Arable News

  • Written by: Farmers Guide
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New stewardship initiative on the use of metazachlor to protect water

BASFand Makhteshim Agan UK (MAUK) are launching a new stewardshipinitiative in order to maintain the long term availability of oilseed rape herbicidemetazachlor. As part of this initiative, new joint measures have been developedand will be promoted ahead of the 2014 season.


Thepresence of pesticides in water threatens the UKs chances of meeting theobjectives of the Water Framework Directive (WFD), EU legislation drawn up toprotect all surface and ground waters across member states by aiming to ensuregood chemical and ecological status, say the companies. Several key pesticidesare at risk of being lost due to their presence in surface waters, particularlythose used to supply drinking water. These include the key slug killermetaldehyde and the important autumn oilseed rape herbicides, metazachlor,clopyralid, carbetamide and propyzamide.


Defrahas, to date, looked at voluntary measures to deliver WFD compliance, point outBASF and MAUK. It considers the regulatory approach as a last resort,understanding growers needs and the agronomic challenges they face, trying tobalance effective crop protection and environmental impact. But the reality is thatpesticides are still getting in water, so more positive results will have to bedelivered to limit further product restrictions being enforced.


Makhteshim-Agan technical lead, Paul Fogg.

Oilseedrape is the most profitable arable break crop and key in the arable rotation, saysMakhteshim-Agan technical lead, Paul Fogg. It is especially important on heavyland where spring crop establishment can be difficult. The crop provides anopportunity to manage problem grass weeds as part of an integrated approachusing herbicides with different modes of action to those generally applied incereals and provides a good agronomic entry point for wheat in the rotation.


Metazachlorforms the platform to herbicide programmes in rape, but increasing regulatorypressures due to an increase in the frequency and magnitude of detections inraw surface water supplies represent a real threat to the long-termavailability of products containing this active ingredient, he warns.


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


Thesecond route for metazachlor to enter the water source is via field sources,such as surface run-off or via field drainage. Avoiding pollution via fieldsources represents a far greater challenge but can be minimised by ThinkingAgronomically.


Theadvice issued by both companies to avoid metazachlor getting into water viarun-off is to follow current best practice guidelines i.e. the VoluntaryInitiative, says BASFs head of business development and sustainability, RobGladwin. The aim should be to establish the crop early, ideally by the firstweek of September.


Specialattention should be paid to the quality of the seedbed and underlyingstructure, with vegetated buffers established adjacent to all ditches and watercourses. The key is to try and maximise the soils infiltration capacity butclearly this will be affected by soil type, weather conditions and the soilmoisture deficit at or around crop establishment and application timing.


Drainedland represents its own unique set of challenges as the tools available tomitigate field losses are restricted to product substitution or a change to theapplication rate and timing. As for surface run-off, it is key that the crop isestablished early, as this gives the crop the best chance of establishing well.However more importantly is that generally early establishment meansmetazachlor will be applied at a less vulnerable time of year. Specific advicefor the 2014 season is to avoid use of metazachlor on drained land after theend of September.


Theseinitial agronomic recommendations form the basis for high yield potential,providing quick establishment, early removal of weed competition while reducingthe risk of metazachor moving to water.


Robexplains that this new advice will not be on product labels so it is notstatutory. But unless the advice is followed and metazachlor is kept out ofwater, its use could be severely restricted or even revoked. So we urgeagronomists and growers to abide by these new guidelines.


TheBASF and MAUK advice applies to all their metazachlor-containing products. Itis recommended that it is also applied to other manufacturers metazachlorherbicides, as it is the active ingredient that is detected not theproducts, they point out.


  • Written by: Farmers Guide
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