Articles | Volume 20, issue 7
https://doi.org/10.5194/bg-20-1529-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-20-1529-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Technical note
| 
17 Apr 2023
Technical note |
| 17 Apr 2023
| 17 Apr 2023
Technical note: The recovery rate of free particulate organic matter from soil samples is strongly affected by the method of density fractionation
Frederick Büks
CORRESPONDING AUTHOR
Dept. of Ecology, Chair of Soil Science, Technische Universität
Berlin, 10587 Berlin, Germany
Related authors
Frederick Büks, Sabine Dumke, and Julia König
EGUsphere, https://doi.org/10.5194/egusphere-2025-771, https://doi.org/10.5194/egusphere-2025-771, 2025
This preprint is open for discussion and under review for Biogeosciences (BG).
Short summary
Short summary
Ultrasonication followed by density fractionation is a frequently used method to determine soil structural stability and the amount of occluded particulate organic matter. Our analyses of three sandy, silty and loamy soils showed that air-drying and gentle rewetting changes SOM fractions depending on the subsequent time of reincubation compared to field-fresh samples. This is important, since e.g. the measurement of archived soils require the handling of air-dried samples.
Frederick Büks and Martin Kaupenjohann
SOIL, 8, 373–380, https://doi.org/10.5194/soil-8-373-2022, https://doi.org/10.5194/soil-8-373-2022, 2022
Short summary
Short summary
The adverse effect of microplastic (MP) on soil biota and soil structure depends on MP particle size and surface characteristics. Since weathering plays a major role in the genesis of these, it must be considered in both the analysis of environmental MP and the production of artificial MP for laboratory experiments. This work integrates recent findings on adverse effects and the genesis of its surface characteristics and discusses how to reproduce them to obtain closer-to-nature designer MP.
Frederick Büks, Gilles Kayser, Antonia Zieger, Friederike Lang, and Martin Kaupenjohann
Biogeosciences, 18, 159–167, https://doi.org/10.5194/bg-18-159-2021, https://doi.org/10.5194/bg-18-159-2021, 2021
Short summary
Short summary
Ultrasonication/density fractionation is a common method used to extract particulate organic matter (POM) and, recently, microplastic (MP) from soil samples. In this study, ultrasonic treatment with mechanical stress increasing from 0 to 500 J mL−1 caused comminution and a reduced recovery rate of soil-derived POMs but no such effects with MP particles. In consequence, the extraction of MP from soils is not affected by particle size and recovery rate artifacts.
Frederick Büks and Martin Kaupenjohann
SOIL, 6, 649–662, https://doi.org/10.5194/soil-6-649-2020, https://doi.org/10.5194/soil-6-649-2020, 2020
Short summary
Short summary
Laboratory experiments that assess microplastic (MP) impact on the terrestrial environment require information on common soil MP concentrations. We reviewed item numbers and mass concentrations recorded in 23 studies, with 223 sampling sites in total with respect to the underlying entry pathways, land uses and vicinities. Common values included amounts of up to 13 000 items kg−1 and 4.5 mg kg−1 dry soil. Based on the collected data, we identified problems in past field studies.
Frederick Büks, Nicolette Loes van Schaik, and Martin Kaupenjohann
SOIL, 6, 245–267, https://doi.org/10.5194/soil-6-245-2020, https://doi.org/10.5194/soil-6-245-2020, 2020
Short summary
Short summary
Via anthropogenic input, microplastics (MPs) today represent a part of the soil organic matter. We analyzed studies on passive translocation, active ingestion, bioaccumulation and adverse effects of MPs on multicellular soil faunal life. These studies on a wide range of soil organisms found a recurring pattern of adverse effects on motility, growth, metabolism, reproduction, mortality and gut microbiome. However, the shape and type of the experimental MP often did not match natural conditions.
Frederick Büks, Philip Rebensburg, Peter Lentzsch, and Martin Kaupenjohann
SOIL Discuss., https://doi.org/10.5194/soil-2016-73, https://doi.org/10.5194/soil-2016-73, 2016
Revised manuscript has not been submitted
Short summary
Short summary
Microbial communities play a role in soil aggregate formation. However, the influence of the microbial community structure on POM occlusion within soil aggregates is still unproved. In this experiment, sterile sandy agricultural soil was incubated in two variants – inoculated with soil extract and infected with air-born microorganisms. After 76 days of incubation soils show a strongly differing microbial populations structure, but no significant difference in POM occlusion.
