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| Titel |
Carbon sink activity is stronger under grazing than under mowing: results from a paired eddy flux towers experiment |
| VerfasserIn |
Krisztina Pintér, János Balogh, Péter Koncz, Dóra Hidy, Dóra Cserhalmi, Marianna Papp, Szilvia Fóti, Zoltán Nagy |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098827
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| Publikation (Nr.) |
 EGU/EGU2014-14542.pdf |
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| Zusammenfassung |
| Effect of grazing vs. mowing on carbon balance of a grassland was investigated by a paired
eddy towers (one of them measuring the grazed, the another the mowed treatment)
experiment at the Bugacpuszta sandy grassland site (HU-Bug, 46.69° N, 19.6° E, 114m asl,
10.4 °C annual mean temperature, 562 mm annual precipitation sum) located in the
Hungarian Plain. Eddy covariance measurements started in July, 2002. The area of the
mowed treatment is 1 ha, it is located within the grazed treatment (500 ha). Electric fence was
set up around the selected area in spring of 2011. Study years include 2011, 2012
and 2013. The pasture is managed extensively (average grazing pressure of 0.5
cattle per hectare), the cattle herd regularly took several kilometres during a grazing
day.
Annual net ecosystem exchange (NEE) of the grassland is strongly limited by
precipitation, there were 2 source years within the 11 years (2003-2013) of measurements,
during which the average annual balance was –109gCm-2year-1 with standard deviation of
106gCm-2year-1.
Carbon sink activity of the grassland was stronger in the grazed treatment than in the
mowed treatment during the three year study period (paired t-test, P=0.058). In the grazed
treatment the average sink strength was –142.8±40gCm-2year-1, while in the mowed
treatment the average sink strength was –61.5±46.5gCm-2year-1.
Differences of carbon balances between the treatments were positively correlated to the
annual sum of evapotranspiration (ET), while ETs of the treatments were almost identical
(differences within a 10mm year-1 range) in each study year. Water use efficiency in the
mowed treatment was 44% of that in the grazed treatment (P=0.045) as a result of the
differences in sink capacity. The higher sensitivity to drought by the mowed treatment
manifested in decreased sink capacity during summer and in decreased regeneration
capacity during autumn rains as shown by the cumulative NEE in the different
years.
Minor but consistent differences in total ecosystem respiration (Reco) (higher in the
mowed treatment by 5-13%) and gross primary production (GPP) (lower in the mowed
treatment by only up to 3%) resulted in significantly weaker sink activity with NEEmowed to
NEEgrazed ratios of 56%, 60% and 10% in 2011, 2012 and 2013, respectively. |
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