September 23, 2025 • 11 mins
Can a small amount of plantain in pasture really reduce nitrogen loss on-farm? New research from trials at Lincoln and Massey Universities suggests it can, and the results might surprise you. Kate Fransen shares the latest findings from DairyNZ’s Plantain Potency and Practice Programme and an update on what’s working, how farmers are using it effectively, and what’s next for the programme.
Find out more about this research programme: Plantain Potency and Practice Programme - DairyNZ | DairyNZ
Read the latest news story on this research: Latest plantain trial results again show role in reducing nitrogen leaching | DairyNZ
Have feedback or ideas for future episodes? Email us at talkingdairy@dairynz.co.nz
Stay up to date with advice, latest research, tools and resources. Read, browse, scroll, listen, or be there in person. Visit dairynz.co.nz/get-connected
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Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Jac McGowan (00:01):
Kia ora and welcome to Talking Dairy in 10.
I'm your host, jack McGowanfrom DairyNZ.
Today we've got an interestingupdate about our research into
reducing nitrogen loss fromplantain use in pasture.
This project has just finishedits fourth year and new trial
results show that even a littleplantain can make a real
difference.
Joining us today is KateFranson, who leads the DairyNZ
(00:24):
Plantain Potency and PracticeProgramme, which is jointly
funded by DairyNZ Ministry forPrimary Industries through the
Primary Growth Sector Fund, pggRights and Seeds and Fonterra.
Kate, it's so great to have youhere.
Thanks, jack.
Cutting straight to the chase,kate, you've got the latest
trial results in from Lincolnand Massey.
(00:44):
What did they show?
Kate Fransen (00:46):
Well, at our Lincoln University Research
Dairy Farm trial over threeyears we measured nitrogen
leaching from ryegrass cloverpastures with and without
plantain.
To measure the leaching we'veused suction cups, which are
little ceramic cups with littletubes in them that we're able to
measure the nitrogen in wateras it goes towards the
groundwater, and they'reinstalled under each of the
(01:08):
paddocks.
The proportion of plantain inthe sward was lower than what we
were targeting.
We had an average of 17% and itranged from 12% to 25% through
the three years of the trial.
But it's been pleasing to seethat even at those lower levels
we've still had a largereduction in leaching.
So nitrate leaching from thepastures with plantain was 26%
(01:31):
lower than the ryegrass clovertreatment.
The results from our Masseyside have been pretty similar.
So they've also had a 26%reduction in leaching from a
treatment with 25% plantain.
So it's really encouragingresults, jack.
Jac McGowan (01:44):
Why did you end up with a lower percentage of
plantain than you were hopingfor in Canterbury?
Kate Fransen (01:49):
Yeah, so plantain's been challenging to
maintain in pastures.
So we know that plantain lastsabout two to three years now.
It's not a long-term perennial.
So while it started out ataround sort of 30%, it gradually
declines and so we've beentopping it up in the pastures
using some undersowing andoversewing of the pasture swords
(02:12):
with plantain seed and that'ssort of the levels that we've
been able to maintain, aroundthat average 17%.
Jac McGowan (02:19):
So you said that in both locations you had a 26%
reduction in N-leaching.
How did that compare tomodelled predictions?
Kate Fransen (02:28):
Yeah.
So our overseer model currentlyaccounts for the effect of
plantain on nitrogen levels inthe urine patch.
We call that the animal effect.
On average this gives around a0.6% reduction in leaching for
every 1% plantain.
So if we look at our resultsfrom Lincoln, with our 17%
plantain, that would haveaccounted for around 10%
(02:50):
reduction in leaching, whereasour measurements showed an
average of 26% reduction.
Okay, so what's accounting forthat extra 16 odd percent?
Well, we know from ourlysimeter and nitrous oxide
trials that have been done inthe past that plantain can
further reduce leaching throughmechanisms that are going on in
the soil.
So we know that there's reduceddrainage under plantain, so
(03:14):
less water going below the rootzone, which then takes less
nitrogen with it.
And we also know that there's aslowing of the conversion of
ammonium, which is sort of thestable form of nitrogen, to
nitrate, which is the stuff thatleaches.
