Category: Boom Sprayers

Main category for sprayers with horizontal booms

Tank Rinse Dilution
If you have a limited amount of clean water to rinse your sprayer, this can help you decide how to make the best use of it. Simple enter two values – the amount of pesticide remaining in your tank sump (including the suction line to the pump and the return line to the tank), and the amount of clean water you want to add. The units (gal, L) are not important as long as they are the same for both entries.
The app allows you to calculate the dilution power of up to 5 sequential rinses.
May 28, 2015
Fungicide Application Basics
Fungicide use appears to be the fastest growing segment of North American crop protection. Here is some advice on how to get the best bang for the buck.
- Timing is the most important part of fungicide application. Diseases can develop and spread quickly. Most fungicides cannot cure a disease infection, they can only protect against it. If an application misses the window, yield is lost. Remember your priorities – become familiar with disease symptoms, the susceptibility of your crop and key growth stages. Make sure your sprayer is ready – your nozzles are installed, calibrated, and you can achieve the necessary boom height. Hire an agronomist to help scout and make recommendations. Make the right decision about whether to spray or not.
- Water volume is the most important application parameter for fungicide application. In years of study, increasing water volume had a greater effect on fungicide performance than changes in droplet size or spray pressure. More water is needed for fungicides than herbicides because of the greater amount of plant material present. Getting coverage on leaf areas deeper into the canopy requires more water. Although finer sprays can also help with coverage, this practice is riskier due to drift potential and higher evaporation rates.
- Double nozzles, in particular the asymmetric types, are becoming more popular with fungicides. Double nozzles are proven effective and recommended primarily for fusarium head blight, or any other disease where an exposed vertical part of the plant canopy is the primary spray target. Double nozzles are also useful for preventing the spray quality from getting too coarse as higher flow-rate nozzles (which tend to have larger droplets) are used.
- Travel speed is important with fungicides. Canopy penetration sometimes improves with slower travel speeds, and this can be used as an advantage by eliminating the need for a special fungicide nozzle. For example, assume a nozzle was used to apply 8 gpa of herbicide at 15 mph at 70 psi (this pressure assumes air-induced tips). For fungicides, this same nozzle and pressure will deliver 12 gpa simply by slowing down to 10 mph.
Boom height and spray quality are both important for single angled sprays or double nozzles. The angle at which a spray leaves a nozzle diminishes quickly as air resistance and gravity exert their influence. If the boom is too high, the initial forward angle will be lost and the spray droplets will actually deposit with gravity and wind. But if the spray is a bit coarser and the boom is low enough, the angle of attack is retained for long enough to make a difference in spray deposition.
Despite these suggestions for making the spray more effective, there is no substitute for an informed decision regarding fungicide use. It’s possible that spraying is unnecessary for a number of reasons, and it’s best to have professional advice help make that call. If you decide to go ahead, ensure that your sprayer is set up to deliver the fungicide to the part of the canopy that needs protection.
May 27, 2015
Water Quality and Spray Application
Water is one of the main inputs into a spray operation. The amount of water applied per acre is closely related to spray coverage and pesticide performance. But water quality – a term encompassing its cleanliness and chemical composition – is also critical to the performance of pesticides. Ensuring good performance means testing water and understanding the results.
There are four main water quality indicators related to pesticide performance:
1. Water Hardness. Water hardness is caused by positively charged minerals, primarily calcium and magnesium, but also sodium and iron. These cations can bind to some herbicides (glyphosate is the best-known example, also 2,4-D amine), reducing its performance. Hardness is usually named “Total Hardness (calculated)”, based on the concentration of calcium and magnesium in the sample, and is expressed in ppm or mg/L of CaCO3 equivalent. Some tests refer to the older unit “Grains”, which is ppm divided by 17. Bayer suggests that total water hardness should be below 350 ppm (20 grains) for the low rate (1/2 L/acre equivalent) of glyphosate, and below 700 ppm for the higher rates.
2. Bicarbonate. Sometimes referred to as alkalinity, the bicarbonate ion can inhibit herbicide activity, and also make some herbicides more difficult to mix. The most commonly affected herbicides are members of the Group 1 modes of action, products like clethodim, sethoxydim, and others, as well as MCPA amine and 2,4-D amine. Definite guidelines are hard to find because the antagonistic effect of the bicarbonate ion depends on the presence of other ions such as sodium and calcium.
