Unraveling the Mysteries Of Sprayer Calibration

Sprayer Calibration Herbicides powerful toolsHerbicides powerful tools –Accurate application essential Many modern herbicides applied at low ratesMany modern herbicides applied at low rates –Ounces of product per acre »Liquid or dry weight Under- or over-application problematicUnder- or over-application problematic –Poor weed control –Excessive collateral damage Proper sprayer calibration key to applying an appropriate doseProper sprayer calibration key to applying an appropriate dose

Sprayer Calibration Factors that influence sprayer output:Factors that influence sprayer output: –Nozzle flow rate Orifice size of nozzleOrifice size of nozzle PressurePressure –Ground speed All other things remaining constant, output decreases as ground speed increasesAll other things remaining constant, output decreases as ground speed increases –Effective spray width Boom widthBoom width Number of nozzlesNumber of nozzles

Sprayer Calibration Calibration methods:Calibration methods: –Spray known area with water Determine amount water usedDetermine amount water used –Calculate rate per acre –Stationary method with water Determine output of each nozzleDetermine output of each nozzle –Should be within 5% of one another »Replace worn nozzles!!! –Calculate average nozzle output/minute Measure boom widthMeasure boom width Determine ground speedDetermine ground speed Calculate rate per acreCalculate rate per acre –Either of these will provide the sprayer output Still need to calculate how many acres will be covered by a tankStill need to calculate how many acres will be covered by a tank And how much herbicide to add for an appropriate rateAnd how much herbicide to add for an appropriate rate

Internet Option –Calculator Calibration calculatorCalibration calculator –Application rate »GPM per nozzle »MPH of sprayer »Nozzle spacing

Sprayer Calibration Backpack Sprayer mathless calibration (BASF):Backpack Sprayer mathless calibration (BASF): 1.Measure 18.5 by 18.5 ft (1/128 th acre; 1 fl oz = 1/128 th gallon) 2.Carefully spray and measure time taken to cover area in seconds 3.Spray into a calibrated bucket for that number of seconds and measure the volume in oz 4.The number of oz collected equals the gallons per acre sprayer output Still must determine area covered by one tank to determine how much herbicide to add to sprayerStill must determine area covered by one tank to determine how much herbicide to add to sprayer

Sprayer Calibration Dimensional analysis:Dimensional analysis: –Multiplication of knowns with unity values Unity values = 1Unity values = 1 –12 inches per foot –5,280 feet per mile –43,560 square feet per acre –128 fluid ounces per gallon –3,756 milliliters per gallon Add unity values to create a series of factors with associated “units” such that all units cancel out during multiplication leaving only the units desiredAdd unity values to create a series of factors with associated “units” such that all units cancel out during multiplication leaving only the units desired

Dimensional Analysis Example:Example: –A car travels 55 feet per second; How fast is it traveling in miles per hour?How fast is it traveling in miles per hour?

Dimensional Analysis Example:Example: –A car travels 55 feet per second; How fast is it traveling in miles per hour?How fast is it traveling in miles per hour? Known value: 55 ft sec

Dimensional Analysis Example:Example: –A car travels 55 feet per second; How fast is it traveling in miles per hour?How fast is it traveling in miles per hour? Known value: 55 ft sec 60 sec min Unity value:

Dimensional Analysis Example:Example: –A car travels 55 feet per second; How fast is it traveling in miles per hour?How fast is it traveling in miles per hour? Known value: 55 ft sec 60 sec min Unity value: 60 min hr Unity value:

Dimensional Analysis Example:Example: –A car travels 55 feet per second; How fast is it traveling in miles per hour?How fast is it traveling in miles per hour? known value: 55 ft sec 60 sec min unity value: 60 min hr unity value: mi 5,280 ft unity value:

Dimensional Analysis Example:Example: –A car travels 55 feet per second; How fast is it traveling in miles per hour?How fast is it traveling in miles per hour? known value: 55 ft sec 60 sec min unity value: 60 min hr unity value: mi 5,280 ft = 37.5 mi hr unity value:

Sprayer Calibration Known Area Method Single nozzle sprayer:Single nozzle sprayer: –Measure out 100 square feet; 10 ft by 10 ft10 ft by 10 ft –Measuring in a weed patch beneficial –Fill sprayer about half full, but exact volume known; –Pump up sprayer and spray marked area just like would spray weeds; –Measure amount of water used; Amount used to spray 100 sq ftAmount used to spray 100 sq ft Can calculate rate per acre and then percentage of an acre sprayer will treatCan calculate rate per acre and then percentage of an acre sprayer will treat

Sprayer Calibration Example Known Area Method 15 fl oz per 100 ft 2 : 15 fl oz 100 ft 2 43,560 ft 2 A gallon 128 fl oz =

Sprayer Calibration Example Known Area Method 15 fl oz per 100 ft 2 : 15 fl oz 100 ft 2 43,560 ft 2 A gallon 128 fl oz = 51 gal A

Sprayer Calibration Example Known Area Method 15 fl oz per 100 ft 2 : 15 fl oz 100 ft 2 43,560 ft 2 A gallon 128 fl oz = 51 gal A What part of an acre will a 3 gal capacity sprayer cover? A 51 gal 3 gal tank =

Sprayer Calibration Example Known Area Method 15 fl oz per 100 ft 2 : 15 fl oz 100 ft 2 43,560 ft 2 A gallon 128 fl oz = 51 gal A What part of an acre will a 3 gal capacity sprayer cover? A 51 gal 3 gal tank = A tank

Sprayer Calibration Example Known Area Method 15 fl oz per 100 ft 2 : 15 fl oz 100 ft 2 43,560 ft 2 A gallon 128 fl oz = 51 gal A What part of an acre will a 3 gal capacity sprayer cover? A 51 gal 3 gal tank = A tank How much herbicide to add if rate is 1 qt per acre? A tank 1 qt A 946 ml qt =

Sprayer Calibration Example Known Area Method 15 fl oz per 100 ft 2 : 15 fl oz 100 ft 2 43,560 ft 2 A gallon 128 fl oz = 51 gal A What part of an acre will a 3 gal capacity sprayer cover? A 51 gal 3 gal tank = A tank How much herbicide to add if rate is 1 qt per acre? A tank 1 qt A 946 ml qt = 56 ml tank

Sprayer Calibration Another stationary method:Another stationary method: 1.Measure boom width in feet or inches 2.Measure total nozzle output per minute Divide by 128 to determine GPMDivide by 128 to determine GPM 3.GPA = 5940 x GPM/MPH x nozzle spacing (5940 spacing inches; 495 spacing feet) Still must determine how many acres per tank and how much herbicide to add

Colorado State University Weed Science Weed Science