Pedosphere 15(6): 728--738, 2005
ISSN 1002-0160/CN 32-1315/P
©2005 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Carbon turnover in a crop rotation under free air CO2 enrichment (FACE) |
H. J. WEIGEL1 , A. PACHOLSKI1, S. BURKART1, M. HELAL1, O. HEINEMEYER1, B. KLEIKAMP1, R. MANDERSCHEID1, C. FRÜHAUF2, G. F. HENDREY3, K. LEWIN3 and J. NAGY3 |
1 Institute of Agroecology, Federal Agricultural Research Centre (FAL), Bundesallee 50, 38116 Braunschweig (Germany). E-mail: hans.weigel@fal.de;
2 German Weather Service, Agriculture Department, Kreuzweg 25, 65366 Geisenheim (Germany);
3 Earth Systems Sciences Division, Brookhaven National Laboratory Building 490D, P.O. Box 5000, Upton, NY 11973 (USA) |
| ABSTRACT |
| Mostly based on assumptions derived from controlled-environment studies, predicted future atmospheric CO2 concentrations [CO2] are expected to have considerable impacts on carbon (C) turnover in agro-ecosystems. In order to allow the in situ examination of C-transformations in the plant-soil system of arable crop rotations under future [CO2], a free air carbon dioxide enrichment (FACE) experiment (550 μmol mol-1 CO2) was started at Braunschweig, Germany in 1999. The crop rotation under investigation comprised winter barley, a cover crop (ryegrass), sugar beets and winter wheat. Assessments of CO2 effects included the determination of above-and belowground biomass production, measurements of canopy CO2- and H2O- fluxes, soil microbial biomass and in situ soil respiration. The results obtained during the 1st crop rotation cycle (3 years) showed that for the selected crops elevated [CO2] entailed significant positive effects (P < 0.05) on aboveground (6%-14% stimulation) and belowground biomass production (up to 90%stimulation), while canopy evapotranspiration was reduced. This resulted in increased soil water content. Also, depending on crop type and season, high CO2 stimulated in situ soil respiration (up to 30%), while soil microbial biomass did not show significant responses to elevated [CO2] during the first rotation cycle. |
| Key Words: agroecosystems, carbon, elevated CO2, FACE, soil |
| Citation: Weigel, H. J., Pacholski, A., Burkart, S., Helal, M., Heinemeyer, O., Kleikamp, B., Manderscheid, R., FrÜhauf, C., Hendrey, G. F., Lewin, K. and Nagy, J. 2005. Carbon turnover in a crop rotation under free air CO2 enrichment (FACE). Pedosphere. 15(6): 728-738. |
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