Frederick Büks and Martin Kaupenjohann
SOIL, 2, 499–509, https://doi.org/10.5194/soil-2-499-2016, https://doi.org/10.5194/soil-2-499-2016, 2016
Short summary
Short summary
Soil aggregate stability and POM occlusion are integral markers for soil quality. Besides physico-chemical interactions, biofilms are considered to aggregate primary particles, but experimental proof is still missing. In our experiment, soil aggregate samples were treated with biofilm degrading enzymes and showed a reduced POM occlusion and an increased bacteria DNA release compared with untreated samples. Thus, biofilms are assumed to be an important factor of POM occlusion in soil aggregates.
Frederick Büks, Philip Rebensburg, Peter Lentzsch, and Martin Kaupenjohann
SOIL Discuss., https://doi.org/10.5194/soil-2016-14, https://doi.org/10.5194/soil-2016-14, 2016
Revised manuscript not accepted
Short summary
Short summary
Soil microbial biofilms are supposed to increase agglomeration of soil particles and therefore reduce erodibility. After inoculation with two strongly differing microbial communities, a sandy agricultural soil did not develop significant differences in aggregate stability. This leads to the assumption that mechanical properties of biofilms do not vary considerably across different biological/chemical compositions, which implies that aggregate stability is a resilient factor of soil fertility.
Frederick Büks, Sabine Dumke, and Julia König
EGUsphere, https://doi.org/10.5194/egusphere-2025-771, https://doi.org/10.5194/egusphere-2025-771, 2025
This preprint is open for discussion and under review for Biogeosciences (BG).
Short summary
Short summary
Ultrasonication followed by density fractionation is a frequently used method to determine soil structural stability and the amount of occluded particulate organic matter. Our analyses of three sandy, silty and loamy soils showed that air-drying and gentle rewetting changes SOM fractions depending on the subsequent time of reincubation compared to field-fresh samples. This is important, since e.g. the measurement of archived soils require the handling of air-dried samples.
Frederick Büks and Martin Kaupenjohann
SOIL, 8, 373–380, https://doi.org/10.5194/soil-8-373-2022, https://doi.org/10.5194/soil-8-373-2022, 2022
Short summary
Short summary
The adverse effect of microplastic (MP) on soil biota and soil structure depends on MP particle size and surface characteristics. Since weathering plays a major role in the genesis of these, it must be considered in both the analysis of environmental MP and the production of artificial MP for laboratory experiments. This work integrates recent findings on adverse effects and the genesis of its surface characteristics and discusses how to reproduce them to obtain closer-to-nature designer MP.
Frederick Büks, Gilles Kayser, Antonia Zieger, Friederike Lang, and Martin Kaupenjohann
Biogeosciences, 18, 159–167, https://doi.org/10.5194/bg-18-159-2021, https://doi.org/10.5194/bg-18-159-2021, 2021
Short summary
Short summary
Ultrasonication/density fractionation is a common method used to extract particulate organic matter (POM) and, recently, microplastic (MP) from soil samples. In this study, ultrasonic treatment with mechanical stress increasing from 0 to 500 J mL−1 caused comminution and a reduced recovery rate of soil-derived POMs but no such effects with MP particles. In consequence, the extraction of MP from soils is not affected by particle size and recovery rate artifacts.
Frederick Büks and Martin Kaupenjohann
SOIL, 6, 649–662, https://doi.org/10.5194/soil-6-649-2020, https://doi.org/10.5194/soil-6-649-2020, 2020
Short summary
Short summary
Laboratory experiments that assess microplastic (MP) impact on the terrestrial environment require information on common soil MP concentrations. We reviewed item numbers and mass concentrations recorded in 23 studies, with 223 sampling sites in total with respect to the underlying entry pathways, land uses and vicinities. Common values included amounts of up to 13 000 items kg−1 and 4.5 mg kg−1 dry soil. Based on the collected data, we identified problems in past field studies.
Frederick Büks, Nicolette Loes van Schaik, and Martin Kaupenjohann
SOIL, 6, 245–267, https://doi.org/10.5194/soil-6-245-2020, https://doi.org/10.5194/soil-6-245-2020, 2020
Short summary
Short summary
Via anthropogenic input, microplastics (MPs) today represent a part of the soil organic matter. We analyzed studies on passive translocation, active ingestion, bioaccumulation and adverse effects of MPs on multicellular soil faunal life. These studies on a wide range of soil organisms found a recurring pattern of adverse effects on motility, growth, metabolism, reproduction, mortality and gut microbiome. However, the shape and type of the experimental MP often did not match natural conditions.
