Category: General Operation

Articles that discuss general field sprayer operation and productivity factors

Techniques to Improve Spray Productivity
Click here for an audio version of this article
In almost all agronomic practices, timing is key. There are certain, and often small, windows of opportunity for getting a task done without losing yield potential or product quality. Weed specialists talk about early weed removal, pathologists talk about symptom monitoring, and entomologists remind us of economic thresholds. Acting at the right time is fundamental.
Sometimes I’m asked about comparing two different methods of spray application. I usually dodge these questions by advising to choose the one that gets the job done on time. “An average application at the right time is much better than an excellent application at the wrong time” is how I put it. Sure, I’m dodging, but I really believe that. It’s mostly in the timing.
Everything we do carries with it some time inefficiencies. Some are rooted in technology, others in habits. It’s the habits that are easier and cheaper to address. That’s why, when evaluating how to improve a spraying operation, I advise to start with a stopwatch and notepad, not a sprayer brochure.
A stopwatch and notepad provides your path to greater productivity.
Remember, if you want to improve a system, you first need to understand it. And to understand it, you need to measure it.
So, do a time accounting. You need to know how your time is used on a spray day. Note the time spent preparing for the job (loading supplies, double checking label instructions, transporting, etc.). The big users of time are sprayer transporting, filling and cleaning, but there are very many small time users and those can add up. This time is doubly important because these tasks occur during the spray day, when the weather is good and you should be maximizing spray time.
Make your own time accounting sheet, including every detail or possibility.
Even within any one operation, time can be subdivided. How much time is spent on a turn? Since a 120’ sprayer will make about 22 of these per half mile, that can add up. Even a spray monitor can play a productivity role if it quickly and consistently locks onto its swath. Needing to stop and back up while it searches for a signal can be costly.
On our farm, we sometimes used custom operators to get the cereals off. I recall how aggravating it was to watch the 8820 inch ahead of my N6. Surely it must be throwing a lot over, I thought (it was). But I usually caught it at the truck, where my unloading speed was over 1 minute faster. Redemption, briefly.
That same principle applies to these small efficiencies. A well-designed tender truck can speed loading and more than make up for lower spray productivity of a smaller sprayer. A lighter sprayer load and flotation tires can save a ton of time if it means the difference between getting stuck or cruising through that spot. A set of extra-coarse nozzles that can be rotated into place in just two minutes can help finish a field if the weather changes, or allow a margin to be sprayed, saving a return trip.
Extra nozzles to allow spraying in higher wind speeds without increasing drift are a productivity tool.
A custom operator shared some very useful tips with me a few years back. He optimized the small things, such as re-locating the switch to deflate his suspension airbags after driving onto the trailer, to the platform beside the cab. He’d deflate while descending the steps, and by the time the tie-down straps were thrown across, the unit was ready to be cinched down. No waiting. He also opted for a slightly wider aftermarket boom so he had an even number of spray passes per quarter, saving another 2 minutes or so per field.
The same operator made me aware of the importance of knowing exactly how much spray is in the tank at any one time. The majority of spray monitors are simply not accurate enough. A factory sprayer can count down from a full tank using its flow meter, but that requires two things to be accurate, the filled amount (entered by the operator, usually from a sight gauge) and the flow meter itself. Point is, when we fill the last load of a field, we don’t want too much left over, but we’d still rather not run out. By using the AccuVolume from Simon Innovations, he was able to fill accurately and he was also able to exactly monitor his liquid usage. If he had two passes left, and knew he needed exactly 150 gallons (also considering when his pump drew air), he could monitor that and make small adjustments to the application rate, if necessary, to get there. It’s a big deal because contending with a larger remainder is wasteful and takes time to deal with. The AccuVolume also helps make multiple small volume batch cleaning more accurate, and therefore easier.
The AccuVolume measures your tank contents, to the nearest gallon, regardless of slope position. It’s a time saver.
A small addition to the tender truck such as an electric hose reel or a swing arm that carries, say 20’ of hose, helps deal with the weight of a full 3” line. Or an air-line at the pump end can be used to blow the remaining water into the tank. Time, and mess, are saved. Still pumping product? Induction using a venturi is much faster.
An electric hose reel makes handling 3″ plumbing manageable.
