scholarly journals Geogenic organic carbon in terrestrial sediments and its contribution to total soil carbon

2020 ◽  
Author(s):  
Fabian Kalks ◽  
Gabriel Noren ◽  
Carsten Mueller ◽  
Mirjam Helfrich ◽  
Janet Rethemeyer ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Sediment Cores ◽  
Sedimentary Rocks ◽  
Loess Soil ◽  
Red Sandstone ◽  
Total Soil ◽  
Incubation Experiments ◽  
Terrestrial Sediments ◽  
Plant Sources

Abstract. Geogenic organic carbon (GOC) from sedimentary rocks is an overlooked fraction in soils that has not been quantified yet, influencing the composition, age and stability of total organic carbon (OC) in soils. In this context GOC is referred to as the OC in bedrocks deposited during sedimentation. However, the contribution of GOC to total soil OC varies with the type of bedrock. So far studies investigating the contribution of GOC derived from different terrestrial sedimentary rocks to soil OC contents are missing. In order to fill this gap, we analysed 10 m long sediment cores at three sites recovered from Pleistocene Loess, Miocene Sand and Triassic Red Sandstone and calculated the amount of GOC based on 14C measurements. 14C ages of bulk sedimentary OC revealed that OC represents a mixture of biogenic and geogenic components. Biogenic refers to OC that entered the sediments recently from plant sources. All sediments contain considerable amounts of GOC (median amounts of 0.10 g kg−1 at the Miocene Sand, 0.27 g kg−1 at the Pleistocene Loess and 0.17 at Red Sandstone) in comparison to subsoil OC contents (between 0.53–15.21 g kg−1). Long-term incubation experiments revealed that this GOC seemed to be comparatively stable against biodegradation. Its possible contribution to subsoil OC stocks (0.3–1.5 m depth) is ~ 2.5 % in soil developed in the Miocene Sand, ~ 8 % in the Loess soil and ~ 12 % at the Red Sandstone site. Thus GOC having no detectable 14C contents influences 14C ages of subsoil OC and thus may partly explain the strong 14C ages increase observed in many subsoils. This is particularly important in soils on terrestrial sediments with comparatively low amounts of OC, where GOC can considerably contribute to total OC stocks.

scholarly journals Geogenic organic carbon in terrestrial sediments and its contribution to total soil carbon

SOIL ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 347-362
Author(s):  
Fabian Kalks ◽  
Gabriel Noren ◽  
Carsten W. Mueller ◽  
Mirjam Helfrich ◽  
Janet Rethemeyer ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Sediment Cores ◽  
Sedimentary Rocks ◽  
Loess Soil ◽  
Soil Mass ◽  
Strong Increase ◽  
Large Contribution ◽  
Red Sandstone ◽  
Total Soil ◽  
Terrestrial Sediments

Abstract. Geogenic organic carbon (GOC) from sedimentary rocks is an overlooked fraction in soils that has not yet been quantified but influences the composition, age, and stability of total organic carbon (OC) in soils. In this context, GOC is the OC in bedrock deposited during sedimentation. The contribution of GOC to total soil OC may vary, depending on the type of bedrock. However, no studies have been carried out to investigate the contribution of GOC derived from different terrestrial sedimentary rocks to soil OC contents. In order to fill this knowledge gap, 10 m long sediment cores from three sites recovered from Pleistocene loess, Miocene sand, and Triassic Red Sandstone were analysed at 1 m depth intervals, and the amount of GOC was calculated based on 14C measurements. The 14C ages of bulk sedimentary OC revealed that OC is comprised of both biogenic and geogenic components. The biogenic component relates to OC that entered the sediments from plant sources since soil development started. Assuming an average age for this biogenic component ranging from 1000–4000 years BP (before present), we calculated average amounts of GOC in the sediments starting at 1.5 m depth, based on measured 14C ages. The median amount of GOC in the sediments was then taken, and its proportion of soil mass (g GOC per kg−1 fine soil) was calculated in the soil profile. All the sediments contained considerable amounts of GOC (median amounts of 0.10 g kg−1 in Miocene sand, 0.27 g kg−1 in Pleistocene loess, and 0.17 g kg−1 in Red Sandstone) compared with subsoil OC contents (between 0.53 and 15.21 g kg−1). Long-term incubation experiments revealed that the GOC appeared comparatively stable against biodegradation. Its possible contribution to subsoil OC stocks (0.3–1.5 m depth) ranged from 1 % to 26 % in soil developed in the Miocene sand, from 16 % to 21 % in the loess soil, and from 6 % to 36 % at the Red Sandstone site. Thus, GOC with no detectable 14C content influenced the 14C ages of subsoil OC and may partly explain the strong increase in 14C ages observed in many subsoils. This could be particularly important in young soils on terrestrial sediments with comparatively low amounts of OC, where GOC can make a large contribution to total OC stocks.

