Comment: As public scrutiny of the use of agrichemicals in New Zealand increases, Phillipa Rawlinson discusses the upcoming EPA review of paraquat use on farms, and WorkSafe's proposed additional measures – and what these could mean for farmers.

There are legitimate concerns about the use of some chemicals that pose risks to human health and the environment. Paraquat is one of those chemicals.

On the basis of the risks to human health, the Environmental Protection Authority (EPA) has announced a reassessment of paraquat and paraquat-containing substances in New Zealand.

The review was triggered by the introduction of new information explaining that the current controls around the use of paraquat and paraquat-containing substances are no longer sustainable.

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Farmers will be interested to know that the EPA is proposing to restrict paraquat and paraquat-containing substances to agricultural uses only and reduce the application rate to 400g ai/ha per year.

The review is of interest as paraquat and paraquat-containing substances are applied to lucerne and clover seed crops.

Additional restrictions

WorkSafe, which does not believe the proposed controls go far enough, is proposing additional risk mitigation measures, including the requirement for human health monitoring, greater certification and licensing, closed systems for mixing, application and loading, and requiring users to prove they have considered other options.

Clover and lucerne

For growers of clover, paraquat and paraquat-containing substances are particularly important. The conditions of the contract to grow mean the crops will only be accepted by buyers if they reach 98-99 percent purity. This can only be achieved through the use of paraquat and paraquat-containing substances.

Lucerne is a perennial legume that provides quality feed for young cattle, sheep and deer, and is a vital tool for sheep, beef and deer farmers in dry areas because of its drought tolerance and ability to retain quality through the summer months when other pasture loses quality, thanks to its deep tap root system.

As our summers become warmer and drier, lucerne use may increase. In 2012, the estimated crop revenue from lucerne was $11.9 million and the total GDP output share was estimated to be $45.6 million.

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Weed control vital

For farmers, gaining good weed control is important in lucerne crops as the seed is expensive and weeds affect the palatability and feed value of that crop.

Paraquat and paraquat-containing substances are vital tools for controlling the weeds in lucerne crops.

They are applied mainly during the winter when the lucerne is dormant and are essential for the longevity of the crop and for maximising the production of high-quality feed.

Farmers are making significant efforts to amend their chemical use and if possible use 'softer' and more environmentally responsible chemistries.

But in the case of lucerne and clover seed crops, the alternative chemistries do not have the same efficacy as paraquat and paraquat-containing substances.

I encourage all farmers to read the EPA's proposals and make your voices heard. Visit www.epa.govt.nz/public-consultations/open-consultations/reassessment-of-paraquat for more information and to make a submission.

Submissions close at 5pm, Tuesday 30 April 2019.

- Philippa Rawlinson is Arable Industry Advisor for Federated Farmers.