Frederick Büks, Philip Rebensburg, Peter Lentzsch, and Martin Kaupenjohann
SOIL Discuss., https://doi.org/10.5194/soil-2016-73, https://doi.org/10.5194/soil-2016-73, 2016
Revised manuscript has not been submitted
Short summary
Short summary
Microbial communities play a role in soil aggregate formation. However, the influence of the microbial community structure on POM occlusion within soil aggregates is still unproved. In this experiment, sterile sandy agricultural soil was incubated in two variants – inoculated with soil extract and infected with air-born microorganisms. After 76 days of incubation soils show a strongly differing microbial populations structure, but no significant difference in POM occlusion.
Frederick Büks and Martin Kaupenjohann
SOIL, 2, 499–509, https://doi.org/10.5194/soil-2-499-2016, https://doi.org/10.5194/soil-2-499-2016, 2016
Short summary
Short summary
Soil aggregate stability and POM occlusion are integral markers for soil quality. Besides physico-chemical interactions, biofilms are considered to aggregate primary particles, but experimental proof is still missing. In our experiment, soil aggregate samples were treated with biofilm degrading enzymes and showed a reduced POM occlusion and an increased bacteria DNA release compared with untreated samples. Thus, biofilms are assumed to be an important factor of POM occlusion in soil aggregates.
Frederick Büks, Philip Rebensburg, Peter Lentzsch, and Martin Kaupenjohann
SOIL Discuss., https://doi.org/10.5194/soil-2016-14, https://doi.org/10.5194/soil-2016-14, 2016
Revised manuscript not accepted
Short summary
Short summary
Soil microbial biofilms are supposed to increase agglomeration of soil particles and therefore reduce erodibility. After inoculation with two strongly differing microbial communities, a sandy agricultural soil did not develop significant differences in aggregate stability. This leads to the assumption that mechanical properties of biofilms do not vary considerably across different biological/chemical compositions, which implies that aggregate stability is a resilient factor of soil fertility.
Related subject area
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We measured concentrations of nuclear fallout in soil samples taken from arable land in South Africa. We find that during the second half of the 20th century, the data strongly correlate with the organic matter content of the soils. The finding implies that wind erosion strongly influenced the loss of organic matter in the soils we investigated. Furthermore, the exponential decline of fallout concentrations and organic matter content over time peaks shortly after native grassland is ploughed.
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Biogeosciences, 22, 417–433, https://doi.org/10.5194/bg-22-417-2025, https://doi.org/10.5194/bg-22-417-2025, 2025
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Mineral fertilization led to increases in total P, available P, high-activity inorganic P fractions, and organic P but reduced the abundance of P-cycling genes by decreasing soil pH and increasing P in bulk soil. Straw retention enhanced organic carbon, total P, and available P concentrations in water-extractable colloids (WECs). Abundances of the phoD gene and phoD-harboring Proteobacteria in WECs were elevated under straw retention, suggesting an increase in P-mineralization capacity.
Kyle E. Smart, Daniel O. Breecker, Christopher B. Blackwood, and Timothy M. Gallagher
Biogeosciences, 22, 87–101, https://doi.org/10.5194/bg-22-87-2025, https://doi.org/10.5194/bg-22-87-2025, 2025
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When microbes consume carbon within soils, it is important to know how much carbon is respired and lost as carbon dioxide versus how much is used to make new biomass. We used a new approach of monitoring carbon dioxide and oxygen to track the fate of consumed carbon during a series of laboratory experiments where sugar was added to moistened soil. Our approach allowed us to estimate how much sugar was converted to dead microbial biomass, which is more likely to be preserved in soils.
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EGUsphere, https://doi.org/10.5194/egusphere-2024-3324, https://doi.org/10.5194/egusphere-2024-3324, 2024
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While laboratory studies have identified many drivers and their effects on the carbon emission pulse after rewetting of dry soils, a validation with field data is still missing. Here, we show that the carbon emission pulse in the laboratory and in the field increases with soil organic carbon and temperature, but their trends with pre-rewetting dryness and moisture increment at rewetting differ. We conclude that the laboratory findings can be partially validated.
Katherine E. Grant, Marisa N. Repasch, Kari M. Finstad, Julia D. Kerr, Maxwell Marple, Christopher J. Larson, Taylor A. B. Broek, Jennifer Pett-Ridge, and Karis J. McFarlane
Biogeosciences, 21, 4395–4411, https://doi.org/10.5194/bg-21-4395-2024, https://doi.org/10.5194/bg-21-4395-2024, 2024
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Soils store organic carbon composed of multiple compounds from plants and microbes for different lengths of time. To understand how soils store these different carbon types, we measure the time each carbon fraction is in a grassland soil profile. Our results show that the length of time each individual soil fraction is in our soil changes. Our approach allows a detailed look at the different components in soils. This study can help improve our understanding of soil dynamics.
