premium curiosity to a mainstream option that a lot of operations are genuinely better off running.
This is a working farmer's guide to pulse width modulation sprayers as the technology stands now: what PWM actually does at the nozzle and why decoupling rate from pressure matters, how turn compensation keeps the rate honest across the boom on a curve, what individual nozzle shutoff buys you in saved chemical and reduced overlap, how holding optimal pressure cuts drift, where the main systems sit against each other, what breaks and how you keep it running, and the honest cost and payback math. The goal is enough detail to decide whether PWM belongs on your next sprayer or as a retrofit on the one you have, not a sales pitch for a technology that does not fit every operation.
The heart of a pulse width modulation system is a fast electric solenoid valve installed at each nozzle body, sitting between the boom plumbing and the tip. Instead of letting spray flow continuously, that solenoid opens and closes many times a second - typically on the order of ten to thirty pulses per second depending on the system - and the rate is controlled by how long the valve stays open during each pulse rather than by changing the pressure behind it. That open-time fraction is the duty cycle. A nozzle running at a hundred percent duty cycle is open the whole time and flowing full bore; a nozzle at fifty percent is open half of each pulse cycle and flowing roughly half the volume; a nozzle at thirty percent is barely cracking open each cycle and putting out a fraction of its full flow. The pulsing is fast enough that the pattern on the ground reads as continuous coverage rather than stripes, especially with the boom moving forward.
The reason this matters is that the system now holds pressure constant and varies flow with duty cycle, which is the exact inverse of how a conventional rate controller works. Because pressure stays put, the droplet size stays put. You pick a nozzle and a pressure that produce the droplet spectrum you want for the job - a coarse, drift-resistant droplet for a dicamba or 2,4-D application, a finer droplet for contact coverage on a fungicide - and the system maintains that pressure while it changes the rate by changing how long each nozzle is open. The droplet size you selected is the droplet size you get, across a wide range of speeds and rates, which is something a conventional sprayer simply cannot promise.
That decoupling is the whole foundation, and everything else PWM does is built on it. Once each nozzle has its own fast valve and the rate is set by duty cycle rather than pressure, you can vary the rate nozzle by nozzle independently, you can shut individual nozzles off, and you can compensate for the speed differences across the boom in a turn - all without touching the pressure and therefore without disturbing the droplet size. The single mechanical change of putting a fast solenoid at every nozzle unlocks the entire feature set, which is why PWM is best understood as a platform rather than a single trick.
The clearest place PWM earns its money is in a turn, and understanding why requires thinking about what actually happens to a wide boom on a curve. When a 120-foot boom swings around a curve or follows the contour of a terrace, the outside end of the boom is traveling much faster over the ground than the inside end, and the machine's center - where the speed sensor lives - is somewhere in between. On a conventional sprayer the rate controller sees one ground speed, the speed at the center, and sets one pressure for the whole boom based on it. The result is that the fast-moving outer nozzles are under-applying, because they are covering more ground per second than the controller thinks, while the slow-moving inner nozzles are over-applying, laying too much product on the tight side of the turn. On a sharp curve the difference between the inside and outside of the boom can be dramatic, and the over-application on the inside is exactly where you tend to see crop response problems and the under-application on the outside is where weeds escape.
PWM turn compensation fixes this directly because each nozzle can run its own duty cycle. The system knows the geometry of the boom and the radius of the turn, calculates how fast each section of the boom is actually moving over the ground, and raises the duty cycle on the outer nozzles so they flow more while lowering it on the inner nozzles so they flow less, all while pressure and droplet size hold constant across the whole boom. The rate stays on target from the inside tip to the outside tip even as the boom sweeps through a curve, which means the contoured fields, the point rows, the waterways, and the terraced ground that make up so much of real-world spraying finally get an even application instead of the streaked over-and-under pattern they have always carried.
This is not a marginal refinement on operations that spray a lot of curved or irregular ground. The acres around terraces, the contour-farmed fields, the grassed waterways you spray around, and the simple reality that almost no field is sprayed in perfectly straight passes from end to end all add up to a meaningful fraction of every application running through some degree of turn. Turn compensation is the feature that, on its own, justifies PWM for a lot of operations that farm hilly or irregular ground, because it directly stops the over-application that wastes chemical and risks the crop and the under-application that lets weeds through.
The next thing a fast valve at every nozzle gives you is individual nozzle shutoff, and this is where PWM connects to the overlap-reduction story that has driven so much precision ag adoption. A conventional sprayer with section control can shut off the boom in sections - maybe five sections, maybe nine, maybe more on a high-end machine - so that when the boom crosses ground that has already been sprayed, or enters a point row or a field boundary, the controller closes the sections that are over the covered ground. That helps, but the granularity is limited by the section width. A section is several nozzles wide, so the controller cannot shut off just the part of a section that is double-covering; it either leaves the whole section on, accepting the overlap, or shuts the whole section off, accepting a skip. On odd-shaped headlands and sharp point rows that compromise costs you either wasted chemical or missed strips.
