Good to the last droplet

Keys to calibrating your sprayer to get more bang for your buck

A miscalibrated sprayer is like a box of chocolates – you never know what you’re going to get. Maybe you’ll get proper coverage or maybe it’ll be lost to drift.

Accurate calibration is the only way to know how much chemical is being applied to your field. Even with the current use of electronics to monitor and control the application of crop protection products, a thorough sprayer calibration procedure is essential to ensure against misapplication. Failure to calibrate a sprayer can injure your crop, cause pollution and worst of all waste money.

“The sprayer itself needs to be operating as efficiently as possible,” says Bob Wolf, K-State extension application technology specialist. “Especially the first time out in the spring, you need to make sure your sprayer is all tuned up. That there are no leaks, the pump works properly, nothing is plugged and every component is functioning properly including electronics.” While that may cover the basics Wolf says there’s more to the calibration process.

“Take into account what kind of coverage the chemical will need and pick the right nozzle type to maximize it’s impact,” Wolf says. “Applicators need to consider what type of activity the chemical has, whether it needs contact area or if it will translocate through the plant, then calibrate for the system to best deliver the proper amount on the target.”

When it comes to selecting nozzles, there’s certainly a plethora of choices these days but no singular silver bullet says application technology research scientist with Syngenta, Dan Kidder. He finds nozzle manufacturer catalogs and the pesticide product labels very helpful in making this decision. “It’s tempting to try to make one set of nozzles work for all products by changing your sprayer pressure and ground speed,” Kidder says.  “But with the diversity of products typically used on today’s state-of-the-art farms this strategy will almost always result in less than optimum application of some of the products.  Less than optimum coverage requires higher product use rates and may cause unnecessary environmental loading.  It pays to invest in several sets of nozzles for your different products.  And better yet, install swivel style multiple nozzle bodies on your boom so you can change spray tips with just a flick-of-the-wrist.”

Some nozzles also produce a broader spectrum of droplet sizes, another important aspect of in terms of crop protection application. “Droplet size impacts coverage and droplet size impacts drift,” Wolf says. “Somewhere we have to find the happy medium because the common thought is smaller droplets means better coverage but we come against some things in the environment that prevent that. Smaller droplets will drift easier and some applicators overlook the evaporation concern. Especially in the Kansas and Nebraska areas that can have wind and dry conditions it’s definitely something to keep in mind.”

Efficient spraying- more for your money

Applying efficiency to your spraying routine
By Shelby Haag

When is comes to spraying, the chemical is only as effective as the application process itself. With a better knowledge of equipment and product, producers can increase spraying efficiency.

Robert Klein, University of Nebraska- Lincoln extension cropping systems specialist, has been offering producers advice through workshops, which include more than simply sprayer calibration. “Calibration is very important, but before we start spraying we take a pressure gage and check the pressure on the boom,” Klein said. “This is critical because often it’s found that there is not even pressure throughout the boom. If the pressure is not even across the boom, calibration is a waste of time.” Klein also recommends checking the pressure gage in the cab to determine if there is a difference, either high or lower in the boom.

Calibration of sprayers includes speed, spacing and nozzle flow rate. Robert Wolf, K-State extension application technology specialist, stresses the importance of setting up a sprayer properly. “Producers need to be actually putting out the amount of chemical that they think they are in order to get effective coverage,” Wolf said. “A lot of times a farmer or commercial applicator is going through the field and paying attention to the rate controller and may not have a good feel for what’s going on in the droplet situation.”

Spray nozzle tip selection is a topic producers should become familiar with. “It’s important to know where various nozzles should be used and what pressure it should be used with,” Klein said. “Different nozzle materials offer different advantages – brass, plastic, stainless steel – you really have to know what your purpose is and what type of droplets are desired.”

A concern is that the nozzles are not putting out the correct amount, or that there is a pattern problem and coverage might not happen as accurately as it should, Wolf said. That’s really a critical issue when you’re trying to get coverage on the targeted surface. “Some producers in Kansas are operating on the edge with low volume of application, and with lower volume of application the more risk you have because it’s smaller droplets and less material being put out,” Wolf said. “If it’s a hot, dry windy day the coverage lessens, and that is something to keep in mind.”

Wolf said it’s important to get the sprayer set up to deliver the right size of droplets. “Applicators are getting more and more focused on that because we are learning that certain types of weed targets are going to require different kinds of coverage and droplet size aspects than others, and the sprayer must be set up for it,” Wolf said. “That is going to require applicators to have a pretty good knowledge on the type of nozzle they are using.”

Klein and Wolf both exhibit a nozzle demonstration at their various spraying workshops and seminars. By using a spray table and strobe light to show the various particle sizes and nozzle types, producers are able to see side-by-side the advantages and disadvantages of each nozzle. “We try to illustrate what the different nozzle technologies will do through our demonstrations,” Klein said. “It gives the operator a visual picture of how the nozzle will perform and after seeing the difference producers understand why it’s so important.”

Chemical companies are starting to do more research to identify what droplet sizes might be in order for farmers to better set-up the sprayers, Wolf said. Also, nozzle manufactures are providing data to the farmers, that information can be used to select the right nozzle for the job. “Chemical labels are also starting to address the droplet size issue,” Wolf said. “The American Society of Agricultural and Biological Engineers has adopted a standard which the EPA is promoting and chemical companies are starting to use. That standard specifies a droplet size spectrum broken down into six categories; very fine, fine, medium, coarse, very coarse and extra coarse.”

Other technologies such as auto-steer and boom control provide opportunity for more efficient application. “Boom height control can be used to maintain a uniform height across the field,” Wolf said. “Boom swath control with GPS and a rate controller system keeps track of areas that are sprayed and not sprayed. The boom will turn on and off in segments so that applicators don’t double spray or miss spots.”

Wolf has noticed that more farmers in the Midwest are doing their own spraying than in previous years. “With the technology changing everyday and the newer nozzles it’s very important that we have the various programs through extension service to get information to applicators,” Wolf said. “From my experience producers are very interested in learning more about the topic, they will come to the meetings and ask good questions – this education something that’s needed.”