Why target-zone rate changes the WEED-IT nozzle decision
Comparison
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Machine: Older trailed WEED-IT with one nozzle firing in isolation
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Nozzle height: 60 cm
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Nozzle spacing: 20 cm
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Travel speed: 16 km/h
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Operating pressure: 3 bar
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Target zone: Central 25 cm beneath the activated nozzle
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EF4003: Generic even fan delivering 1.20 L/min, calculated using a uniform-pattern assumption
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EF4003 spray width: 43.7 cm
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EF4003 target-zone rate: 103 L/ha—equal to its calculated spray-width rate
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CFLD-XC4002: Tapered fan delivering 0.80 L/min, with 80% of its output measured inside the central 25 cm
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CFLD-XC4002 target-zone rate: 96 L/ha
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CFLD-XC4002 spray-width rate: 69 L/ha
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Target-zone difference: The XC4002 is approximately 7% lower
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Total water use: The XC4002 uses 33% less
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Overlapping rate: Reduced from 225 L/ha to 150 L/ha when neighbouring nozzles activate
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Label context: Both target-zone rates are close to 100 L/ha. The EF4003’s calculated spray-width rate is 103 L/ha, while the XC4002’s is 69 L/ha. Always check the applicable product label and actual operating configuration.
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Not claimed: Identical spray deposit, biological efficacy or permission to reduce the labelled chemical dose
When selecting a nozzle for an optical spot sprayer, the important comparison is not simply nozzle size or the blanket rate created when every nozzle overlaps.
The useful figure is the carrier rate each nozzle places in the target zone that caused it to activate.
For an older trailed WEED-IT operating at 60 cm nozzle height, 20 cm spacing, 16 km/h and 3 bar, we compared:
- A generic EF4003 even fan
- An ARAG CFLD-XC4002 tapered fan
- A central target zone 25 cm wide
The result
The calculated target-zone rates are:
- EF4003: 103 L/ha
- CFLD-XC4002: 96 L/ha
An XC4002 puts within 7% of the EF4003’s target-zone rate on a third less water. Both sit around the 100 L/ha label rate, and the 7% gap is inside normal field calibration.
However, it achieves that result using substantially less total water.
Why the smaller nozzle works
The EF4003 spreads 1.20 L/min relatively evenly across a spray footprint approximately 43.7 cm wide.
The XC4002 delivers only 0.80 L/min, but its tapered pattern concentrates more of that output beneath the centre of the nozzle. Patternator measurements show approximately 80% of its output within the central 25 cm target zone at 60 cm height and 3 bar.
That concentration allows the smaller XC4002 to maintain a similar average carrier rate where a correctly centred weed should be detected.
The practical benefits
Compared with the EF4003 in this example, the CFLD-XC4002 provides:
- Approximately 33% less total water use
- Approximately 50% more potential nozzle-on operating time per tank, assuming a similar activation pattern
- Approximately 69% less flow outside the central target zone
- A 33% lower overlapping rate when neighbouring nozzles activate
- A spray-width rate of 69 L/ha rather than 103 L/ha
The potential increase in hectares per tank comes from the difference in nozzle flow. A nozzle using 0.80 L/min can operate for 50% longer on the same tank than one using 1.20 L/min.
Actual paddock hectares will still depend on weed density, target size, nozzle activation time and field conditions.
Pattern placement still matters
The XC4002 produces a tapered distribution. Its rate is strongest through the middle of the target zone and lower near the edges.
That makes accurate weed detection, firing timing, nozzle height and boom stability important. When the weed is correctly positioned beneath the centre of the nozzle, the tapered pattern concentrates carrier where it is most useful.
If weeds are regularly positioned near the edge of the strip, the flatter distribution of an even fan may be more forgiving.
The practical conclusion
The XC4002 does not create a dramatically higher average target-zone rate than the EF4003.
Its advantage is that it delivers a similar spot rate with:
- A smaller total flow
- Less water outside the target zone
- Lower rates when neighbouring nozzles overlap
- Greater potential operating time from each tank
That is the real reason a smaller tapered nozzle can be a better choice for an older WEED-IT.
Check your own machine
Nozzle height, pressure, speed, spacing and target-zone width all affect the result.
Run your own comparison in SpraySpotter
Read the complete calculation and technical explanation on The Nozzleista
These figures describe carrier-water distribution under the stated operating conditions. They do not guarantee identical biological performance or authorise a reduction in chemical dose.
Always calibrate your sprayer and apply agricultural chemicals strictly in accordance with the registered product label and your actual operating configuration.
Fantastic Nozzles supplies ARAG nozzles, and SpraySpotter was developed by Dave Young. This commercial connection is disclosed so readers can assess the comparison with that knowledge.