Jet Rijnders, Arthur Vienne, and Sara Vicca
EGUsphere, https://doi.org/10.5194/egusphere-2024-3022, https://doi.org/10.5194/egusphere-2024-3022, 2024
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A mesocosm experiment was set-up to investigate how maize responds to basalt, concrete fines and steel slags application, using a dose-response approach. Biomass increased with basalt application, but did not change with concrete fines or steel slags, except for increased tassel biomass. Mg, Ca and Si generally increased in the crops, while heavy metal concentrations remained unaffected or even decreased in the plants. Overall, crops were positively affected by application of silicate materials.
Peter Levy, Laura Bentley, Peter Danks, Bridget Emmett, Angus Garbutt, Stephen Heming, Peter Henrys, Aidan Keith, Inma Lebron, Niall McNamara, Richard Pywell, John Redhead, David Robinson, and Alexander Wickenden
Biogeosciences, 21, 4301–4315, https://doi.org/10.5194/bg-21-4301-2024, https://doi.org/10.5194/bg-21-4301-2024, 2024
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We collated a large data set (15 790 soil cores) on soil carbon stock in different land uses. Soil carbon stocks were highest in woodlands and lowest in croplands. The variability in the effects was large. This has important implications for agri-environment schemes seeking to sequester carbon in the soil by altering land use because the effect of a given intervention is very hard to verify.
Marija Stojanova, Pierre Arbelet, François Baudin, Nicolas Bouton, Giovanni Caria, Lorenza Pacini, Nicolas Proix, Edouard Quibel, Achille Thin, and Pierre Barré
Biogeosciences, 21, 4229–4237, https://doi.org/10.5194/bg-21-4229-2024, https://doi.org/10.5194/bg-21-4229-2024, 2024
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Because of its importance for climate regulation and soil health, many studies focus on carbon dynamics in soils. However, quantifying organic and inorganic carbon remains an issue in carbonated soils. In this technical note, we propose a validated correction method to quantify organic and inorganic carbon in soils using Rock-Eval® thermal analysis. With this correction, the Rock-Eval® method has the potential to become the standard method for quantifying carbon in carbonate soils.
Claude Raoul Müller, Johan Six, Daniel Mugendi Njiru, Bernard Vanlauwe, and Marijn Van de Broek
EGUsphere, https://doi.org/10.5194/egusphere-2024-2796, https://doi.org/10.5194/egusphere-2024-2796, 2024
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We studied how different organic and inorganic nutrient inputs affect soil organic carbon (SOC) down to 70 cm in Kenya. After 19 years, all organic treatments increased SOC stocks as compared to the control, but mineral nitrogen had no significant effect. Manure was the organic treatment that significantly increased SOC the deepest as its effect could be observed down to 60 cm. Manure was the best strategy to limit SOC loss in croplands and maintain soil quality after deforestation.
Frank Hagedorn, Joesphine Imboden, Pavel Moiseev, Decai Gao, Emmanuel Frossard, Daniel Christen, Konstantin Gavazov, and Jasmin Fetzer
EGUsphere, https://doi.org/10.5194/egusphere-2024-2622, https://doi.org/10.5194/egusphere-2024-2622, 2024
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At treeline, plant species change abruptly from low stature plants in tundra to trees in forests. Our study documents that from tundra towards forest, the litter layer gets strongly enriched in nutrients. We show that these litter quality changes alter nutrient processing by soil microbes and increase the nutrient release during decomposition in forest than in tundra. The associated improvement of nutrient availability in the forest potentially stimulates tree growth and treeline shifts.
Armando Molina, Veerle Vanacker, Oliver Chadwick, Santiago Zhiminaicela, Marife Corre, and Edzo Veldkamp
Biogeosciences, 21, 3075–3091, https://doi.org/10.5194/bg-21-3075-2024, https://doi.org/10.5194/bg-21-3075-2024, 2024
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The tropical Andes contains unique landscapes where forest patches are surrounded by tussock grasses and cushion-forming plants. The aboveground vegetation composition informs us about belowground nutrient availability: patterns in plant-available nutrients resulted from strong biocycling of cations and removal of soil nutrients by plant uptake or leaching. Future changes in vegetation distribution will affect soil water and solute fluxes and the aquatic ecology of Andean rivers and lakes.
