Agricom science lead Dr Glenn Judson points to an 89 per cent reduction in nitrogen leaching in one trial.
A genotype of a common weed may become a super-saviour in helping reduce N-leaching
A plantain that started life as a common weed has been shown to have the ability to significantly reduce nitrogen leaching from the urine patch.
Proprietary seed company Agricom has bred the specific plantain genotype and
says the breakthrough could significantly reduce the nitrogen leaching from
New Zealand's 6.5 million dairy cattle.
Most nitrogen leaching from animal farms comes from urine patches that hold a concentrated amount of nitrogen.
"It means that we can add effective plantain cultivars to the range of options we are building for farmers to reduce nutrient loss."
Agricom has been working alongside researchers at Lincoln and Massey universities and Plant & Food Research to discover how this unique genotype of plantain, called Ecotain, can function in pasture systems to reduce nitrogen leaching.
The plantain, officially deemed a herb, began life as a common flat weed (Plantago lanceloata) which has been commercialised into a successful forage cultivar.
The resulting plantain, Ecotain, is part of Agricom's nitrogen management system NSentinel4, and works across a variety of environmental processes on-farm to decrease leaching.
Agricom NZ sales and marketing manager Mark Brown says the system has huge potential.
"Ecotain is a simple and effective tool to help combat the incredibly complex issue of nitrogen leaching, and it's a solution that has been developed by industry, for industry."
Science lead Dr Glenn Judson says, depending on various on-farm factors and the extent to which Ecotain is used, the nitrogen reduction is "very significant". In one trial, leaching was reduced by 89 per cent.
Ecotain can be used as a special purpose crop, often with clover, or in a grass/clover/Ecotain mixed pasture system. It can also be oversown into existing pasture.
A pure sward of Ecotain is favoured for its high summer yield and cool season activity, suited to dairy farms where the amount and quality of summer pasture often limits milk production.
Ecotain is highly complementary in a mixed pasture system, providing a good balance of seasonal production and summer quality.
Dr Judson says sheep and beef farmers are the predominant users of the plantain. While dairy farmers are more familiar with the use of chicory, due to its high feed value and resilience to dry periods, results from the Ecotain research so far have been impressive.
"The plants and soil surrounding the urine patch can't absorb all that nitrogen, so it's easily leached away below the root zone and into the water table. Research is showing us that controlling the nitrogen in the urine patch is the most practical way of reducing leaching."
Ecotain does this in four ways: it increases the volume of cows' urine which dilutes the concentration of nitrogen; it reduces the total amount of nitrogen in animals' urine; it delays the process of turning ammonium into nitrate in the urine patch; and it restricts the accumulation of nitrate in Ecotain-growing soil. In the NSentinel 4 nitrogen management system, these four mechanisms are referred to as dilute, reduce, delay, restrict.
DairyNZ, New Zealand's dairy farmer representative body, has carried out work with plantain as part of its Pastoral21 and FRNL programmes. Both programmes aim to reduce nitrate leaching losses by 20-30 per cent by delivering proven, adoptable, and profitable pasture and forage crop options.
Bruce Thorrold, strategy and investment leader for productivity at DairyNZ,
hails the research as "important and exciting".
"It means that we can add effective plantain cultivars to the range of options we are building for farmers to reduce nutrient loss." There is still a lot to be learnt before we can be confident in predicting the farm scale impact of different plantains across New Zealand, and experience has taught us that it is important to test new innovations in whole systems, across several years and under different soil types and climates."