Are there memory effects on greenhouse gas emissions (CO2, N2O and CH4) following grassland restoration?

Abstract. A 5-year greenhouse gas (GHG) exchange study of the three major gas species (CO2, CH4 and N2O) from an intensively managed permanent grassland in Switzerland is presented. Measurements comprise 2 years (2010 and 2011) of manual static chamber measurements of CH4 and N2O, 5 years of continu...

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Autores principales: Merbold, Lutz, Decock, Charlotte, Eugster, Werner, Fuchs, Kathrin, Wolf, Benjamin, Buchmann, Nina, Hörtnagl, Lukas
Formato: Journal Article
Lenguaje:Inglés
Publicado: Copernicus GmbH 2021
Materias:
Acceso en línea:https://hdl.handle.net/10568/129339
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author Merbold, Lutz
Decock, Charlotte
Eugster, Werner
Fuchs, Kathrin
Wolf, Benjamin
Buchmann, Nina
Hörtnagl, Lukas
author_browse Buchmann, Nina
Decock, Charlotte
Eugster, Werner
Fuchs, Kathrin
Hörtnagl, Lukas
Merbold, Lutz
Wolf, Benjamin
author_facet Merbold, Lutz
Decock, Charlotte
Eugster, Werner
Fuchs, Kathrin
Wolf, Benjamin
Buchmann, Nina
Hörtnagl, Lukas
author_sort Merbold, Lutz
collection Repository of Agricultural Research Outputs (CGSpace)
description Abstract. A 5-year greenhouse gas (GHG) exchange study of the three major gas species (CO2, CH4 and N2O) from an intensively managed permanent grassland in Switzerland is presented. Measurements comprise 2 years (2010 and 2011) of manual static chamber measurements of CH4 and N2O, 5 years of continuous eddy covariance (EC) measurements (CO2–H2O – 2010–2014), and 3 years (2012–2014) of EC measurement of CH4 and N2O. Intensive grassland management included both regular and sporadic management activities. Regular management practices encompassed mowing (three to five cuts per year) with subsequent organic fertilizer amendments and occasional grazing, whereas sporadic management activities comprised grazing or similar activities. The primary objective of our measurements was to compare pre-plowing to post-plowing GHG exchange and to identify potential memory effects of such a substantial disturbance on GHG exchange and carbon (C) and nitrogen (N) gains and losses. In order to include measurements carried out with different observation techniques, we tested two different measurement techniques jointly in 2013, namely the manual static chamber approach and the eddy covariance technique for N2O, to quantify the GHG exchange from the observed grassland site. Our results showed that there were no memory effects on N2O and CH4 emissions after plowing, whereas the CO2 uptake of the site considerably increased when compared to pre-restoration years. In detail, we observed large losses of CO2 and N2O during the year of restoration. In contrast, the grassland acted as a carbon sink under usual management, i.e., the time periods 2010–2011 and 2013–2014. Enhanced emissions and emission peaks of N2O (defined as exceeding background emissions 0.21 ± 0.55 nmol m−2 s−1 (SE = 0.02) for at least 2 sequential days and the 7 d moving average exceeding background emissions) were observed for almost 7 continuous months after restoration as well as following organic fertilizer applications during all years. Net ecosystem exchange of CO2 (NEECO2) showed a common pattern of increased uptake of CO2 in spring and reduced uptake in late fall. NEECO2 dropped to zero and became positive after each harvest event. Methane (CH4) exchange fluctuated around zero during all years. Overall, CH4 exchange was of negligible importance for both the GHG budget and the carbon budget of the site. Our results stress the inclusion of grassland restoration events when providing cumulative sums of C sequestration potential and/or global warming potential (GWP). Consequently, this study further highlights the need for continuous long-term GHG exchange observations as well as for the implementation of our findings into biogeochemical process models to track potential GHG mitigation objectives as well as to predict future GHG emission scenarios reliably.
