title: Soil carbon isotopic composition and soil carbon content in an agroecosystem during six years of Free Air Carbon dioxide Enrichment (FACE).
abstract: The Free Air Carbon dioxide Enrichment (FACE) experiment conducted at the Federal Agricultural Research Centre (FAL) in Braunschweig in an arable crop rotation (total duration six years) allowed us to trace carbon (C) input in the soil C pool, as the CO(2), used in the experiment to increase the atmospheric CO(2) concentration, was depleted in (13)C. Accurate assessment of the C input by means of stable C isotope analysis requires detailed knowledge on the spatial distribution of both the C isotopic composition and the C content in the soil C. Assumed changes in these parameters were examined. CO(2) enrichment treatment over a six year period resulted in a clear trend towards an increase of soil C content in the uppermost 10 cm of soil. About 4.9% of the soil C present under ambient air conditions, and 10.7% present under elevated CO(2) conditions were determined as new input. However, the results are not statistically significant yet.
authors.affiliation: Institute of Agricultural Climate Research, Johann Heinrich von Thunen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries, Braunschweig, Germany. anette.giesemann@vti.bund.de
authors.forename: Anette
authors.initials: A
authors.lastname: Giesemann
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Weigel
mesh_terms: D000383:Agriculture; D000388:Air / Q000032:analysis*; D002244:Carbon / Q000032:analysis; D002245:Carbon Dioxide / Q000032:analysis*; D002247:Carbon Isotopes / Q000032:analysis*; D018556:Crops, Agricultural; D017753:Ecosystem; D007553:Isotope Labeling / Q000379:methods; D012987:Soil / Q000032:analysis*
chemical_list: D002247:Carbon Isotopes; D012987:Soil; D002245:Carbon Dioxide; D002244:Carbon