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Pre-em Application

Pre-emergence applications can be high risk for drift due to bare soils that release stored heat causing air/spray to rise, and there being no crop to intercept spray. Small spray droplets are particularly susceptible to spray drift.

Product drift not only reduces efficacy but also risks contaminating ‘non target’ areas. Crop protection chemistry is already under significant political and public pressure so minimising residue detection through controlling drift is key to protecting products in the future.

There are four main areas to consider for drift reduction:

Watch the latest virtual tour of Barton Innovation Centre and see how to get the best results with your pre-em applications

TTI nozzles at work

Nozzles for best efficacy

Get the best from your pre-ems with 90% Drift Reduction Nozzle Technology.

Barton Black-grass Focus Site

Barton Black-grass Focus Site

3 year trial investigating the 3 key components of black-grass control

Get the best from your Pre-em Application

Application trials tour

See how application techniques can make a difference to your pre-emergence performance this season. Application specialist James Thomas guides you through results of revealing trials at the Syngenta Black-grass Innovation Centre near Cambridge, and the practical implications for your sprayer set up in the autumn.

Weather

The biggest influence on drift is the wind speed, ideal wind conditions are force 2 on the Beaufort scale. Higher speeds can cause spray to be carried away from its target. Avoid spraying in completely still conditions which could cause spray to hang in the air. Double the wind speed; double the drift.

Wind speed
Forward speed graph

Forward speed

Excessive speeds can lead to decreased boom stability and create turbulence behind the boom, which may lead to increased drift and reduced product efficacy. The optimum speed for applying pre-emergence herbicides in 2016 trials was below 12 kph, this delivered the best balance of work rate and efficacy.

Boom height

With a steady forward speed, the next step is to ensure correct boom height. In trials reducing the boom from 100cm above the crop to 50cm efficacy went up from 70% to 87% control. To aid stable and correct boom height ensure correct tyre pressure, grease the boom suspension, lubricate bushes and bearings and check wear, attach a Syngenta cable tie to the boom which guides 50cm boom height, set-up sensitivity of boom-levelling system for minimal drift.

Boom height plots
Nozzle choice graph

Nozzles

Coarse to extra coarse droplet size will reduce drift further. Current application work has shown strong performance from 90% drift reduction nozzles, proving drift reduction doesn’t have to compromise efficacy.

2018 recommended pre-emergence nozzles

NozzleWater volume (l/ha)Pressure (bar)Speed (kph)LERAP ratingDrift reduction ratingComments
3D nozzle
3D 83-062002.112*** Up to 1.0 bar (alternating fwd & bkw)N/AIdeal spray conditions ONLY. Low pressures under LERAP conditions
3D 83-052002.110N/AN/A
90% drift reducing nozzle
Teejet TTI110-052002.010*** Up to 7.0 bar90% up to 2.0 barTop recommendation for 90% drift reduction and good efficacy
Lechler ID120/031002.112*** Up to 8.0 bar90%Delivers 90% drift reduction at 100 l/ha

Ongoing trials work allows us to continually update our best application advice to fit with the changing agronomic and environmental landscape. The Syngenta 3D Nozzles still remain a class leading nozzle for efficacy against grassweeds, however their drift reduction operating pressures are low, therefore in sub optimal conditions, a drift reduction nozzle with higher operating pressures should be used. We have seen that Drift Reduction Nozzles can also offer the same level of controls as the 3D.

If using 3D Nozzles, it is important to choose a Nozzle with a larger orifice size which will allow you to apply higher water volumes with coarser droplet to minimise drift. 

In ever more challenging grass-weed conditions 200 l/ha has been shown to give better results, compared to 100 l/ha that had previously worked effectively.