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spelling CGSpace1293392025-12-08T09:54:28Z Are there memory effects on greenhouse gas emissions (CO2, N2O and CH4) following grassland restoration? Merbold, Lutz Decock, Charlotte Eugster, Werner Fuchs, Kathrin Wolf, Benjamin Buchmann, Nina Hörtnagl, Lukas greenhouse gas emissions restoration effects memory gas emissions Abstract. A 5-year greenhouse gas (GHG) exchange study of the three major gas species (CO2, CH4 and N2O) from an intensively managed permanent grassland in Switzerland is presented. Measurements comprise 2 years (2010 and 2011) of manual static chamber measurements of CH4 and N2O, 5 years of continuous eddy covariance (EC) measurements (CO2–H2O – 2010–2014), and 3 years (2012–2014) of EC measurement of CH4 and N2O. Intensive grassland management included both regular and sporadic management activities. Regular management practices encompassed mowing (three to five cuts per year) with subsequent organic fertilizer amendments and occasional grazing, whereas sporadic management activities comprised grazing or similar activities. The primary objective of our measurements was to compare pre-plowing to post-plowing GHG exchange and to identify potential memory effects of such a substantial disturbance on GHG exchange and carbon (C) and nitrogen (N) gains and losses. In order to include measurements carried out with different observation techniques, we tested two different measurement techniques jointly in 2013, namely the manual static chamber approach and the eddy covariance technique for N2O, to quantify the GHG exchange from the observed grassland site. Our results showed that there were no memory effects on N2O and CH4 emissions after plowing, whereas the CO2 uptake of the site considerably increased when compared to pre-restoration years. In detail, we observed large losses of CO2 and N2O during the year of restoration. In contrast, the grassland acted as a carbon sink under usual management, i.e., the time periods 2010–2011 and 2013–2014. Enhanced emissions and emission peaks of N2O (defined as exceeding background emissions 0.21 ± 0.55 nmol m−2 s−1 (SE = 0.02) for at least 2 sequential days and the 7 d moving average exceeding background emissions) were observed for almost 7 continuous months after restoration as well as following organic fertilizer applications during all years. Net ecosystem exchange of CO2 (NEECO2) showed a common pattern of increased uptake of CO2 in spring and reduced uptake in late fall. NEECO2 dropped to zero and became positive after each harvest event. Methane (CH4) exchange fluctuated around zero during all years. Overall, CH4 exchange was of negligible importance for both the GHG budget and the carbon budget of the site. Our results stress the inclusion of grassland restoration events when providing cumulative sums of C sequestration potential and/or global warming potential (GWP). Consequently, this study further highlights the need for continuous long-term GHG exchange observations as well as for the implementation of our findings into biogeochemical process models to track potential GHG mitigation objectives as well as to predict future GHG emission scenarios reliably. 2021-03-02 2023-03-10T14:33:27Z 2023-03-10T14:33:27Z Journal Article https://hdl.handle.net/10568/129339 en Open Access Copernicus GmbH Merbold, Lutz; Decock, Charlotte; Eugster, Werner; Fuchs, Kathrin; Wolf, Benjamin; Buchmann, Nina; Hörtnagl, Lukas. 2021. Are there memory effects on greenhouse gas emissions CO2, N2O and CH4 following grassland restoration?. Biogeosciences 18: 1481-1498
spellingShingle greenhouse gas emissions
restoration
effects
memory
gas emissions
Merbold, Lutz
Decock, Charlotte
Eugster, Werner
Fuchs, Kathrin
Wolf, Benjamin
Buchmann, Nina
Hörtnagl, Lukas
Are there memory effects on greenhouse gas emissions (CO2, N2O and CH4) following grassland restoration?
title Are there memory effects on greenhouse gas emissions (CO2, N2O and CH4) following grassland restoration?
title_full Are there memory effects on greenhouse gas emissions (CO2, N2O and CH4) following grassland restoration?
title_fullStr Are there memory effects on greenhouse gas emissions (CO2, N2O and CH4) following grassland restoration?
title_full_unstemmed Are there memory effects on greenhouse gas emissions (CO2, N2O and CH4) following grassland restoration?
title_short Are there memory effects on greenhouse gas emissions (CO2, N2O and CH4) following grassland restoration?
title_sort are there memory effects on greenhouse gas emissions co2 n2o and ch4 following grassland restoration
topic greenhouse gas emissions
restoration
effects
memory
gas emissions
url https://hdl.handle.net/10568/129339
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