This short article is a reminder for sprayer operators to respect the possibility of tipping a sprayer. Every spring I catch wind of someone tipping over. When I can ask the operator questions I start with “Is everyone alright?” and “Was the sprayer full?“. Hopefully the answers are “Yes” and No“, but not always.
The following factors are always involved:
Driving too fast. Usually entering a field at road speed.
Entering the field on a downhill slope and/or catching a pothole or soft shoulder.
Turning in a tight radius, usually 180 degrees. This is made worse when the sprayer is towed.
Sprayer is not completely full and “slosh” changes the centre of gravity.
Narrow tires and a narrow base.
Fortunately the sprayer wasn’t damaged and the spill was minor.A tight turn at high speed coupled with a depression in the entryway and tank slosh was enough to tip the unit. They had it righted and hauled out soon after. No one was hurt.
I’ve heard as many cases involving seasoned operators as new operators. The next few pictures are of a veteran operator’s sprayer carrying 28%/ATS. Just like the images above, a tight turn at high speed sloshed the load just as a deep pot hole caught the outside front wheel. This sent the sprayer into a lane of traffic before it tipped back and over into the field. No one was hurt.
Fortunately for the operator, the spill was contained in their field (not the road or ditches). The 90′ boom had to be cut off before the sprayer could be towed back to the yard to be sold off as parts. While the operator has looked at the bright side (an opportunity to upgrade) it has left them relying on a custom operator for spring spraying and making a hasty in-season equipment purchase.
Lost a tire during the tow back to the yard.Crumpled boom after having to be cut from the sprayer.Not the way anyone wants to see their sprayer.
Major Spill
What follows are generic steps for what to do if there is a major spill. Always defer to the process outlined by your regional authority.
If you do tip the sprayer, first protect yourself, then others, then animals in that order.
Stop any exposure by removing clothing and washing as best you can.
Stop people from entering the area.
If it is safe to do so, try to prevent the spill from spreading.
Contact your local spill centre. In Ontario, the Spills Action Centre will receive calls 24 hours a day at 1-800-268-6060. Consult with your municipality for their spill reporting contact numbers.
Take home
Of course we’d rather avoid this problem altogether. Be sure to slow down before turning into a field. Take the turn as gradually as possible. Remember that soft spring ground and new pot holes can become serious obstacles – consider scouting the entry before the first spray or at minimum getting out of the cab and checking before entering.
Herbicide resistance has been called the number one threat to conventional herbicide-based weed management strategies.
Since the 1970s, the number of cases of herbicide resistant weeds has shown a linear increase both globally (currently at about 500 documented unique weed species x mode of action cases) and within Canada (at about 70 such cases), according to the herbicide resistance website WeedScience.org. The rate of increase has been constant, and there is not yet any reason to believe that growth in the number of cases will slow.
Figure 1: Growth of global herbicide resistance cases (Source: WeedScience.org)
By using herbicides, we select for weed biotypes that, for some reason, can tolerate the product. Mutations which confer herbicide resistance are rare, but present at very low levels in most weed populations. Repeated use of the same mode of action will increase the relative frequency of the resistant biotype until it becomes noticeable, and shortly thereafter, problematic.
The best-known forms of resistance involve single-gene mutations that alter herbicide target sites (target sites might be enzymes that produce essential plant cell building blocks) so that herbicide binding is reduced, resulting in reduced control. As a result, the target pathway keeps working, and the plant grows normally after herbicide application. Other forms of resistance involve the overproduction of the target enzyme by the plant, mechanisms that either metabolize or sequester the herbicides, or changes in uptake of the herbicide. The main mechanisms are summarized in this table:
Table 1: Mechanisms of herbicide resistance*
Resistant Class
Mechanism
Target Site
Target site mutation
Increased gene copy number
Enzyme over-expression
Non Target-Site
Enhanced metabolism
Differential uptake
Differential redistribution
Sequestration
Delayed germination
Rapid necrosis / defoliation
*Source: Bo AB, Won OJ, Sin HT, Lee JJ, Park KW. 2017. Mechanisms of herbicide resistance in weeds. Korean Journal of Agricultural Science 44:001-015.
