Field trials of High Metabolisable Energy (HME) ryegrass in the United States have confirmed laboratory forecasts of growth 50% higher than conventional species, higher energy levels promoting livestock growth, more resistance to drought through more efficient water use and 23% less methane emissions because of high levels of lipids.
AgResearch principal scientist Greg Bryan said modelling also predicted lower nitrogen excretion from animals, meaning less nitrate leaching and lower emissions of nitrous oxide.
The results were from a two-month preliminary trial he said does not have statistical merit but scientists saw increased photosynthesis, replicating what happened with plants in greenhouses.
Bryan said while the findings are preliminary they potentially raise questions for NZ about the role of genetically modified organisms (GMOs) as the farming sector grapples with nitrate leaching and methane emissions.
“Is the way the plant is derived here more important than the benefits it provides?”
The field trials are being held in the US midwest because that is easier than getting approval in NZ.
That created some logistical issues for AgResearch scientists who rely on their US counterparts to do some measuring and monitoring.
Bryan said NZ laws could mean framers are not allowed to use HME, which could be made available to farmers overseas.
That decision would be made by partners in the $25 million project, which has received funding from the Ministry of Business, Innovation and Employment’s Endeavour Funds and DairyNZ as well as AgResearch.
Bryan said the Royal Commission on Genetic Modification reported in 2001 it would be unwise to turn our backs on the potential advantages on offer.
Potentially HME’s benefits are significant, boosting farm revenues by $900 a hectare while also helping farmers manage nitrogen run-off and greenhouse gas emissions.
He also noted the area of genetically modified crops internationally is 187 million hectares with the greatest increase occurring in developing nations.
Bryan is pleased with the research progress into HME, which is now turning to animal trials and plant growth.
“In this full trial now under way we will be measuring the photosynthesis, plant growth and the markers that lead to increased growth rates.
“While the growth has previously been studied in glasshouses in pots and as plants spaced out in the field this will be the first opportunity to assess the growth in a pasture-like situation where plants compete with each other.
“The five-month timeframe will allow us to determine if increased growth is consistent across the summer and autumn and we will simulate grazing by cutting plants back every three to four weeks.
“Animal feeding trials are planned to take place in two years, which we will need regulatory approvals for, and the information we get over the next two years will help us with our application for those feeding trials.”
Those trials involve a small number of animals being fed HME pasture in containment rooms for six weeks so researchers can measure plant nutrients and methane and urine nitrate emissions.
Bryan said before that researchers havce to multiply the seed to grow a plot of HME grass big enough to sustain the trial livestock.
The specific cultivars to be used in the trial have been chosen and will be multiplied in greenhouses at AgResearch Grasslands in Palmerston North before shipping to the US.
