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| Titel |
Effect of reed canary grass cultivation on greenhouse gas emission from peat soil at controlled rewetting |
| VerfasserIn |
S. Karki, L. Elsgaard, P. E. Lærke |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 2 ; Nr. 12, no. 2 (2015-01-29), S.595-606 |
| Datensatznummer |
250117792
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| Publikation (Nr.) |
 copernicus.org/bg-12-595-2015.pdf |
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| Zusammenfassung |
| Cultivation of bioenergy crops in rewetted peatland (paludiculture) is
considered as a possible land use option to mitigate greenhouse gas (GHG)
emissions. However, bioenergy crops like reed canary grass (RCG) can have a
complex influence on GHG fluxes. Here we determined the effect of RCG
cultivation on GHG emission from peatland rewetted to various extents.
Mesocosms were manipulated to three different ground water levels (GWLs),
i.e. 0, −10 and −20 cm below the soil surface in a controlled
semi-field facility. Emissions of CO2 (ecosystem respiration, ER),
CH4 and N2O from mesocosms with RCG and bare soil were measured at
weekly to fortnightly intervals with static chamber techniques for a period
of 1 year. Cultivation of RCG increased both ER and CH4 emissions, but
decreased the N2O emissions. The presence of RCG gave rise to 69, 75 and
85% of total ER at −20, −10 and 0 cm GWL, respectively. However,
this difference was due to decreased soil respiration at the rising GWL as
the plant-derived CO2 flux was similar at all three GWLs. For methane,
70–95% of the total emission was due to presence of RCG, with the
highest contribution at −20 cm GWL. In contrast, cultivation of RCG
decreased N2O emission by 33–86% with the major reductions at
−10 and −20 cm GWL. In terms of global warming potential, the increase
in CH4 emissions due to RCG cultivation was more than offset by the
decrease in N2O emissions at −10 and −20 cm GWL; at 0 cm GWL the
CH4 emissions was offset only by 23%. CO2 emissions from ER
were obviously the dominant RCG-derived GHG flux, but above-ground biomass
yields, and preliminary measurements of gross photosynthetic production,
showed that ER could be more than balanced due to the photosynthetic uptake
of CO2 by RCG. Our results support that RCG cultivation could be a good
land use option in terms of mitigating GHG emission from rewetted peatlands,
potentially turning these ecosystems into a sink of atmospheric CO2. |
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