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16 Design the life you want Vol 22 No 29, July 29, 2024
View online at farmersweekly.co.nz
Richard Rennie
TECHNOLOGY
A
Arable
SCIENTIFIC review paper has torpedoed research underpinning a multimillion-dollar plantain project hoping to see the plant deployed as a nitrate busting solution for dairy farmers. The New Zealand Journal of Agricultural Research has just published a scientific review of 15 years of plantain research in NZ. The report’s authors include Dr Tony Connor of Lincoln Genetics, a former manager of AgResearch’s forage science division. The review’s findings indicate aspects of plantain’s ability to absorb nitrates and to mitigate losses are suspect, and say there may be better alternative species worthy of further research work. The review comes as the sevenyear Sustainable Food and Fibre Futures (SFFF) plantain potency project passes the halfway mark, having spent $12.6 million of its $22m funding. The project was launched in 2021 to help improve waterway quality and nitrate losses. It comprises $9m of funding from the Ministry for Primary Industries and $10.47m in cash from DairyNZ, Fonterra and PGG Wrightson Seeds. The remaining $2.8 million is provided in kind. Plantain has been promised to farmers as one of the most viable tools to help deliver improvements
to nitrate levels, thanks in part to its claimed diluting effects on cow urine N levels, and its ability to reduce nitrate runoff through the soil profile. DairyNZ’s own modelling has estimated it could reduce N losses by 15,000 tonnes a year, and provide savings of $1 billion between 2031 and 2040. Three other areas the research is focusing on include plantain’s ability to partition more N into dung than urine, to directly prevent N leaching through soil, and to indirectly mitigate N breakdown in soils, thanks to particular metabolites in the grass. Connor said other forages have not been adequately studied for their potential value as N-mitigation tools. “Clearly plantain increases urination, we suspect that’s because it has a relatively high water content. But there are other forage with a higher water content that might perform as equally well as plantain.” These include chicory and tetraploid ryes. While helping lower N levels, plantain has also proven difficult for farmers to establish in their pasture swards and is consistently lower in yield than diploid ryegrasses. In an extensive written response to Farmers Weekly, DairyNZ scientists defend the move to focus on plantain in the project. Continued page 3
S FOECT CU OR S
Review rips into plantain as N buster
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