The Voluntary Initiative (VI) has warned that the wet weather in December and January has left fields very wet and there is now a high risk that pesticide residues will reach drinking water.
Patrick Goldsworthy of the VI says: “Applying oilseed rape herbicides in the right weather and soil conditions is critical to reducing the risks to drinking water sources. Application only when there is no risk of heavy rain after spraying, and when drains are not flowing, is essential to reducing the risks to drinking water sources. Recent weather across the UK highlights the need for farmers to be vigilant and seek advice from their agronomist if they still need to control weeds in their rape crops.”
Oilseed rape herbicides often detected in drinking water sources are carbetamide, clopyralid, propyzamide, metazachlor and quinmerac. The latest date for propyzamide application is January 31st, and for carbetamide it is the end of February.
Jon Bellamy, a NIAB TAG agronomist, adds: “It was a relatively dry and exceptionally warm autumn in the south and many of my growers delayed their oilseed rape herbicide applications for blackgrass control until late November. I think they have got it about right. There’s been good weed control and the soil conditions, while still a bit warm, meant there was a much lower risk of the herbicides reaching water.
“While probably 90% of oilseed rape herbicides have been applied, there will still be a few growers needing to make their applications, especially as some products will be approaching their latest application date. My advice to them is to take note of the weather and soil conditions at application and do the best they can to reduce the risks to water.”
For advice on protecting water, see the VI’s water protection advice sheets available on its website at www.voluntaryinitiative.org.uk.