Sahiti Bulusu, Cristina Prieto García, Helen E. Dahlke, and Elad Levintal
Biogeosciences, 21, 3007–3013, https://doi.org/10.5194/bg-21-3007-2024, https://doi.org/10.5194/bg-21-3007-2024, 2024
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Do-it-yourself hardware is a new way to improve measurement resolution. We present a low-cost, automated system for field measurements of low nitrate concentrations in soil porewater and open water bodies. All data hardware components cost USD 1100, which is much cheaper than other available commercial solutions. We provide the complete building guide to reduce technical barriers, which we hope will allow easier reproducibility and set up new soil and environmental monitoring applications.
Violeta Mendoza-Martinez, Scott L. Collins, and Jennie R. McLaren
Biogeosciences, 21, 2655–2667, https://doi.org/10.5194/bg-21-2655-2024, https://doi.org/10.5194/bg-21-2655-2024, 2024
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We examine the impacts of multi-decadal nitrogen additions on a dryland ecosystem N budget, including the soil, microbial, and plant N pools. After 26 years, there appears to be little impact on the soil microbial or plant community and only minimal increases in N pools within the soil. While perhaps encouraging from a conservation standpoint, we calculate that greater than 95 % of the nitrogen added to the system is not retained and is instead either lost deeper in the soil or emitted as gas.
Sean Fettrow, Andrew Wozniak, Holly A. Michael, and Angelia L. Seyfferth
Biogeosciences, 21, 2367–2384, https://doi.org/10.5194/bg-21-2367-2024, https://doi.org/10.5194/bg-21-2367-2024, 2024
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Salt marshes play a big role in global carbon (C) storage, and C stock estimates are used to predict future changes. However, spatial and temporal gradients in C burial rates over the landscape exist due to variations in water inundation, dominant plant species and stage of growth, and tidal action. We quantified soil C concentrations in soil cores across time and space beside several porewater biogeochemical variables and discussed the controls on variability in soil C in salt marsh ecosystems.
Andrés Tangarife-Escobar, Georg Guggenberger, Xiaojuan Feng, Guohua Dai, Carolina Urbina-Malo, Mina Azizi-Rad, and Carlos A. Sierra
Biogeosciences, 21, 1277–1299, https://doi.org/10.5194/bg-21-1277-2024, https://doi.org/10.5194/bg-21-1277-2024, 2024
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Soil organic matter stability depends on future temperature and precipitation scenarios. We used radiocarbon (14C) data and model predictions to understand how the transit time of carbon varies under environmental change in grasslands and peatlands. Soil moisture affected the Δ14C of peatlands, while temperature did not have any influence. Our models show the correspondence between Δ14C and transit time and could allow understanding future interactions between terrestrial and atmospheric carbon
Emiko K. Stuart, Laura Castañeda-Gómez, Wolfram Buss, Jeff R. Powell, and Yolima Carrillo
Biogeosciences, 21, 1037–1059, https://doi.org/10.5194/bg-21-1037-2024, https://doi.org/10.5194/bg-21-1037-2024, 2024
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We inoculated wheat plants with various types of fungi whose impacts on soil carbon are poorly understood. After several months of growth, we examined both their impacts on soil carbon and the underlying mechanisms using multiple methods. Overall the fungi benefitted the storage of carbon in soil, mainly by improving the stability of pre-existing carbon, but several pathways were involved. This study demonstrates their importance for soil carbon storage and, therefore, climate change mitigation.
Huimin Sun, Michael W. I. Schmidt, Jintao Li, Jinquan Li, Xiang Liu, Nicholas O. E. Ofiti, Shurong Zhou, and Ming Nie
Biogeosciences, 21, 575–589, https://doi.org/10.5194/bg-21-575-2024, https://doi.org/10.5194/bg-21-575-2024, 2024
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A soil organic carbon (SOC) molecular structure suggested that the easily decomposable and stabilized SOC is similarly affected after 9-year warming and N treatments despite large changes in SOC stocks. Given the long residence time of some SOC, the similar loss of all measurable chemical forms of SOC under global change treatments could have important climate consequences.
Haoli Zhang, Doudou Chang, Zhifeng Zhu, Chunmei Meng, and Kaiyong Wang
Biogeosciences, 21, 1–11, https://doi.org/10.5194/bg-21-1-2024, https://doi.org/10.5194/bg-21-1-2024, 2024
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Soil salinity mediates microorganisms and soil processes like soil organic carbon (SOC) cycling. We observed that negative priming effects at the early stages might be due to the preferential utilization of cottonseed meal. The positive priming that followed decreased with the increase in salinity.
