Carbon-dioxide balance of grassland ecosystems

Grassland ecosystems are providing a wide range of important ecosystem services. These services include climate change mitigation (grasslands are potential sinks for atmospheric CO2) and food production. The carbon sequestering capacity of grasslands can be impaired by climate extremes (Nagy et al. 2007, 2011a; Pintér et al 2011) and improper management practices. Vulnerability of these ecosystems can be measured by their annual scale variability of carbon balance (net ecosystem exchange, NEE).

Research goals include quantification of carbon balance components in the long term at two eddy covariance grassland sites (referred to as HU_BUG and HU_MAT int he fluxnet database). Interannual variation of NEE is a key feature of grassland ecosystems and may show their vulnerabilities and adaptation potentials under a warmer and drier climate (Nagy et al 2011a; Pintér et al 2011).
Management can seriously affect the full GHG balance (including other GHGs like N2O and CH4) of pastures. In this respect effect of mowing and grazing are investigated and modelled using the Biome-BGC and PASIM models using local management data (lateral transfers, grazing pressure, etc.).
One of the critical issues in ecosystem responses to warming is the response by the soils. The main question here is whether and to what degree are the ecosystems able to modify the classical exponential rise of respiration in response to warming, what can be the traits of the adaptive behaviour, and how the different soil respiration components respond to warming (Balogh et al., 2011).
Ongoing supporting studies include those on grassland phenology (LAI, biomass) on spatial heterogeneity of primary functions like NEE and evaporation (remotely sensed multi and hyperspectral data).

We investigate the carbon balance of two grasslands in Hungary by eddy covariance method:

Results of the eddy covariance measurements (NEE)

- blue shades indicate CO2 uptake (photosynthesis)
- green/yellow/red colors indicate CO2 release (respiration)

Participants:
Dr. Nagy Zoltán, Dr. Balogh János, Dr. Pintér Kriszta, Dr Hidy Dóra, Dr. Péli Evelin, Déry Helga,Dóra Cserhalmi, Marianna Papp, Peter Koncz
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Running projects and research supports
AnimalChange FP7 , Plant Ecological Research Group (MTA-SZIE), Hungarian National Research Fund (OTKA) PD 100575, PD 105944: Decrease of uncertainty of natural grassland's carbon dioxide exchange

Closed projects
Hungarian National Research Fund (OTKA) K75638, CarboEurope (FP6), NitroEurope (FP6), CarboMont (FP5), GreenGrass (FP5

Partners
CzechGlobe, Biotechnical Faculty, University of Ljubljana, INRA

Selected publications:

Extensive grazing in contrast to mowing is climate-friendly based on the farm-scale greenhouse gas balance
Péter Koncz, Krisztina Pintér, János Balogh, et al.
AGRICULTURE, ECOSYSTEMS & ENVIRONMENT 240: http://dx.doi.org/10.1016/j.agee.2017.02.022 (2017)

J. Balogh, K. Pintér, Sz. Fóti,M. Papp , D. Cserhalmi , Z. Nagy (2011): Dependence of soil respiration on soil moisture, clay content, soil organic matter and CO2 uptake in dry grasslands. SOIL BIOLOGY & BIOCHEMISTRY 43: pp. 1006-1013. IF: 3.504

Z. Nagy, K. Pintér, M. Pavelka, E. Darenová, J. Balogh (2011): Carbon balance of surfaces vs. ecosystems: advantages of measuring eddy covariance and soil respiration simultaneously in dry grassland ecosystems, BIOGEOSCIENCES 8: pp. 2523-2534. IF: 3.859

K. Pintér, J. Balogh, Z. Nagy (2010): Ecosystem scale carbon dioxide balance of two grasslands in Hungary under different weather conditions. ACTA BIOLOGICA HUNGARICA 61: pp. 150-155. IF: 0.793

K. Pintér, Z. Barcza, J. Balogh,Sz. Czóbel, Zs. Csintalan, Z. Tuba, Z. Nagy (2008): Interannual variability of grasslands' carbon balance depends on soil type. COMMUNITY ECOLOGY 9:(Supl. 1. ) pp. 43-48. IF: 0.898

Z. Nagy, K. Pintér,Sz. Czóbel, J. Balogh, L. Horváth, Sz. Fóti, Z. Barcza, T. Weidinger, Zs. Csintalan, N.Q. Dinh, B. Grosz, Z. Tuba (2007): The carbon budget of a semiarid grassland in a wet and a dry year in Hungary. Agriculture, Ecosystems & Environment 121:(1-2) pp. 21-29. IF: 2.308