Preventing problems is probably a better use of time than dealing with them. Take tank mixes, for example. With more products in the tank, and adjuvants such as conditioners, fertilizers, or low-drift products making their way in, anticipating mixing problems may require a jar test. Get the tools, and learn how to do them. It’s important to use the actual tended water in these tests, at the temperature it will be, because that, and water quality such as hardness and bicarbonates, can affect mixing. And don’t over-agitate, as that can create its own problems, especially as the tank runs down.
Consider a hot tank. If extra labour is available, it removes a lot of time pressure for mixing dry, or multiple products. At filling time, simply pump it over and go.
A hot tank gives you more time to mix properly, and makes transfers faster. (Some additional labour required).
Consider improvements in the plumbing to save time. The new Hypro Express End Cap features a ball valve for flushing (existing Express End Caps can be retrofitted), and this valve can soon be fitted with the ProStop E (electric) valve. Flushing can then be done from the cab, saving time and mess. It’s a small change, but it brings joy.
A new valve addition is available for the Express End Cap. Manual (shown) or electric available.
The importance of time on a spray day can also be viewed economically. Let’s say a large area needs to be sprayed today, and the weather forecast calls for rain overnight. The rain will stop spraying for 5 days. What is the yield potential lost in those five days if weed or disease pressure is high? If 100 acres don’t get treated, what is the lost revenue? (for example, if 3 bpa is lost, at $6/b, that’s $18/acre or $1,800.) That’s what that hour is worth. Tell your boss.
Getting more done means getting more done on time. Evaluate your habits and technologies on that basis.
Evaluate your spray productivity with our
January 19, 2019
Do Labels Help us Apply Pesticides Properly?
It happened three times this spring. As is often the case, I was contacted by growers who wanted help with herbicide application. In most of these calls, the discussion revolves around the proper choice of nozzles for a specific task, perhaps some questions on spray pressure, water volume and travel speed.
But these three were different. Instead of being seasoned applicators, all three were new to the business. And more importantly, they had done their homework by looking at product labels before calling.
Labels give us important information on product rates, crop and weed staging, mixing order, sprayer cleaning, and personal and environmental protection. They’re very valuable there. But they also provide application information, and that’s where the problems begin.
Perseverance Required
I have to commend my three clients: they showed great tenacity by actually finding application information on a pesticide label in the first place. This document is so mired in legalese protectionist language at the front that it discourages all but the most persistent.
And often, the application information comes in several parts, interspersed among other information. Mixing instructions. A little later, application. Somewhere nearby, buffer zones. Another paragraph for cleaning. Rainfastness? Keep looking.
It forces the reader to skim through the document, hunting for relevant information.
But once my clients found application instructions, they obviously questioned if they should believe it, or else they wouldn’t have called. The application statements on many labels, simply put, are from long ago, and it’s obvious.
Consider the following two label excerpts, the first from a product initially registered in the mid 1980s and still available, the second from one registered about 30 years later:
1980s:
Application should be made using a minimum of 55-110 litres of water per hectare, at a pressure of 275 kPa, or 310 kPa if using check valves, and at a ground speed of 6-8 kph.
The use of 80° or 110° flat fan nozzles is recommended for optimum spray coverage.
Do not use flood jet nozzles, controlled droplet application equipment or Sprafoil® equipment.
Application of the spray at a 45° angle forward and higher water volumes will result in better spray coverage and penetration of the crop canopy.
Uniform, thorough coverage is important to obtain consistent weed control. Higher water volumes should be used under dense crop and weed canopies to ensure thorough coverage of the target weeds.
2010s:
Apply in a spray volume of 46.8 – 93.5 L/ha unless otherwise specified in tankmix partner section of this label – at 207-345 kPa (30-50 PSI) pressure to ensure proper weed coverage.
Flat fan nozzles of 80° or 110° are recommended for optimum coverage.
Do not use floodjet or controlled droplet application equipment or Sprafoil® equipment.
Nozzles may be oriented 45° forward to enhance crop penetration and to give better weed coverage.
Uniform, thorough coverage is important to obtain consistent weed control. Higher water volumes should be used under dense crop and weed canopies to ensure thorough coverage of the target weeds.
Thirty years apart, but remarkably similar.
Crop protection companies spend about 10 yrs. and $250 million to produce a new pesticide and register it for use. Having made this commitment, it would be most useful to see a small further investment to provide current application information that is relevant to applicators.