Joséphine Hazera, David Sebag, Isabelle Kowalewski, Eric Verrecchia, Herman Ravelojaona, and Tiphaine Chevallier
Biogeosciences, 20, 5229–5242, https://doi.org/10.5194/bg-20-5229-2023, https://doi.org/10.5194/bg-20-5229-2023, 2023
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This study adapts the Rock-Eval® protocol to quantify soil organic carbon (SOC) and soil inorganic carbon (SIC) on a non-pretreated soil aliquot. The standard protocol properly estimates SOC contents once the TOC parameter is corrected. However, it cannot complete the thermal breakdown of SIC amounts > 4 mg, leading to an underestimation of high SIC contents by the MinC parameter, even after correcting for this. Thus, the final oxidation isotherm is extended to 7 min to quantify any SIC amount.
Bo Zhao, Amin Dou, Zhiwei Zhang, Zhenyu Chen, Wenbo Sun, Yanli Feng, Xiaojuan Wang, and Qiang Wang
Biogeosciences, 20, 4761–4774, https://doi.org/10.5194/bg-20-4761-2023, https://doi.org/10.5194/bg-20-4761-2023, 2023
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This study provided a comprehensive analysis of the spatial variability and determinants of Fe-bound organic carbon (Fe-OC) among terrestrial, wetland, and marine ecosystems and its governing factors globally. We illustrated that reactive Fe was not only an important sequestration mechanism for OC in terrestrial ecosystems but also an effective “rusty sink” of OC preservation in wetland and marine ecosystems, i.e., a key factor for long-term OC storage in global ecosystems.
Han Sun, Tomoyasu Nishizawa, Hiroyuki Ohta, and Kazuhiko Narisawa
Biogeosciences, 20, 4737–4749, https://doi.org/10.5194/bg-20-4737-2023, https://doi.org/10.5194/bg-20-4737-2023, 2023
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In this research, we assessed the diversity and function of the dark septate endophytic (DSE) fungi community associated with Miscanthus condensatus root in volcanic ecosystems. Both metabarcoding and isolation were adopted in this study. We further validated effects on plant growth by inoculation of some core DSE isolates. This study helps improve our understanding of the role of Miscanthus condensatus-associated DSE fungi during the restoration of post-volcanic ecosystems.
Xianjin He, Laurent Augusto, Daniel S. Goll, Bruno Ringeval, Ying-Ping Wang, Julian Helfenstein, Yuanyuan Huang, and Enqing Hou
Biogeosciences, 20, 4147–4163, https://doi.org/10.5194/bg-20-4147-2023, https://doi.org/10.5194/bg-20-4147-2023, 2023
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We identified total soil P concentration as the most important predictor of all soil P pool concentrations, except for primary mineral P concentration, which is primarily controlled by soil pH and only secondarily by total soil P concentration. We predicted soil P pools’ distributions in natural systems, which can inform assessments of the role of natural P availability for ecosystem productivity, climate change mitigation, and the functioning of the Earth system.
Imane Slimani, Xia Zhu-Barker, Patricia Lazicki, and William Horwath
Biogeosciences, 20, 3873–3894, https://doi.org/10.5194/bg-20-3873-2023, https://doi.org/10.5194/bg-20-3873-2023, 2023
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There is a strong link between nitrogen availability and iron minerals in soils. These minerals have multiple outcomes for nitrogen availability depending on soil conditions and properties. For example, iron can limit microbial degradation of nitrogen in aerated soils but has opposing outcomes in non-aerated soils. This paper focuses on the multiple ways iron can affect nitrogen bioavailability in soils.
Shane W. Stoner, Marion Schrumpf, Alison Hoyt, Carlos A. Sierra, Sebastian Doetterl, Valier Galy, and Susan Trumbore
Biogeosciences, 20, 3151–3163, https://doi.org/10.5194/bg-20-3151-2023, https://doi.org/10.5194/bg-20-3151-2023, 2023
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Soils store more carbon (C) than any other terrestrial C reservoir, but the processes that control how much C stays in soil, and for how long, are very complex. Here, we used a recent method that involves heating soil in the lab to measure the range of C ages in soil. We found that most C in soil is decades to centuries old, while some stays for much shorter times (days to months), and some is thousands of years old. Such detail helps us to estimate how soil C may react to changing climate.
Adetunji Alex Adekanmbi, Laurence Dale, Liz Shaw, and Tom Sizmur
Biogeosciences, 20, 2207–2219, https://doi.org/10.5194/bg-20-2207-2023, https://doi.org/10.5194/bg-20-2207-2023, 2023
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The decomposition of soil organic matter and flux of carbon dioxide are expected to increase as temperatures rise. However, soil organic matter decomposition is a two-step process whereby large molecules are first broken down outside microbial cells and then respired within microbial cells. We show here that these two steps are not equally sensitive to increases in soil temperature and that global warming may cause a shift in the rate-limiting step from outside to inside the microbial cell.
