PARENT SESSION
Poster Session # 13: Biogeochemistry, Photosynthesis, and Respiration.
Tuesday, August 5 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Carbon dynamics of a restored tallgrass prairie chronosequence assessed with stable isotopes.
Smith, Elizabeth*,1, Gonzalez-Meler, Miquel1, Matamala, Roser 2, Jastrow, Julie 2, Miller, Richard2, 1 University of Illinois @ Chicago, Chicago, IL, USA2 Argonne National Laboratory, Argonne, IL, USA
ABSTRACT- Restoration of agricultural fields back to native vegetation has the potential to serve as a sink for atmospheric carbon and therefore mitigate the effects of elevated CO2. At FermiLab (Batavia, IL), tallgrass prairies have been sequentially planted since the mid 1970s establishing a chronosequence in which soil carbon dynamics can be studied. Plant communities consist of forbs, shrubs, and C3 and C4 grasses, and the relative dominance of vegetation type depends on time of the season and restoration age. The different isotopic 13C signatures of C3 and C4 plant tissues are used to determine the C3 and C4 origin of belowground carbon dynamics. Soil respiration, root composition, and soil organic matter were measured for their carbon content as well as their d13C signatures for three restored tallgrass prairies that vary in restoration age from 3 to 25 years of age and compared to a C3 pasture and a remnant prairie (not cultivated for over 500 yrs). Throughout the chronosequence, root biomass and soil respiration increased coinciding with increased plant cover and C4 vegetation dominance in older plots. Fractions of SOM show an increase in C3 carbon in the stable clay fraction. Our results suggest that in soils of a restored tallgrass prairie, carbon of C3 origin has more potential for carbon sequestration than carbon of C4 origin. Implications for carbon sequestration are discussed.
Key words: carbon isotopes, carbon cycling, soil ecology