DairyNZ has kicked off a potentially game-changing research project to test the benefits of plantain in Tararua pastures.

At the moment, a significant proportion of dairy farms are operating without consent for intensive farming activities.

Farmers are faced with reducing nitrogen leaching by an average of 60 per cent to meet targets outlined in the Horizons Regional Council One Plan.

It's a massive challenge, but in a new approach, DairyNZ scientists are working with unconsented farmers in Tararua to help them reduce their farm's environmental footprint.

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DairyNZ catchment engagement leader Adam Duker, working with Horizons Regional Council, Massey University, agronomists, and a six-strong project team, has developed the Tararua Plantain Project – a seven-year plan to test the benefits of plantain on 125 dairy farms in our district. The project began in the 2018-19 season and will run for seven years.

The Tararua Plantain Project, which secured funding through the Sustainable Farming Fund, is a new approach by DairyNZ to reduce farm N loss through a combination of plantain and good management practice.

"Plantain provides us with an excellent low-cost opportunity to meet this challenge," Duker said. "It can be used as a pasture mix for dairy cattle feed, but its properties have also been proven to reduce nitrogen loss.

"Farmers in the catchment have already been making on-farm changes to reduce nutrients and sediment impacting the Manawatū River. The river water quality is improving as a result and by adopting plantain as a fodder crop on their farms, we expect to see further improvements over time."

The Tararua Plantain Project involves paddock-scale research on six farms where plantain crops are expected to reduce nitrogen from cow urine. Plantain roots also lock more nitrate into soil, preventing run-off into waterways.

"The project is farmer-led and focuses on tangible, practical solutions to the environmental challenge by testing the feasibility of plantain at the farm and catchment scale. We'd like to see plantain as a staple part of the dairy cow's diet in this area by 2025," Duker said.

"It will allow our farmers to maintain similar levels of milk production and we hope the project will demonstrate how to keep their businesses profitable, reduce environmental impact and minimise the effect on the community."

Plantain research could help Tararua dairy farmers reduce their nitrogen leaching requirements to meet their One Plan obligations. Photo / Supplied
Plantain research could help Tararua dairy farmers reduce their nitrogen leaching requirements to meet their One Plan obligations. Photo / Supplied

Dr Nic Peet, Horizons Regional Council's strategy and regulation manager, said the project's success will help drive water quality improvement in the Manawatū River and help farms meet regulatory requirements to reduce nitrogen.

"Without tools like the use of plantain, farmers in much of the Tararua are unlikely to meet the One Plan N-leaching targets and remain viable," he said. "The plantain project is important and has the potential to make a significant difference – economically and environmentally."

Tararua dairy farmers Blair Castles, Mark Diamond and Brad McNaughton are already using plantain in their pastures. As System 2 and System 3 farmers and members of the project's monitoring group, they're keen for others to learn from their results.

Castles said when he found DairyNZ was suggesting plantain to reduce nitrogen (N) leaching, he was keen to get on board.

And his neighbour McNaughton has already done a few farm trials of his own and is including chicory and plantain in his pastures.

Diamond has been using plantain for three years. In a 10ha trial, he's using about 2kg plantain/ha as part of a mixed sward with ryegrass and clover, which he sows after the summer turnip crop has been lifted.

The Tararua Plantain Project capitalises on research findings from the DairyNZ Forages for Reduced Nitrate Leaching (FRNL) programme which established that New Zealand bred plantain cultivars reduce soil N concentration under cows' urine patches.

This allows plants to take up a greater proportion of N, reducing N leaching (estimated to be between 5 and 30 per cent, depending on soil type and the proportion of plantain in the cows' diet).

Testing the benefits of plantain in local pastures is at the heart of the project. Simultaneous research locally and on research farms recognises the size and the urgency of the task ahead. Paddock-scale research has begun on six local farms and the findings will be shared with other farmers in the area.

Project support is coming from Massey University, which is carrying out research at a university farm, measuring N leaching from plantain pastures compared with ryegrass pastures. They're supporting farmers by sharing the results of this research. In turn, Tararua farmers are contributing to the Massey research by evaluating ways to best integrate plantain into their farm systems.

The project aims to achieve plantain use on 125 dairy farms to increase farm business and community resilience, and quantified gains in water quality.

To find out more about the research, visit www.dairynz.co.nz/tararua.