Skip to main content

page search

Library Soil-atmosphere exchange of nitrous oxide and methane in New Zealand terrestrial ecosystems and their mitigation options: a review

Soil-atmosphere exchange of nitrous oxide and methane in New Zealand terrestrial ecosystems and their mitigation options: a review

Soil-atmosphere exchange of nitrous oxide and methane in New Zealand terrestrial ecosystems and their mitigation options: a review

Resource information

Date of publication
December 2008
Resource Language
ISBN / Resource ID
AGRIS:US201300914494
Pages
25-42

The two non-CO₂ greenhouse gases (GHGs) nitrous oxide (N₂O) and methane (CH₄) comprise 54.8% of total New Zealand emissions. Nitrous oxide is mainly generated from mineral N originating from animal dung and urine, applied fertiliser N, biologically fixed N₂, and mineralisation of soil organic N. Even though about 96% of the anthropogenic CH₄ emitted in New Zealand is from ruminant animals (methanogenesis), methane uptake by aerobic soils (methanotrophy) can significantly contribute to the removal of CH₄ from the atmpsphere, as the global estimates confirm. Both the net uptake of CH₄ by soils and N₂O emissions from soils are strongly influenced by changes in land use and land management. Quantitative information on the fluxes of these two non-CO₂ GHGs is required for a range of land-use and land-management ecosystems to determine their contribution to the national emissions inventory, and for assessing the potential of mitigation options. Here we report soil N₂O fluxes and CH₄ uptake for a range of land-use and land-management systems collated from published and unpublished New Zealand studies. Nitrous oxide emissions are highest in dairy-grazed pastures (10-12 kg N₂O-N ha⁻¹ year⁻ ¹), intermediate in sheep-grazed pastures, (4-6 kg N₂O-N ha⁻¹ year⁻¹), and lowest in forest, shrubland and ungrazed pasture soils (1-2 kg N₂O-N ha⁻¹ year⁻¹). N deposited in the form of animal urine and dung, and N applied as fertiliser, are the principal sources of N₂O production. Generally, N₂O emissions from grazed pasture soils are high when the soil water-filled pore-space is above field capacity, and net CH₄ uptake is low or absent. Although nitrification inhibitors have shown some promise in reducing N₂O emissions from grazed pasture systems, their efficacy as an integral part of farm management has yet to be tested. Methane uptake was highest for a New Zealand Beech forest soil (10-11 kg CH₄ ha⁻¹ year⁻¹), intermediate in some pine forest soils (4-6 kg CH₄ ha⁻¹ year⁻¹), and lowest in most pasture (

Share on RLBI navigator
NO

Authors and Publishers

Author(s), editor(s), contributor(s)

Saggar, Surinder
Tate, K. R.
Giltrap, D. L.
Singh, J.

Publisher(s)
Data Provider
Geographical focus