Future Farming Systems Trial

A Future Farm Systems trial being carried out on a research farm in Northland is giving farmers nationwide a taste of options for farming in a changing climate. Comparison of three farmlets examined alternatives to ryegrass, which is failing in the increasingly wet and warm Northland climate. This study of farm systems also tracked the productivity of a Low Emissions Greenhouse Gas Farm. The profitability of each farmlet varied, partly dependent on payout in a particular season. 

The Northland Agricultural Research Farm (NARF) is located just north of Dargaville, on the west coast of Tai Tokerau Northland, and is celebrating 100 years of community ownership and pastoral research in 2024. The 84ha farm is run as a commercial dairy farm by a dedicated group of volunteers who manage the farm business and staff. The Northland Dairy Development Trust, established in 2007, designs and oversees the trials on the farm.  

The farm has been split into three 27ha farmlets for the Future Farm Systems trial, with individual milk vats dedicated to each farmlet. The scale and flexibility of the trial means it can provide robust data for measuring and comparing differences in milk production and composition, pasture effects and relative profitability of the different feeding regimes. 

The farm committee meets fortnightly to discuss and set farm management under the oversight of the NDDT Science Manager, Chris Boom. This makes the research farm somewhat unique, in that farmers make the management decisions and run the farm within science protocols. “There are no technicians running the farm here. This is why we get good engagement from the Northland farming community,” Boom says. 

Farm Committee chairman Kerry Chestnut says the key to successful research is to make sure it addresses farmer concerns and is relevant to “as many of us as possible”. 

The current Future Farm Systems trial was set up in 2021 in response to farmer concerns about the impact of climate change on pasture performance. 

And there is growing interest outside of Northland in these pastoral productivity trials, including in Waikato and Bay of Plenty, where the effects of climate change are also being felt. Climate change can no longer be considered just a Northland issue, Chestnut says. 

The farm is split into three identical areas sown with three different sward mixes: Italian ryegrass and kikuyu (known as Current Farm) which represents the existing standard mix for most dairy farms in Northland; one farmlet with at least 75% alternative pastures including cocksfoot and tall fescue (Alternative Farm) and a low emissions property growing ryegrass and kikuyu (Low Emissions Farm). 

The different herds remain on their own farm paddocks. For example, as mapped, the Alternative Pastures herd stays on ‘Blue Paddocks’ and milk into their own vat all season. This allows trial managers to capture whole farm system data and effects. Fonterra also takes regular milk samples to measure composition changes resulting from different diets.  It also means system profits can be compared and cumulative effects measured over several years. 

Chestnut says the Alternative Pastures farm has been set up in response to climate change impacts, and to farmers looking for alternatives other than ryegrass, which is failing.  

“The farm system allows us to learn the different management required when the alternatives make up 75% of the farm, as compared to just a few paddocks.” 

The Low Emissions farmlet was designed to meet 2050 GHG emissions targets as indicated by central government. This farm has standard kikuyu/ryegrass pastures but carries a lower stocking rate and does not use any N fertiliser, in order to meet the targets of 25% lower methane and 50% lower nitrous oxide emissions than the Current Farm. 

 Boom says a drier summer in the first year of the trial helped the kikuyu-based systems, while the wetter summer in Year 2 boosted the Alternative Pastures Farm. Milk production on the lower emissions farm was higher in the second season, probably because pasture had more clover and was better grazed. Lower milk prices and higher input costs in the second season also affected profitability across the farms. 

On the Low Emissions Farm, removing all N fertiliser triggered a significant and rapid increase in clover content. “This was surprising and was a key driver of milk production on this farm. This should give farmers confidence about cutting back N fertiliser in the future,” Boom says. 

Clover was the key to pasture quality on the Low Emissions block. Here, clover content was 30 to 50% of the pasture for most of the second season. This was a key contributor to increased milk production per cow on the farm. 

As might be expected, the Low Emissions Farm produces the lowest greenhouse gas (GHG) per kilogram of milksolids. Using the OverseerFM model to calculate GHG emissions, the trial found significant reductions in GHG compared to the Current Farm. 

It was a surprise to see the calculated CO2 emissions/kg product was also lower on the Low Emissions Farm, despite it having a 25% reduction in milk production, compared to existing kikuyu/ryegrass pasture. This impact on efficiency is thought to be mostly down to the lower farm inputs (N and supplements) and relatively high milk production per cow. This trend was evident across the first two seasons of the trial. 

Comparing relative profitability, using actual milk price for each price, the Low Emissions Farm was less profitable in the first year, but this reversed in the second year in the face of a lower milk price and higher N and supplement costs. 

In early 2023 the trial had a major hiccup with Cyclone Gabrielle, forcing the suspension of the trial for 10 weeks. The big wet flooded about 90% of the Alternative Pastures farm and most of the paddocks were under water for 3-5 days. All temperate grasses died, including ryegrass, fescue and cocksfoot, herbs, and clovers. 

In contrast, kikuyu plants recovered rapidly showing excellent flood resilience. Areas of long or silted pasture were mown and removed by baling or mulching. Kikuyu regrowth provided good quality leafy feed for the herd throughout the autumn. 

About 60% of the Alternative Pastures farm was re-sown back into tall fescue and cocksfoot-based pastures during March and April, while all kikuyu was mulched and under-sown with Italian ryegrass, as it would normally. 

The results presented for the 2022/23 season are actual results until 14 February, then estimated numbers based on modelling the remainder of the season (assuming actual rainfall without the impact of flooding). The trial began again on 1 May 2023. The re-sown pastures appear to have established well, partly because of the low presence of poa, a weedy annual meadow grass. 

Boom says as the trial nears the end of a 3rd season, there is no clear advantage, or disadvantage, to replacing kikuyu/Italian ryegrass-based pastures with tall fescue/cocksfoot combinations. Reducing stocking rate and eliminating N to reduce GHG emissions resulted in a significant drop in farm profit in the first season. However, “it seems the system stabilised” in the second season. Several further seasons of study may be needed to draw firmer conclusions, Boom says.