3. pH. This is a complex parameter because it is related to pesticide solubility, hard water antagonism, and pesticide degradation. In most cases, pH values between 4 and 7 are considered acceptable. But some herbicides, notably those in the Group 2 modes of action, have specific pH needs to dissolve properly. For example, the sulfonylureas (FMC products such as Refine, Express), triazolopyrimidines (Corteval products such as Frontline, Simplicity), Triazolones (Bayer products such as Varro, Velocity M3) and Sulfonylaminocarbonyltriazolinone (UPL products such as Everest) dissolve better at higher pH, whereas the imidazolinones (Odyssey, Pursuit, Ares) tend to require lower pH. Some Group 14 products such as saflufenacil (BASF products Heat, Eragon) also prefer higher pH values for solubility. Label directions are important, sometimes calling for specific adjuvants to adjust the pH prior to adding the pesticide. Some pesticides, particularly insecticides, can break down rapidly in higher pH water. The rate of breakdown is usually not of importance on a spray day but may matter if a mixed tank needs to be stored for many hours or days.
4. Cleanliness / turbidity. Water may contain suspended solids such as clay. Glyphosate and diquat (Reglone) are sensitive to this, as these chemicals are readily adsorbed to soil particles, and turbid water can reduce their effectiveness. This is also why dust generated by the sprayer can reduce these herbicides’ performance.
Ensuring good performance
Select clean water sources and conduct a water test to identify possible problems. Well water is more likely to be hard than surface water. If a laboratory water test is not available, then some quick home testing can provide the necessary guidance. First, use a conductivity meter to test the electrical conductivity (EC) of the spray water. Although this test does not identify the ions present, it shows if a potential problem exists. EC values less than 500 µS/cm are considered safe. For values above 500, a hardness test is necessary to confirm the presence of antagonizing cations. Paper test strips compared to a colour scale are a quick way to determine hardness.
If you have done a water test and want to know what all the numbers mean, have a look here.
If the water is hard, a generally accepted solution is to add ammonium sulphate (AMS) fertilizer at rates between 1 – 3% w/v of 21-0-0-24 to the spray tank, preferably before adding the herbicide. Spray grade liquid concentrate AMS product is available from Bayer CropScience, Winfield United, and some other suppliers. The sulphate anions tie up the hard water cations, preventing them from antagonizing the herbicide. Liquid urea-ammonium nitrate (UAN, 28-0-0) has also been shown to improve herbicide activity for some products, but because it does not contain the sulphate ion, it is not as effective as AMS.
Certain weak organic acids can also function as water conditioners. For example, citric acid can chelate hard water ions so long as the pH is not too low, that is, the necessary dissociable groups are ionic. If the pH is very low, these groups will be protonated and the chelating action is suppressed.
Be careful when lowering pH. It does affect the solubility of many herbicides and possibly the function of some formulations. The outcome may be an unusable tank mix.
Caution is also advised when adding foliar fertilizer specialty products. Adding a blend of fertilizer salts, combined with associated changes in pH, can result in unpredictable interactions with pesticides and water, resulting in sticky precipitates that may be very difficult to clean out of tanks and plumbing. Ask for compatibility data, and always conduct a jar test to be sure that the planned mixture mixes as expected. A recent study shows the effects of adding herbicides to UAN and ammonium thio-sulphate (ATS) plus nitrate stabilizers, where mixing order is critical.
Turbidity is a problem with surface waters, especially in areas of clay soils and after surface runoff. If spray water is taken from a pond, its turbidity can be reduced by adding aluminum sulphate at rates between 10 to 60 mg/L of pond water. Thorough agitation is required, and 80 to 95% removal of turbidity is achieved within 24 to 48 h (technical information here).
Pesticide manufacturers are usually aware of potential problems when their products are used in poor quality water. Consult with your local rep to learn of know issues and solutions before spraying.
Check out this 2022 Real Agriculture interview with Tom and Greg Dahl of Winfield United. Pan ahead to the 16 minute mark for a discussion on water quality.
May 27, 2015
Top Five Tips for the Spray Season
This article was originally written by @nozzle_guy as a guest blog for Farm At Hand, and is reproduced with permission.
Spray season is here, but are you ready? Here are 5 tricks to give you a productivity edge.
1. Choose a spray pressure in the middle of your nozzle’s operating range. All spray nozzles have a range of pressures throughout which the manufacturer believes the spray pattern is acceptable. We’ve come to assume that the correct spray pressure for a nozzle is about 40 psi, largely because of tradition. In fact, 40 psi is merely the mid-point of a traditional nozzle’s pressure range, between 20 and 60 psi. Modern air-induced nozzles have much higher and wider pressure ranges, usually from 30 to 100 psi. The new middle ground is about 70 psi.
