Propyzamide stewardship

Sprayer in OSR field

Oilseed rape is an integral part of the UK arable rotation, and a profitable break crop.

Renowned herbicides such as AstroKerb® and Kerb® Flo 500 contain propyzamide and are the cornerstones of many herbicide programmes.
They are key to controlling grassweeds, especially blackgrass and ryegrass in oilseed rape, and with no known resistance, propyzamide can help manage and reduce the burden of these weeds across the rotation. 

After a heavy rain event there is a risk of propyzamide attached to soil particles getting washed into surface water. Appropriate planning, management and adoption of stewardship practices must be followed to mitigate this risk.

Oilseed rape growers are urged to consider the actions they can take to protect watercourses. Field selection, tramline placement and buffer zones can all play an important role in effective risk mitigation.

In line with best practice guidance from the Voluntary Initiative, growers are advised to implement simple steps which will help ensure autumn and winter-applied products don’t reach watercourses. 

What can you do?

Follow best management practices


Aim to grow OSR on low-risk fields i.e. those that don’t slope to a watercourse, are less susceptible to run-off or further away from a water course.

Consider appropriate establishment, direction of working travel, soil type and topography. Lay out tramlines so that they do not provide a direct route for water to leave the field. Disturb the surface compaction in the tramlines if possible.

To reduce the risk of run-off (both water and sediment), that may contain pesticides, from reaching water courses, the VI guidelines recommend a 6m buffer along watercourses if possible. Wider buffers are advisable in particularly vulnerable areas.

Refer to the Environment Agency website “Drinking Water Protected Areas Safeguard Zones (SgZs)” to check if planned oilseed rape fields are in a Safeguard Zone. Consider not growing this crop if mitigation methods cannot be put in place and there is a high risk of herbicides moving into water.

Use pesticides only when necessary. Consider cultural methods (e.g. cultivations, drilling dates, crop monitoring). Use the right product for the job and at the right timing. Make sure you are utilising herbicides less likely to move to water where there is a risk.  Take every opportunity to mitigate the risk of pesticides getting into water. 

Take steps to stop propyzamide reaching water


Ensure at least 5 of the following are met before propyzamide application


1.  There is no risk of heavy rainfall within 48 hours of application.

2.  Field drains are not flowing and unlikely to flow within 7 days of application.

3.  Field slope is less than 5% (1m fall in 20m).

4.  The field is NOT bordered by a watercourse. 

5.  The field has at least a 6m vegetative buffer strip adjacent to water. 

6.  There are NO field drains. 

7.  The field has NOT been deep sub-soiled (below plough layer) or mole-drained within the preceding 6 months.

8.  The crop has been established with true minimum tillage working the top 4-6cm only or by direct drilling.

Best use of propyzamide



Consider stewardship principles when planting oilseed rape. Read more here.



OSR Herbicides? Think Water!” The VI is working with water companies and the farming and crop protection industry to raise awareness of the issue, improve practices and develop new tools that will support farmers in continuing their responsible use of these herbicides/

You can also download the propyzamide advice sheet from the Voluntary Initiative here.



Check if your location is a Drinking Water Protected Areas Safeguard Zones on the Environment Agency’s ‘Check Zones’ website.


The Kerb Weather Data tool is meant to be used as a guide to local weather conditions to aid growers and advisors in making local tactical decisions to optimise their Astrokerb® and Kerb® Flo 500 applications and thus their activity against blackgrass. Kerb Weather Data (KWD) is available from mid-October to 31 January each year. Find out more here.