 |
| Titel |
Effect of elevated atmospheric CO2 concentration on soil CO2 and N2O effluxes in a loess grassland |
| VerfasserIn |
Dóra Cserhalmi, János Balogh, Marianna Papp, László Horváth, Krisztina Pintér, Zoltán Nagy |
| Konferenz |
EGU General Assembly 2014
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098932
|
| Publikation (Nr.) |
 EGU/EGU2014-14656.pdf |
|
|
|
|
|
| Zusammenfassung |
| Increasing atmospheric CO2 concentration proved to be the primary factor causing global
climate change. Exposition systems to study the response to increasing CO2 levels by the
terrestrial vegetation include the open top chamber (OTC) exposition system, also used in this
study.
Response of biomass growth and ecophysiological variables (e.g. emission of greenhouse
gases (CO2, N2O) from the soil) to elevated atmospheric CO2 concentration were
investigated in the OTC station, located in the Botanical Garden of the Szent István
University, GödöllÅ , Hungary. Loess grassland (Salvio nemorosae – Festucetum rupicolae)
monoliths were studied in OTCs with target air CO2 concentration of 600 mikromol.mol-1 in
3 chambers. The chamber-effect (shade effect of the side of the chambers) was measured in 3
control chambers under present CO2 level. This management was compared to
3 free air parcels under the natural conditions. Changes of soil temperature and
soil water content were recorded in each treatment, while PAR, air temperature,
precipitation, wind velocity and humidity were measured by a micrometeorological station.
Plant biomass was cut down to 5 cm height once a year. Leaf area index (LAI) was
estimated weekly from ceptometer measurements, soil CO2 and N2O effluxes were also
measured weekly during the growing period and less frequently during the rest of the
year.
Soil water content in the upper 30 cm of the soil was lower in the chambers by 3 % (v/v)
in average than in the field plots. Soil temperature in the chambers at 3 cm depth was 1.5oC
lower than in the free air parcels probably due to the shading effect of the larger biomass in
the chambers. In the chambers (both the high CO2 and control ones) biomass values (536.59
±222.43 gm-2) were higher than in the free parcels (315.67 ±73.36 gm-2). Average LAI
was also higher (3.07 ± 2.78) in the chambers than in the free air treatment (2.08 ±
1.95).
Soil respiration values in the high CO2 treatment was higher in the high CO2 chambers
than in the control ones by 12% (P=0.03) during the 3 year of the study.
There was no significant differences between the above ground biomass values in the
elevated CO2 OTC and control OTC in 2010-2012, though the values were higher in the
high CO2 treatment in each year by 5% in average. LAI also did not differ, in the
elevated CO2 OTC its value was 3.07 (±2.37), and in the control OTC was 3.06
(±2.39) in average. N2O emission was monitored between 2007-2012. There was no
demonstrable change in N2O emission of the soil due to the elevated CO2 treatment. |
|
|
|
|
|
|