Science Centres: Energy

Nitrous oxide in the paddock

Nitrous oxide (N₂O) is a potent greenhouse gas accounting for about 20% of New Zealand’s current inventory of 'Kyoto emissions'.

Roughly half of New Zealand’s N₂O emissions come from the breakdown of cattle excreta and another 15% from nitrogen fertiliser. The emissions have increased by about 30% between 1990 and 2003. Not surprisingly, the farming and fertiliser industries have a strong interest in N₂O (including the use of commercial nitrification inhibitors).

NIWA is part of the N_ZO Net technical group, including Landcare Research, AgResearch, Ministry of Agriculture & Forestry, and the Ministry for the Environment, which has been refining the inventory estimates over the past six years.

N₂O is a difficult gas to measure, especially on a farm: background levels are low compared with methane or carbon dioxide, and the levels fluctuate seasonally and in irregular, short-term ways. We are developing methods to conduct field measurements and to estimate regional scale emissions under contract to Landcare Research. We look at paddock-scale fluxes and examine the climate factors (e.g., soil moisture and temperature) which influence N₂O levels. Later this year, NIWA will conduct a major field study with leading experts from Agriculture and AgriFood Canada to produce precise measurements of dairy farm greenhouse gas production.