There are three types of sprayers available; each with advantages and limitations of various situations.
- Fully mounted sprayers – maximum capacity is limited by available horsepower but this type of sprayer results in fewer sets of wheel marks than trailed sprayers. These machines are generally the best option for a smaller operator.
- Trailed sprayers – these are a way to access greater capacity than with a fully mounted machine.
- Self-propelled sprayers – these are really only an option where a large amount of spraying work is needed, for example spraying contractors.
One of the biggest opportunities to gain efficiency through sprayer use is the purchase of an appropriate capacity machine. The downtime spent travelling to and from a refill point, as well as time spent at the refill point, can incur substantial running cost.
Nozzles
Technology advances in spray nozzles in recent years have seen increasingly efficient components available. Nozzles determine, to a large degree, the effectiveness obtained from a spray and the amount of drift. With a larger selection of features available than in the past, choosing the right nozzle can be challenging. Nozzle selection should be based on the application goals, target plants or pests, the chemical to be used, environmental factors and sprayer capabilities.
Most arable farmers would have a need for at least three sets of nozzles:
- Smaller nozzles for small plants (up to growth stage 31 in cereals)
- Angled nozzles designed to hit the stem on taller plants (past growth stage 31 in cereals)
- Larger nozzles for larger plants.
Ideally a compromise can be found – a nozzle that will do most work a machine faces. This helps to avoid having to change nozzles frequently for different jobs.
When it is necessary to change nozzles, water should be run through to check for and clear any blockages.
Newer nozzles offer the ability to travel faster, reduce drift and apply a lower water rate. This ensures more coverage out of a tank.
Filtration
Filtration is an area where skimping on price and quality can cause subsequent problems. One option is to purchase a machine with a self-cleaning main filter, eliminating the need for filters in every jet. This saves labour from cleaning blockages on multiple jets.
Calibration
It is good practice to carry out an annual flow test on a sprayer because jets do wear out over time. This test is as simple as timing water running through a jet into a measuring jug to calculate the rate.
Flow kits
Most modern sprayers have a flow kit which will require at least a light bar GPS system to operate. It might be worth considering a more advanced GPS guidance system.
A rate variation flow meter works regardless of speed and stopping or starting, ensuring a consistent application rate.
A step beyond this is automatic boom section switching. This technology requires more advanced GPS guidance but paints the screen map of the paddock to show coverage, with no overlaps.
Combining automatic boom section switching with auto-steer and variable rate application is the top of the line in spray technology. This allows the operator to create an application map based on soil, plant or yield variation, and apply spray accordingly.
Safety
As a minimum, a tractor or sprayer cab should be fitted with a carbon filter which is changed annually.
All personal protective equipment should be used when dealing with chemicals, in accordance with the label directions.
Most modern sprayers have an induction hopper. This system has a vent to suck chemical into the main tank and allows the operator to measure chemical into the sprayer while keeping two feet firmly on the ground.
Wintering a sprayer
Drain completely from the machine’s lowest point to prevent liquid freezing in the sprayer. On some machines it is also advisable to drain the lowest point on each boom section when folded up.
Wrap pump to prevent frost damage – this is the most sensitive part of a sprayer
House in a fully enclosed shed.
