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Field spray drift studies to mature winter cereal crops with modern application practices to inform policy on setting of buffer zones in the UK - PS2017

As part of the current review of unsprayed buffer zones and potential harmonisation with other EU member states, CSL and SSAU are involved with project PS2015. This is generating new datasets for the modern operating conditions of boom width, boom height and forward speed under field conditions. The initial data from PS2015 indicated levels of drift similar to those in the datasets generated in the Netherlands by van de Zande. Such levels of drift are greater those indicated by Rautman et al or from previous CSL field studies (1995-2001).
The datasets with PS2015 were generated with a short crop, therefore data are required to indicate spray drift from a taller crop such as winter cereals after ear emergence. A previous study by CSL (PA1728) indicated that drift from spraying of a mature cereal crop may be less than from spraying a short crop such as 15cm tall grass. However this was a limited dataset with a 12m boom at 8km/h forward speed. To be able to consider the effect of modern operating conditions on the levels of drift occurring in the UK, field studies need to be done with a tall crop, such as cereals. The data gap needs to be filled so that policy issues for setting of UBZ in the UK can be considered with adequate scientific knowledge. These data would not only provide supporting key information for aquatic risk assessments, but also for provide extra information for potential bystander exposure in conjunction with the BREAM project
The primary objective of the work will be to generate data for airborne and ground deposited spray drift arising from typical arable current spraying practices. Modern practices for arable spraying involve spraying with tractor forward speeds of >10k/h and boom heights of 0.5 to 1.0m above the crop with boom widths of 24m or greater. There is evidence to suggest that operators use boom heights of upto 0.7m above a tall crop, as there is less risk of boom damage during contact with the crop than when grounding the boom. CSL will discuss boom height settings with the arable farmers and contractors currently involved with a range of field studies with CSL and collaborators, and agree boom height settings with PSD.

The use of nozzles such the XR (extended range) is more widespread now and wind tunnel studies indicate that drift from the XR is greater than that from the standard flat fan nozzles (FF). Data from PS2015 confirms data from wind tunnel studies indicating that an increase of boom height and forward speed increases the amount of spray drift losses from the cropped area. Studies are therefore proposed with vehicle mounted boom sprayers operating in the range of conditions likely to be encountered in the UK for spraying of tall crops.

Tractor forward speed of 12 and 16 kph;
Boom heights of 0.5 and 0.7 above a tall crop (to be confirmed following grower feedback)
Boom width 24m (12m headland swath sprayed)
Nozzles - Standard flat fan nozzle used as reference nozzle for LERAP assessments (11003)
and XR11003 nozzle

In addition a treatment which involves the use of a fine spray quality (e.g. 11002) on the penultimate 12m swath will be used to determine drift from the application to the field which could be used in environmental risk assessments by adding together quantities of drift from the 12m pass with LERAP low drift nozzles with the adjacent pass with traditional flat fan nozzles. This drift will be collected at the same downwind distances (2-20m), but from the application made to the crop at the distances of 12-24m from the field boundary.

The proposed field studies would be done with tracers at sites where field studies are already planned with ongoing collaborative project PS2005 with Silsoe Spray Application Unit (SSAU) of The Arable Group (TAG) generating datasets for potential dermal bystander exposure.
There is a substantial cost saving to be made by carrying out the proposed studies to run concurrently with existing field trials. Time in the field can be optimised by generating extra data sets with the ongoing PS2005 (BREAM) project, which use the same operational settings (e.g. boom height, nozzle type, forward speed).
The protocol for the field studies would follow that used in PS2015, with a minimum of 3 replicates for each of the 12 operating condition would be generated.

The primary objective of the work will be to generate data for airborne and ground deposited spray drift arising from typical current spraying practices for mature cereal crops.

Specific objectives are:
1. Generate data for 2 nozzles types and 2 boom heights for ground deposited and airborne drift at distances up to 20m down wind of the treated area consisting of a mature wheat or barley crop.
2. Provide an evaluation of the data for use by PSD investigating the setting of buffer zones for the UK.
Project Documents
• FRP - Final Report : Field spray drift studies to mature winter cereal crops with modern application practices to inform policy on setting of buffer zones in the UK.   (475k)
Time-Scale and Cost
From: 2008

To: 2008

Cost: £24,673
Contractor / Funded Organisations
Central Science Laboratory
Arable Farming              
Environment and Health              
Environmental monitoring              
Environmental Protection              
Monitoring and evaluation              
Pesticide use              
Public Health              
Risk assessment and management              
Fields of Study
Pesticide Safety