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.

Spatial-Temporal Changes of Soil Organic Carbon Content in Wafangdian, China

“…Dramatic land-use change, such as shifts from forest to cultivation or grassland, resulted in a completely different soil environment in terms of soil moisture and temperature regimes. It significantly influenced organic matter accumulation and decomposition dynamics [6,64]. Zhao et al [7] reported that soil organic matter (SOM) in about 26 year, when upland was changed to paddy field, had the largest increase of 5.41 ± 3.95 g k −1 in Jiangsu Province of China.…”

“…In addition, SOC is closely related to soil quality, nutrient availability and crop yield [5]. Its decomposition can increase atmospheric CO 2 levels [6], and its sequestration can significantly mitigate global climate change [7]. Changes in land use from native vegetation to agriculture are able to cut down on SOC levels [8,9] and increase atmospheric carbon dioxide concentration [10].…”

Biogeochemical silicon cycle and carbon sequestration in agricultural ecosystems

“…Organic C can be chemically fixed and protected by silt and clay particles through various organo-mineral associations including interactions with aluminosilicates and hydrous oxides (Hassink, 1997;Jastrow et al, 2007;Vogel et al, 2014;Wiesmeier et al, 2014). For example, complexation of organic C with aluminosilicates may occur through multivalent cation bridges between clay platelets and organic C in soils dominated by smectite and/or illite (Jastrow et al, 2007).…”

Carbon sequestration in agricultural soils via cultivation of cover crops – A meta-analysis

“…Cultivation leads to SOC losses of 30-40% compared to natural or semi-natural vegetation Poeplau et al, 2011). In a regional study, Wiesmeier et al (2013) calculated a mean carbon saturation for Bavarian cropland soils of 53%. Historically, between 32.5 and 35.7 million km 2 of natural vegetation, encompassing forests, woodlands, savannas, grasslands and steppes have been converted to croplands (DeFries et al, 1999).…”