# Calibration using the Test Strip Method (Long Hand) Cecil Tharp Pesticide Education Program Montana State University Extension.

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Calibration using the Test Strip Method (Long Hand) Cecil Tharp 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 Pesticide Application Equipment  Pre-calibration  Testing Nozzles  Calibrating Output  Proper Tank Mixing

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

Goal: To verify the output of your sprayer. This depends on:  Speed  Pressure  Type of nozzle

Pre-calibration  Verify your Speed Make a test strip to verify MPH Distance (feet) x 60 Time (seconds) x 88* Distance (feet) x 60 Time (seconds) x 88* It takes 1 minute to travel 88 feet How many mph does that equal? 1 MPH

Calibrating your Backpack Sprayer using Long Hand Methods #1 Measure a test strip area and flag  Area = Length x Width  (example: 15 ft by 15 ft area.  225 square feet) #2 Convert test strip to acres  Acres = Area in Square Feet / 43,560  (example: 225 / 43,560 ft = 0.00516 acres

Calibrating your Backpack Sprayer using Long Hand Methods #3 Spray test strip area with water and time how long it takes (example: 40 seconds)  Take 3 assessments  Constant speed and constant pressure #4 Collect in a container for same amount of time. same amount of time.  Example: 40 seconds in 1 container =.1 gallons

Now Determine GPA! #5 Determine GPA  GPA = Gallons Applied in Test Strip / Test Strip Acres  Example: 19.38 gallons =.1 gallon / 0.00516 acres #6 Output = 19.38 Gallons Per Acre

Sample Scenario – Find GPA for Backpack Sprayer #1 Measure out an area that is 14 x 14 ft. How many square feet is that? 196 square feet #2 How many acres is that? 196/43,560 = 0.004 acre  then what? #3 Spray and time. Sprayed area in 65 seconds. Then what? #4 Sprayed into container for 65 seconds  Get 0.2 Gallons  then what #5 Convert to GPA! GPA = Gallons in Test Strip / Test Strip Acres  Example: 50 GPA =.2 gallon / 0.004 acres

CALIBRATING BOOM SPRAYERS CALIBRATING BOOM SPRAYERS Find GPA? How?

Check nozzle spacing and height

Boom Level or Nozzle Angle Correct

Worn Spray Tips

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   Nozzle outputs between 43.2 and 52.8 is OK!

GPA for Boom Sprayer 1.Determine Nozzle Output is the same. 2.Establish Spray Strip Dimensions -Nozzle spacing (ft) x Test Strip Distance -Example: Nozzle spacing is 3 ft; test strip is 200 ft 3.Convert to Acres -Square feet in test strip / 43,560 = Acres -Example: 600 / 43,560 = 0.0137 acres. 4.Spray the test strip while measuring time. -Spray in gear and rpm you will use when spraying -Example: 27 seconds to spray the 0.0137 acre test strip.

GPA for Boom Sprayer – cont. 5. Collect and measure liquid from 1 nozzle example. collected 1.1 gal from nozzle in 27 seconds. 6. Determine GPA -GPA = Gallons Applied to Test Strip / Test Strip Acres -Example: 1.1 gallon / 0.0137 acres 80.29 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

Speed effects output!

Spray Pressure for adjusting GPA  Increasing spray pressure raises the flow rate  You would need to increase pressure by 4 times to double flow rate  Increasing spray pressure decreases droplet size  This causes drift  Less than 30 psi generally considered low drift  Read your nozzle specifications on pressure  Only small adjustments in pressure are recommended for altering output.

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 6000 gallons You need to apply 2 oz / acre of Warrior 1E. #2 - How much product do you put in that same tank? 600 oz of Warrior 600 oz of Warrior

Questions Continued #3 You have a 2 ft wide nozzle spacing and travel 204’ in 25 seconds. - How many square feet is this strip? Length x Width = 408 square feet -How many acres is this strip? square feet / 43,560 = 0.0093 acres

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