So our research is currentlyreally focused on understanding
and quantifying those mechanismswith the aim of the full effect
(03:37):
of plantain being reflected inthat overseer model.
Jac McGowan (03:41):
Right.
So it sounds, based on that,like there's been a shift in
thinking around how muchplantain is needed in pasture to
achieve a large reduction innitrogen leaching.
What's the new insight and howachievable is that on farm?
Kate Fransen (03:54):
Yeah, so there was an early animal trial on
plantain which concluded thatyou need 30% plantain in a
pasture s ward to have thisstatistically significant effect
on urinary nitrogen.
So that was an animal trial runin a metabolism stall facility.
But our more recent research isshowing these sizable
reductions in leaching at levelsas low as 12% as an average
(04:18):
across a farm.
Now our plantain partnerfarmers we've got about 20, up
to 25 at times throughout theprogram partner farmers across
New Zealand and they're showingthat 10 to 20% plantain is an
achievable target.
That's what they're achievingat the moment across their farms
.
Jac McGowan (04:35):
Okay, so you're already working with farmers
that are making it work.
What are some of the successfulapproaches you're seeing across
regions?
Kate Fransen (04:43):
Yeah.
So some of the examples inRotorua where farmers are using
ecotain plantain to meet theirnitrogen leaching limits.
They're achieving up to 20%across their farms just through
broadcasting two to three kilosof seed each year with their
annual phosphorus fertiliser.
They do this by either addingthe seed into the top of the
fertiliser truck or spinning iton with a fertiliser spreader.
(05:06):
Prillcoat seed is often used toincrease the weight of the seed
and help give it a more evenspread.
As it spins out of thefertiliser truck, the increased
weight means that you need todouble the seeding rate.
So to get three kilos of seedyou need to spread six kilos per
hectare of prillcoat.
Right yeah, broadcasting worksparticularly well in Rotorua,
(05:28):
from what we've seen, wherepasture swathes are a bit more
open on those light volcanicsoils over there.
Moving to Southland farmers areregrassing in Southland about
every seven years and they'remaintaining around eight to 10%
plantain across their farms justby including it in the
re-grassing mix about threekilos per hectare.
Plantain's a pretty small seed,so it's important that you
(05:53):
don't sow it too deep, and someof these Southland farmers have
had particular success wherethey've prepared the seed bed by
cultivation and they're justusing a roller drill, so
dropping the seed on the surfaceand rolling over it.
And that's just using a rollerdrill, so dropping the seed on
the surface and rolling over it,and that's been really
successful in getting quite highpercentages of plantain.
The proportion of plantain innew grass paddocks, pretty
(06:15):
universally across New Zealandwe're seeing around 20 to 40%,
up to 50% after around six to 12months.
It's not a long-term perenniallike ryegrass, so it's lasting
two to three years in pasturesbefore it starts to decline.
So these farmers in Southland,similar to what I talked about
(06:36):
with our LURDF site, lincolnUniversity Research Dairy site,
they're currently trialingbroadcasting seed to top up
those paddocks that they've sownand also just broadcasting
across the whole farm to see ifthey can get plantain
established that way.
Lastly, in Canterbury farmersare able to maintain around 10%
(06:56):
plantain and up to 15% plantainacross their farms through a
combination of including it intheir regrassing mix and
broadcasting quite low rates inCanterbury, around one to two
kilos per hectare of seed acrossthe whole farm with fertiliser
each year.
And in Canterbury we found onceagain, broadcasting does work
(07:16):
best where the swords are a bitmore open.
This year some of ourCanterbury farmers are
increasing their seeding ratewhen they're broadcasting just
to see if that gives them somehigher percentage in those
broadcasted paddocks.
So that gives you a bit of anidea, jack, as to sort of the
different things that are goingon around the country and the
sort of rates that we're gettinghopefully.
Jac McGowan (07:37):
Yeah, cool, Thank you, Kate.
Now looking ahead what's nextfor this programme?
Kate Fransen (07:41):
Well, now that we're confident that plantain is
an effective tool for reducingleaching, we're turning our
attention to adoption innitrogen-sensitive catchments.
So some examples of catchmentswe're working closely with at
the moment are Edendale inSouthland, amuri in North
Canterbury, waikakahi in SouthCanterbury, rotorua Lake and
(08:01):
Upper Waikato.
