Course: Spraying advice | Last Updates: 12th October 2015
Getting your sprayer set-up right, by paying attention to detail, will improve efficacy, reduce drift, minimise wear and tear and bring yield advantages.
In this academy, we take you through the simple steps for success.
Draw bar level
Start by getting the draw bar level.
Most machinery is similar and will need to be adjusted using the bolts on the draw bar. Aim for a horizontal bar, using an even area of ground and a spirit level to check.
Mounted sprayers will need to be levelled up on the three-point linkage.
Keep all nozzles and filters maintained by replacing the whole set every year. Keeping a couple of new ones on the tractor allows you to replace them when needed.
With pliers, use the lugs to pull out the inner part of the nozzle for cleaning. An ultrasonic bath with soapy water is best for this job and can be purchased for around £20.
All nozzle bodies should be pointing downward.
Modern, high-tech nozzles have an in-built angle of incidence, to even up spray deposition or increase the amount of spray hitting the plant. As a result, they must be facing the right way.
To check, consult the nozzle recommendation card that comes with them at purchase.
Level up each side of the boom by adjusting the link on the boom break back with a spanner.
Stand back and assess both ends visually, to see if it is level.
Adjust by slackening the clamps each nozzle is attached to and rotate around so they are vertical.
Nozzles vertical in the X-axis
Walk along the length of the boom and gently twist each nozzle, making sure they are all vertical. This is especially important on older sprayers.
Nozzles in the Y-axis
Nozzles may face too far forwards or backwards, even on new sprayers.
Ensure each nozzle is aligned vertically. If not, adjust by slackening the clamps each nozzle is attached to and rotate them around, so that they are vertical.
Make sure all suspension joints are fully lubricated and that springs and shock absorbers are working correctly.
Listen out for the oil moving in the shock absorbers. Grease nipples should be cleaned before and after, to prevent any build-up of dirt.
Check the suspension is working by pushing the boom down 30cm. It should return to the same height, in a horizontal position, without oscillating up and down.
Check the tyre pressures, on both the tractor and the sprayer, against those in the manufacturer’s handbook.
Correct pressures are important for a smooth ride and boom stability, as tyres act as a spring and a shock absorber. If pressures are too high, traction will be reduced and surface irregularities will be amplified.
While the sprayer and tractor will require different pressures, always aim for the lowest pressures recommended for the load to be carried.
Tractor tyres should be facing the opposite way to the sprayer tyres, so that they clear mud as they are going forwards.
This means the sprayer wheels should be mounted so that the orientation of tyre lugs is the opposite to that of the tractor wheels.
To ensure that the boom is set at the correct height, attach cable ties marked with 5cm intervals to the end of the boom.
Cut to a suitable length – usually 50cm – and lower the boom to this height above the target.
Maximum pressure for leaks
Check for leaks by running the sprayer at 5 bar, walking around to look for any signs. This should be done in the yard or in the field, with a tank of water.
Calibration – forward speed
Measure out a run of 100m in the field, using canes to mark the ends.
With a stopwatch, start as soon as you drive over the first cane at full spraying speed, stopping it as you go over the second cane. Remember that with traditional fan jets, penetration will decrease as you go faster.
A simple calculation can then be carried out: km/h = 360 ÷ time to travel 100m.
Calibration – nozzle output
Modern nozzles are hard wearing and may well last several seasons.
However, gritty water and trace elements will take their toll, with nozzles becoming worn out within a few hundred hectares.
Keep some spare nozzles aside when fitting a new set and check nozzle output at least twice a year. Refer to the manufacturer's nozzle output chart to establish the expected flow rate.
Using a measuring cylinder, fill the tank with clean water and collect the output from each nozzle for 30 seconds. If they have previously been used, check their output against that of a new pair.
Where output is +/-4% of the average, nozzles are unacceptably worn and the complete set should be replaced. If they don’t look to be spraying well, change the set regardless of flow rate.
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