Jackie Harrigan

One year into the Tararua plantain project, farmers are embracing the concept on dairy farms across the region.

Lower North Island catchment engagement leader for Dairy NZ, Adam Duker is leading the seven-year project which aims to introduce enough plantain on farms across the Tararua region to drive down nitrogen leaching at a catchment level.

“We are aiming for 30% of the cows’ diets to be plantain from January to May, which is the critical period for N leaching from the soils when the autumn rains come and grass growth is slowing going into the winter,” he says.

Modelling work is in progress to determine the associated level of nitrogen leaching reduction able to be achieved, he added.

In the upper Manawatu River catchment in the Tararua region, a high number of the 125 dairy farms are unconsented, due to the inability to meet the N leaching targets in the Horizons Regional Council’s One Plan. (see Pg 81 about recalibrating the One Plan N leaching levels).

“While the farmers can’t reach to 60% reduction of N leaching that is required (before potential plan change) on a farm basis, the plan is to try and reach the reduction on a whole catchment basis.”

The first year of the project included extension events (where about 60% of farmers turned up to hear about the plantain potential) and the remaining 40% of farms were visited individually onfarm.

Duker says the level of engagement and enthusiasm was great to see.

“The bulk of farmers already knew about the project, and many had already been planting the plantain.”

Only one farmer had not heard about the project, Duker says.

A working group of 19 dairy farmers are leading the development of plantain-rich farm

systems and their results will be fed through to all the other farmers through field days, media and extension opportunities.

On farm monitoring is in full swing, taking regular pasture cuts to track seasonal growth, plant counts in year one to measure establishment, visual assessment of plantain in the sward with a focus on January-May over time to measure percentage of plantain in the sward.

By year three the group plan to have a cost benefit analysis of the plantain in comparison with other mitigations and an idea of what farm system would be to achieve 30- 40% plantain in the sward.

Farmers are already moving and getting a feeling for what they can do on their properties, Duker says.

“We are hoping to get to full adoption by 2025, and in the meantime are looking at barriers to uptake and hoping to wrap a support package around farmers to provide them with confidence they can overcome the barriers.”

Potential barriers include:

  • Weeds and pest control – but there are options Duker says, that come down to time to treat and costs of treatments.
  • Persistence – how long will it stay in the sward?

“Last year it was very dry through to April and the plantain seemed to bounce back better than the pasture after the dry period – but it’s not a bulk feed like a crop of turnips.”

  • Establishment: getting into plantain – farmers are waiting for more information but are actively tracking the project, Duker says, and many are incorporating plantain in their autumn regrassing as part of a pasture mix.
  • Many farmers are waiting for the credit under Overseer – we are on the cusp of seeing that, Duker says.

Multiple advantages

While the Tararua region is leading the project in terms of catchment uptake, the project team are already looking at opportunities in other catchments, especially where N is a high priority.

There are numerous reasons to use the plant, Duker says.

“When we first started to look for farmers using plantain we looked at why they were finding it worked in their system and they weren’t so much around the N leaching reduction capability of the herb. They were using it for the deep rooting system and the productive benefits in a mixed sward, the animal health and mineral benefits, and to get a more diverse sward.

“When you add the N advantages into the equation, they are all really compelling reasons, and a great package.

“With all of the advantages we could go nationally where there are priority catchments but the focus is local at this stage before we extend our knowledge through wider areas.”

Plain talk about plantain

ptake of plantain in the Tararua region is growing fast, with retail outlets saying farmers are jumping into it, Agricom Western North Island territory manager Laura Keenan reports.

“It’s not a system change – it’s just an agronomic flex in a new direction and with a few new grazing management skills, it’s an easy and simple solution to a complex problem,” she says.

“We have been dealing with Ecotain as an agronomic solution since 1996 and the environmental functionality is the icing on the cake.”

Laura is consulting agronomist for the plantain project in the Tararua region and oversaw Neil Filer’s plantain crop establishment. She says the method is tried and true:


  • Get as clean a seed bed as possible, need firm and fine seedbed for good seed-to-soil contact
  • Neil sprayed out with Roundup and tank partner to kill tough perennial weeds + slug bait and lime.
  • 285kg DAP on at sowing, followed up with seasonal N
  • Drilled Ecotain at 12kg/ha one way on 31st Oct, Dec 8th sprayed with 600ml/ha Kamba 500.
  • Cost to establish out of grass $946/ha.
  • Planted when soils 10-12C and rising
  • Monitor the weeds – easy to do in a straight Ecotain sward, harder if clover is included.


An Ecotain crop also fits well as a short rotation crop or break crop and as part of a continued pasture renewal program on farm, Laura says.

“Think about it as part of a rotation, so you can control the hard weeds before the crop goes in.”

  • Apply N 3-4 weeks post planting
  • First grazing when the plants have seven true leaves and the sward is 25cm high (about the top of the RedBand boot.)
  • Aim to leave a residual 3-5cm after the first grazing
  • Use a round length of 14-30 days depending on summer moisture
  • Keep an eye on pests and diseases – monitor and spray when required. (None found in Neil’s sward)
  • Grass grub – easy to control with chemicals, often occurs April to August in the first two or three years of the sward.
  • Plantain moth: Often comes when there is lots of dead matter in pasture – therefore important to get grazing right. Spray with Kaiso.
  • Forage mass in first year best at 12-14tonnes drymatter/ha, drops after that. (7 grazings to 31st May, 1 paddock had 8)
  • Expected life of the sward is two-three years , various options to extend – undersow or broadcast, or undersow Italian ryegrass to extend pasture life.
  • If weed and insect infestation rife then might be best to start again, Laura says.