Calibration of your Field Sprayers using Shortcut Methods Pesticide Education Program Montana State University Extension

Calibration Benefits You! You will not under apply Maintains the Best Pest Control Will not over-apply Environmental and human safety risks No need to re-apply Effective use of time Save $$

Follow Along Using MSU Reference Materials Use the MontGuide titled “Calibrating Ground Sprayers Using Shortcut Methods Save time with the 5940 method 128th Acre Method Backpack Sprayers Boom Sprayers Shortcut for Broadjet Sprayers

Suggested Calibration Tools Stopwatch Measuring Tape Measuring Container Pencil and paper Source of fresh water

5940 Method can be used to Select Appropriate Nozzles Can get you close to your target GPA. Your product label often describes the proper GPA (gallons per acre) for your sprayer. example. 20 GPA is recommended Use the 5940 METHOD to find nozzle size

What is the 5940 method? GPA = Gallons Per Acre (product label) GPM = Gallons per Minute collected from a single nozzle (Make sure all nozzle are within a 10% range.) 5940 is a constant MPH = Field Speed W = 1) width between nozzles in inches or 2) width of a broadjet swath in inches.

Selecting the Appropriate Nozzle GPM = GPA * W * MPH / 5940 Let’s say you need to spray 20 GPA, you have 30” spaced nozzles, and you will drive 5 mph. GPM = 20 GPA * 30” * 5mph / 5940 0.505 or 0.5 GPM nozzles needed Purchase nozzles rated at 0.5 GPM!

Using 5940 to get an idea what your field speed should be Let’s say you need to spray 10 GPA, you have 24” spaced nozzles, and your nozzles deliver .2 gallons per minute. Speed = (GPM x 5940) / (GPA x W) Speed = 1188 / 240 Field speed = 4.95 miles per hour

Shortcut Method to Calibrating Backpack Sprayers

Backpack Sprayer (Calibrating GPA) 128th Acre Method Use water when calibrating Use same nozzles and filters as when spraying Measure an 18 ½ by 18 ½ ft area. Spray area with water and time how long it takes Constant speed and constant pressure Spray into container for same amount of time. Ounces = Gallons Per Acre Applied

Sample Scenario Using 128th Acre Scenario Takes 10 seconds to spray 128th Acre In 10 seconds you spray 10 ounces into a container. What is the GPA output? 10 GPA

SHORTCUT METHOD TO CALIBRATING BOOM SPRAYERS Find GPA? How?

Check nozzle spacing and height

Worn Spray Tips

Boom Level or Nozzle Angle Correct

Verify that all nozzles are equal

Due to problems with wear you must test uniformity of nozzles annually Check nozzle output for 1 minute and get average If each nozzles output is not greater or less than 10% off of average, all is well. How?

10% error level To find 10% Find your average…48 oz Move the decimal place one space to the left. 48. = 4.8 This is a 10% error Now add 4.8 to 48 for +10% Subtract 4.8 from 48 for -10% 10% Error range = 43.2 and 52.8 Any nozzle output between 43.2 and 52.8 is OK!

GPA for Boom Sprayer cont. Shortcut Method 1st – Determine Nozzle output is same. 2nd – Flag out Course Length based on your nozzle spacing 18” = 227’ course length 20” = 204’ course length 30” = 136’ course length 40” = 102’ course length Or 340 / spacing in feet 3rd - Drive course in gear and rpm you will use when spraying and time yourself. Repeat 2 – 3 times.

GPA for Boom Sprayer cont.. 4th - Collect liquid from 1 nozzle for this amount of time 5th - Ounces of liquid collected = GPA

Sample Scenario Boom Sprayer 18” wide nozzles, 6 nozzles What to do? Travel 227’ and time 30 seconds Measure amount delivered in that 30 seconds 15 ounces in 30 seconds 15 GPA

Broadjet Sprayers Determine Test Strip Distance: Divide your spray swath (ft) into 340.3 then multiply times 10. This is your test strip distance (example: 340.3 / 30 feet = 11.34 x 10 = 113.4 feet. Run test strip and time (it took 25 seconds to drive 113.4 ft). Collect your broadjet output (ounces) For the time it took to drive test strip (Collected 130 ounces in 25 seconds). Divide the amount collected in ounces by 10. This equals GPA.130 / 10 = 13 GPA

Sample Scenario - Broadjet 25’ wide swath, 1 Broadjet What to do? Travel 136’ and time 27 seconds Measure solution delivered in 27 seconds 200 ounces in 27 seconds What is the GPA? 20 GPA

Fine tune your GPA by adjusting: Speed Slower speed increases output Pressure Only slight adjustments Nozzle size Use 5940 to get you close Not meant for fine adjustments Nozzle spacing Often preset

You know GPA, now how much solution do you need? Acres * GPA = Volume in Tank 10 acres * 30 GPA = 300 Gallons

How much chemical do you need? Acres * product rate = Total Product Product Rate = 2 pints / Acre You will be spraying 10 acres 20 pints of product

Sample Questions You have an output of 20 GPA You need to spray 300 acres #1 - How much of a spray mixture will you need? 6000 gallons You need to apply 2 oz / acre of Warrior 1E. #2 - How much product do you put in tank? 600 oz of Warrior

Questions Continued #3 You have 20” nozzles and travel 204’ in 25 seconds. What next? -You collect 10 ounces in 25 sec. -What is your GPA? GPA = 10 GPA

Question continued You are trying to select a nozzle and it reads XR11004B. #4 What type of nozzle is this? Extended Range Flat Fan #5 What angle of spray mist is emitted from these nozzles? 110 degrees #6 How low can you hold this boom at this spray angle? 15 – 18” #7 How many gallons per minute does this nozzle emit at a standard pressure? .4 Gallons Per Minute (standard 40 PSI) #8 What material is this? Brass #9 What is the nozzle life of this nozzle? Poor

Questions? #10: What width and length would easily qualify for using the short cut 128th acre method for calibrating your backpack sprayer? 18 1/2 x 18 ½ feet

Making this even more easy with the ‘Calibration Assistant’. Contains the tools to make calibration easier. Can aid in testing output of nozzles Aids in determining output (GPA) for many types of equipment Conversion Page Instructions Determines product to add to tank acres you can cover

Aids in Testing Uniform Nozzle Flow Critical prior to assessing output of boom sprayers. Calibrations Assistant Makes the math easier, while walking applicators through the process.

Aids in Determining Output of Boom Sprayers

Aids in Determining Hand Sprayer output (GPA)

Aids in Determining Broadjet Sprayer Output

Aids in Determining the Output of your Rotary or Drop Spreaders

Includes a Spreadsheet to Aid in Conversions

Practical Tool Not meant for initial training purposes Important that applicators have a base understanding of calibration Not meant as a crutch which allow applicators in initial training to slack Support tool useful for Certified Applicators who have some base knowledge

Available from the MSU Distribution Center The Calibration Assistant CD $3.00 copy Distribution Center Communications & I.T. Po Box 172040 Bozeman, MT 59717 Tel: (406)994-3273 Fax: (406) 994-2050 Location: 115 Culbertson orderpubs@montana.edu

Questions