Oilseed Rape Herbicides: Think Water! Planning 2020/21 season
There were significant challenges with establishment and crop management of oilseed rape crops in 2019/20, due to dry seedbeds and cabbage stem flea beetle.
It seems likely that the area grown for 2021 harvest season will decrease and, if this is the case on your farm, this may give more flexibility choosing which fields to grow OSR in for harvest 2021.
The Voluntary Initiative is working with water companies to help minimise the movement of oilseed rape herbicides – metazachlor, propyzamide, quinmerac, clopyralid and carbetamide to water this autumn. For this to be successful requires everyone to do their bit.
It is important to only use pesticides when necessary and there are a number of ways to reduce reliance on pesticides including cultivations, drilling dates, regular crop inspections among others.
Below are points to consider an integrated management approach to minimise the movement of these herbicides to water:
- FIELD SELECTION: Although dictated by rotation, aim to grow oilseed rape on a field that is lower risk i.e. doesn’t slope to a watercourse, is less susceptible to run-off or further away from a water course.
Fields that are high risk include those that have underdrainage or slope down to a watercourse. High risk fields might also include those that have problem levels of black-grass or other grass-weeds that require a programme of herbicides to maintain control.
- CULTIVATION AND TRAMLINES: Cultivation is a key factor in managing risk. Consider the appropriate cultivations, crop establishment and direction of working travel based on soil type and field topography to minimise the risk of pesticides attached to soil moving to water.
Lay out tramlines in order that they do not provide a direct route for water to leave the field e.g. enter the crop at the top of the field. Lifting tramlines will minimise soil compaction in the tramline and reduce runoff of soil.
If you have GPS guidance on your sprayer consider switching off tramlining kits when drilling OSR.
- BUFFERS: Buffer zones next to watercourses can be effective in reducing movement of soil particles that may contain pesticides reaching watercourses. A wider buffer zone is more effective. Cross compliance dictates a 2m minimal buffer zone, but the VI recommends establishment of a 6m buffer alongside watercourses if possible. Wider buffers are advisable in particularly vulnerable areas.
- CHECK DESIGNATIONS: Use the Environment Agency’s Drinking Water Safeguard Zones Website (http://bit.ly/EA_Farmers) to check whether planned oilseed rape fields are in a Drinking Water Safeguard Zone. Avoid growing rape in these areas if at all possible, if you might use herbicides likely to move to water, particularly in high risk fields.
- Why not try the VI’s Check It Out Tool to review and improve spraying practices and so reduce the risk of pesticides reaching water - http://checkitout.voluntaryinitiative.org.uk/tool/
- Talk to your BASIS-registered agronomist to make sure that where possible any herbicides you may use are less likely to move to water where there is a risk of this occurring. Aim to time herbicide application to minimise movement to water. As always, use the right product, at the right time and to best practice.
- Link here to the current campaign leaflet or click the logo on the right to go to the main OSR Herbicides: Think Water! webpage