CarboZALF and greenhouse gas emission research Jürgen Augustin Müncheberg, March 17th 2010
Role of terrestrial biosphere in the anthropogenic carbon cycle is unclear (reduced sink efficiency?) fossil fuel emissions 2000-2008 PgC CO 2 flux (PgC y -1 ) Sink Source deforestation atmospheric CO 2 land 7.7 1.4 4.1 3.0 0.4-4.7 PgC ocean 2.3 Time (y) 0.3 Residual Global Carbon Project 2009; Le Quéré et al. 2009, Nature Geoscience
Particularly unclear: Significance of agricultural landscapes Influence of land management on the soil functions, carbon dynamics, and global warming potential? Possibilities for the reduction of the agricultural climate impact? (Applies especially to energy crop cultivation controversial discussion) Creation of the project CarboZALF CO 2 exchange steady state CO 2 exchange Sink? Transfer: DOC, DIC, SOC solid CO 2 exchange Source? Photo: R.J. Michel
CarboZALF target results Methodical Multi-scale and multidisciplinary approach for the investigation of the C dynamics (process analysis + modeling) Procedure for the assessment of land use and climate change impact at the complete landscape C dynamics Answers Effect of current land use systems, sites, and climate at the exchange of greenhouse gases and the C sequestration in agricultural landscapes Landscape use systems with reduced climate impact und long-term preservation of the C sequestration potential
First step: Establishing of a multidisciplinary field experiment as a seed crystal (CarboZALF-D) Objective Clearing up the influence of the energy crop cultivation and erosion on soil functions, greenhouse gas exchange, C dynamics, and the climate impact of the north-east German glacial landscape
Leibniz-Centre for Agricultural Landscape Research (ZALF) e. V. What is new at CarboZALF-D? Site selection based on landscape reference and process relevance (Uckermark north-east German glacial landscape: hummocky moraines, peaty lowlands) All relevant C fluxes are included (gaseous, solid, liquid) Manipulation experiments for the erosion Long term field trial (> 10a) experimental site
Greenhouse gas exchange and global warming potential: chamber measurements Manual chambers Big automated chambers: 2.5 m
Parallel: Integration of gas flux investigations on peatlands Up to 5000 t C and 120 t N per ha > 95% of German peatlands drained/rewetted Effects on greenhouse gas exchange are unknown to a large extend! Succow 1988
Approach: Long term gas flux measurements by enclosure and eddy technique (5 sites, 23 variants) Cropland + grassland Willow swamp forest Alder swamp forest Rewetted + flooded fen grassland
Example: reflooding increased global warming potential of former fen grasland (temporally?) Fluctuating wt CO 2 -C equivalents (kg CO 2 -C*ha -1 *a -1 ) Reflooded CO 2 -C equivalents (kg CO 2 -C*ha -1 *a -1 ) 2005 2006 2007 2005 2006 2007 CO 2 * CH 4 N 2 O -62 1 188-85 -1 492 1790 633 372-5000 15239 13 503 29351 13 98 12829 27 Total global warming potential 127 408 2995 10252 29867 12954 (* deducting C export by harvest)
C balances on drained sites: influenced by weather, land use, and ground water level at the same time 1400 g C m -2 yr -1 1200 1000 800 600 400 200 maize 2008 maize 2008 intensiv pasture 2008 extens meadow 2008 extens pasture 2008 pasture 2008 canary meadow 2008 y = -0,1748x 2-33,542x - 256,79 R 2 = 0,8239 pasture 2007 extens meadow 2007 0 extens pasture 2007-70 -60-50 -40-30 -20-10 pasture 0 2007 10 20-200 canary meadow 2007-400 mean groundwater table (cm)
Intermediate conclusion Drained and newly reflooded fens: very strong sources for greenhouse gases Gas fluxes, climate and C balance are influenced by ground-water level, land use, and weather at the same time A reduction of the climate effect seems possible; however, requires sound knowledge
Next step: Clearing up the role of small waters for the carbon dynamics of agricultural landscapes ( CarboAqua ) Hot spots of C/N dynamics and gas fluxes in agricultural landscapes?? Photo: M. Sommer
Outlook: from CarboZALF to Carbo-Landscape Separation and dynamics of the assimilate fluxes in the plant soil system (isotope studies) Modeling of the interactions between a lateral matter transfer and soil C dynamics (different scales, erosion specialists etc.) Including other landscape compartments: grassland, forest, wetlands) Development of a landscape and regional model (+ urban rural relations) General: fund raising, integration into research networks
Thank you for attention!