Background

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 percent 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 the catchment to help them reduce their farm’s environmental footprint.

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 the area. The project began in the 2018-19 season and will run for seven years.

The Tararua Plantain Project capitalizes 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 percent, 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 recognizes 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

Massey University
Professor Peter Kemp, Soledad Navarrete and David Horne from the School of Agriculture and Environment are 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.

Horizons Regional Council
Dr Nic Peet, Horizons strategy and regulation manager, says the project’s success will help drive water quality improvement in the Manawatu River and help farms meet regulatory requirements to reduce N.

“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. The plantain project is important and has the potential to make a significant difference – economically and environmentally.”

Early adopters

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.

• Blair Castles

  Dannevirke dairy farmer Blair Castles is a farmer on a mission. He says when he found out DairyNZ was suggesting using plantain to reduce nitrogen (N) leaching, he was keen to get on board.

  He’s just one of several farmers in the area who are tackling the issue head-on – and sharing their findings with other farmers, thanks to DairyNZ’s newly established Tararua Plantain Project.

  “I like what DairyNZ is trying to achieve and I’m keen to show other farmers what plantain is like in a sward,” says Blair. “To reach the Horizons Regional Council targets, we have to reduce N leaching on our farm by eight to nine kilograms per hectare (kg/ha). All of us in the region need to get on board and do our best to be compliant.”

  Blair has been using plantain, along with chicory, for about six years. He’s looking at taking out chicory and lifting the rate of plantain. At present, chicory is 10 percent of his sward; plantain’s about the same.

  “It wasn’t difficult to establish but it’s been very effective. We wanted to use more herbs in our ‘fruit salad’ pasture of ryegrass and clovers. We’ve achieved this and the cows like it. Depending on the trials, we could increase plantain in the future. We’ll do anything we can to be compliant with the council regulations.”

  Blair plants plantain in autumn, after the summer turnip crop has been lifted. He has a 15 percent regrassing programme underway, so it’s early days in terms of results with plantain.

  “When I first started using it, I had some concerns around bloat on plantain, which doesn’t happen with chicory. We had to monitor it but so far, we haven’t had any problems. As a precautionary measure we add bloat oil to the drinking water, which covers the clover as well, and this seems to be working well.”

  He plants kale in winter and will also add fodder beet to the mix this year.

  “We used to grow swedes for our main winter crop, but this year we’re changing to fodder beet on the runoffs and a bit on the milking platform as well.”

  Blair tries to keep his use of urea low: about four tonnes per year on the 100ha milking platform. He says this seems to be an effective ratio, so it’s not necessary to pump more on.

  “Farmers in the area are being proactive and we have council support, so working with the scientists has to be a good thing – I’m all for it. The One Plan limit-setting process can be quite overwhelming for farmers, but when you’ve got DairyNZ scientists doing this research it’s not so daunting. I’m very happy to help and be part of it.”

• Brad McNaugton

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

  About four years ago he started using ‘Rocket Fuel’ – a mix of plantain and chicory with white and red clovers.

  “Plantain did well, so we’re now including it in our regular regrassing programme,” says Brad. “We’re regrassing about 12 percent of the pasture a year, incorporating two kilograms (kg) plantain with 25kg ryegrass and 4kg clover. “Plantain has deep roots and is drought-tolerant, which is good for us because we’re not irrigated and it can get very dry here in the summer. I’m waiting to see how we go in autumn and whether the cows find plantain less palatable.”

  Brad says the monitoring group meets every three months, or before drilling, to gauge what everyone’s doing and share information about the trial.

  “Next season we'll sow in spring. I find you have to be exact with sowing plantain. We spray out with a herbicide after the turnips are lifted and direct drill the seed. “I learned farming through DairyNZ discussion groups and talking to others, but it will be a big step to plant 30 percent plantain. To some extent, it will come down to cost. Herbs are just another species in the paddock but if the trials are successful, we’ll aim to gradually increase plantain in our pastures until we reach 30 percent.”

• Mark Diamond

  Mark 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.

  “Plantain is easy to grow and is part of our ongoing regrassing plan. It’s easier to manage than chicory and the cows love it.”

  Mark says farmers know they must make changes but, because every property is different, there’s no ‘one size fits all’ solution.

  “We all live in houses of different shapes and sizes with different coloured roofs. Farms are much the same. Brad’s property is completely different to mine, even though we share a boundary fence. It’s definitely a hard one. Some farms have higher rainfall than others, and there are different options available to help reduce leaching, like off-paddock infrastructure and changes to farm systems – but these all come at a cost.”

  Mark is also trying a few other things, like using gibberellic acid and liquid urea, to strategically-reduce N losses and increase pasture growth at times when growth rates are typically low.

  “The project has just started and I think there is merit in it, but we’ll have more information in 12 months’ time. The scientists are going to measure everything and tell us if plantain has made a difference to production and the bottom line. I’m hoping it’s a ‘goer’.”

Led by DairyNZ, the Tararua Plantain Project is helping unconsented farmers keep on top of nitrogen leaching. (Left to right: DairyNZ catchment engagement leader Adam Duker and local dairy farmers Mark Diamond, Blair Castles and Brad McNaughton).