In farmlet trials and on farms across the country, the grazing herb is demonstrating its value as an N loss reduction tool.
Inside Dairy
4 min read
Research shows Ecotain® plantain can help farmers reduce their environmental footprint by decreasing nitrogen losses without requiring major changes to their farm systems or management.
The Plantain Potency and Practice programme led by DairyNZ has measured an average reduction in nitrogen (N) leaching of 26% over four years at Massey University and 23% over two years at Lincoln University from ryegrass/clover based pastures with 20-30% plantain compared with standard ryegrass/clover pastures.
These results come from farmlet experiments at both universities, which are testing whether the positive outcomes seen in smallscale lysimeter studies also work on a full farm system. The research will increase understanding of how using the grazing herb plantain variety Ecotain® can help reduce N loss.
The programme (co-funded by the Ministry for Primary Industries through Sustainable Food and Fibre Futures) also collaborates with 20 farmers across New Zealand who integrate plantain into their farming systems in diverse ways (Figure 1).
Plantain is now recognised as an N leaching mitigation option by regional councils in Southland, Canterbury, Manawatū, Bay of Plenty and Waikato.
These farmers are working on ways to establish, maintain and manage plantain pastures. So far, they’ve achieved up to 20% plantain across their farms by sowing it in new pastures and broadcasting seeds into existing ones.
An independent review of the Plantain Potency and Practice programme concluded that “the scientific inquiry being undertaken is of a high standard and leading to strong evidence that supports the adoption of plantain as a tool to reduce nitrate leaching.”
The science director at Environment Canterbury (ECan), Tim Davie, welcomed the review’s findings.
“It’s encouraging to see the growing scientific evidence supporting plantain’s role in reducing nitrogen leaching. ECan acknowledges plantain as an effective tool to help farmers meet nutrient limits and reduce their environmental footprint.”
Plantain is now recognised as an N leaching mitigation option by regional councils in Southland, Canterbury, Manawatū, Bay of Plenty and Waikato, where N leaching limits are in place.
Stephanie Fraser from Bay of Plenty Regional Council explains that Lake Rotorua is subject to strict nutrient management regulations aimed at reducing nitrogen levels to improve its water quality.
“These regulations pose both challenges and opportunities for local farmers. As a result, the farming community is increasingly adopting plantain, with approximately threequarters of dairy farmers in the catchment area planning to make the transition to plantain use by 2032,” she says.
Farmers facing N loss targets need to be recognised for their gains. Research has shown plantain’s potential as a cost-effective tool for mitigating nitrogen loss.
It seemed like a bonus – it was a tool which would help us to reduce nitrogen leaching but allow us to keep cow numbers up.
A better understanding of how plantain works is helping to measure its impact more accurately. The well-proven mechanisms – such as reduced urine nitrogen due to dilution and changes in how animals process nitrogen – are now included in the OverseerFM model.
The next step for the Plantain Potency and Practice programme is to deepen knowledge of plantain’s effects on soil processes across different soil types and climates. This will allow these benefits to be added to OverseerFM and acknowledged in farmers’ N budgets.
This research will also help evaluate how new plantain cultivars and other forages, like chicory or Italian ryegrass, impact N leaching.
DairyNZ is expanding this important forage-based work through the LowN system project.
Find out more dairynz.co.nz/low-n
When grazing livestock eat highnitrogen pastures or crops, they use only a fraction of the N consumed to support the production of milk and meat.
The rest is excreted and can create concentrated N patches in the soil that exceed plant growth requirements. This N can’t be fully used and is lost (leached) in the form of nitrate below the plant’s root zone, or lost to the atmosphere as nitrogen gasses, including nitrous oxide, which is a potent greenhouse gas.
Leached N can reach waterways and, at high levels, can harm aquatic ecosystems, reduce biodiversity and impact water quality for human use. Addressing N leaching contributes to improving overall waterway health.
Providing farmers with cost-effective options for reducing N leaching is important for meeting current and future environmental regulations in catchments where N loss reduction is a priority.
Check out dairynz.co.nz/plantain to find out more about plantain.
Farming in the Lake Rotorua catchment, Richard Fowler knew he would need to make some changes to meet the strict nutrient management regulations. Working toward his 2032 nutrient discharge limit of 40kg/ha of nitrogen, he’s made significant progress, with plantain as a key tool in reducing nitrogen leaching.
“When we were looking at options to reduce our leaching, plantain came up,” Richard says.
“It seemed like a bonus really. It was a tool we could use which would help us to reduce nitrogen leaching but allow us to keep cow numbers up.”
Richard has been broadcasting plantain seed over the whole farm with his annual fertiliser applications for the past five years. In the first year, he used a rate of 4 kilograms of seed per hectare, which resulted in 20% plantain content, and he has continued to apply 2kg since, maintaining 20% plantain across the farm.
“We didn’t see much in the first summer, but it really started showing up in the autumn and the following season. It seems to be cost effective and working well in our catchment.”
The farm is 100ha milking 260 crossbreed cows. Along with adopting plantain, Richard has reduced his total stocking rate, removes cull cows early and winters about 100 cows off the farm. He has also used less N fertiliser across the system.
“We have gone for a low nitrogen input system as well, which seems to work hand in hand with plantain. So by using less N, we’re giving it a good chance to get established.
“I have been quite aggressive taking nitrogen fertiliser out and it’s going well. It’s a win-win for me and the farm – we’ve dropped our nitrogen leaching and, as a bonus, we’ve simplified the system. It’s saving money and time, and I don’t feel like I’m chasing nitrogen fertiliser.”
OverseerFM modelling is showing a 6kg/ha (14%) reduction in N leaching from the 20% plantain, which is a significant figure towards their target.
“When I first modelled our 2032 target, I thought we would have to drop some cows and retire some land, but at this stage, I don’t think we’ll need to, thanks to our efforts, including plantain.
“We may still retire some of the steeper land, but I don’t think we’ll need to reduce cow numbers as much.”
Richard’s recommendation to other farmers is to consider plantain and try adding it to fertiliser applications. He also promotes having a go at reducing N fertiliser usage, even for a period to gain some confidence.
This article was originally published in Inside Dairy February-April 2025.