The simple act of using a herbicide can select for resistance to that herbicide. While we can’t predict or prevent resistance entirely, we can slow its onset by reducing the frequency of herbicide use, for example by integrating cultural controls such as crop rotation, seeding rate, cultivar competitiveness, and other factors into our agricultural systems.
A powerful option to slow resistance development is to reduce our reliance on a single mode of action, either by rotating modes of action in successive sprays, or, more importantly, by tank mixing multiple effective modes of action (MEMoA) whenever we make an application.
Let’s not kid ourselves. The recent discovery of glyphosate (e.g. Roundup) -resistant wild oats in Australia, and glufosinate (e.g. Liberty) -resistant ryegrasses in several countries is sobering. Relying more on these herbicides will only increase selection pressure.
If we decide to use herbicides, we need to look at the situation from the perspective of delaying the onset of resistance. What we’re trying to do is buy some time, so that new strategies can be developed.
How can spray application methods slow the onset of resistance?
The use of herbicides will continue to select for resistance. The best we can hope to achieve within a herbicide system is to delay that eventuality.
To better understand our options, we need to talk about a specific type of herbicide resistance called polygenic resistance. This refers to accumulation of additive genes of small effect over time, a process that is more efficient in plants that share genetic material among plants in a population, i.e., they outcross.
Outcrossing plants receive genetic material from others, increasing their genetic diversity, and therefore their ability to adapt.
In a field, a population of any specific weed may contain some individuals that have slightly greater tolerance to a herbicide than others. If we apply a slightly lower than label herbicide dose to those individuals, they might survive the application and eventually cross with other survivors and set seed. Their offspring may be as tolerant or even more tolerant than their parents. If this repeats itself over successive generations, the additive effects build until finally, low-level resistance becomes full-blown resistance and even label rate herbicides no longer work. This resistance isn’t a single gene mutation, it’s simply an accumulation of tolerance due to several genes which impact how much of the herbicide active ingredient reaches the target site.
In a recent study at the University of Arkansas, susceptible Palmer amaranth (P. amaranth has both male and female plants and is therefore an obligate outcrosser) was treated with a range of dicamba doses to identify individuals that survived the higher doses. The researchers allowed the survivors to cross, and then grew out their seed, then repeating the procedure. After just three generations, the experiment produced individuals with a three-fold increase in LD50 (compare LD50 at P0 (111) to P3 (309) in Table 2). Recall that LD50 refers to the dose required to observe 50% of the full effect.
Table 2: Dicamba doses (g ae/ha) required for 50% (LD50) and 90% (LD90) control of Palmer amaranth populations selected following sublethal doses of dicamba in the greenhouse.*
Herbicide resistance cannot be prevented if herbicides are applied.
To prevent polygenic resistance, we need to apply the full label rate and avoid repeated sublethal doses, so that all weeds are killed;
We need to apply Multiple Effective Modes of Action (MEMoA) whenever possible so that when one fails, the others have its back;
How can this be achieved?
Prevent application practices that result in less effective dosing. Larger weeds, or weeds growing in difficult environmental conditions, may require higher herbicide doses. Early application is helpful because small weeds are easier to control. In addition, crop canopy shading at later staging leads to dose reduction and increases dose variability. Spraying under windy conditions also reduces dose, and can increase deposit variability. For some herbicides such as glyphosate or diquat, the dust generated by wind or fast travel speeds can reduce effectiveness.
Figure 2: Smaller, exposed weeds require lower doses to controlFigure 3: Crop canopies provide valuable competition to help suppress weeds, but they can also intercept spray, reducing the dose received by weeds.
