What we learned

  • One size does not fit all - tailored solutions necessary
  • Small reductions can be made.
  • Understanding your starting position makes a difference. 
  • Some mitigations increased emissions. 
  • Good farm data is important. 
  • Accurate modelling is key.

Why we did this study

Dairy farmers are increasingly being asked to take a closer look at their environmental footprint and to make changes where they can make reductions. This isn’t just coming through in regulation but in community and consumer expectation too. We know farmers want to make improvements but often don’t know where to start.

The Partnership Farms research is part of the Dairy Action for Climate Change commitment by DairyNZ to support dairy farmers as they work to address on-farm methane and nitrous emissions long-term. The project modelled options into how participating dairy farms might reduce both nitrogen loss and greenhouse gas emissions.

New Zealand is already the most emissions efficient producer of dairy milk in the world but it’s important we continue to reduce our emissions to remain the best. Maintaining that world-leading status will require all of us to do what we can – no matter how small the change maybe it all adds up.

For a better understanding of how changes to reduce greenhouse gas (GHG) emissions and nitrogen (N) leaching may impact a farm’s profitability and productivity DairyNZ created the Greenhouse Gas Partnership Farm Project. The results of the project provide insights into the outcomes of different options.

About the study

The project established 12 partnership farms across New Zealand in 2018 and initially modelled 44 different farm systems options. The farms were based in Waikato, Bay of Plenty, Southland, Canterbury and Manawatu.

Case studies on six of the farms were developed to demonstrate potential options for farmers to reduce emissions and nitrogen loss, while exploring the effect on profitability. These six farms were selected to ensure representative and robust farm system data and modelling.

For each of the case study farms, changes to the system have been modelled in Overseer and Farmax to estimate the reduction in N leached, changes in GHG and profit.

What we learned

  1. One size does not fit all. Packages of mitigations need to be farm specific. Opportunities are currently available on some farms to improve both profit and reduce emissions through good management practices, however there is not a ‘one-size-fits-all’ package of mitigations that every farmer can use.
  2. Small reductions can be made. There is high correlation between reducing nitrogen loss and emissions, this mainly focuses on reducing N surplus. Lower N surplus will reduce feed imported/harvested, which reduces methane. Options to reduce methane are closely related to total dry matter intake. Small incremental environmental gains in emissions and nutrient loss can be achieved and are still important for long-term progress.
  3. Understanding your starting position makes a difference. Depending on the farm and how efficient it is at the start, determines the mitigation options available and their cost. Some farms have an opportunity to reduce environmental losses and improve profitability by a meaningful amount through farm system change. We also found that other farms don’t have this opportunity as they are already very efficient.
  4. Some mitigations increased emissions. Some mitigations resulted in conflicting environmental outcomes. This was mainly around infrastructure where reduced N loss, through less time spent on paddock, could lead to increased emissions from increased supplement intake.
  5. Good farm data is important. A good understanding of the farm, the people involved, and the farm system, is important at the start of the process. Modelling farm system options for reducing both N loss and GHG emissions is complex and requires a high level of information about the farm to accurately represent the farm system.
  6. Accurate modelling is key. A deep understanding of how to model environmental mitigations and the effect on the farm system, production, and profitability is needed. Training of rural professionals to provide consistent guidance, information, and modelling is a critical component to ensure accuracy for any farmer looking to make changes.

How to use this information

In these case studies you may be able to see farms similar to your own whether that be location or farming system. Although each farm is unique, you will be able to see the implications of different actions.

This may help you as you consider steps to reduce your footprint on-farm.

Next steps

Next steps for the partner farms include:

  • following their journey of implementation
  • demonstration days
  • updating modelling for the 2021 financial year.

Case study farms

The case study farms below demonstrate potential options for reducing emissions and nitrogen loss, while exploring the effect on profitability.

AB Lime, Southland

Options tested: effluent use, feed-pad use, timing of culls, reducing nitrogen fertiliser, planting native plants.

Download full case study

Flemington Farm, Canterbury

Options tested: reducing N fertiliser use, cropping area, and young stock replacement and use of low N supplements.

Download full case study

Owl Farm, Waikato

Options tested: de-intensification, and intensification while investing in infrastructure.

Download full case study

Tait Family Trust, Canterbury

Options tested: move to more pasture-based system, and infrastructure investment.

Download full case study

Tokoroa Pastoral, Waikato

Options tested: reducing replacement rate, reduced imported supplement.

Download full case study

Willsden Farm, Canterbury

Options tested: soil monitoring for irrigation, removing nitrogen applications, culling early, and increasing effluent area.

Page last updated:

1 Sep 2023