Trials assess impact in field

Article taken from the Agronomist & Arable Farmer

This is one question being addressed in this year’s trials at Agrovista’s Stoughton and Maidwell sites, which will be open for demonstration in June.

While of academic interest, results from wind tunnels are not necessarily a reliable indication of how a nozzle will perform in the field; and comparisons in small plot trials bear little resemblance to how products are applied in the field.

Nozzle choice, settings and boom height are being investigated in the fully replicated application trials, using bespoke application machinery.

In addition we will be continuing to evaluate drift reducing technologies; as well as application aids which can improve the performance of products applied using drift reducing nozzles.

The work takes on increasing significance with the introduction of the use of drift reduction technology into the authorisation process for plant protection products (to protect surface water).  This means that for some products the label will specify the use of three star drift reduction technology as a statutory condition of use; with addition buffer zone restrictions where products are applied close to surface water.

In our trials in previous years we have seen that drift can have a significant impact on the performance of herbicides for black-grass control and on the performance of fungicides in winter wheat.  We have also seen that there can be a significant reduction in biological performance of herbicides for black-grass control and on the performance of fungicides in winter wheat.  We have also seen that there can be a significant reduction in biological performance and yield when products are applied with air inclusion nozzles with some products which claim to reduce drift.

A few examples of the importance of correct nozzle choice and value of application aids from previous years trials:  In the trial below 12 nozzle / boom height combinations were tested with a flufenacet based pre-emergence herbicide (the trial was oversprayed with a mesosulfuron based herbicide.

Final black-grass control ranged from 75 to 94% showing the importance of correct nozzle choice and boom height.  Adding Grounded as an application aid improved control by an average 10%.

Some drift-reducing adjuvants are very effective at reducing drift – for instance Companion Gold (commonly used with glyphosate) gives equivalent drift reduction to a three-star rated nozzle – as proven in the Silsoe LERAP nozzle test.