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23/06/15 Tougher recommendations from Adama and BASF on the use of metazachlor to protect water this autumn

At a meeting in London today, Adama and BASF announced more stringent recommendations for the autumn use of oilseed rape herbicides containing metazachlor.

As the pressure grows on water companies to tackle the issue of herbicides in drinking water, active substances like metazachlor are increasingly under the spotlight; along with others such as carbetamide, propyzamide and quinmerac.

Dealing with diffuse pollution is a challenge said Dr Dinah Hillier, Catchment Control Manager at Thames Water. “If the water companies cannot show progress in reducing pesticide concentrations in raw water, there will be further restrictions on their use. Water companies need the help of the farming community. We really don’t want these restrictions to happen, because farmers need these products; but farmers must start Thinking Water.”

The presence of pesticides in raw water threatens the UK’s chances of meeting the objectives of the Water Framework Directive (WFD), the EU legislation drawn up to protect all surface and ground waters.

Adding to Dr Hillier’s comments, Dr Jodie Rettino, Catchment Manager at Severn Trent Water said: “Methaldehyde is the primary concern, but concerns are growing about the autumn-applied oilseed rape herbicides. We have no effective treatment processes for metaldehyde and we struggle to remove quinmerac. At a cost, most other pesticides can effectively be removed when they are at low concentrations. However, when we have a number of pesticides at high concentrations over the autumn and winter they challenge our treatment processes.”

DEFRA and the Drinking Water Inspectorate (DWI) has to date looked at voluntary measures to deliver WFD compliance. It considers the regulatory approach as a last resort, understanding growers’ needs and the agronomic challenges they face. But the reality is we are still getting pesticides in water, so we will need to deliver some more positive results if we are to limit further product restrictions being enforced.

In response and as part of a wider European Metazachlor Stewardship Initiative, BASF and Adama have strengthened their autumn guidance for metazachlor use; their drive is focused on agronomic best practice and changing on-farm practices to maintain the long term availability of metazachlor.

“Oilseed rape is an important break crop in the arable rotation. It is especially important on heavy land where spring crop establishment can be difficult. The crop provides an opportunity to manage problem grass-weeds as part of an integrated approach using herbicides with different modes of action to those generally applied in cereals, and provides a good agronomic entry point for wheat in the rotation,” says Dr Paul Fogg, Senior Crop Team Leader at Adama.

Metazachlor can get into water via two main sources. The first is via farm yard sources during the handling, mixing and cleaning down processes. These sources can be significant but can be avoided by adopting good operator practice.

The second route for metazachlor to enter the water source is via field sources, such as surface run-off or via field drainage. Avoiding pollution via field sources represent a far greater challenge but can be minimised by “Thinking Agronomically”.

“We are reiterating the importance of following the advice issued by the Voluntary Initiative,” says Rob Gladwin, Head of Business Development and Sustainability, BASF. “Growers should aim to establish the crop early, ideally by the first week of September, and also to apply metazachlor early which is particularly important on drained soils where the risk of movement increases the later you go and limit metazachlor applications to 750g of active substance per hectare.

The guidance for autumn applications of metazachlor announced today is as follows:

Early establishment is key;

  • Dose - Maximum 750g metazachlor/ha;
    • Reducing the amount of active ingredient applied, reduces the risk of movement to water
  • Timing:
  • Where there are no field drains, there are no application timing restrictions;
  • Where fields are drained, including temporary drains, aim for 1st October, with a cut off of 15th October. Applications after the 1st October can be made as long as soil and seedbed conditions are good and drains are not flowing;
  • Drained fields in Drinking Water Safeguard Zones cut off 1st October, visit to establish if you have fields in a higher risk area.

The BASF and Adama advice applies to all their products containing metazachlor. It is recommended that it is also applied to other manufacturers’ metazachlor herbicides, as it is the active ingredient that is detected not the products. The two companies are collaborating under the Metazchlor Matters branding for the first time, the brand is aimed at capturing agronomists and growers attention, to raise awareness and as a call to action this autumn.


June 23, 2015

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