Transcript Calibration of Sugarcane Sprayers

Calibration of Sugarcane
Sprayers
Curtis Rainbolt, Ron Rice, and Les Baucum
University of Florida/IFAS
Calibration
• Mathematical determination of the amount of spray
solution (water) applied in gallons per acre (GPA)
• Insures that the appropriate amount of herbicide is
applied
• The GPA can be changed by adjusting one or more of
the following:
– Pressure
– Nozzle size
– Ground speed
– Spacing of nozzles on spray boom
• Pressure has least effect on spray volume but important
in maintaining proper spray pattern
• Pressure affects spray droplet size and drift
Why Calibrate?
• Proper calibration of sprayers will eliminate the over or
under application of herbicides
• Under application
– Poor weed control
– Need for reapplication
– Yield losses due to competition
• Over application
– Increased chance of crop injury (narrow margin for some
herbicides)
– Environmental pollution (off label application rates)
– Increased cost
Cost estimate for over or under application
Under application resulting in re-spray*
$30/acre x 100 acres
$30/acre x 1000 acres
$3,000
$30,000
*Does not include additional time/labor, fuel, and machinery expense
Over application by 10%
($30/acre x 10% ) x 100 acres
($30/acre x 10% ) x 1000 acres
($30/acre x 10% ) x 5000 acres
$300
$3,000
$150,000
Nebraska Calibration Survey
• Two of every three pesticide applicators were
making significant application errors
• These mistakes were costing farmers from $2 to
$15 per acre in added chemical expense,
potential crop damage, and threatened weed
competition
• 75% of applicators who calibrated more than
once per year were within 5% of target
• How would you compare?
Prior to Calibrating
• Inspect your spray equipment
– Check for leaks
– Look at nozzle spray patterns
– Replace all faulty nozzles
– Make sure screens are clean
• Determine if application is banded or
broadcast
Calibration Procedure
• Determine calibration
distance in feet from the
table using band width if
banding or nozzle
spacing for broadcast
applications
• To determine the
calibration distance for a
nozzle spacing not in the
table divide 4080 by the
nozzle spacing or band
width in inches
Nozzle spacing/
band width
(inches)
Required calibration distance
(ft)
12
340
18
227
20
204
24
170
36
113
48
85
Calibration (continued)
• Stake out the designated calibration
distance
– Do this in a field rather than a hard surface to
account for tire slippage that might occur
• With the sprayer in operation record
number of seconds it takes to travel
specified distance – repeat for accuracy
and record tractor used and gear and
throttle setting (RPM)
Calibration Procedure (continued)
• With tractor in neutral and the throttle setting
determined earlier, collect water from all nozzles
for band application or from 1 nozzle for
broadcast applications for the required number
of seconds
• The number of ounces collected equals gallons
per acre on a broadcast basis.
• Check delivery of all nozzles on spray boom and
replace if output is off by more than 10%
• Remember that total ounces may represent
delivery from more than one nozzle depending
on whether the herbicide is banded or
broadcast.
Calibration Procedure (continued)
• Ways to increase GPA
– Decrease speed
– Increase spray
pressure
– And/or use a larger
spray tip
To Calculate Treated Acres when Banding
• Divide band width (inches) by row
width (inches) and multiply by
total number of acres
• Asulox broadcast rate of 4 qt/A
– In a 20 acre field the row width is 60
inches and a 36 inch band will be
treated. Using the formula above the
number of treated acres is 12
– If Asulox is broadcasted, 4 qt will treat
one acre; if banded, 4 qt will treat
1.67 acres
– Remember – whether broadcasted or
banded the concentration of the
herbicide in the water is the same
and rate per treated acre is the same
Banded Calibration Example
• Asulox applied at a broadcast rate of 4 qt/A
• You are spraying a 36 inch band (3 nozzles) and the row
spacing is 60 inches
• If you collect 20 ounces from 3 nozzles/row for time it
took to travel 113 ft (36 inch band = 113 ft), then you are
applying 20 gallons per acre in the banded area
• A 200 gallon spray tank will treat 10 acres broadcast or
16.6 acres if the spray solution is banded.
• Asulox should be added at 40 qt (10 gallons) to 190
gallons of water.
• Remember the concentration of the herbicide in the
water is the same whether applied on a band or
broadcast.
Broadcast Example
• Aatrex is being applied broadcast using a boom
that has nozzles spaced 20 inches apart
• In the time it took you to travel 207 ft, you caught
15 ounces of water from a single nozzle. Thus
you are applying 15 GPA
• You have a 300 gallon tank, so you can treat 20
acres
• For a rate of 4 qts/acre you should add 80 qts
atrazine to 220 gallons of water.