Individual nozzle shutoff takes the granularity all the way down to the single nozzle. Because every nozzle has its own valve, the system can shut off exactly the nozzles that are over already-sprayed ground and leave the rest flowing, following the boundary of the covered area nozzle by nozzle rather than section by section. On a point row the boom can feather off one nozzle at a time as it approaches the already-sprayed headland, and on an irregular boundary it can match the field edge far more closely than any sectional system. The practical effect is a real reduction in the double-coverage overlap that section control still leaves on the table, and on operations with a lot of irregular fields, terraces, waterways, and point rows that overlap reduction is chemical you stop buying and crop you stop over-treating.
The savings from this are the easiest part of the PWM case to quantify, because reduced overlap is directly reduced chemical purchased, and the more irregular your fields the more it adds up. An operation spraying rectangular, full-width fields with long straight passes will see modest overlap savings because there is not much overlap to cut. An operation spraying terraced, contoured, point-row-heavy ground will see substantial savings, because that is exactly the geometry where conventional section control leaves the most overlap on the ground. As with so much precision ag, the value of individual nozzle shutoff scales with how irregular and how numerous your fields are, and the operations that benefit most are the ones whose ground has always made spraying inefficient.
Drift is the part of the PWM story that matters most to your neighbors, your regulators, and your peace of mind, and the way PWM reduces drift follows directly from the pressure-droplet decoupling. Spray drift is driven heavily by droplet size, because the fine droplets at the small end of the spectrum are the ones that hang in the air, get caught by wind, and move off target, while the coarse droplets fall fast and stay where they were aimed. The whole modern approach to drift management is to choose nozzles and pressures that produce a coarse, drift-resistant droplet spectrum, and the auxin herbicide labels in particular are explicit and legally binding about the droplet size you must produce and the pressure range you must hold to produce it.
The problem on a conventional sprayer is that holding the labeled droplet size is hard precisely because the rate controller changes pressure to manage rate. Slow down for a turn or a wet spot and the controller drops pressure, which on many nozzles pushes the droplet coarser and the pattern toward collapse; speed up and it raises pressure, which drives the droplets finer and the drift risk up, potentially right out of the label-compliant range you are required to stay within. The operator is caught between maintaining the rate and maintaining the droplet size, and the conventional machine cannot do both at once because it has only the one lever.
PWM resolves this by holding pressure - and therefore droplet size - constant while it manages rate with duty cycle. You set the system at the pressure that produces the labeled, drift-resistant droplet for the product you are spraying, and it stays there across the speed and rate changes that would have forced a conventional machine off that pressure. The droplet spectrum that the label requires and that minimizes drift is maintained continuously, not just at the one speed where the conventional controller happened to land. This is a genuine drift-reduction benefit and, with the auxin herbicides under such tight regulatory scrutiny, it is also a compliance benefit, because the machine is far better equipped to hold the labeled pressure and droplet size through the real-world variation of an actual application. It is worth being honest that PWM does not repeal physics - in the wrong wind with the wrong product you can still drift - but holding the optimal pressure removes one of the largest practical sources of unintended fine droplets, and that is a real improvement.
The PWM market in 2026 has both factory-integrated systems on new sprayers and aftermarket systems you can retrofit, and the names worth knowing sort into a few groups. Capstanag, with its PinPoint system, is the company that pioneered nozzle-level pulse width modulation and remains the reference point for the aftermarket retrofit path, offering systems that bring PWM to sprayers that did not come with it from the factory. For an operation that has a good sprayer it is not ready to replace but wants the turn compensation, individual nozzle control, and pressure-holding benefits, the retrofit route is the way in, and Capstanag's long track record in the technology is part of what you are buying.
On the factory-integrated side, Raven's Hawkeye nozzle control system is widely fitted and available across a range of machines, John Deere's ExactApply is the integrated PWM offering on its sprayers, and Case IH and New Holland offer their own integrated nozzle-control systems on current machines. These factory systems carry the advantage of being engineered into the sprayer from the start, tied into the machine's existing rate control, guidance, and display, so the turn compensation knows the boom geometry precisely and the whole system speaks one language. The tradeoff is that you get them by buying or specifying the machine that carries them, rather than adding them to what you have.
The choice between the retrofit and the factory path is mostly a question of where you are in your equipment cycle. If you are buying a new or newer sprayer, specifying the factory PWM system is the clean route and the integration is tight. If you have a sound sprayer with years of life left and want the PWM benefits now, a retrofit system is the way to get them without replacing a machine that does not need replacing. As with most precision ag decisions, the strength of your local dealer and support for whichever system you choose matters more over the life of the machine than the spec-sheet differences between comparable systems, because a nozzle-level control system with a solenoid at every tip is something you want supported when a problem shows up in the middle of a spray window.
A PWM system trades the simplicity of a conventional boom for a fast electric solenoid at every single nozzle, and that trade is the honest cost side of the technology that the brochures spend less time on. More valves, more wiring, and more electronics mean more things that can go wrong, and an operation considering PWM should go in understanding the failure modes rather than discovering them in the field. The good news is that the failures tend to be individual and localized - one nozzle, not the whole boom - and the systems are generally built to flag a problem nozzle so you can find it, but you are still maintaining a more complex machine than a conventional sprayer.
