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Learn how to calibrate your orchard sprayer step-by-step to ensure accurate spraying. Includes methods for flow-rate measurement, adjusting spray volume, and more.
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START Spray Orchard sprayer calibration CHECK sprayer and mend Measure tractor SPEED Measure FLOW-RATE Calculate SPRAY VOLUME Use water only when calibrating the sprayer Adjust SPRAY VOLUME if required Adjust sprayer to the CROP Prepare TANK-MIX Picture source: Syngenta
Estacas Poles Measuring jug 2 L Measuring tape 20-50 m Stopwatch Calculator Nozzle brush Logbook Knife Water sensitive paper & stapler Orchard sprayer calibration Calibration Materials Hoses 30 cm (as many as calibrated nozzles) Flagging-tape Roll measure 2-3 m
Orchard sprayer calibration Before calibration CHECK sprayer and mend • Tank size (maximum volume of spray mixture) _______L • Hoses in good conditions • Nozzles • Symmetrical on left and right sides • All the same size • All the same type • Clean nozzles and filters
Orchard sprayer calibration Before calibration Check with water (fill half tank with clean water) • Start sprayer pump and run tractor throttle at 540 rpm (PTO) • Open valve to fill tubing and start spraying • Clean nozzles (filters) producing distorted patterns • Closed nozzles shall not drip • Replace damaged nozzles • Check and fix • Leaks • Valves working properly • Agitation working • Read pressure at pressure gauge bar (kg/cm2)
Poles Measuring tape 20-50 m logbook Stopwach Calculator Orchard sprayer calibration Measure the tractor speed Mark a test strip of e.g. 100 m Fill tank about half with water Set tractor speed (gear, throttle at 540 rpm on PTO) as for spraying Reach selected speed and engine rpm before entering the test strip. Maintain constant speed and record time to travel 100 m Measure time: _____ sec. (example: 45 sec.) Calculate tractor speed = Distance 100 m Conversion Factor 3.6 X 5.0 km/h Time measured 72 sec.
Orchard sprayer calibration Calibrate the flow-rate • There are two methods to determine the nozzles flow-rate: • Precise method: Measurement of individual nozzle output during 1 min. • Good estimation: Measurement of tank volume sprayed during 5 min.
Notebook Stopwatch Calculator Orchard sprayer calibration Measurement of individual nozzle output during 1 min. Measuring jug 2 L Hoses 30 cm (as many as nozzles to be calibrated) If required fix hoses on nozzles with clamps or O-rings For uniform flow rate, variability between the nozzles should be < +/- 5% from the average flow rate Nozzles differing > +/- 5% should be cleaned or replaced and flow rates checked again Choose same engine rpm as used in speed measurement Open valve(s) to start spraying Collect the water from each nozzle (via hose on nozzle) during 1 minute in a measuring jug Record the water output from each nozzle Calculate the average flow-rate per nozzle (L/min)
Orchard sprayer calibration Measurement of tank volume sprayed during 5 min. Step 1-3: do not change the position of the sprayer! Fill the spray tank with water up to a clearly defined level, e.g. the top level (including pump, etc.) Leave tractor running throughout the calibration process Spray for 5 min.; pressure and engine rpm settings as for spraying Measure the volume to refill the sprayer to the defined level Calculate the flow-rate per nozzle Refilled amount 80 L 1.6 L/min per nozzle = Spraying time in minutes 5 min Open nozzles 10 pieces X
Spray Volume per ha Orchard sprayer calibration Calculate the Spray Volume (L/ha) Row width Flow-rate 1.6 L/min Factor 600 Open nozzles 10 pieces X X 480 L/ha = Row width 4 m Tractor speed 5.0 km/h X
Orchard sprayer calibration Recommended spray volumes (L/ha) If the calculated spray volume is within the recommended range of spray volumes, continue with ‘Adjustment of the sprayer to the crop’ crop width Recommended spray volumes Follow pesticide label information Indicative spray volume for tractor mist blower: 200-1,000 L/ha Avoid run-off There are models which take the row width and crop height, but also the crop width into consideration Crop height row width
Orchard sprayer calibration How to adjust spray volumes (L/ha) • Change nozzle size (large adjustment): • For large adjustments, change nozzle size (check nozzle manufacturers catalogue) • See calculation next slides • Adapt tractor speed (medium adjustment): • Application volumes can be adjusted by altering the tractor speed. • See calculation next slides • Adapt spray pressure (small adjustment): • Small adjustments in flow rate can be made by adjusting the pressure • See calculation next slides
Orchard sprayer calibration Change nozzle size (large adjustment) Calculate the required flow-rate per nozzle based on the calibrated tractor speed and targeted spray volume Select appropriate nozzle size / colour, e.g. GREY for 2.0 L/min. Measured Measured Targeted spray volume Required flow-rate X X = Speed 5.0 km/h Row Width 4 m Spray Volume 600 L/ha 2.0 L/min per nozzle Factor 600 X Open nozzles 10 pieces km/h – L/min Counted