Mercedes Román Dobarco, Alexandre M. J-C. Wadoux, Brendan Malone, Budiman Minasny, Alex B. McBratney, and Ross Searle
Biogeosciences, 20, 1559–1586, https://doi.org/10.5194/bg-20-1559-2023, https://doi.org/10.5194/bg-20-1559-2023, 2023
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Soil organic carbon (SOC) is of a heterogeneous nature and varies in chemistry, stabilisation mechanisms, and persistence in soil. In this study we mapped the stocks of SOC fractions with different characteristics and turnover rates (presumably PyOC >= MAOC > POC) across Australia, combining spectroscopy and digital soil mapping. The SOC stocks (0–30 cm) were estimated as 13 Pg MAOC, 2 Pg POC, and 5 Pg PyOC.
Tino Peplau, Christopher Poeplau, Edward Gregorich, and Julia Schroeder
Biogeosciences, 20, 1063–1074, https://doi.org/10.5194/bg-20-1063-2023, https://doi.org/10.5194/bg-20-1063-2023, 2023
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We buried tea bags and temperature loggers in a paired-plot design in soils under forest and agricultural land and retrieved them after 2 years to quantify the effect of land-use change on soil temperature and litter decomposition in subarctic agricultural systems. We could show that agricultural soils were on average 2 °C warmer than forests and that litter decomposition was enhanced. The results imply that deforestation amplifies effects of climate change on soil organic matter dynamics.
Joseph Okello, Marijn Bauters, Hans Verbeeck, Samuel Bodé, John Kasenene, Astrid Françoys, Till Engelhardt, Klaus Butterbach-Bahl, Ralf Kiese, and Pascal Boeckx
Biogeosciences, 20, 719–735, https://doi.org/10.5194/bg-20-719-2023, https://doi.org/10.5194/bg-20-719-2023, 2023
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The increase in global and regional temperatures has the potential to drive accelerated soil organic carbon losses in tropical forests. We simulated climate warming by translocating intact soil cores from higher to lower elevations. The results revealed increasing temperature sensitivity and decreasing losses of soil organic carbon with increasing elevation. Our results suggest that climate warming may trigger enhanced losses of soil organic carbon from tropical montane forests.
Johanna Pihlblad, Louise C. Andresen, Catriona A. Macdonald, David S. Ellsworth, and Yolima Carrillo
Biogeosciences, 20, 505–521, https://doi.org/10.5194/bg-20-505-2023, https://doi.org/10.5194/bg-20-505-2023, 2023
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Elevated CO2 in the atmosphere increases forest biomass productivity when growth is not limited by soil nutrients. This study explores how mature trees stimulate soil availability of nitrogen and phosphorus with free-air carbon dioxide enrichment after 5 years of fumigation. We found that both nutrient availability and processes feeding available pools increased in the rhizosphere, and phosphorus increased at depth. This appears to not be by decomposition but by faster recycling of nutrients.
Rodrigo Vargas and Van Huong Le
Biogeosciences, 20, 15–26, https://doi.org/10.5194/bg-20-15-2023, https://doi.org/10.5194/bg-20-15-2023, 2023
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Quantifying the role of soils in nature-based solutions requires accurate estimates of soil greenhouse gas (GHG) fluxes. We suggest that multiple GHG fluxes should not be simultaneously measured at a few fixed time intervals, but an optimized sampling approach can reduce bias and uncertainty. Our results have implications for assessing GHG fluxes from soils and a better understanding of the role of soils in nature-based solutions.
Kristine Karstens, Benjamin Leon Bodirsky, Jan Philipp Dietrich, Marta Dondini, Jens Heinke, Matthias Kuhnert, Christoph Müller, Susanne Rolinski, Pete Smith, Isabelle Weindl, Hermann Lotze-Campen, and Alexander Popp
Biogeosciences, 19, 5125–5149, https://doi.org/10.5194/bg-19-5125-2022, https://doi.org/10.5194/bg-19-5125-2022, 2022
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Soil organic carbon (SOC) has been depleted by anthropogenic land cover change and agricultural management. While SOC models often simulate detailed biochemical processes, the management decisions are still little investigated at the global scale. We estimate that soils have lost around 26 GtC relative to a counterfactual natural state in 1975. Yet, since 1975, SOC has been increasing again by 4 GtC due to a higher productivity, recycling of crop residues and manure, and no-tillage practices.
