Exploring Regen Ag With An Evidence-Driven Approach

Ngāi Tahu Farming is designing a farm-scale trial that will transition an iwi-owned dairy block to regenerative agriculture principles and practices. This trial will see Ngāi Tahu Farming monitor and measure multiple variables, to build a data set of information that demonstrates the difference between its conventional and regenerative dairy systems. The farm-scale trial will build on a completed trial of regenerative practices on an iwi-owned 114-hectare dairy support block.

The design of the dairy system trial has also spurred discussion about te ao Māori and farming values within Ngāi Tahu. A new iwi consultancy group has been formed for the purpose of helping Ngāi Tahu shape the mātauranga Māori principles in the trial, and to help filter information coming out of the trial back to the iwi.

The decision to undertake these trials, applying a scientifically rigorous approach, was influenced by Ngāi Tahu Farming’s earlier collaboration on Farm Soil Health with the Next Generation Systems research programme, led by Dr Robyn Dynes, strategy lead and senior scientist at AgResearch, and funded by Our Land and Water.

Another important influence came from frequent consultation with Dr Gwen Grelet, senior scientist at Manaaki Whenua – Landcare Research, the lead author of an Our Land and Water co-funded white paper on regenerative agriculture in New Zealand.

Ngāi Tahu Farming has been exploring regenerative agriculture for 24 months, says Rhys Narbey, general manager of sustainability and assets at Ngāi Tahu Farming, triggered by a single sentence in the Farm Soil Health report summarising the Ngāi Tahu research collaboration: “All soils rated poorly in soil biological indicators, and may require action beyond standard practice to create an environment to enhance soil biology and the services they provide.”

“When you sum up the report, that one sentence meant the most,” says Mr Narbey. “That led us to exploring regenerative agriculture farming practices, and we have since implemented a trial on one of our support blocks.”

“All soils rated poorly in soil biological indicators, and may require action beyond standard practice to create an environment to enhance soil biology and the services they provide.”

Soil health dashboard

The lead author of the Farm Soil Health report was Dr Nicole Schon, AgResearch scientist, with co-author Ants Roberts, Ravensdown chief scientific officer. With the support of AgResearch communications staff, Dr Schon developed a ‘soil health dashboard’ illustration to help Ngāi Tahu clearly communicate the research results to iwi trustees, decision-makers, and marae communities.

“We used the illustrations and report to help get others on board” for the regenerative trials, says Mr Narbey. “It wasn’t a very hard sell. Our shareholders are really supportive of more holistic approaches.”

Ngāi Tahu Farming’s whenua has stony silt loam soils and a long history under pine plantation. The iwi entity joined the Next Generation Systems research programme with a goal to maintain the life-sustaining capacity of soils during the change from forestry (P.radiata) to dairy farming, and to build knowledge of baseline soil fertility and health to inform its long-term plans.

Our Land and Water’s holistic understanding of the agri-food and fibre system and its place within te ao Māori empowered the research team to address questions of importance to Ngāi Tahu Farming, and bring together the right team to assess baseline soil health and explore new ways to present findings.

The key finding of the research was that the conversion of pine forest to irrigated dairy pasture tended to improve soil health. The soil health score was highest at the sites that had been out of forestry the longest.

The research involved sampling from a chronosequence of five sites previously from Eyrewell Forest, north of the Waimakariri River near Christchurch, including a site still in forest and a site out of forestry for more than 10 years. Soil health was assessed in May 2019 against target ranges suitable for high-producing pasture agriculture. The closer to these targets, the better the soil health status.

The key finding of the research was that the conversion of pine forest to irrigated dairy pasture tended to improve soil health. The soil health score was highest at the sites that had been out of forestry the longest. However, even the site with the highest soil health score was poor in soil biological indicators, with the number of earthworms remaining low.

These results suggested opportunities to accelerate soil health improvement, such as understanding how regenerative agriculture might influence a faster increase in some aspects of soil health.

This finding has important implications for the Our Land and Water objective to maintain and improve the quality of the country’s land for future generations, because of the potential impact on soil health of increasing land use change to forestry. 

This article was prepared as an impact case study for MBIE as part of Our Land and Water's 2020–21 annual reporting requirement.

December 2021 update

For the past 12 months, Dr Schon and AgResearch colleagues have been developing a soil health study that builds on this research, with food producers Synlait Milk and Danone, and co-funded by the Ministry for Primary Industries (MPI) Sustainable Food & Fibre Futures Fund. The easily understood soil health dashboard illustration, developed by Next Generation Systems research, was important in developing this partnership, and will be integral in communicating progress to farmers through the project.

The five-year project includes ten farms located in Canterbury, Waikato and Otago, and will align on methodology being undertaken at the Ngāi Tahu Farming regenerative block.

More information:

• Next Generation Systems research
• Farm Soil Health: Assessment across a forestry to pasture chronosequence (report prepared for Ngai Tahu, February 2020)
• Farm Soil Health: Healthy soil, healthy plants, healthy people (visual summary, February 2020)