Good sources of information on how agrochemicals should be applied are often found on the agrochemical label. You may still need to adjust your sprayer to the specific spraying conditions you choose for volume rate, driving speed, nozzles and spray pressure.
Often volume rate and driving speed are decided first – then the nozzle choice is limited to the possibilities within the accepted pressure range (normally 2 to 2.5 bar for conventional nozzles). This is easily found on the HARDI calibration disc or you can calculate the required nozzle flow and find the nozzles in a nozzle table.
Example: We want to apply 150 l/ha at 7 km/h
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Check driving speed:
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- Drive the measured distance (with a ½ filled tank) and measure the time.
- Calculate the speed:
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Measure 100 meters. It may be useful to have some ‘permanent’ markers that are located in a convenient place (in a field or field like conditions). From the table in the tractor you find the gear to achieve the speed you want at a given rpm.
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Examples of speed calculations
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Sec/100 m
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40
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46
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52
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56
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60
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64
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70
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76
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80
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Km/h
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9.0
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7.8
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6.9
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6.4
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6.0
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5.6
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5.1
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4.7
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4.5
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Select nozzle
To find the right nozzles use our calibration program
OR
Use the calibration disc or formula (nozzle spacing 50 cm):
Example: By aligning 150 l/ha and 7 km/h on the calibration disc the line in the "window" (l/ha) shows that we need a flow of 0.875 l/min.
Then a suitable combination of nozzle size and pressure can be found on the lower half of the calibration disc: ISO 025 at 2,3 bar (or ISO 02 at 3,6 bar).
If using the formula: (7 km/h x 150 l/ha)/1200 = 0.875 l/min
 .
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Nozzle and pressure to obtain 0,875 l/min can also be found in the nozzle catalogue
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Check liquid system
- Mount the chosen nozzles on the boom.
- Turn on the sprayer and spray at minimum 7 bar whilst you check the liquid system for any leakages.
- Check the agitation
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Check nozzle output
- Set the pressure.
- Adjust the pressure equalising valves
- Measure the nozzle output for one minute.
- Repeat this process - measuring at least 2 nozzles for every boom section.
- Calculate average nozzle output