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The Importance of Good Application By Nick Swayne and Luke Bullock

For my first article since joining the Crop Management Partners team, we are going to look at the importance of good application.

Application technology for crop protection products has evolved tremendously in recent decades, allowing precision application to get the best performance from increasingly valuable products.

Sprayer technology has indeed played a huge role in this, with many of the newest sprayers offering a staggering number of gizmos and gadgets. But unfortunately, the latest machines often do not come without an equally staggering cost and an alarming depreciation rate.

Luckily, we can seek further improvement in the performance of our crop protection products through the careful (and cost effective) consideration of our droplet sizes.

Droplet size

The slightest manipulation of spray quality can enable us to produce a surprisingly large range of droplet sizes in different spray patterns and at different pressures. This produces spray which is best suited to different scenarios.  

Larger droplets in a coarser spray will decrease our risk of spray drift, but also opens the risk of potentially reducing our target coverage as larger droplets tend to bounce and runoff leaves. In awkward contrast, smaller droplets will improve our target coverage, but may reduce the ability of products to penetrate larger canopies and may increase the risk of drift.

Evidently, adjusting spray quality is not without its challenges. Thankfully, the careful consideration and selection of appropriate spray nozzles for an application allows us to master this fine art!

Nozzle Selection

Nozzle selection is often spoken about but is frequently overlooked. This oversight is increasingly likely when operators have many hectares to cover and much stress to contend with! The wet spring of 2023 may present this dreaded scenario for many. Luckily my colleague Nick Swayne has some valuable wisdom for us on nozzle selection:

Now that the weather has finally changed for the better, minds turn to the ever-increasing backlog of spraying jobs. With the workload stacking up, farmers might be tempted to try and improve work rates by reducing water rates and going with a larger nozzle size. However, it would be naïve to think that going down this route will not affect the efficacy of products and the coverage achieved. I have compiled below just a few of my favourite nozzle choices and the scenarios in which they might want to be used in.

Flat Fan- FF110-03

The classic Flat Fan has been a favourite among farmers for some time, with its fine droplet size best for applying herbicides to small targets. An example would be blackgrass sprays Cintac and Pacifica Plus. When trying to hit a potentially small 1 leaf blackgrass, a fine spray is preferable to improve coverage. The rule of 8 states that halving droplet sizes gives 8x the droplets, therefore improving coverage. Operators must be aware however of this nozzle’s tendency to produce drift.


BFS Air Bubble Jet- 03 Air Inclusion

The Air Bubble Jet would be my preferred nozzle of choice. Rated as a 3-star nozzle and possessing air-inclusion technology, it significantly reduces drift on windy days. With application rates varying from 20L/ha up to 905L/ha dependant on size this meets a lot of spraying criteria. This medium droplet nozzle allows for better penetration into thick crop canopies and works well being used for fungicide, plant growth regulator applications and some herbicide applications.

 3D Defy Angled Nozzle- 05

The Defy Angle Nozzle is my go-to nozzle of choice for applying all autumn and spring pre-emergence sprays as it produces fantastic coverage if nozzles are positioned alternating front and backwards. Possessing this alternation of nozzle direction is beneficial if seedbeds are cloddy, and conditions are challenging. I would recommend a 05-size nozzle as this allows water rates of 200L/ha at a reasonable pressure and speed, thus also improving coverage.

As Nick has kindly outlined, these are his preferred nozzles of choice for good reason, but we must consider the compatibility of these nozzles with our sprayer. For example, some spacings between nozzle points will be too great for some nozzle types, and some nozzles will not suit Pulse Width Modulation sprayers. The at times perplexing job of nozzle selection may not be the task for which even the most enthusiastic sprayer-operators are thankful for, but the time taken for selection and nozzle changing is certainly made up for in product performance.