For this nozzle, the manufacturer recommends pressures from 30 to 100 psi. The middle ground is 60 to 70, allowing travel speed flexibility
Why so high? There are two reasons.
- Air-induced tips perform optimally at higher pressures, and remain lower drift than conventional nozzles even at those pressures.
- Travel speed range. As a sprayer changes speed, the spray pressure is automatically adjusted to maintain a constant application volume. Even a small reduction in speed, due to changes in terrain, for example, can put the spray pressure too low for good nozzle operation. A nozzle that is sized for a higher average operating pressure will permit a reduction in speed without a nozzle performance penalty at lower speeds.
1. Measure your boom’s pressure drop and add this value to your target operating pressure. All sprayers experience a drop in pressure as the solution moves further away from the pump. This is due to friction caused by a number of factors, including length of tubing, elbows, valves, screens, and other flow obstructions. The pressure transducer that reports pressure to the cab is usually located between the pump and the manifold that divides the spray into the various boom sections. After this point, the spray liquid experiences those additional restrictions, and pressure at the nozzle will therefore be lower than the cab reading indicates.
By adapting a pressure gauge to a nozzle cap, boom pressure can be measured directly
The nozzle pressure can be measured with a gauge placed on a nozzle body. Simply purchase a gauge and a threaded nozzle cap, combine the two and install in place of a nozzle. Operate the sprayer and read this pressure, comparing it to the pressure in the cab. The difference between the two is the pressure drop. Do this for your lowest, as well as your highest expected flow rates. Higher flow rates cause greater pressure drops. If you want to spray at 60 psi and your pressure drop is 10 psi, then the cab pressure should read 70 psi.
1. Install a clean water tank and wash-down nozzle on your sprayer. One of the more time-consuming aspects of a spray operation is cleaning the sprayer when you switch products. The quickest way to clean a sprayer starts with accurately calculating your last tank needs, and spraying any remainder (if you’ve done your math, this will be small) out in the field. Depending on the product, overspraying the crop a second time can be an option, simply reduce the application rate to prevent doubling the dose.
On-board clean water tanks save time
When the spray tank is empty, introduce clean water from your clean water tank through the wash-down nozzle, allow to mix with remaining spray in plumbing (make sure agitation is on) and spray out. The spray mixture will quickly become increasingly dilute and flush through all sprayer parts that contained the product. The clean water tank can contain a cleaning adjuvant such as ammonia or a detergent depending on the properties of the product to be removed. After the sprayer is cleaned, stop and inspect all screens to ensure there are no pockets of residue.
1. Obtain a faster transfer system and strive to load faster. Most sprayer refills can take longer than planned, and before you know it, 15 or more minutes have passed. That can be a significant portion of the total spray time, resulting in lost productivity. By moving to a 3” transfer pump and plumbing, fills in 5 minutes are possible. Care is required to ensure that products are properly mixed, and dry products may need to be hydrated in advance to prevent screen and nozzle plugging.
A good tender system may be the most important productivity component in your spray operation
The fastest operators have a capable person on the tender truck, and have the tender truck move to the sprayer at the field edge, not the other way. Front fill attachments save further time. Think of it like a Nascar pit stop, and watch productivity increase.
1. Say goodbye to boom end valves. Traditional 1” wet boom sections have a “boom end” that is capped about 4 to 6” beyond the last nozzle body. The boom end is a dead end, and any pesticide mixture that ends up there, as well as any air in the boom, is virtually impossible to remove.
The Hypro Express End Cap system prevents boom ends from retaining spray mix.
Two problems result:
- Boom end residues can cause contamination.
- The air in a boom acts as a bladder, preventing diaphragm check valves from shutting nozzles off until enough liquid has left the boom to reduce the bladder pressure.
The most common way to remedy this is to install valves at each boom end, flushing the air and contamination out. But this has to be repeated twice for each boom section, which can number anywhere from 5 to 11 per boom. A product called the Hypro Express Nozzle Body End Cap automates the process. The end cap has a novel design that eliminates the dead reservoir and bleeds air from the boom continuously during normal operation. The result is easier sprayer cleaning and better shutoff responsiveness.
Spraying is an important operation, and timing is critical. Small changes in productivity can add up, preventing problems and getting more acres treated each day.
May 25, 2015
How to Use a Nozzle Flow Chart, With a Surprising Twist
Undoubtedly, the number one question we get from operators is: “Which nozzle should I get”? Luckily there’s no simple answer, or we wouldn’t have jobs! The reason it’s not simple is because selecting the “right” nozzle for a sprayer is a process. It can be broken down into two steps:
- identifying the right flow rate (aka nozzle size)
- choosing a specific nozzle model (i.e. brand, spray pattern type, spray quality, etc.)