Get Pulse Width Modulation (PWM) with turn compensation. If your sprayer makes the same turn around the same feature year after year, then the outer boom region will under-dose the same part of the field over and over. This is the breeding ground for polygenic resistance. Look for this in field corners, around water bodies or tree bluffs, rock piles, etc.
Figure 4: PWM correction of under-dosing during a turn
Prevent boom sway and yaw. Boom movements result in uneven application, which results in lower control. Pull-type sprayers with supporting wheels are best, but these are becoming rare. Suspended boom performance depends on the manufacturer and the levelling technology they use. However, boom movement is usually more consistent with slower travel speeds.
Figure 5: Boom yaw causing over- and under-application (Source: Farmonline.com.au)
Minimize air turbulence. Large sprayers, and those moving at fast speeds, create aerodynamic turbulence that can displace spray. The main problem spots are wheels, in whose tracks measurably less spray is deposited. The exact dynamics of turbulence is still unknown, but we do know that its magnitude can be reduced with slower travel speeds.
Figure 6: Turbulence due to sprayer speed (Source: Dr. Hubert Landry, PAMI)
Consider spot spraying. The use of optical spot spray equipment, such as the new WEEDit Quadro, or Trimble’s WeedSeeker II, save product during burnoff or post-harvest. These savings can make the use of more elaborate, expensive tank mixes containing multiple effective modes of action, affordable.
Avoid spray drift. Field margins that harbour weeds rarely receive a full dose of herbicide. Exposing these weeds to spray drift won’t kill them. But it will, over time, select for weeds that are more able to tolerate the herbicide.
Implications
Aside from specific technology such as PWM, improved booms, or a spot sprayer, the most effective fix for variable application doses is slower travel speed.
While this may seem problematic when timing is critical and greater productivity is required, there is a way to drive more slowly and still get more done. We simply need to look at productivity differently.
We tend to equate productivity with speed. Travel speed. But a spray day is filled with many hours of non-spray time – filling, cleaning, transporting, repairing, fueling, record-keeping, etc. How much time is lost to these activities depends on the operation, but for everyone, it’s useful to do time accounting.
Record how a spray day’s time is spent. Pay attention to activities during which you can save time without much expense.
Action
Actual Time
Target Time
Fuelling, lubing
Loading jugs and totes
Checking label (rates, rainfastness…)
Filling tender tanks
Loading sprayer (in yard)
Transport to field
Entering field data into monitor
Checking, recording weather
Checking for pest, stage
Changing nozzles
Spraying load
Unplugging / replacing nozzles
Replacing nozzle body
Making turn
Filling sprayer
Getting sprayer unstuck
Driving to tender truck
Waiting for tender truck
Spraying out tank remainder
Cleaning tank
Cleaning filters
Flushing boom ends
Loading sprayer (in field)
TOTAL
On any given spray day, less time spent filling, or transporting, is credited to spray time. Our analysis shows that time lost to driving slower can more than be made up with these changes. The productivity gain gives more opportunity to spray under more ideal conditions that save yield and also ensure more uniform application.
Using productivity analysis, spraying can become more uniform and help delay the onset of resistance.
Note: The assistance of Dr. Charles Geddes, Research Scientist at AAFC Lethbridge, in drafting this article is appreciated.
In this episode of Exploding Sprayer Myths we reduce a complicated best practice to black and white… literally. Watch as Jason and Tom get a creepy lesson in the do’s and do not’s of no-spray areas. Under the watchful eye of Dr. Jim Todd (OMAFRA Industrial Crops Specialist and Rod Serling cos-player), brace yourself as you enter The Buffer Zone.
Learn more about how vegetative filter strips mitigate runoff on this Health Canada webpage.
Thanks to the staff at the Simcoe Resource Station and to RealAgriculture for making this video possible.
And if you’re curious about the kitchen-appliance cameo, you’ll have refer back to earlier episodes.