After all, these applicators purchase the active ingredient to provide a return on this multi-million dollar investment, to the tune of about 2 billion dollars per year in Canada alone. They deserve good application information.
Imagine this scene:
“Doctor, thank you for this new high tech pharmaceutical engineered to help me with my serious illness. How should I take it?”
“Not sure. Here, read this cough syrup label I found in my drawer. Should be pretty close.”
It’s clearly ridiculous
Let’s dissect these labels to see how they could be improved.
Flat fan nozzles of 80° or 110° are recommended for optimum coverage…
Our sample labels refer to what we assume are conventional flat fan nozzles. While popular in the 80s, these have all but disappeared from sprayers over the course of the past 20 years or so. We haven’t recommended them since then because they drift too much. They’ve been replaced by low-drift nozzles, either pre-orifice, or air-induction.
Nozzle fan angles are now generally 110 degrees or more, and frankly, the difference between 80 and 110 degrees is not that important. What’s important is proper overlap, achievable with a visual assessment followed by boom height and pressure adjustments. Unfortunately the label is silent on that.
Application should be made … at a pressure of 275 kPa, or 310 kPa if using check valves…
A nozzle’s recommended operating pressure depends on the specific nozzle model and on the spray quality (average droplet size) required. With literally many dozens of nozzles now available to each applicator, general pressure suggestions are likely to be wrong, and are more of a liability than a help. And they force label non-compliance when over-ruled by a nozzle manufacturer’s recommendations.
Speaking of spray quality, growers crave to know at what spray quality a product should be applied for best performance and lowest drift. Some labels refer to spray quality (e.g. “apply with a Coarse spray”), but this is with reference to spray drift and buffer zone distances, not efficacy, and that distinction is not made. Knowing the right quality for efficacy would help applicators choose the right nozzle and pressure to meet that criteria.
Higher pressures if using check valves? Nobody has brass screens with check valves anymore. Sprayers have had modern diaphragm check valves for a generation, and those don’t produce pressure losses.
And we all know that six to eight km/h is hardly a common speed these days.
Do not use floodjet or controlled droplet application equipment or Sprafoil^® equipment
Sprafoil nozzles have not been produced in Canada for about 25 years, in fact their manufacturer is no longer in business. Controlled droplet atomizers, while becoming more popular again on aircraft, were last seen on ground sprayers in the 1980s. Even then, total installed numbers were probably in the single digits.
As for FloodJet nozzles, those went out of style for herbicides in the late 70s, and were replaced by the very successful TurboTeeJet nozzles shortly after.
Nozzles may be oriented 45° forward…
Nozzles are rarely tilted 45 degrees forward for herbicide application anymore. Maybe that’s because spray booms aren’t built that way today, or because modern booms on self-propelled sprayers are now about 30” (75 cm) above ground, and we travel at about 15 mph (22 km/h). So the forward tilting, though shown to be effective for grassy weeds at 5 mph (8 km/h) and 20” (50 cm) boom heights, as researched in the 1970s, isn’t relevant for herbicides with higher booms.
Uniform, thorough coverage is important to obtain consistent weed control.
Statements advocating for good coverage are nice, but they aren’t useful. Everybody knows we want good coverage. What applicators need to know is how they should measure coverage, and what good coverage actually is. Can we use water-sensitive paper? How much of the target should be covered? How many droplets should be in each square centimetre? How can we measure that in the field, right now? How does it depend on the crop canopy, on weed stage, and on spray quality? The more information an applicator gets, the higher the chance of success.
Apply in a spray volume of 46.8 – 93.5 L/ha…
The only statement that survives our little examination is about water volume. Water volume is important. But even there we have a problem. The volume is in L/ha. This is useful in some parts of Canada, but not in the west, where producers communicate primarily in US gallons per acre. And in the west, provincial guidelines have generated this odd hybrid of L/acre, which few people use for spray volume. But 46.8 to 93.5 L/ha? How is that level of precision justified? (I know that this is a conversion from 5 and 10 US gpa…so why not just say so?)
A Solution
The problem with having outdated or impractical information on labels is that it creates disrespect. Since labels are documents enforceable by federal law, applicators want to comply. At this time, they can’t, and probably shouldn’t, if they want to do the job right.
A vision for a good label should be one that respects the needs of the applicator. Such a label:
- places the information that applicators need at the top;
- is updated regularly to reflect modern practice and useful advice;
- helps a new applicator work out how to apply the product with any equipment;
- identifies a spray quality that offers good coverage and low drift;
- makes reference to research that supports variations in the application guidelines;
- is available electronically, readable on a mobile device, i.e., not pdf.