In a few of these catchmentswe're hoping to measure the
effect of plantain adoption onnitrogen in groundwater and
streams.
Some of these catchments, likeMuri and Waikakehi in particular
, are quite unique becausethey've got sort of
hydrologically isolated so wecan measure all of the
groundwater coming off them andsee what the mitigations like
(08:23):
plantain are doing directly tothat groundwater and in the
streams.
As mentioned earlier, we're alsolooking to further understand
how plantain works in the soilso the full effect can be
quantified in the overseer model.
That's a huge focus for ourprogram at the moment.
And finally, agritonic plantain, which is the cultivar marketed
(08:46):
as Ecotain, is what we've usedin our trials.
So we're really confident thatthat cultivar works to reduce
nitrogen leaching.
What we're now doing is lookingto roll out a plantain cultivar
evaluation system which aims toprovide confidence in the use
of a range of plantain cultivarsfor reducing nitrate leaching
(09:07):
and we're hoping that futureresearch may also help us to
include other species, likechicory, into our evaluation
system as well.
So, yeah, those are the keyfocuses for the program for the
next couple of years, jack.
Jac McGowan (09:20):
You talked about the different methods of
maintaining plantain in thesward or increasing the amount
of plantain in the sward thatyou were seeing being successful
in different regions.
Where can farmers find thatinformation?
Kate Fransen (09:33):
So there's some basic information on our website
.
So look for the plantain pageon our website and you'll find
some information there.
There's a more detailed page onour website specifically about
the Plantain program and some ofthe results that we've been
getting.
You'll see some links therealso to some of our farmer case
studies.
We're increasing the amount ofcase studies at the moment on
(09:56):
our website, so there's moreexamples available.
Jac McGowan (09:59):
Brilliant Thanks, kate.
And thanks so much for joiningus on this episode of Talking
Dairy in 10.
If you'd like to know more,we'll link to more information
in the show notes.
Thanks for tuning into thisepisode of Talking Dairy.
Make sure to hit follow so youcan keep up to date with our
(10:21):
latest episodes.
You can also keep up with DairyNZ News on Facebook, instagram
and LinkedIn, or go to ourwebsite and sign up for our
fortnightly Dairy NZ News emails.
As always, if you have anyfeedback on this podcast or have
some ideas for future topics orguests to have on the show,
please email us at talkingdairyat dairynzconz Mā te wā mauri
(10:44):
ora.
Catch you next time.
Kia ora and welcome to Talking Dairy in 10.
I'm your host, jack McGowanfrom DairyNZ.
Today we've got an interestingupdate about our research into
reducing nitrogen loss fromplantain use in pasture.
This project has just finishedits fourth year and new trial
results show that even a littleplantain can make a real
difference.
Joining us today is KateFranson, who leads the DairyNZ
(00:24):
Plantain Potency and PracticeProgramme, which is jointly
funded by DairyNZ Ministry forPrimary Industries through the
Primary Growth Sector Fund, pggRights and Seeds and Fonterra.
Kate, it's so great to have youhere.
Thanks, jack.
Cutting straight to the chase,kate, you've got the latest
trial results in from Lincolnand Massey.
(00:44):
What did they show?
Kate Fransen (00:46):
Well, at our Lincoln University Research
Dairy Farm trial over threeyears we measured nitrogen
leaching from ryegrass cloverpastures with and without
plantain.
To measure the leaching we'veused suction cups, which are
little ceramic cups with littletubes in them that we're able to
measure the nitrogen in wateras it goes towards the
groundwater, and they'reinstalled under each of the
(01:08):
paddocks.
The proportion of plantain inthe sward was lower than what we
were targeting.
We had an average of 17% and itranged from 12% to 25% through
the three years of the trial.
But it's been pleasing to seethat even at those lower levels
we've still had a largereduction in leaching.
So nitrate leaching from thepastures with plantain was 26%
(01:31):
lower than the ryegrass clovertreatment.
The results from our Masseyside have been pretty similar.
So they've also had a 26%reduction in leaching from a
treatment with 25% plantain.
So it's really encouragingresults, jack.
