title: Carbon sequestration potential of soils in southeast Germany derived from stable soil organic carbon saturation.
abstract: Sequestration of atmospheric carbon (C) in soils through improved management of forest and agricultural land is considered to have high potential for global CO2 mitigation. However, the potential of soils to sequester soil organic carbon (SOC) in a stable form, which is limited by the stabilization of SOC against microbial mineralization, is largely unknown. In this study, we estimated the C sequestration potential of soils in southeast Germany by calculating the potential SOC saturation of silt and clay particles according to Hassink [Plant and Soil 191 (1997) 77] on the basis of 516 soil profiles. The determination of the current SOC content of silt and clay fractions for major soil units and land uses allowed an estimation of the C saturation deficit corresponding to the long-term C sequestration potential. The results showed that cropland soils have a low level of C saturation of around 50% and could store considerable amounts of additional SOC. A relatively high C sequestration potential was also determined for grassland soils. In contrast, forest soils had a low C sequestration potential as they were almost C saturated. A high proportion of sites with a high degree of apparent oversaturation revealed that in acidic, coarse-textured soils the relation to silt and clay is not suitable to estimate the stable C saturation. A strong correlation of the C saturation deficit with temperature and precipitation allowed a spatial estimation of the C sequestration potential for Bavaria. In total, about 395 Mt CO2 -equivalents could theoretically be stored in A horizons of cultivated soils - four times the annual emission of greenhouse gases in Bavaria. Although achieving the entire estimated C storage capacity is unrealistic, improved management of cultivated land could contribute significantly to CO2 mitigation. Moreover, increasing SOC stocks have additional benefits with respect to enhanced soil fertility and agricultural productivity.
authors.affiliation: Lehrstuhl für Bodenkunde, Department für Ökologie und Ökosystemmanagement, Wissenschaftszentrum Weihenstephan für Ernährung, Landnutzung und Umwelt, Technische Universität München, Freising-Weihenstephan, 85350, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wiesmeier
authors.forename: Rico
authors.initials: R
authors.lastname: Hübner
authors.forename: Peter
authors.initials: P
authors.lastname: Spörlein
authors.forename: Uwe
authors.initials: U
authors.lastname: Geuß
authors.forename: Edzard
authors.initials: E
authors.lastname: Hangen
authors.forename: Arthur
authors.initials: A
authors.lastname: Reischl
authors.forename: Bernd
authors.initials: B
authors.lastname: Schilling
authors.forename: Margit
authors.initials: M
authors.lastname: von Lützow
authors.forename: Ingrid
authors.initials: I
authors.lastname: Kögel-Knabner
mesh_terms: D000383:Agriculture; D002244:Carbon / Q000032:analysis; D057965:Carbon Sequestration; D017753:Ecosystem; D005858:Germany; D012987:Soil / Q000737:chemistry*
chemical_list: D012987:Soil; D002244:Carbon
keywords: CO2 mitigation; agricultural management; climate change; soil fractionation; soil organic carbon stocks; stabilization of soil organic matter