The country’s waterways will be cleaner thanks to a joint effort proving that a leafy green holds the key to tackling nitrogen leaching.
At a glance
A collaboration between rural services company PGG Wrightson Seeds and Callaghan Innovation has potentially solved one of the greatest environmental problems facing Kiwi farmers.
Nitrogen leaching from paddocks into waterways is a serious threat to New Zealand’s clean, green image and increasingly a limitation on farmers’ licence to operate.
Now a new plantain developed by PGG Wrightson Seeds offers a means of reducing nitrogen leaching by up to 90 per cent compared with traditional ryegrass-based pastures.
Offers a means of reducing nitrogen leaching by up to 90 per cent
Known as Ecotain, its strong winter growth is a clear advantage over most of its plantain cousins which are semi-dormant in the cooler months. But it turns out this unassuming leafy green has even greater abilities.
Nitrogen leaching is a problem in all livestock operations but particularly in the dairy industry. A majority of the nitrogen a cow eats end up in its urine, and when it pees it dumps around two litres of liquid in one spot. While plants need nitrogen, the pasture can’t take up all that nitrogen at once, and even less so in the winter when the ground is wetter and the plants grow more slowly. The result is excess nitrogen moving down through the soil and into waterways.
While nitrogen leaching is not the only cause of water pollution, it has been one of the harder factors to control.
Power of plantain
Plantain itself is nothing new, and Kiwi farmers have been using it as a stock forage for the last two decades. PGG Wrightson Seeds business, Agricom, has had varieties of the herbaceous weed in the market for some time.
The company suspected that its Ecotain cultivars reduced nitrogen leaching, but the issue was understanding exactly how and proving the results scientifically.
The Callaghan Innovation-backed Greener Pastures project was born. Working alongside Lincoln and Massey Universities and Plant & Food Research, Agricom demonstrated that Ecotain works in four different ways and together these mechanisms create a drastic reduction in nitrogen leaching.
“It was a high-risk project, and there was not a lot of certainty around what we thought,” Greener Pastures Leader Glenn Judson says.
“It’s been a really good partnership in tackling what is a national issue,” he says. “We are hugely appreciative of the help we got from Callaghan Innovation. With that support we’ve been able to answer a lot of questions.”
Justin Andrist, Callaghan Innovation’s Christchurch-based Customer Manager for Agritech, says the agency provided a significant co-funded project grant and plenty of advice. “I met with PGG Wrightson Seeds’ R&D team every couple of months for around two years, as we worked through the project’s risks and identified the partners they would use for the project,” Justin says. “With R&D there are some risks you can’t mitigate, but a lot more you can do with good planning.”
Four features in one plant
Agricom has been able to show that Ecotain used as forage works in four ways:
Dilute – the plant acts as a diuretic, which means that animals eating it produce more urine with a lower concentration of nitrogen;
Reduce – stock grazing on Ecotain utilise more nitrogen in their systems, leading to less in their pee;
Delay – the plant slows down the nitrification process in the soil, giving the pasture more time to take it up;
Restrict – Ecotain also suppresses the nitrification process meaning there’s less nitrogen available for leaching.
There is now plenty of evidence showing the effect of the four mechanisms, Judson says. Following the Greener Pastures project, and the Dairy NZ-led Forage for Reduced Nitrate Leaching programme, there is a series of peer-reviewed scientific papers supporting the findings, he says.
“We’ve come to the point in some water catchments where, unless something changes, farmers are going to have to reduce stock numbers to meet their environmental obligations,” Judson says.
Unless something changes, farmers are going to have to reduce stock numbers to meet their environmental obligations.
“Ecotain is that game-changer. For some people it will be a licence to continue farming.”
The proof of the pudding will be in the paddock, and the first bags of Ecotain seeds are now on the market. Farmers will have the opportunity this winter to see how the plant can fit into their pasture management systems and improve their environmental footprint.
Meanwhile Agricom continues to develop new and improved Ecotain cultivars.
Updated: 8 July 2019