This label would protect the environment and bystanders, and would foster better pesticide performance.
This label is easy to generate.
This label would be read by applicators.
What’s it going to take?
Additional:
This article created a great deal of discussion. We decided that if we were going to point out issues with the current labelling system, we should also propose a way forward. Read about our Label Summary Sheet proposal.
November 7, 2018
Smart Spraying Tips and Tricks
This 2018 article was written by Victoria Berry for the Ontario Grain Grower.
In the era of social media and keyboard warriors, it’s easy to feel like someone is always watching and ready to force their opinion on the world. The “tweet first, think later” mentality often adds to misinformation, and worse, it can leave science as a bystander — especially when it comes to modern farming techniques.
Farmers feed the world and they need to ensure they are growing high quality, high yielding crops. One of the most important elements of protecting high-quality crops is spraying. As farmers and custom applicators become more innovative and more knowledgeable about spraying techniques they have to strike a delicate balance, according to Jason Deveau, Application Technology Specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA).
Deveau recently sat down for a Q&A session to discuss tips and tricks for smart spraying, understanding drift, and how important it is for farmers to share smart practices and be champions to others in the community.
V.B.: WHAT ARE SOME OF THE KEY AREAS TO SPRAYING? WHAT ARE THE TOP MUST-DOS?
J.D.: First and foremost, the laws of physics have never changed. We may present the facts in different ways to help people understand, or to make them more accessible, but when it comes to spray coverage and spay drift, there are three speaking points:
1. We want farmers to use the largest droplet size they can without compromising coverage.
2. We want the boom at the lowest practicable height to the field.
3. We want farmers to adjust their spraying practices to match weather conditions, and know when spraying isn’t advisable.
V.B.: OK. LET’S START FROM THE TOP. WHY AND HOW DO FARMERS CHOOSE THE LARGEST DROPLET SIZE?
J.D.: Droplet size is an effective tool for combating physical drift. Larger droplets have more mass, which means they are more likely to fall rather than be carried away. But, for a given rate, the number of droplets a nozzle produces decreases as average droplet size increases. It’s the same amount of pie no matter how many slices.
Fewer droplets might compromise spray coverage, particularly when targeting small weeds or when using a contact pesticide in a dense canopy. The answer is to use more volume to bring the droplet count back up, but that means more refills for the sprayer operator, which is time consuming. A good operator is always considering the balance between drift potential, coverage, and efficiency. Even with sophisticated technologies, these considerations always lead to nozzle choice.
Traditionally, a grower would choose a nozzle based on the desired rate (e.g. gallons per minute) for a given pressure. As the sprayer changed speed, this would lead to over — or under — application. So, for convenience and consistency, most growers use rate controllers that monitor speed and auto-adjust the rate using pressure. But pressure also changes droplet size and spray pattern. Patterns can collapse at lower pressures (say <30 psi) and average droplet size decreases as pressures increase. You can see that droplet size wasn’t really on the radar. Pulse-width systems have changed this, but they are still few and far between.
And even if a grower chooses a nozzle with a coarse spray quality, they may be surprised to learn it still produces some fine droplets, too. Look at a bell curve. That’s how a nozzle is rated for droplet size — a lot of average sizes in the middle, and then a few smaller or larger sizes. A coarse nozzle does not make you bullet proof; there will still be some drift. That is why we always observe weather and time-of-day restrictions and adhere to the buffer zones that appear on the pesticide label.
V.B.: HOW DO LOW BOOMS IMPACT DRIFT AND WHY DO SOME FARMERS RESIST THIS ADVICE?
J.D.: Imagine holding out your arm and dropping a feather. It will move a ways downwind before landing. Now climb a ladder and do the same thing — it goes considerably further. It’s exactly the same for water droplets. To add insult to injury, releasing spray from a higher point also prolongs evaporation, making it even smaller and exacerbating the problem. And if that weren’t enough incentive to lower booms, the high booms create inconsistent spray coverage, undermining the whole reason for spraying in the first place.