scholarly journals Supplementary material to "Geogenic organic carbon in terrestrial sediments and its contribution to total soil carbon"

2020 ◽  
Author(s):  
Fabian Kalks ◽  
Gabriel Noren ◽  
Carsten Mueller ◽  
Mirjam Helfrich ◽  
Janet Rethemeyer ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Soil Carbon ◽  
Total Soil ◽  
Terrestrial Sediments ◽  
Supplementary Material

The Effects of Long‐term Fertiliser Applications on Soil Organic Carbon and Hydraulic Properties of a Loess Soil in China

2015 ◽  
Vol 27 (1) ◽  
pp. 60-67 ◽  
Author(s):  
Yinguang Shi ◽  
Xining Zhao ◽  
Xiaodong Gao ◽  
Shulan Zhang ◽  
Pute Wu
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Hydraulic Properties ◽  
Loess Soil

scholarly journals Long-term dynamics of buried organic carbon in colluvial soils

2013 ◽  
Vol 10 (8) ◽  
pp. 13719-13751 ◽  
Author(s):  
Z. Wang ◽  
K. Van Oost ◽  
A. Lang ◽  
W. Clymans ◽  
G. Govers
Keyword(s):  
Organic Carbon ◽  
Long Term Effects ◽  
Incubation Experiments ◽  
C Cycle ◽  
Favourable Environment ◽  
Colluvial Soils ◽  
Global Carbon ◽  
Soc Decomposition ◽  
Burial Efficiency

Abstract. Colluvial soils are enriched in soil organic carbon (SOC) in comparison to the soils of upslope areas due to the deposition and subsurface burial of SOC. It has been suggested that the burial of SOC has important implications for the global carbon cycle, but the long-term dynamics of buried SOC remains poorly constrained. We address 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 quantify the turnover rate of deposited SOC by establishing sediment and SOC burial chronologies. The SOC stability is derived from soil incubation experiments and the δ13C values of SOC. The C burial efficiency was found to decrease exponentially with time reaching a constant ratio of approximately 17%. This exponential decrease is attributed to the increasing recalcitrance of buried SOC with time and a less favourable environment for SOC decomposition with increasing depth. Buried SOC is found to be more stable and degraded in comparison to SOC sampled at the same depth at a stable site. This is due to preferential mineralization of the labile fraction of deposited SOC resulting in enrichment of more degraded and recalcitrant SOC in colluvial soils. In order to better understand the long-term effects of soil erosion for the global C cycle, the temporal variation of deposited SOC and its controlling factors need to be characterized and quantified.

scholarly journals Soil Organic Carbon Sequestration after Biochar Application: A Global Meta-Analysis

Agronomy ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2474
Author(s):  
Arthur Gross ◽  
Tobias Bromm ◽  
Bruno Glaser
Keyword(s):  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Field Experiments ◽  
Meta Analysis ◽  
C Sequestration ◽  
Scale Production ◽  
Fecal Matter ◽  
Incubation Experiments ◽  
Sequestration Potential

