Wool may be a rare rural winner in the carbon emissions debate.
As a stable product that maintains its chemical form for a very long time, one researcher believes it could be a valuable livestock “carbon sink” as pressure builds for farm systems to take into account carbon emissions.
Greenhouse gas researcher John Graham, who has been tracking the movement of gases and carbon within crops and pastures, said the carbon content of wool was quite high – "something like 20 per cent".
Mr Graham told producers at a recent field day at Hamilton rough figures suggested on an average farm, tree plantations covering about 10pc of the property could be enough to offset carbon emissions from livestock run on the property.
He’s now looking into the implications for pastures but said monitoring greenhouse gases such as nitrous oxide and carbon dioxide within a living system had proven to be very complicated science.
His research uses data from small controlled carbon monitoring enclosures currently set up at the Hamilton Pastoral and Veterinary research station.
The chambers monitor carbon dioxide readings every half hour.
"When a plant is growing you can see the carbon it is using during the day and the carbon dioxide it releases during the night," Mr Graham said.
"We flush the chamber with a known quantity of gas and measure with a precise laser instrument just what comes out after a certain period of time and we naturally take soil samples as well."
To take away the effect the small enclosure may have, small fans keep outside air circulating through the system and automatic vents also open and close regularly.
Mr Graham said research based on data from the chambers has so far shown there was no significant greenhouse gas difference between high and low fertiliser regimes for pastures.
"You would think that the high producing pasture would be putting in more carbon than the low fertility system but that hasn’t been the case," he said.
In fact it appeared that lighter soils low in carbon may be able to build up their carbon over time but on the heavier soils at the Hamilton research site there had been no significant difference - even within a trial that had been running the fertility down over 25 years.
Conveniently the research station houses a long-term phosphate trial and by monitoring pasture production from both the high and low fertility plots, Mr Graham can see no great difference.
That said he remains concerned for the consequences of ruminants in any carbon trading scheme as the methane emitted by sheep or cattle far outweighs any carbon that may be sequestered in the plants that animal has eaten.
"We need to come any negotiating table with solid figures to back up our position because a carbon trading scheme is on the way and the more positives we find such as wool, the better."
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