Carbon cycling in eroding landscapes: geomorphic controls on soil organic C pool composition and C stabilization

Doetterl, Sebastian; Six, Johan; Wesemael, Bas van; Oost, Kristof Van

doi:10.1111/j.1365-2486.2012.02680.x

Cited by 209 publications

(149 citation statements)

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“…temperature, climate, management, plant inputs, soil aggregation, etc.) as the reference locations and the mineralogical characteristics of the soils are also very similar (Doetterl et al, 2012a). As a result, the C content and C quality of the top soil do not show spatial variations within a field and are only weakly associated with topographical variables, even if significant lateral fluxes of C due to erosion occur .…”

Section: Discussionmentioning

confidence: 66%

The fate of buried organic carbon in colluvial soils: a long-term perspective

et al. 2014

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Abstract. Colluvial soils are enriched in soil organic carbon (SOC) in comparison to the soils of upslope areas due to the deposition and progressive burial of SOC. This burial of SOC has important implications for the global carbon cycle, but the long-term dynamics of buried SOC remain poorly constrained. We addressed this issue by determining the SOC burial efficiency (i.e. the fraction of originally deposited SOC that is preserved in colluvial deposits) of buried SOC as well as the SOC stability in colluvial soils. We quantified the turnover rate of deposited SOC by establishing sediment and SOC burial chronologies. The SOC stability was derived from soil incubation experiments and the δ 13 C values of SOC. The C burial efficiency was found to decrease with time, reaching a constant ratio of approximately 17 % by about 1000-1500 yr post-burial. This decrease is attributed to the increasing recalcitrance of the remaining buried SOC with time and a less favourable environment for SOC decomposition with increasing depth. Buried SOC in colluvial profiles was found to be more stable and degraded in comparison to SOC sampled at the same depth at a stable reference location. This is due to the preferential mineralisation of the labile fraction of the deposited SOC. Our study shows that SOC responds to burial over a centennial timescale; however, more insight into the factors controlling this response is required to fully understand how this timescale may vary, depending on specific conditions such as climate and depositional environment.

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Section: Discussionmentioning

confidence: 66%

The fate of buried organic carbon in colluvial soils: a long-term perspective

et al. 2014

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“…Total CO 2 respiration rates of bare soil are often measured as a proxy for potential maximum hetereotrophic respiration (e.g. Doetterl et al 2012), but the processes contributing to CO 2 efflux from soil are greatly changed in the presence of growing roots (Kuzyakov 2006;Paterson et al 2006). The contribution of root-derived CO 2 to total soil CO 2 efflux in experiments in grass species ranges from 36 to 70 % (Werth et al 2006).…”

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confidence: 99%

Investigation of photosynthate-C allocation 27 days after 13C-pulse labeling of Zea mays L. at different growth stages

et al. 2013

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Aims Pulse labeling of crops using 13 C is often employed to trace photosynthesized carbon (C) within crop-soil systems. However, few studies have compared the C distribution for different labeling periods. The overall aim of this study was to determine the length of the monitoring interval required after 13 C-pulse labeling to quantify photosynthate C allocation into plant, soil and rhizosphere respiration pools for the entire growing season of maize (Zea mays L.). Methods Pot grown maize was pulse-labeled with 13 CO 2 (98 at.%) at the beginning of emergence, elongation, heading and grainfilling growth stages. The routing of 13 C into shoot and root biomass, soil CO 2 flux and soil organic carbon (SOC) pools was monitored for 27-days after 13 C-pulse labeling at the beginning of each growth stage. Results The majority of the 13 C was recovered after 27 d in the maize shoots, i.e., 57 %, 53 %, 70 % and 80 %, at the emergence, elongation, heading, and grainfilling stages, respectively. More 13 C was recovered in the root biomass at elongation (27 %) compared to the least at the grainfilling stage (3 %). The amount recovered in the soil was the smallest pool of 13 C at emergence (2.3 %), elongation (3.8 %), heading and grainfilling (less than 2 %). The amount of 13 C recovered in rhizosphere respiration, i.e. 13 CO 2 , was greatest at emergence (26 %), and similar at the elongation, heading and grainfilling stages (~16 %). Conclusions At least 24 days is required to effectively monitor the recovery of 13 C after pulse labeling with 13 CO 2 for maize in plant and soil pools. The recovery of 13 C differed between growth stages and corresponded to the changing metabolic requirements of the plant, which indicated labeling for the entire growth season would more accurately quantify the C budget in plantsoil system.

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“…Hence, there is a higher abundance of easily decomposable organic substances in the topsoils of the depositional sites [74] which was confirmed by higher SOC mineralization rates with regard to total SOC content in the colluvial soils (Figure 3). Additionally, results clearly elucidated that fertilization solely with urea induced positive PEs on SOC ( Table 4) and soil N mineralization (Figure 2).…”

Section: Eroded Versus Colluvial Soilsmentioning

confidence: 51%