The resistance to low booms comes from the desire to drive fast. North American booms sway and yaw, even with boom leveling systems. Higher speeds may get the job done faster, but it requires most farmers to raise the boom to prevent it hitting the ground. It may seem counter-intuitive, but there are several ways a farmer can slow down, drop the boom, and spray more acres in a day — it just requires them to look at their spray operation differently. A great deal of time is spent filling, idling, turning, and travelling between jobs. It’s been demonstrated that saving time on sprayer-related tasks has a big impact on efficiency — more than simply driving faster.
V.B.: HOW DO YOU KNOW WHEN THE WEATHER IS RIGHT FOR SPRAYING?
J.D.: Everyone knows the obvious cues. If your hat blows off, it’s probably not the time to spray. But, we’re learning that calm conditions may contribute to chemical trespass even more than wind. There’s no hard and fast rule, but three kilometres an hour to 10 kilometres an hour winds are a good range.
In calm weather, you may find yourself in a thermal inversion, which does not allow fine particles (or volatiles) to disperse and ground. Instead, they hang in a layer of undisturbed air, either moving downhill like water, or eventually moving in an unpredictable direction when the wind picks back up. It’s suspected that this phenomenon has played a significant role in the off target crop damage issues in the U.S. in 2016 and 2017.
In a very telling demonstration, an Ontario agrichemical rep showed that the smoke from a smoke bomb (representing pesticide vapour) travelled 1.7 kilometres during an inversion. In another demo, he showed it moving back and forth across the same field for hours after the application. Learning how to recognize a strong inversion, and knowing when there is too much or too little wind will require a different way of thinking, but will greatly reduce the potential for chemical trespass.
V.B.: WHAT OTHER PRACTICES SHOULD FARMERS BE AWARE OF TO COUNTER DRIFT?
J.D.: There are a lot of other considerations, but let’s highlight two.
First – Downwind neighbours (residential and agricultural) can take actions based on your spraying schedule. If there’s a possibility of chemical trespass, it’s a courtesy to let them know your plans, or at least make spray records available and be prepared to answer questions. Quite often explaining what’s happening prevents them getting misinformation elsewhere. It may sometimes be a nuisance, but educating others is part of maintaining the public trust. Ontario farmers are experienced and certified and, frankly, the industry needs them to help educate people on all the good work being done.
Second – Night spraying. Please stop. Time is short and weather can force us to take opportunities where we find them, but calm, clear nights represent the highest potential for a strong thermal inversion. Knowing the weather conditions that affect product performance (for better or for worse), minding pollinator presence, knowing what’s downwind, and STILL following integrated pest management means there seem to be fewer hours left to spray. But, it’s really a matter of understanding which of those factors trumps the others in the decision to spray, or wait. It requires today’s farmer to play an active role when it comes to spraying.
V.B.: YOU MENTIONED PUBLIC TRUST. HOW WILL SPRAYING AND PUBLIC TRUST IMPACT FARMERS’ BUSINESSES?
J.D.: We talk about soil, stewardship, and environmental sustainability. But at the core of all those important considerations is the customer driving those agendas. We are getting close to the day (if we’re not there already) where the grocery store dictates farm practices.
Many broad acre farms are still self-regulating to a large degree. They do their best to maintain high standards for safety, transparency, and record-keeping. But, as specialty crop and livestock operations already know, we are moving towards tracing the history of a farm product from the customer all the way back to the seed. Farmers should adopt best practices proactively, before they become mandatory.
So, the level of attention on field crops is more acute than ever before. Many are not used to being under the public microscope. Customers are asking when, how, and what was it sprayed, and they want to know the weather and cleaning practices that were followed. We need to have those answers ready to show what we’ve always known — that farmers are self-aware, are stewards, and are responsible partners in public health and safety.
So spray like everybody’s watching… because they are.
April 24, 2018
Agrifac Launch – Endurance II is a High Tech Offensive
Agrifac shunned the Agritechnica show last year, choosing instead to introduce its latest Condor Endurance II alongside a wide range of high-tech controls at the opening of its new factory at Steenwijk, in The Netherlands.
Booms up to 80m wide can be tested in the new 14,000m² factory, which Agrifac has constructed on its existing site at Steenwijk in the Netherlands.
Agrifac has seen quite remarkable growth in recent years, no doubt the result of investment from its owner – the sprayer specialist group, Exel Industries – which bought the struggling manufacturer in 2012.
Since then, sales of self-propelled sprayers have rocketed – from 20/year in 2008 to more than 200 today. The new factory is currently building a machine a day and Agrifac is now looking to boost sales further by expanding operations in Australia, North America as well as central and eastern Europe.
