An expert report commissioned by MAF has confirmed what agricultural leaders have been at pains to avoid acknowledging. The agriculture sector can nearly halve its growth in greenhouse gas emissions since 1990 simply by applying nitrification inhibitors to dairy pasture.

Prepared by Landcare Research, the report estimates this would reduce the emissions New Zealand must otherwise pay for under the Kyoto Protocol by about $400 million at the current market price for quality carbon credits of $30/tonne. And the Sustainability Council has previously reported that farmers can apply these inhibitors to dairy pasture at a profit.

Yet the taxpayer is currently picking up the tab for all agricultural excess emissions – a liability of about $1.5 billion at $30 a tonne. This is a result of Government plans to exempt agriculture from all responsibility for its livestock emissions until 2013.

In other words, taxpayers are being told they need to fork out a $1.5 billion subsidy when it is now confirmed that farmers can cut emissions worth at least $400 million using just one of a number of cost-effective techniques available. It is galling that farming leaders continue to maintain that: “the only way to reduce emissions is to reduce production”.

Nitrification inhibitors significantly reduce nitrous oxide emissions at a profit because the product displaces more expensive urea fertiliser otherwise used to fix nitrogen. Nitrous oxides account for a third of agricultural emissions and are equivalent to twice the greenhouse gas emissions of all New Zealand’s power stations.

The Landcare findings paint a similar picture to the Sustainability Council’s report, A Convenient Untruth, which in June pointed out the national significance of major reductions in nitrous oxide emissions that can be achieved cost-effectively.

Landcare assumes a 67% average rate of effectiveness for nitrification inhibitors whereas the Sustainability Council assumed 70%, and Landcare assumes lower total emissions under business as usual than the MAF projections the Sustainability Council relied on. However, both modelling approaches concur that the use of inhibitors on all dairy pasture would roughly halve the growth in total agricultural emissions since 1990 – up 5.2 Mt in 2005 from the Kyoto base year of 1990.

Landcare also confirms that this tool has the technical potential to eliminate the growth in all agricultural emissions above 1990 levels. This would involve applying it to all sheep and beef pasture as well as dairy land – an approach that has yet to be reported on for its cost-effectiveness.


The Landcare Research report, Developing Revised Emission Factors for Nitrous Oxides Emissions from Agricultural Pastures treated with Nitrification Inhibitors, was first released to the Sustainability Council under the Official Information Act.