Two contrasting years of continuous N2O and CO2 fluxes on a shallow-peated drained agricultural boreal peatland

Stephanie Gerin, Henriikka Vekuri, Maarit Liimatainen, Juha-Pekka Tuovinen, Jarkko Kekkonen, Liisa Kulmala, Tuomas Laurila, Maiju Linkosalmi, Jari Liski, Erkki Joki-Tokola, Annalea Lohila

Tutkimustuotos: ArtikkelijulkaisuArtikkeliTieteellinenvertaisarvioitu

Abstrakti

Drained agricultural boreal peatlands comprise a large source of nitrous oxide (N2O) and carbon dioxide (CO2) but a small sink or source of methane (CH4). N2O fluxes have high spatial and temporal variability and are often measured with the chamber technique. Therefore, continuous measurements of N2O fluxes are needed to better understand how N2O emissions are triggered and to reduce the uncertainty of annual N2O budget estimations. Here we present a two-year-long time series of continuous measurements of CO2 and N2O fluxes of a shallow-peated drained agricultural boreal peatland cultivated for grass silage. The fluxes were measured with the area-averaging eddy covariance technique. Several N2O peak events were observed throughout all seasons. The peaks were associated with meteorological or management events, such as soil thawing or freezing, precipitation, fertilization and glyphosate application. The annual N2O budget was 4.74 PLUSMN;0.47 and 6.08 PLUSMN;0.49 kg N2O-N ha-1 y-1in 2020 and 2021, respectively. The annual CO2 budget, comprising the sum of net ecosystem exchange and biomass export, was 3.70 PLUSMN;0.22 and 5.54 PLUSMN;0.33 t CO2-C ha-1 y-1 in 2020 and 2021, respectively. The N2O budget during the first, warmer winter was 106 meteorologically more typical winter, due to the higher frequency of soil freezing-thawing cycles. The average annual N2O budget was 3650EF) while the CO2 budget was in accordance with the IPCC EF. CO2 emissions dominated the total CO2-eq emissions of our site but N2O also had a significant contribution of 12O emissions in the last quarter of 2021. However, the full rotation should be measured to confirm whether there is a need to re-evaluate the N2O IPCC EF for `grassland drained boreal' land-use class.
Alkuperäiskielienglanti
Artikkeli109630
LehtiAgricultural and Forest Meteorology
Vuosikerta341
Sivumäärä12
ISSN0168-1923
DOI - pysyväislinkit
TilaJulkaistu - 15 lokak. 2023
OKM-julkaisutyyppiA1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä, vertaisarvioitu

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