Tackling N-Loss Targets

‘Let’s keep the momentum going’ was the theme for a field day hosted at Pencarrow Farm in early December. Presenters balanced acknowledging current action, which is proven to reduce nitrogen (N) losses, with new and emerging science targeting further reductions.

Collaboration across the sector is evident and remains a critical part of collective action to manage N. Acton Farmers Irrigation, Ashburton Lyndhurst Irrigation, Barhill Chertsey Irrigation, DairyNZ, Enviro Collective, Fonterra, MHV Water, Mid Canterbury Catchment Collective, and Rangitata South Irrigation all had input to ensure the day was both thought provoking and practical.

So, where are we at?

Extensive community-led water monitoring programmes are in place across multiple catchments to collect valuable data, which helps inform catchment-scale decisions. An estimated 30-year lag time reminds everyone this is an intergenerational challenge, and what we do today determines the quality of our waterways for generations to come.

In spite of the ever-changing regulatory landscape and divisive media commentary over the years, farmer ownership of the water quality challenges in Mid Canterbury has helped to develop a solution-focused mindset.  

Farm owner’s Andy and Trish Macfarlane, along with contract milkers Brad and Viana Fallaver, shared information about Pencarrow’s journey over time to increase productivity while reducing N losses. Andy reinforced to the audience that “we can all do something, and collectively we will get a better result when we just get on with it. Plantain research shows a roughly 20% reduction in N losses to groundwater, so is there for the taking.”

Nutrient loss requirements vary between the Ashburton and Hekeao Hinds Plains zone, however the key message for both zones is to continue improving on farm practices to minimise nutrient losses below the root zone.

DairyNZ shared results to date from the Low N Systems research programme that is investigating how combining various mitigation options can help farmers to significantly reduce N losses, while also meeting their farm business viability goals. This programme is researching 40-60% reductions in N losses across the combined milking platform and support land. It’s seeking practical, economical solutions to support farmers to further lower their N environmental footprint, delivering additional positive implications for ground and surface water quality.

In conjunction with Fonterra, the programme is developing a bulk milk urea indicator tool. This will provide timely on-farm information to assess the herd’s dietary protein status and indicate potential farm management opportunities to improve N use efficiency and manage N loss risk.

Presenters also covered the latest research from the Plantain Potency and Practice programme.  Led by DairyNZ, the programme focuses on using the forage herb plantain (Ecotain®) to significantly reduce N losses to freshwater and reduce greenhouse gas emissions. Research has shown plantain's potential as a cost-effective tool for N-loss mitigation. This includes an average 26% reduction in N leaching over three seasons (2022-2024) at Lincoln University Research Dairy Farm, in ryegrass / clover pastures containing an average of 17% plantain.

By working together and embracing proven practices like plantain, farmers can lead the way in mitigating N losses, while keeping their businesses strong.

Angela Cushnie is the Mid Canterbury Catchment Collective coordinator