Spray Technology – Sure-fire win #2

Last week I spoke to a group about some sure-fire wins that are guaranteed to improve your surfaces with little work. We spoke about measuring greens correctly in my last blog. The next quick win is nozzle technology.

As time has gone by nozzle technology has developed dramatically. Yet still I’m surprised at the number of flat fan nozzles that I see attached to sprayers when I visit courses.

I’ll admit it, as a course manager I placed very little thought into my nozzle choice. Yes I had different sets for different water volumes and they were all air induction (as I perceived my site to be windy with limited spray windows) and I invested heavily in what I perceived to be the best sprayer on the market. I just assumed that the actual delivery would be as good as all the over features on the machine. However, I didn’t think much further than that after all we’re all busy, aren’t we!

It would be really helpful if you could let us know what type of nozzles your using, and when you last changed them? Complete the quick poll at the end of this blog.

Today’s operators have to be more mindful than ever of the good spray stewardship, avoiding problems of waste and minimising risk to the environment but probably most importantly getting the best out of your product.

Nozzle mechanics – the droplet spectrum

All nozzles produce an array of droplet sizes; large nozzles tend to produce larger droplets with greater velocity and small nozzles create smaller droplets. In general, small droplets are well retained on the shiny leaves of turfgrass plants. However large solid droplets tend to bounce or roll off.

Small droplets with low velocity are far more susceptible to drift. With dense fine grass surfaces, such as a golf green, there is nowhere for the displaced air to go, so any fine spray particles with low velocity find it tough to reach the surface and high percentages are lost as drift.

Simply increasing droplet size is not the solution to overcome drift. When the drop size is doubled with a flat fan 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 for any given volume of water. 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 runoff and loss.

More recent 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.

Utilising this technology the Syngenta Turf XC Nozzles produce significantly more droplets per ml of spray liquid, compared to other AI or low-drift nozzles tested. This helps to ensure good coverage of the target leaf. Importantly, tests have shown the 04 XC foliar nozzle, produces less than 3% small sub 100 micron-sized droplets that are highly susceptible to drift, compared to 14% with a traditional flat fan nozzle helping to ensure you get more product to the target.

The extra velocity of the larger droplets means they are significantly less susceptible to drift. This can widen the spray window oppurtunities giving you a better chance of optimum timings for application again ensuring you get the best from your product.

The below picture shows conventional flat fan nozzles in the left hand section and XC Turf Nozzles in the right hand section of the boom.

Spray height sets pattern coverage

Nozzle height is a critical factor in achieving even coverage across the turf surface. On flat sports fields and stadia it is relatively straightforward and an even height can be constantly maintained.

However, on golf courses where slopes and undulations are integral to creating a challenge for players, the variation in nozzle height can have a profound impact on the spray pattern and consistent application.

Most nozzles are designed for optimum performance when operating at a height of 50cm above the target. The problem arises when a sprayer starts to go up a slope, the boom drops down and the nozzle height can drop to 30cm or less. When the sprayer reaches the top of a slope, the nozzle height may jump up to 70cm or more.

Testing trials with traditional flat fan nozzles at 30cm spraying height have consistently shown a difference in excess of 25% variation in spray volume across the boom. This has significant implications for product performance of fungicides and fertilisers. Even if you eliminate all other factors a 25% variation on it’s own could easily be the difference between success and failure.

To overcome this problem the Syngenta Turf XC Nozzles have been designed to give a far more consistent spray pattern if the nozzle height falls to 30cm or less.

The XC Nozzles give a spray overlap across three nozzle widths at a nozzle height of 50cm. But if the height is reduced to 30cm when encountering a slope, it will still maintain a far more consistent and even coverage – typically within two to five % difference across the full spray boom.

How old are your nozzles?

I’ve recently had the pleasure of spending time with some Nozzle design engineers (a career I had no ideas existed) and just 10 minutes into our conversation I realised how much work goes into designing and making these things. I then thought back to how often I used to change my nozzles and the amount of different product I would pump through them and then still expect them to perform. With the use of abrasive products and the regular spray operations now going on on golf courses I suggest more attention to nozzle technology would seriously help.

Please spend 20 seconds letting us know what nozzle technology you’re using.

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