Plantain study may help NZ waterway health

Massey University plantain potency and practise programme officer Sole Navarrete shows off leaf from a plantain crop. Photo: David Unwin/Stuff.

New research has found feeding cows the leafy herb plantain can reduce nitrogen leaching from dairy farms by up to 60 per cent and may help improve the quality of the country’s waterways.

The Dairy NZ-led plantain potency and practice programme has just announced the research results which show using ecotain, an environmental plantain from Agricom, in pasture can significantly reduce nitrogen entering waterways.

The research has been done for the past four years at Massey University in Palmerston North and more recently at Lincoln University, putting dairy cows in pasture with varying levels of plantain and measuring the nitrogen levels going into the soil from the animals’ urine.

Method adoption

Ecotain reduces nitrogen leaching by increasing cows’ urine volume, diluting the nitrogen in urine and reducing the total amount of nitrogen excreted in urine. It also retains nitrogen in the soil, preventing it entering waterways.

The results are compared to traditional perennial ryegrass and clover paddocks.

The programme has run on 21 farms across the country and it’s hoped the method is adopted widely.

Dairy NZ chief executive Tim Mackle says the results are exciting.

“We now have robust scientific evidence that Ecotain plantain is an effective solution to help dairy farmers further reduce farm footprint and continue playing their part in improving water quality.”

He says a 20 per cent to 60 per cent reduction in nitrogen leaching was a material reduction and was worth fighting for.

“When you get that kind of technology come through it's a real change.

“It's up to us to make sure that farmers can use it and do use it at scale so we get the benefits for them, the communities and the water.”

Mackle says it will save farmers more than $1 billion per decade by spending less on nitrogen reduction.

He says dairy accounts for almost half of the country’s nitrogen in waterways, so farmers would want to reduce that because it was the right thing to do.

Massey University Professor Emeritus Peter Kemp says this research supports work to protect the environment and improve waterways.

They had seen a 20 per cent-60 per cent decrease in nitrogen leaching by using between 25 per cent-55 per cent plantain in pasture.

“Overall you’ve got a dramatic decrease in nitrogen leaching.

“From a farmer’s point of view there's no change in the pasture dry matter production and no change in milk production.”

The study used a drainage system under the paddocks the cows graze. Water from the soil in each paddock is piped into a container and sampled.

The cows’ urine, dung and plasma are tested, as well as the pasture and leachate.

Some farmers already use plantain as a forage crop so this would not be a big step for many.

“Farmers have bought into the fact that they have got to decrease nitrogen leaching. Typical farmers have bought into it.

Plantain use

“This offers a way to do it that I think is an easy adjustment to their farming system.”

Thomas Read farms more than 1000 dairy cows across three farms at Dannevirke in Tararua and has been using plantain in his pasture for about seven years.

“Plantain is a tool we reached for, for simplicity and low cost and then now to see the science behind it, there's the added benefit of doing better in regards to nitrogen leaching and overall better water quality across New Zealand.”

Nitrogen levels had decreased on his farm and he believed it was only a matter of time before others adopted the method.

The $22 million seven-year programme is funded by DairyNZ, the Ministry for Primary Industries, PGG Wrightson Seeds and Fonterra, working with six research and delivery partners.


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