Orchard sprayer calibration Adapt tractor speed (medium adjustment) Slower speeds increase the spray volume (L/ha) and faster speeds reduce it (prerequisite : the distance between the crop rows is the same) Present spray volume 480 L/ha Present tracor speed 5.0 km/h X New tractor speed 4.0 km/h = Targeted spray volume 600 L/ha
Orchard sprayer calibration Adapt spray pressure (small adjustment) Always stay within the optimal pressure range of nozzles. Changes in pressure can change the droplet size and may cause drift or run-off. Optimal pressure range Flat fan and hollow cone nozzles: 5-10 bar (kg/cm2) Air-injector (Anti-drift, ID nozzles: 10-14 bar (kg/cm2) 2 Targeted spray volume 600 L/ha New Pressure 6.25 bar Present pressure 5 bar x = Present spray volume 480 L/ha
Orchard sprayer calibration Adjustment of blower performance to the crop Blower performance (m3/h) and tractor speed need to be adapted to the orchard in such a way that the spray mist just leaves the back of the trees Blower performance too high: bad collection of spray by leaves/fruits, drift Blower performance too low: spray deposit in the inner part of the trees insufficient
Orchard sprayer calibration Calculation of blower performance Air displacement required to fill the tree rows m3/h during spraying (see picture) Example Row width 4 m Height of leaf wall 3 m x Tractor speed 5 km/h Factor 1,000 20,000 m3/h x x = Air displacement factor 3 Row width • Air displacement factors • tree crown large: 2 • tree crown normal: 3 • tree crown narrow: 4 Height of leaf wall m3/h
Poles Orchard sprayer calibration Adjustments of air stream to the crop Roll measure 2-3 m • Prepare two poles, at least 50 cm higher than the crop • Place poles in rows and fix flagging tapes at 4 levels: • 50 cm above crop • At top of crop • At bottom of crop • 50 cm below crop • Place flagging tapes at upper and lower baffle • Adjust the air-flow with baffles so that the tapes on the top and bottom of the crop are moving, and the ones 50 cm above and below the crop do not move Flagging-tape above crop: should not move Top of crop: movement Bottom of crop: movement Below crop: should not move
Orchard sprayer calibration Dynamic spray-pattern and distribution test Water sensitive paper & stapler Staple water-sensitive paper onto a wooden lath and place the lath vertically in the crop rows Water sensitive papers can also be stapled on leaves within the crop Adapt nozzle setting if required, e.g. close top and/or bottom nozzles
Orchard sprayer calibration Calculation of how much pesticide to add to the spray tank
Prepare tank mix Calculation of how much pesticide to add to the spray tank There are three possibilities how the product dose is indicated on the pesticide label: • Label indication: Use xxx L/ha or g/ha • Label indication: Use xxx L or g /100 L water in a specific spray volume, e.g. 1,000 L of water /ha • Label indication: Use xxx L or g /10,000 m2 ‘Leaf Wall Area’ per ha ground area
Prepare tank mix Label indication: Use xxx L/ha or g/ha Example: Pesticide label indication: use 3 L/ha product Sprayer tank content: 800 L of water; the calibrated spray volume of the sprayer is 480 L/ha With 800 L of water 1.67 ha can be treated (800 L / 480 L/ha = 1.67 ha) Product needed in the tank is: 3 L /ha product x 1.67 ha = 5.0 L Pesticide label Measured Product in tank Label indication (product per ha) 3 L / ha X Volume of water in spray tank 800 L 5 L product = Spray volume per ha 480 L /ha Calibrated
Prepare tank mix Label indication: Use xxx L or g /100 L water in a specific spray volume, e.g. 1,000 L of water /ha) Example: Pesticide label indication: use 300 g/100 L of water ..... Use spray volume of 1,000 L/ha Sprayer tank content: 800 L of water; calibrated spray volume per ha 480 L/ha If 1,000 L /ha are used then 300 g x 8= 2,400 g of product must be added to the tank If 480 L/ha are applied then the concentration needs to be 2.08 times higher, i.e. 1,000 L/ha / 480 L/ha = 2.08). (This because the same amount per cm² needs to be on leaves / fruits independent whether 480 L/ha or 1000 L/ha are applied). Product in sprayer tank = 2400g x 2.08 = 5,000 g = 5 Kg Pesticide label Measured Product in tank Pesticide label Use rate 300 g/100 L Spray volume information 1000 L/ha Volume of water in spray tank 800 L X X 5,000 g product = Conversion Factor 100 Spray volume per ha 480 L /ha Calibrated
Prepare tank mix Label indication: Use xxx L or g /10,000 m2 Leaf Wall Area (LWA) The LWA for a specific orchard is calculated as follows: Measured crop (foliage) height Ground area 10,000 m2 Height of leaf wall 3 m Represents row length per ha ground area Both sides of leaf wall: Factor 2 LWA 15,000 m2 x x = Row width 4 m Example: Pesticide label indication: use 3 L product per 10,000 m2 LWA (LWA per ha ground area) When the LWA for our specific orchard is 15,000 m2, then 15,000 m2 / 10,000 m2 = 1.5 times more product is needed, i.e. 3 L x 1.5 = 4.5 L for 15,000 m2 LWA Sprayer tank content: 800 L of water; the calibrated spray volume of the sprayer is 480 L/ha (ground area) With 800 L of water 1.67 ha can be treated (800 L / 480 L/ha = 1.67 ha) Product needed in the tank is: 4.5 L /ha product x 1.67 ha = 7.50 L