Biofilters and vaccines to stop cattle belching large amounts of methane could be viable solutions to combat New Zealand's agricultural greenhouse gases, scientists say.
The industry and crown partnership, the Pastoral Greenhouse Gas Research Consortium, today outlined some of its research into options for reducing agricultural greenhouse gases, which are cited for producing nearly half the this country's emissions.
The consortium has so far spent $24 million on research into the subject since it started in 2002, and is now spending $5m to $6m each year.
Consortium manager Mark Aspin said he believed the group was well placed for achieving solutions to combat methane and nitrous oxide emissions.
"We still believe real solutions for methane are seven to 10 years away. Nitrous oxide is a little more advanced but it needs proving nationally and across the sectors."
Reducing farming emissions had to be done in an economically viable way and allow the farming industry to stay competitive.
Scientists had to find solutions that really worked, had to be widely adopted to make the maximum impact, and be recognised by climate legislation.
They also needed time to be developed, proved and commercialised. A range of approaches and didn't believe there would be one silver bullet, he said.
The consortium was accelerating its vaccine and inhibitors programme, Mr Aspin said.
Most animal emissions, 80 to 90 percent, came from enteric fermentation in an animal's gut, while most of the balance came from effluent ponds and a smaller amount from dung in pastures.
AgResearch microbiologist Graeme Attwood said the genomics programme had sequenced a prominent methane-producing bacteria genome to try to better understand it.
The idea was to make enzyme inhibitors which would interfere with methane formation reaction in the rumen.
An unexpected discovery was the discovery of a lytic enzyme which could be used to break down methane-producing cells in the rumen.
Vaccines could generally be made cheaply, had a long history of use in farming and were widely accepted, said AgResearch senior scientist Neil Wedlock.
The idea was to generate antibodies in the saliva, which sheep and cattle produce copious amounts of, that would neutralise methane-producing bacteria, and therefore methane in the rumen.
Scientists had proved the vaccine concept could work and was a feasible option to research, he said.
"The vaccine will likely need a cocktail of antigens for perhaps a number of different species."
However, he said a crude vaccine was not the answer and scientists needed to identify the proteins involved.
Once it was produced it would be tested on animals to see if it worked in the real world.
Landcare Research scientist Adrian Walcroft said methane biofilters could be used on dairy farms' effluent ponds and animal housing, such as wintering barns.
The biofilters contain methane consuming bacteria, called methanotropes, and release the much less potent greenhouse gas carbon dioxide.
Methanotropes are found in landfill cap soils, and proved to be effective and responded instantly to process about 98 percent of the methane in lab tests, he said.
"They are sitting there waiting for more and more food to eat."
Methane biofilters could be cost effective on small to medium sized farms , he said.
Methane could be captured and the gas used to generate energy but most dairy farms were too small to warrant the cost, he said.
A prototype biofilter is about to be installed on a Massey University dairy farm.