Capstan Ag brought Pulse Width Modulation (PWM) to spraying in the mid 1990s. Over the past 20 years, it has become commonplace on Case sprayers as AIM Command and AIM Command Pro, and as an aftermarket product, called Sharpshooter or PinPoint, on any brand sprayer. If you’re new to the concept, read about it here and here.
A sprayer turn, without turn compensation. Note the darker dye on the innermost nozzles and lighter deposits on the outer wing.
The latest versions (AIM Command Pro and PinPoint) offer turn compensation and individual nozzle sectional control. But there remains a large base of older AIM Command units that lack turn compensation. And of course, sprayers that lack PWM alltogether, possibly because of cost.
The Capstan EVO addresses both issues. Introduced in January of 2019, it gives older AIM Command units affordable turn compensation. As a bonus, a complete new EVO install on non-PWM sprayers is available at a significant discount compared to most other PWM products.
EVO features many of the same basic PWM capabilities as its bigger cousins, but with a shortcut, explain Capstan representatives.
As always, a change in travel speed changes the duty cycle of the pulsing solenoid, adjusting flow rate of the nozzle without a change in pressure. This provides the consistency in performance that we love about PWM. Drift or coverage are controlled by the operator who makes changes to spray pressure from the cab, with a commensurate background adjustment in duty cycle so that travel speed is unaffected.
With the EVO, the shortcut is that sectional control is by plumbed section. Technically it’s possible to add sections, but the rate controller and the sprayer wiring would have to allow it.
Spray dosage for sectional turn compensation for six sections of equal size, with the centre of each section applying the target dose. As always, some lateral movement of spray from adjacent nozzles will occur.
Turn compensation is part of EVO, and this is an important benefit that was previously only available in more expensive versions of a PWM product. Each section will have a fixed turn compensation based on the speed of the centre of the section. Its performance will depend on the size of the sections.
For a 100′ boom with six 10-nozzle sections turning around an object with a 60′ diameter, our modelling shows that the deviation from perfect turn compensation is least on the outer wings (where it’s most important) and grows towards the inside of the turn. In this example, the outer section’s end nozzle under-applies by 6% relative to the ideal, and the innermost nozzle on this section over-applies by 7%.
On the next section, these deviations are 7% under and 8% over, then 8% under and 9% over.
Moving from the centre of the sprayer to the inner wing, deviations are 9% under and 12% over, then 12% under and 16% over, and finally 16% under and 24% over.
Spray deposition on an un-compensated turn.
On an uncompensated boom with the same dimensions, the outermost nozzle would be under-dosing 38% and the innermost nozzle would be over-dosing by 267%.
Recall that it’s more important to be accurate on the outer wing than on the inner, for the purpose of delivering the full spray dose in a turn.
Repeated year-after-year under-dosing at the periphery of a turn such as field corners, or around permanent features such as sloughs, trees, or stone piles results in weed problems.
EVO is intended for users with an original SharpShooter or AIM Command who would like turn compensation but don’t want to a whole new PWM system. EVO provides new modules and a new screen, but users save money because they can keep their existing solenoids, says Capstan.
Capstan says that EVO is for every brand of sprayer ordered without pwm control from new to 15 years old. It’s an easy upgrade for owners of AIM Command & SharpShooter systems because these already have most of the components, and install times are therefore lower for these machines. Existing solenoids and wiring harnesses can be retained.
Owners of high clearance pull type sprayers will also see the advantage of turn compensation and pressure control at an attractive price point.
EVO modules and tools needed for installation
I was present during an installation of these new modules on an existing Case 3330 sprayer with AIM Command. It took one person, with occasional assistance from a second, less than 1 h to do the conversion.
Removal of AIM Command modulesInstallation of EVO board containing all modules and replacement plugins
A new installation would require an additional several hours to install wiring harnesses and solenoids. Times will vary with sprayer model and technical experience of the installers.