Jac McGowan (01:44):
Why did you end up with a lower percentage of
plantain than you were hopingfor in Canterbury?
Kate Fransen (01:49):
Yeah, so plantain's been challenging to
maintain in pastures.
So we know that plantain lastsabout two to three years now.
It's not a long-term perennial.
So while it started out ataround sort of 30%, it gradually
declines and so we've beentopping it up in the pastures
using some undersowing andoversewing of the pasture swords
(02:12):
with plantain seed and that'ssort of the levels that we've
been able to maintain, aroundthat average 17%.
Jac McGowan (02:19):
So you said that in both locations you had a 26%
reduction in N-leaching.
How did that compare tomodelled predictions?
Kate Fransen (02:28):
Yeah.
So our overseer model currentlyaccounts for the effect of
plantain on nitrogen levels inthe urine patch.
We call that the animal effect.
On average this gives around a0.6% reduction in leaching for
every 1% plantain.
So if we look at our resultsfrom Lincoln, with our 17%
plantain, that would haveaccounted for around 10%
(02:50):
reduction in leaching, whereasour measurements showed an
average of 26% reduction.
Okay, so what's accounting forthat extra 16 odd percent?
Well, we know from ourlysimeter and nitrous oxide
trials that have been done inthe past that plantain can
further reduce leaching throughmechanisms that are going on in
the soil.
So we know that there's reduceddrainage under plantain, so
(03:14):
less water going below the rootzone, which then takes less
nitrogen with it.
And we also know that there's aslowing of the conversion of
ammonium, which is sort of thestable form of nitrogen, to
nitrate, which is the stuff thatleaches.
So our research is currentlyreally focused on understanding
and quantifying those mechanismswith the aim of the full effect
(03:37):
of plantain being reflected inthat overseer model.
Jac McGowan (03:41):
Right.
So it sounds, based on that,like there's been a shift in
thinking around how muchplantain is needed in pasture to
achieve a large reduction innitrogen leaching.
What's the new insight and howachievable is that on farm?
Kate Fransen (03:54):
Yeah, so there was an early animal trial on
plantain which concluded thatyou need 30% plantain in a
pasture s ward to have thisstatistically significant effect
on urinary nitrogen.
So that was an animal trial runin a metabolism stall facility.
But our more recent research isshowing these sizable
reductions in leaching at levelsas low as 12% as an average
(04:18):
across a farm.
Now our plantain partnerfarmers we've got about 20, up
to 25 at times throughout theprogram partner farmers across
New Zealand and they're showingthat 10 to 20% plantain is an
achievable target.
That's what they're achievingat the moment across their farms
.
Jac McGowan (04:35):
Okay, so you're already working with farmers
that are making it work.
What are some of the successfulapproaches you're seeing across
regions?
Kate Fransen (04:43):
Yeah.
So some of the examples inRotorua where farmers are using
ecotain plantain to meet theirnitrogen leaching limits.
They're achieving up to 20%across their farms just through
broadcasting two to three kilosof seed each year with their
annual phosphorus fertiliser.
They do this by either addingthe seed into the top of the
fertiliser truck or spinning iton with a fertiliser spreader.
(05:06):
Prillcoat seed is often used toincrease the weight of the seed
and help give it a more evenspread.
As it spins out of thefertiliser truck, the increased
weight means that you need todouble the seeding rate.
So to get three kilos of seedyou need to spread six kilos per
hectare of prillcoat.
Right yeah, broadcasting worksparticularly well in Rotorua,
(05:28):
from what we've seen, wherepasture swathes are a bit more
open on those light volcanicsoils over there.
Moving to Southland farmers areregrassing in Southland about
every seven years and they'remaintaining around eight to 10%
plantain across their farms justby including it in the
re-grassing mix about threekilos per hectare.
Plantain's a pretty small seed,so it's important that you
(05:53):
don't sow it too deep, and someof these Southland farmers have
had particular success wherethey've prepared the seed bed by
cultivation and they're justusing a roller drill, so
dropping the seed on the surfaceand rolling over it.
And that's just using a rollerdrill, so dropping the seed on
the surface and rolling over it,and that's been really
successful in getting quite highpercentages of plantain.
