As oilseed rape (OSR) growers turn their attention to weed control, the Voluntary Initiative is urging them to take steps to ensure herbicide active ingredients do not end up in drinking water catchment areas, putting their long-term use at risk.
Drinking Water Safeguard Zones are catchment areas that influence drinking water quality where action by water companies and the Environment Agency to address water contamination, is targeted.
Growers can check whether their land is in such a zone by visiting the WIYBY (what’s in your backyard) section of the Environment Agency website, said VI consultant, Patrick Goldsworthy.
“Every farmer needs to know whether they are in a Water Safeguard Zone. Check every year as boundaries change and you may be on the edge or the water company may designate a new zone.”
OSR herbicide active ingredients (AIs) under particular scrutiny by water companies are metazachlor, quinmerac, carbetamide and propyzamide. VI has recently fine-tuned its water protection advice sheets for these AIs to ensure they are consistent with best practice across the industry. They are available on its website www.voluntaryinitiative.org.uk
Key advice is to avoid applying herbicides if drains are flowing or likely to flow within seven days of application or if heavy rainfall is likely within 48 hours. With dry, cracked soils it is wise to delay application until soils are more moist, according to Mr Goldsworthy.
ADAMA has developed a WaterAware app which assimilates soil type and soil moisture deficit information as well as forecasted weather conditions, using a traffic light system to advise farmers and sprayer operators when it is safe or unsafe to make chemical or slug pellet applications.
Lincolnshire-based independent agronomist Sean Sparling said most metazachlor and quinmerac had been applied to OSR in his area. “We have an issue with weeds such as cranesbill and poppy. These are best controlled pre-em in these soil conditions.
“Where fields have been sub-soiled we’re not using metazachlor because of the risk of cut through but where fields have been drilled, metazachlor seems to be working with no signs of run off.”