It’s a big question, so let’s tackle just the first bullet: identifying the right flow rate.
All sprayer nozzles come in standardized (ISO) sizes, and these sizes are usually identified by numbers stamped on the nozzle as well as the colour of the nozzle itself. The nozzle’s key characteristics (i.e. the fan angle and nominal flow rate), are identified in a format that looks like some version of this (Fig. 1):
Fig. 1: Typical information printed on modern nozzles.
The 110 refers to the fan angle (110°) and the 04 refers to the flow rate. 04 means 0.4 US gallons of water per minute (gpm) at 40 psi. Each nozzle brand has a slightly different convention, but no matter how the information is presented it ought to be on the nozzle somewhere.
Nozzle colour has an ISO standard across fan-style nozzles, and we have this table to match the nozzle colour to the flow rate:
Fig 3: ISO nozzle colours and flow rates
You’ll note that the nozzle we pictured earlier was “flame red”, matching the 0.4 gpm on the table. So how do we use the table to pick the right size nozzle?
Application rate (i.e. gallons per acre or L/ha) is a function of travel speed, nozzle spacing along the boom, and nozzle flow rate. Traditionally, this has been expressed as the following formula in US units:
This formula is famously represented in nozzle charts found in all sprayer catalogues (Fig 4). Along the left side are nozzle sizes and pressures. Along the top is sprayer speed. The body of the table contains application volume. Pick your speed, and look for your application volume in the columns. If you want to apply five gpa, you need to look for the number 5 (or as close as you can get to it), among these numbers.
Fig 4: Typical nozzle flow rate chart, with speed at top and volumes in body. Ugh.
The format of the chart can be confusing because it doesn’t follow a modern sprayer operator’s priorities. Usually, an operator decides on an application volume first, and this decision is not very flexible. Travel speed, decided second, has more flexibility.
We’ve therefore re-worked the table to make more sense (Fig. 5). Along the top are common water volumes. The body of the table are travel speeds. Pick a water volume at the top and follow the column underneath this value to find a speed range you’re comfortable with. To the left, the nozzle size and corresponding operating pressures are now visible.
Fig. 5: Nozzle flow rate chart with volumes at top makes it user friendly.
Try to operate at a spray pressure that’s in the middle of the nozzle’s operating range. For an air-induced nozzle, the range is usually from 30 to 90 psi, so the middle is 60 to 70 psi. That should be the target pressure. Look for a nozzle size that delivers this pressure at your expected travel speed.
These columns can be used to work out a nozzle’s travel speed range. If a nozzle can be operated between 30 and 90 psi, for example, the corresponding speeds are listed in the same rows in the volume column.
For example, say you want to apply seven gpa and think that 13 mph would be a good average travel speed.
Fig 6: Five solutions for the question, “which nozzle to apply 7 gpa at 13 mph?”
Move down the seven gpa column, and you’ll encounter a value close to 13 mph five times – the yellow nozzle at 90 psi, the lilac nozzle at 60 psi, the blue nozzle at 40 psi, the dark red at 30 psi, and the red at about 25 psi. Now use the columns to see which of these three best matches your expected travel speed range.
The yellow nozzle would allow between seven and 12.5 mph from 30 and 90 psi, the lilac nozzle nine to 16 mph, the blue nozzle 11 to 19 mph, the dark red 13 to 22 mph, and the red 15 to 26 mph.
The best choice for a typical air-induced tip would be the lilac 025 size, since it would meet the target speed of 13 mph at a perfect 60 psi, about right for nozzles of that size, and allowing some travel speed flex on the slower side.
Some operators try to extend that range, but dropping below 30 psi will likely result in too narrow a pattern, or too coarse a spray quality, so it’s not advised.
Note that the three-fold change in pressure from 30 to 90 psi translates to only a 1.73-fold change in travel speed. That’s due to the square-root nature of the relationship, as illustrated by this formula:
This exercise applies to sprayers with rate controllers that adjust pressure to regulate flow rates. However, if you use pulse-width modulation (e.g. Case AIM Command, Capstan Sharpshooter, Raven Hawkeye, or TeeJet DynaJet) check out this article describing these systems.
There are a number of apps and websites, usually developed by nozzle manufacturers, which provide similar answers. These are also very useful, and all of them rely on the same formulas used in our new, simplified table. You can go here to download a high resolution version, suitable for framing, in both US and metric units.
May 22, 2015