Sales of Agrifac self-propelled sprayers have risen from 20/year in 2008 to more than 200 today. Its new factory has the capacity to build one machine every day.
Indeed the impressive new, architect designed factory is set-up to test booms up to 80m (~262 ft) wide, which is a massive jump from its current 52m (~170 ft) maximum. Unsurprisingly it’s looking at carbon fibre to reach these widths.
While not launched officially, Agrifac made no secret of this at the open day, showing a ‘hybrid’ with carbon fibre outer sections fitted to the existing steel one. While there are few details about this prototype, it uses a lattice-work construction, with the nozzles mounted at the top of a triangle.
Targeting greater precision
Under the banner of ‘Need Farming’ Agrifac is promoting a range of systems to apply products with ultimate precision. Top of the technology tree is AiCPlus, which identifies individual plants and applies a specifically-tailored product rate – on the move.
By the way, Agrifac explains AiC is pronounced ‘I See’, with the AI an abbreviation of Artificial Intelligence.
Cameras, mounted along the boom, scan 3m (~10 ft) wide bands of crop in ‘real time’ and, use special software algorithms to interpret what they detect. This could be individual weeds, diseases or pest damage.
Ultimate spraying precision and control delivered by AiCPlus, which uses boom-mounted sensors to identify areas down to 50cm and deliver targeted treatments with single nozzle accuracy.
Applications are targeted using control to single nozzles, which are operated by Pulse Width Modulation (PWM). This enables the nozzles to be turned on/off at up to 100 times/sec, allowing the system to not only vary and apply the dose for the target, but also maintain the correct droplet size for the product.
Solenoid valves switch nozzles on/off up to 100 times/sec and maintain the application rate without changing pressure. The system also reduces flow to the inner nozzles and increases it to the outside automatically during turns.
To accomplish this degree of precision application, Agrifac has introduced a range of other new technology. Along with the sensors and single control there is another new system, DynamicDosePlus (here’s a smartphone video), which implements control down to a resolution of a single nozzle.
Pesticide rates, rather than just the total application volume, are changed on the move using SmartDosePlus. And to ensure products are applied accurately there is StrictSprayPlus, which includes turn compensation.
Precise prescription maps
For precise applications, without using AiCPlus on the move sensing, Agrifac has developed DynamicDosePlus. This, it claims, is the first system to create application plans to one nozzle precision.
As well as planning applications it also executes the operations, not only controlling applications, turning nozzles on/off, but also varying the pesticide rate between 0-100%. To do this AiCPlus requires high precision prescription maps.
Agrifac has developed a completely new high resolution system for creating prescription maps and executing the instructions on machines equipped with single nozzle control.
Mixing on the move
With AiCPlus varying pesticide rates on the move and to one-nozzle precision, Agrifac says it is difficult, or even impossible, to predict the chemical concentration required before application.
To overcome this, it has developed its SmartDosePlus direct injection system. Just clean water is held in the spray tank with the concentrated chemical stored separately. According to required pesticide rates detected by the sensors or stored on the map, the system’s software then meters the precise quantity of active required for the specific area and mixes it ahead of the boom.
The valve system and full boom circulation and priming ensures each nozzle receives the correct mix. It also doesn’t matter how many nozzles are in operation at the time.
It also enables other active ingredients to be added to treat certain areas and turned off when the patch is passed. Similarly, pesticide rates can be reduced dramatically or even stopped completely in environmentally sensitive areas.
Another big advantage of carrying just clean water in the tank, adds Agrifac, is it significantly cuts cleaning time and the amount of washings. This not only speeds up turnarounds between products, but can also help reduce the risk of cross contamination when working in sensitive crops.
The right rate and droplet size
As well as single nozzle control, StrictSprayPlus also provides application volume control that is unrelated to pressure, which maintains the droplet size regardless of changes in forward speed or pressure.
Automatic controllers normally set the application volume, according to speed by varying the pressure. In most cases as speed rises the droplet size reduces, increasing the risk of drift. As the pressure falls the droplets get larger and this may have adverse effect on efficacy.
Pulse Width Modulation overcomes this by using solenoids to turn the flow to the nozzle on/off up to 100 times/sec to maintain the correct application volume. The pressure is unaltered, so the droplet size remains the same.
