As field drains start to run after recent rain, oilseed rape growers and spraying contractors are being encouraged to use decision support tools that help ensure effective weed control while minimising the risk of residual herbicides such as propyzamide and carbetamide being lost through drains.
Dow AgroSciences’ Andy Bailey acknowledged the importance of such products to prevent yield loss and the build-up of problem weeds such as blackgrass. However, best practice is to keep herbicides in the field for optimum effect, he said.
Decision support tools, allowing growers to check risk, include: Adama’s WaterAware app www.adama.com/uk/en/wateraware/, Dow AgroSciences’ postcode checker uk.dowagro.com/check-application-conditions-local-postcode/, and the AHDB soil monitoring tool: cereals.ahdb.org.uk/soilmonitor
Mr Bailey said: “We aim to be as practical as possible with our advice on applying propyzamide. The chances are that some drains are now running and won’t stop until April.
“If that’s the situation we suggest holding off spraying whenever significant rain is forecast which could wash herbicide down the soil profile.
“The longer the herbicide remains in the upper soil layers the less likely it is to find its way into the drains and the better the weed control will be.
“Unless we, as an industry, do more to protect our natural water resources, key pesticides may be restricted,” said Adama’s Kuldip Mudhar.
Typical of farmers following best practice guidelines is Lincolnshire farmer Ben Atkinson whose 2,750ha (6,875-acre) farm includes 570ha (1,425 acres) of oilseed rape.
“As farmers we’re all too aware of pesticide run-off. We carefully monitor soil moisture, drain flows and weather forecasts before any applications are made,” said Mr Atkinson.
“Obviously the environment is at the forefront of our minds, but also with pesticide resistance being a major problem there is no margin for error or failure. With financial margins also being squeezed we can’t afford to throw products down the drain.”