The proportion of plantain innew grass paddocks, pretty
(06:15):
universally across New Zealandwe're seeing around 20 to 40%,
up to 50% after around six to 12months.
It's not a long-term perenniallike ryegrass, so it's lasting
two to three years in pasturesbefore it starts to decline.
So these farmers in Southland,similar to what I talked about
(06:36):
with our LURDF site, lincolnUniversity Research Dairy site,
they're currently trialingbroadcasting seed to top up
those paddocks that they've sownand also just broadcasting
across the whole farm to see ifthey can get plantain
established that way.
Lastly, in Canterbury farmersare able to maintain around 10%
(06:56):
plantain and up to 15% plantainacross their farms through a
combination of including it intheir regrassing mix and
broadcasting quite low rates inCanterbury, around one to two
kilos per hectare of seed acrossthe whole farm with fertiliser
each year.
And in Canterbury we found onceagain, broadcasting does work
(07:16):
best where the swords are a bitmore open.
This year some of ourCanterbury farmers are
increasing their seeding ratewhen they're broadcasting just
to see if that gives them somehigher percentage in those
broadcasted paddocks.
So that gives you a bit of anidea, jack, as to sort of the
different things that are goingon around the country and the
sort of rates that we're gettinghopefully.
Jac McGowan (07:37):
Yeah, cool, Thank you, Kate.
Now looking ahead what's nextfor this programme?
Kate Fransen (07:41):
Well, now that we're confident that plantain is
an effective tool for reducingleaching, we're turning our
attention to adoption innitrogen-sensitive catchments.
So some examples of catchmentswe're working closely with at
the moment are Edendale inSouthland, amuri in North
Canterbury, waikakahi in SouthCanterbury, rotorua Lake and
(08:01):
Upper Waikato.
In a few of these catchmentswe're hoping to measure the
effect of plantain adoption onnitrogen in groundwater and
streams.
Some of these catchments, likeMuri and Waikakehi in particular
, are quite unique becausethey've got sort of
hydrologically isolated so wecan measure all of the
groundwater coming off them andsee what the mitigations like
(08:23):
plantain are doing directly tothat groundwater and in the
streams.
As mentioned earlier, we're alsolooking to further understand
how plantain works in the soilso the full effect can be
quantified in the overseer model.
That's a huge focus for ourprogram at the moment.
And finally, agritonic plantain, which is the cultivar marketed
(08:46):
as Ecotain, is what we've usedin our trials.
So we're really confident thatthat cultivar works to reduce
nitrogen leaching.
What we're now doing is lookingto roll out a plantain cultivar
evaluation system which aims toprovide confidence in the use
of a range of plantain cultivarsfor reducing nitrate leaching
(09:07):
and we're hoping that futureresearch may also help us to
include other species, likechicory, into our evaluation
system as well.
So, yeah, those are the keyfocuses for the program for the
next couple of years, jack.
Jac McGowan (09:20):
You talked about the different methods of
maintaining plantain in thesward or increasing the amount
of plantain in the sward thatyou were seeing being successful
in different regions.
Where can farmers find thatinformation?
Kate Fransen (09:33):
So there's some basic information on our website
.
So look for the plantain pageon our website and you'll find
some information there.
There's a more detailed page onour website specifically about
the Plantain program and some ofthe results that we've been
getting.
You'll see some links therealso to some of our farmer case
studies.
We're increasing the amount ofcase studies at the moment on
(09:56):
our website, so there's moreexamples available.
Jac McGowan (09:59):
Brilliant Thanks, kate.
And thanks so much for joiningus on this episode of Talking
Dairy in 10.
If you'd like to know more,we'll link to more information
in the show notes.
Thanks for tuning into thisepisode of Talking Dairy.
Make sure to hit follow so youcan keep up to date with our
(10:21):
latest episodes.
You can also keep up with DairyNZ News on Facebook, instagram
and LinkedIn, or go to ourwebsite and sign up for our
fortnightly Dairy NZ News emails.
As always, if you have anyfeedback on this podcast or have
some ideas for future topics orguests to have on the show,
please email us at talkingdairyat dairynzconz Mā te wā mauri
(10:44):
ora.
Catch you next time.
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