StrictSprayPlus nozzle control also delivers turn compensation – to maintain the correct application volume when spraying around corners. As the sprayer turns the nozzles on tip of the outside boom move considerably faster than those on the inside of the turn.
With a fixed application volume, this results in under-dosing on the outside and overdosing on the inside. Agrifac says its system detects the speed differences and calculates the rate required for each nozzle across the boom.
But, experts warn, it’s important to note that PWM currently does not work with many of the popular Air-Inclusion (AI) nozzles in use today.
On the level
Regardless of the other technology on board, setting and maintaining the best boom height is crucial to maintaining spray efficacy and cutting drift.
For its new StrictHeightPlus auto-boom height control, which works in conjunction with the BalancePlus and variable geometry on its J Boom, Agrifac has developed new ‘wide view’ sensors.
Three sensors are fitted into four separate clusters, mounted across the boom that, it adds, scan a wider area than other systems. This is said to provide a better overview of the crop as well as help to distinguish between irregularities, misses and tramlines, which can affect performance.
A new auto-boom height control system, developed in house, uses three sensors in a cluster to scan a wider crop area. Four clusters are used on the boom.
The system is also now fully integrated into the firm’s own EcoTronic terminal, eliminating the need for another box in the cab.
More power and control for Endurance II
The Endurance II is powered by a 420hp engine and is equipped with a new, advanced control panel and joystick.
The sleek new EcoTronicPlus II joystick and touch-pad clusters commonly used controls into areas, providing finger-tip control of operations.
While the manufacturer sticks with the Claas Vista cab, inside operators will find a sleek new, modern control panel. Called EcoTronicPlus II, it is designed solely for use on a sprayer and incorporates a stylish joystick ahead of the armrest pad, which is surrounded by touch buttons.
These are accompanied by a single touch-screen, which is used for both the sprayer and the GPS-controlled equipment, such as section control, mapping and even road navigation. The screen changes automatically to display only information that is required for the current operation.
Elsewhere the Endurance II retains familiar equipment such as the existing StabiloPlus chassis, GreenFlowPlus multi-stage centrifugal pump and spray system as well as the 8,000 litre (~2,110 gal.) capacity tank and booms from 24m (~80 ft) to 55m (~180 ft).
Be sure to check out Pro Operator Magazine’s Facebook page and stay tuned for their new website!
April 5, 2018
Sprayer Turn Compensation
Turn compensation is a feature in pulse width modulation (PWM) sprayers in which nozzle output matches the boom’s speed during a turn. When turning, the inside and outside of a boom travel at different speeds, resulting in over-dosing on the inside and under-dosing on the outside. Read about PWM systems here, here, and here.
The degree of the problem depends on the inside turn diameter. Clearly, the tighter the turn, the more severe the over-and under-dosing. The ability of a PWM sprayer to compensate also depends on the turn tightness, as well as the Duty Cycle (DC) the system is operating at during the turn.
In the above example, a 120 ft boom makes a turn around an object with a 60 ft diameter. Assuming a 12 mph speed and an application volume of 10 gpa, the inside of the boom travels at 4 mph and applies 30 gpa, or 3x. On the outermost nozzle, the speed is 20 mph with an application volume of 6 gpa, or 0.6 x. A sprayer operating at 60% DC would be able to correct the application in this turn by operating at 100% DC on the outside and 20% DC on the inside.
But completing the turn at other DCs may be problematic. In this case, lower sprayer DC would require the inside DC to operate below 20%, which may not be possible, depending on the system. Conducting the turn at higher DC would prevent the outer boom from meeting the flow requirements, resulting in under-dosing.
Optimizing the benefit of turn compensation requires the operator to enter the turn at a DC that meets the objectives. Is it more important to prevent under-dosing of the outside perimeter? If so, slow down in the turn (reducing DC) and maximize the extra capacity at the outside of the boom, possibly at the cost of over-dosing the inside.
The agronomic benefit of turn compensation is to provide sufficient pesticide dosage where it’s needed. It’s been reported that repeatedly applying sublethal herbicide dosages at the same site can lead to the development of polygenic resistance in some outcrossing weed species. These areas are likely to occur at the outside boom location of a permanent landscape feature that the sprayer moves around year after year.
Turn compensation is a valuable feature in all agricultural operations where input distribution uniformity is important. Spraying is no exception, and PWM makes it possible.
April 3, 2018