The EVO electronics run in parallel to the existing sprayer monitor. It allows the existing monitor to control sections and determine the flow requirements. It does not control pump speed, it simply reads the flow, pressure, and gps signal from the sprayer’s systems and uses them to determine the duty cycle (DC) that ensures the spray pressure remains constant. On AIM Command units, the pressure control module remains installed and pressure adjustment remains possible through AIM Command in cab controls.
Entering system settings into new EVO monitor
It’s possible to set the pulsing frequency between 3 and 30 Hz in EVO, an industry first. The lower the frequency, the wider the dynamic flow rate. Capstan advises to maintain a frequency above 10 Hz for spray operations. Lower frequencies may be used for fertilizer applications, where prescription maps require a higher rate range and where uniformity requirements are more relaxed.
EVO Monitor contains an option in which to select pulsing frequency
Testing of completed EVO Installation
The monitor has an intuitive readout of average DC and a bar graph showing the DC across sections in a turn. If this bar maxes out on the outer sections during a turn, simply slow down to lower average DC and provide extra capacity to those sections.
EVO monitor during operation. Readout includes current spray pressure, duty cycle, and turn compensation status.
Lowering the cost of PWM makes it attractive to a new group of users. It also offers a more affordable upgrade path for owners of AIM Command or SharpShooter systems that currently do not have turn compensation.
Press play to listen to an audio version of this article
Agronomists help farmers manage their crop with advice on everything from crop cultivars to fertilizer rates to marketing. It’s challenging to be an expert on everything, but a few core competencies can go a long way to improving the level of service.
Agronomists are also responsible for communicating environmental
best practices. Along with fertilizer rates come messages of source, time, and
place, the 4R principles. The same is true for spraying, with messages of spray
drift, resistance management, and economic thresholds part of the consultation.
Let’s remember that we should not be indifferent to the potential consequences
of our recommendations.
Here are six skills that an agronomist should know about spray technology.
1. Recognizing major nozzle models and their spray quality and pressure requirements.
Application technologists are often asked to identify
nozzles and recommend spray pressures for clients. It’s a skill that anyone can
develop with just a bit of homework.
First, learn the colour-coding of nozzles – colours identify
flow rates and follow an international standard that all manufacturers have
adopted.
ISO Colour coding of major nozzle sizes, as well as application volumes at benchmark speeds.
Next, focus on the common nozzles on the major sprayers. John Deere sprayers will typically have three main air-induced nozzles, made for John Deere by Hypro, the Low-Drift Air (LDA), the Ultra Low-Drift (ULD), and the GuardianAIR Twin (GAT). Those with ExactApply, John Deere’s PWM system, will see the non air-induced 3D, the Guardian (LDX), and the Low-Drift Max (LDM). Recall that PWM flow control should not be used with air-induction tips.
Almost all Case sprayers have PWM, called AIM Command. Case uses Wilger ComboJet bodies and nozzles, with the ComboJet ER, SR, and MR most common, sometimes the DR or UR for dicamba.
New Holland/Miller with PWM (called IntelliSpray) are also likely to have these tips, but because these brands have TeeJet bodies on their booms, they require an adaptor for the proprietary ComboJet caps.
Otherwise, PWM units often use TeeJet’s TurboTeeJet (TT), Turbo
TwinJet (TTJ60), and Air-Induced TurboTwinJet (AITTJ60), the only air-induced
tip approved for PWM use by TeeJet.
Conventional spray systems (i.e., no PWM), will commonly
have (in alphabetical order) the Air Bubble Jet (ABJ, actually labelled BFS for
their manufacturer, Billericay Farm Systems), the Greenleaf AirMix (AM), the
Hypro GuardianAIR (GA), and the TeeJet AIXR.
Many sprayers will have a twin fan for fungicides, primarily for fusarium headblight (FHB) management. The Greenleaf Turbo Asymmetric Dual Fan (TADF), the Hypro GuardianAIR Twin (GAT), and the TeeJet AI3070 dominate, as well as a number of custom configurations using splitters and twincaps.