Biochar application to soil has the potential to sequester carbon in the long term because of its high stability and large-scale production potential. However, biochar technologies are still relatively new, and the global factors affecting the long-term fate of biochar in the environment are still poorly understood. To fill this important research gap, a global meta-analysis was conducted including 64 studies with 736 individual treatments. Field experiments covered experimental durations between 1 and 10 years with biochar application amounts between 1 and 100 Mg ha−1. They showed a mean increase in soil organic carbon (SOC) stocks by 13.0 Mg ha−1 on average, corresponding to 29%. Pot and incubation experiments ranged between 1 and 1278 days and biochar amounts between 5 g kg−1 and 200 g kg−1. They raised SOC by 6.3 g kg−1 on average, corresponding to 75%. More SOC was accumulated in long experimental durations of >500 days in pot and incubation experiments and 6–10 years in field experiments than in shorter experimental durations. Organic fertilizer co-applications significantly further increased SOC. Biochar from plant material showed higher C sequestration potential than biochar from fecal matter, due to higher C/N ratio. SOC increases after biochar application were higher in medium to fine grain textured soils than in soils with coarse grain sizes. Our study clearly demonstrated the high C sequestration potential of biochar application to agricultural soils of varying site and soil characteristics.

scholarly journals Soil aggregation and aggregate associated organic carbon and total nitrogen under long-term contrasting soil management regimes in loess soil

2015 ◽  
Vol 14 (12) ◽  
pp. 2405-2416 ◽  
Author(s):  
Jun-yu XIE ◽  
Ming-gang XU ◽  
Qiangjiu Ciren ◽  
Yang YANG ◽  
Shu-lan ZHANG ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Total Nitrogen ◽  
Soil Management ◽  
Loess Soil ◽  
Soil Aggregation ◽  
Management Regimes

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

2014 ◽  
Vol 11 (3) ◽  
pp. 873-883 ◽  
Author(s):  
Z. Wang ◽  
K. Van Oost ◽  
A. Lang ◽  
T. Quine ◽  
W. Clymans ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Depositional Environment ◽  
Incubation Experiments ◽  
Favourable Environment ◽  
Colluvial Soils ◽  
Global Carbon ◽  
Insight Into ◽  
Soc Decomposition ◽  
Burial Efficiency

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 δ13C 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.

scholarly journals Sources and characteristics of terrestrial carbon in Holocene-scale sediments of the East Siberian Sea

2017 ◽  
Author(s):  
Kirsi Keskitalo ◽  
Tommaso Tesi ◽  
Lisa Bröder ◽  
August Andersson ◽  
Christof Pearce ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Climate Warming ◽  
Sediment Cores ◽  
Carbon Sources ◽  
Climate Feedback ◽  
Terrestrial Carbon ◽  
Long Term Storage ◽  
East Siberian Sea ◽  
Natural Climate

Abstract. Thawing of permafrost carbon (PF-C) due to climate warming can remobilise considerable amounts of terrestrial carbon from its long term storage to the marine environment. PF-C can be then buried in sediments or remineralised to CO2 with implications for the carbon-climate feedback. Studying historical sediment records during past natural climate changes can help to understand the response of permafrost to current climate warming. In this study two sediment cores collected from the East Siberian Sea were used to study terrestrial organic carbon sources, composition and degradation during the past ~ 9500 cal yrs BP. The CuO-derived lignin and cutin products combined with δ13C suggest that there was a higher input of terrestrial organic carbon to the East Siberian Sea between ~ 9500 and 8200 cal yrs BP than in all later periods. This high input was likely caused by marine transgression and permafrost destabilisation in the early Holocene climatic optimum. Based on source apportionment modelling using dual-carbon isotope (∆14C, δ13C) data, coastal erosion releasing old Pleistocene permafrost carbon was identified as a significant source of organic matter translocated to the East Siberian Sea during the Holocene.

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