Technical
The latest turf protection products are capable of achieving exceptional results. But it is the skills of the sprayer operator and developments in the technology he uses that can make the crucial difference between an acceptable level of control, and outstanding
performance in maintaining the high turf quality increasingly demanded by today's players.
By Tom Robinson, Syngenta Application Specialist
Nozzle Technology on Target The Art of
urf sprayer operators face a number of unique challenges to achieve accurate and consistent results, often whilst under the close appraisal of a critical audience among players - who are largely unaware and unappreciative of the efforts being made on their behalf. Understanding the fundamentals of the mechanics of spray application, recognising the targets to be hit and the need for effective timing are all key elements of the Art of Application. Furthermore, today’s operator has to be ever more mindful of the essential area of spray stewardship, avoiding problems of waste and minimising risk to the environment.
T
Nozzle mechanics - the droplet spectrum
All nozzles produce an array of droplet sizes; large nozzles tend to produce more large droplets with greater velocity, whilst small nozzles create more small droplets. In general, small droplets are well
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retained on the shiny leaves of turf grass plants, where large solid droplets tend to bounce or roll off. However, small droplets with low velocity are far more susceptible to drift. This problem is especially difficult when spraying fine turf surfaces. As the spray descends, it has to force the air below out of the way. In long grass rough, that is relatively easy and, in practice, the air movement effectively pulls the spray into the target. However, with a short cut fine grass surface, such as a golf green, there is nowhere for the displaced air to go, so any fine spray particles with low velocity find it very difficult to reach the surface and many are lost as drift. Fairways and sports turf surfaces are typically somewhere between the two extremes. However, simply increasing droplet size per se is not the solution to overcoming drift. For any given volume of water using a traditional flat fan nozzle, when the drop size doubles, the number of drops produced is reduced by a factor of eight,
and the coverage of a flat area or ground may be four times less. Also, using larger flat fan nozzles to produce larger water droplets tends to result in higher water volumes, which can lead to overwetting of the leaf surface and excessive product run-off and loss.
New nozzle technology has seen the advent of air induction (AI) nozzles, where every droplet contains a tiny bubble of air. As the spray passes through the nozzle, air is sucked in by venturi-effect and mixed with the spray liquid. Although the drops are larger, size for size, the air- cushion acts as a shock absorber when the droplets hit the leaf, which means they tend to be better retained on the leaf surface, compared to a large solid water drop.
The design of the new Syngenta Turf
XC Nozzles produces significantly more droplets per ml of spray liquid, compared to other AI nozzles tested. This helps to ensure good coverage of the target leaf. Importantly, tests have shown the 04 XC
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