Where dicamba is applied on Xtend trait soybeans, some special nozzles may be used to meet label requirements for coarseness. The TeeJet TTI is very common, but Greenleaf developed a special set of tips called the TurboDrop XL-D and the TADF-D. Wilger’s version, mentioned earlier, is the UR. John Deere has just announced their new ULDM.
That covers 95% of what you’ll encounter in the North American market. In Europe, add some Lechler nozzles (ID3, IDTA, IDK, IDKT) to the mix. In Australia, Arag is gaining ground.
Identifying the nozzles on sight is the prerequisite to
finding out their average droplet size, called spray quality. Often, the
inscriptions are worn off, so visual recognition is required to get there.
We’ve published a visual identification guide with pictures of the major nozzles here.
Knowing the relative spray qualities produced by these
various nozzles will get you bonus points, but you’ll need to do some extra
research to get there.
2. Using a spray calibration chart
This skill will make you popular on the farm and at the office. A very frequent question is “what size nozzle do I need for this new sprayer?”. The best way to approach the answer is to ask several questions.
Does the sprayer have 20” nozzle spacing? (90% of sprayers do).
What is the desired water volume?
What is the expected average travel speed?
The first question guides you to the appropriate calibration chart, which can be downloaded here or can also be found in all sprayer catalogues. We explain how to use these charts here.
Calibration chart for 20: spacing, in US units.
If you don’t have a chart handy, use this shortcut: on a boom with 20” spacing, at 5 mph, every 0.1 US gpm capacity at 40 psi delivers 6 US gpa. So if you need to apply 12 gpa at 15 mph, an 06 size will get you there at 40 psi. That’s ballpark.
In metric, with 50 cm spacing, at 10 km/h every 400 mL/min (01 size) at 3 bar delivers about 50 L/ha. To deliver 200 L/ha at 20 km/h would require an 08 (white) tip.
Of course, if the tip is air-induced, make adjustments to speed or size to accommodate the higher pressure requirement of these types of nozzles.
Remember that spray pressure is key to performance, therefore the operator needs to drive at a speed, or use a volume, that results in the correct spray pressure.
3. Understanding Pulse Width Modulation
PWM technology has been on the North American and Australian market for two decades, but it remains poorly understood by those who do not use it. PWM will continue to gain popularity and has implications for nozzle selection and sizing.
Traditional rate control in the field involves the use of spray pressure to match liquid flow rates to travel speed. The rate controller knows the width of the boom (entered by the user), the travel speed (from gps), and the desired application volume (entered by the user). It does some math to identify the flow rate it needs, and compares that to the sprayer’s current flow meter reading. If the current flow is less than what’s needed, the sprayer increases pressure to increase flow. This happens continuously in the background.
When an operator speeds up, the pressure increases, and vice versa. As a result, the pressure (and therefore droplet size) will fluctuate with travel speed, and that can result in inconsistent spray patterns, coverage and drift.
PWM involves the installation of electronic solenoid valves at each nozzle body. These valves pulse on and off at 10, 15, 50, or 100 Hz, depending on the manufacturer. Each pulse contains a brief, complete shutoff of the flow. The proportion of the time the valve is open during a pulse is called the Duty Cycle (DC), and this is proportional to the flow through the nozzle.
Capstan PWM solenoid on Case AIM Command
When the system requires more flow, it no longer increases pressure. Instead, it increases the DC. The advantage of this approach is that nozzle pressure can now stay constant, ensuring consistent coverage and drift.
There are other advantages of these systems. Each nozzle can be controlled independently, offering high resolution sectional control and turn compensation.
Nozzle selection and sizing are both affected by this technology. Nozzles need to be sized larger, with about 30 to 40% more flow capacity ideal. The DC will therefore run at 60 to 70%, optimal for speed fluctuations and turn compensation. Air-Induced tips are not usually recommended because their pattern deteriorates with pulsing.