The most common issue is a solenoid that sticks or fails, leaving a nozzle either stuck closed - a skip in the pattern - or stuck open and flowing continuously regardless of the commanded duty cycle. Sticking is often a contamination problem, which makes clean water, good filtration, and thorough cleanout after every application more important on a PWM machine than it already was on a conventional one, because dried product and debris are what gum up a fast-cycling valve. The valves are serviceable and replaceable individually, so a failed solenoid is a nozzle-body repair rather than a boom-wide catastrophe, but staying ahead of it with clean operation and end-of-day flushing is the difference between an occasional valve and a chronic problem.
The pulsing itself brings two things operators notice and should expect. The first is sound - a PWM boom makes a distinct pulsing or buzzing noise as the valves cycle, which is normal and not a fault, though a change in that sound can be an early clue that something is off. The second is that the electrical and wiring side of the system carries real importance, because every nozzle valve needs clean power and a good signal, and the harnesses, connectors, and grounds out on a boom that flexes and vibrates and gets washed down are exactly the kind of environment where electrical gremlins develop. Keeping connections clean and tight, protecting the wiring, and treating an intermittent nozzle as a wiring suspect as much as a valve suspect will save a lot of frustrating diagnosis. None of this is beyond a competent operator, but it is a maintenance burden that a conventional sprayer does not carry, and budgeting the time and attention for it is part of running PWM well.
PWM costs real money, whether as a factory option that adds to the price of a new sprayer or as an aftermarket retrofit that is a substantial purchase plus installation on the machine you own, and an honest payback analysis has to weigh that against savings that vary enormously from one operation to the next. The single biggest driver of whether PWM pencils out is the geometry of the ground you spray, because the two largest, most quantifiable savings - reduced overlap from individual nozzle shutoff and reduced over-application from turn compensation - both scale directly with how irregular, contoured, and point-row-heavy your fields are. The operation farming large rectangular fields in straight passes will see modest savings and a long payback; the operation farming terraced, contoured, irregular ground will see substantial chemical savings and a much faster return, because that is precisely the geometry where conventional spraying wastes the most.
The chemical savings are the part you can put a number on. Add up the overlap you currently accept on point rows and irregular boundaries, the over-application on the inside of every turn, and the value of the products you spray, and on an operation with irregular fields and expensive chemistry the saved product alone can build a credible payback over a few seasons. Layer onto that the value of consistent, on-target rate across the whole field rather than the streaked over-and-under of a conventional boom, which shows up as better weed control where the outer nozzles used to under-apply and less crop stress where the inner nozzles used to over-apply, and the agronomic return - harder to put in dollars but real - strengthens the case.
The drift and compliance benefits belong in the analysis even though they resist a clean dollar figure, because holding the labeled pressure and droplet size through real-world spraying reduces the risk of an off-target drift event, and the cost of a single serious drift incident - to a neighbor's crop, to your relationships, to your standing with the regulators, and potentially in legal exposure - dwarfs the cost of the system. For an operation spraying auxin herbicides near sensitive crops, the risk reduction alone can justify PWM regardless of the chemical-savings math, because it is buying down a low-probability, high-cost event.
The honest bottom line is that PWM is a strong buy for operations that spray a lot of irregular, contoured, or point-row-heavy ground, that run expensive chemistry, or that spray drift-sensitive products near vulnerable neighbors, and a harder case for operations spraying large rectangular fields with cheap products in calm conditions, where conventional section control already captures most of the available savings. Decide which description fits your ground and your chemistry, weigh the added maintenance burden of a solenoid at every nozzle against the savings your specific operation will actually capture, and choose the retrofit or the factory path based on where you are in your sprayer's life. Run that analysis honestly and PWM turns out to be one of the better-justified precision ag investments for the operations it fits - and an easy one to skip for the operations it does not.
A fast electric solenoid at each nozzle opens and closes on the order of ten to thirty times a second, and the rate is set by how long the valve stays open each cycle, the duty cycle, rather than by changing pressure. Because the system holds pressure constant and varies flow with duty cycle, the droplet spectrum you selected stays put across a wide range of speeds and rates.
On a curve, the outer end of a 120 foot boom travels much faster over the ground than the inner end, so a conventional sprayer under-applies on the outside and over-applies on the tight inside. PWM turn compensation raises the duty cycle on the outer nozzles and lowers it on the inner ones, holding the target rate from the inside tip to the outside tip while pressure and droplet size stay constant.
Yes, indirectly. Drift is driven heavily by fine droplets, and a conventional rate controller changes pressure to manage rate, which pushes droplets finer when you speed up. PWM holds pressure and therefore droplet size constant, so you can set the coarse, drift-resistant droplet an auxin herbicide label requires and hold it through the speed changes that would force a conventional machine off that pressure.
Capstan's PinPoint pioneered nozzle-level pulse width modulation and remains the reference point for aftermarket retrofits on a sprayer you already own. On the factory-integrated side, Raven's Hawkeye, John Deere's ExactApply, and the nozzle-control systems from Case IH and New Holland are engineered into the machine from the start. The retrofit path fits a sound existing sprayer; the factory path fits a new purchase.
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