Partnership farm trials show GHG possibilities

OWL farm manager Louise Cook.

The first of 12 farms across New Zealand to take part in an 18-month project, to understand how changes on-farm to reduce greenhouse gas emissions may impact a farm’s profitability and productivity, has released its results.

And DairyNZ chief executive Tim Mackle says one clear message from the work is every farm is different “and there isn’t a ‘one-size-fits-all’ package of changes that every farmer can use”.

“But they can learn from these case studies to compare against their own farm and see what might be possible,” says Tim.

“The other clear message is to measure, or estimate, biological greenhouse gas emissions – to know your numbers – as that is the first step to knowing how to manage them.”

New Zealand’s ruminant animals’ methane emissions make a substantial contribution to total NZ greenhouse gases emissions and the global warming that our emissions have contributed to so far, according to DairyNZ.

Most methane is emitted when cattle burp. Nitrous Oxide (N2O) is emitted from soil when urine, faeces and fertilisers are broken down by microbes in the soil.

Tim says the Partnership Farm Project’s aim was to model and apply practical measures to see how to adapt NZ’s highly efficient pastoral farm systems to meet the country’s climate change goals.

“The outcome of this project is important to helping us understand the impact of making improvements or changes to how a farm operates in order to reduce emissions and nitrogen leaching.”

The project farms model 44 different farm systems. The Owl demonstration farm in Cambridge released its results in late-March – the first farm to do so.

Tim says farmers who took part in this project are now looking closely at the changes that have been recommended to them to decide whether they implement these on-farm.

On Owl farm, one change involved reducing feed use and lowering the stocking rate. This is expected to result in a 21 per cent increase in profitability, a 14 per cent reduction in nitrogen leaching and 13 per cent reduction in GHG emissions.

Mitigations modelled on the partnership farms fell into three categories: farm management changes, infrastructure investment, and retiring or planting land. When selecting a package of mitigations suitable for each farm, options from all three may be chosen together.

“The results of this project, and the huge amount of data we are still compiling, reinforce the complexity of the challenge we face as a sector,” says Tim. “Mitigation options vary depending on the farm system and the region. To see nationwide reductions in GHG emissions we need a specifically designed package of changes for each farm.

“This is why DairyNZ is supportive of customised Farm Environment Plans, which recognise the differences between each farm and factor in a holistic systems approach to recognise efforts across GHGs, water quality, biodiversity, and financial sustainability.”

Tim says it will be critical the Government supports adequate training and capability of rural professionals as part of a low emissions transition plan.

“Expert advice must be available to help farmers understand what improvements or changes they could make to the way they run their farms that will make the biggest difference to their total emissions. It will take years to build up to that level of capacity.

“We’re also hopeful that as the use of Overseer spreads, more farmers will be increasingly aware of their current emission levels, which can provide useful benchmarks for improvements.

“What this work in the partnership project highlights is largescale reductions will rely on the development of a new workable technological solution well in advance of 2050.

“We’re aiming for a slow-release inhibitor compatible with the NZ farming system to be developed by 2050, and this could achieve a 30 per cent reduction in methane. We must continue our investment in research and development to pursue that option or our ability to cut emissions will be limited.

“Leading efforts for our sector to reduce our greenhouse gases is part of our Dairy Tomorrow sector strategy. Above all, Dairy Tomorrow takes a holistic approach which means managing GHG emissions is part of a broader set of challenges including water quality, people, animal care, and critically, ensuring we have profitability and resilient farming systems that underpin our ability to resolve these challenges.”


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