We’ve written about PWM here, here and here to get you started.
4. Validating coverage of the target
A very useful indicator of the success of a spray operation is an assessment of “coverage”. This term refers to a qualitative combination of droplet density and percent area covered, and can be quickly assessed using water sensitive paper. We’ve explained the use of WSP here and here.
It’s very useful to have some of this paper on hand (available from any retailer that sells TeeJet or Hypro products, or on-line from Sprayer Parts Warehouse in Winnipeg or Nozzle Ninja in Stettler, AB). The coverage can be assessed in four different ways:
Water-sensitive paper being used to assess spray coverage.
using the “DropScope” scanner (gives a comprehensive assessment of coverage, density, size, plus image editing tools);
using a template of coverage examples;
using experience built on years of doing this.
Water-sensitive paper is also useful as a record, for
quality assurance. A spray application is conducted and part of the record is
an image of the deposit. Should a performance issue arise, this will help
settle it.
5. Understand basic sprayer plumbing
Often, a sprayer problem can be traced back to an issue with
its plumbing. There could be mysterious sources of contamination. The pump might
not be building pressure. The agitation isn’t running. Or you need to drain all
the remaining liquid from the tank.
Sprayer plumbing seems intimidating for a number of reasons.
It’s become complex on most modern sprayers. It’s hidden under the sprayer
belly. All the lines are the same black colour, so they’re hard to tell apart.
But it’s not as bad as it seems. Basic plumbing is the same
on all sprayers. The pump draws the spray mix from the bottom of the tank, the
sump. It may also have options to draw clean water from an external supply, or
from the clean water tank for wash-down.
The pressurized supply goes to three places:
to the booms, via sectional valves;
back to the tank, via a control valve that can be used to adjust the spray pressure;
to the wash-down nozzles.
Typical sprayer plumbing for a centrifugal pump (Courtesy TeeJet).
When spraying, the less is returned to the tank, the higher the boom pressure. There may be several ways back to the tank, via agitation, via bypass (sparge), or via wash-down (used only when the pump draws water from the wash-down tank). Usually engineers can’t help themselves and introduce several what-if features that complicate the situation. But with a bit of know-how, and a flashlight, the plumbing system can be deciphered.
Pro tip: A centrifugal pump’s inlet (suction) is always the centre of the pump, its outlet (pressure) is at the periphery.
6. Matching a pesticide recommendation with application advice
It’s commonplace to recommend a specific crop protection product that matches the crop and pest situation. Recommending an ideal crop or pest stage improves the recommendation. But a truly successful outcome requires one additional step, advice on the application method. The customer may need to know if product performance depends on water volume and droplet size. Some products are more sensitive to this than others. Perhaps there is a specific nozzle type that may be helpful.
The classic example for application method is Fusarium headblight in wheat. The basics are straightforward. An agronomist recommends the fungicide, and guides the tight application window with a field visit to stage the crop, plus a look at the disease risk forecast map. But true application success requires an angled spray, with a coarser spray quality plus relatively low boom height to make it all worthwhile. That’s a full-featured recommendation.
Common herbicide applications also benefit from additional
information. Some tank mixes and weed spectra allow for coarser sprays than
others, and the ability to spray coarser means a wider application window and
therefore more accurate timing. Other tank mixes may pose a significant risk to
drift damage, requiring special measures to prevent a problem. Identifying
those opportunities adds value.
Water volume and spray quality recommendations for major herbicide mode of action groups.
Newer labels for dicamba (Xtendimax, Engenia, Fexapan) and 2,4-D
(Enlist Duo) have very specific instructions for drift prevention. This
information must be shared with customers to ensure that their drift liability
is covered.
Are there other skills that you feel agronomists should have?
Please share them with us by contacting us at the bottom of this page.