Petri Kiuru, Marjo Palviainen, Arianna Marchionne, Tiia Grönholm, Maarit Raivonen, Lukas Kohl, and Annamari Laurén
Biogeosciences, 19, 5041–5058, https://doi.org/10.5194/bg-19-5041-2022, https://doi.org/10.5194/bg-19-5041-2022, 2022
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Peatlands are large carbon stocks. Emissions of carbon dioxide and methane from peatlands may increase due to changes in management and climate. We studied the variation in the gas diffusivity of peat with depth using pore network simulations and laboratory experiments. Gas diffusivity was found to be lower in deeper peat with smaller pores and lower pore connectivity. However, gas diffusivity was not extremely low in wet conditions, which may reflect the distinctive structure of peat.
Rachael Akinyede, Martin Taubert, Marion Schrumpf, Susan Trumbore, and Kirsten Küsel
Biogeosciences, 19, 4011–4028, https://doi.org/10.5194/bg-19-4011-2022, https://doi.org/10.5194/bg-19-4011-2022, 2022
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Soils will likely become warmer in the future, and this can increase the release of carbon dioxide (CO2) into the atmosphere. As microbes can take up soil CO2 and prevent further escape into the atmosphere, this study compares the rate of uptake and release of CO2 at two different temperatures. With warming, the rate of CO2 uptake increases less than the rate of release, indicating that the capacity to modulate soil CO2 release into the atmosphere will decrease under future warming.
Giuseppe Cipolla, Salvatore Calabrese, Amilcare Porporato, and Leonardo V. Noto
Biogeosciences, 19, 3877–3896, https://doi.org/10.5194/bg-19-3877-2022, https://doi.org/10.5194/bg-19-3877-2022, 2022
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Enhanced weathering (EW) is a promising strategy for carbon sequestration. Since models may help to characterize field EW, the present work applies a hydro-biogeochemical model to four case studies characterized by different rainfall seasonality, vegetation and soil type. Rainfall seasonality strongly affects EW dynamics, but low carbon sequestration suggests that an in-depth analysis at the global scale is required to see if EW may be effective to mitigate climate change.
Vao Fenotiana Razanamahandry, Marjolein Dewaele, Gerard Govers, Liesa Brosens, Benjamin Campforts, Liesbet Jacobs, Tantely Razafimbelo, Tovonarivo Rafolisy, and Steven Bouillon
Biogeosciences, 19, 3825–3841, https://doi.org/10.5194/bg-19-3825-2022, https://doi.org/10.5194/bg-19-3825-2022, 2022
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In order to shed light on possible past vegetation shifts in the Central Highlands of Madagascar, we measured stable isotope ratios of organic carbon in soil profiles along both forested and grassland hillslope transects in the Lake Alaotra region. Our results show that the landscape of this region was more forested in the past: soils in the C4-dominated grasslands contained a substantial fraction of C3-derived carbon, increasing with depth.
Katherine E. O. Todd-Brown, Rose Z. Abramoff, Jeffrey Beem-Miller, Hava K. Blair, Stevan Earl, Kristen J. Frederick, Daniel R. Fuka, Mario Guevara Santamaria, Jennifer W. Harden, Katherine Heckman, Lillian J. Heran, James R. Holmquist, Alison M. Hoyt, David H. Klinges, David S. LeBauer, Avni Malhotra, Shelby C. McClelland, Lucas E. Nave, Katherine S. Rocci, Sean M. Schaeffer, Shane Stoner, Natasja van Gestel, Sophie F. von Fromm, and Marisa L. Younger
Biogeosciences, 19, 3505–3522, https://doi.org/10.5194/bg-19-3505-2022, https://doi.org/10.5194/bg-19-3505-2022, 2022
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Research data are becoming increasingly available online with tantalizing possibilities for reanalysis. However harmonizing data from different sources remains challenging. Using the soils community as an example, we walked through the various strategies that researchers currently use to integrate datasets for reanalysis. We find that manual data transcription is still extremely common and that there is a critical need for community-supported informatics tools like vocabularies and ontologies.
Alessandro Montemagno, Christophe Hissler, Victor Bense, Adriaan J. Teuling, Johanna Ziebel, and Laurent Pfister
Biogeosciences, 19, 3111–3129, https://doi.org/10.5194/bg-19-3111-2022, https://doi.org/10.5194/bg-19-3111-2022, 2022
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We investigated the biogeochemical processes that dominate the release and retention of elements (nutrients and potentially toxic elements) during litter degradation. Our results show that toxic elements are retained in the litter, while nutrients are released in solution during the first stages of degradation. This seems linked to the capability of trees to distribute the elements between degradation-resistant and non-degradation-resistant compounds of leaves according to their chemical nature.
Laura Sereni, Bertrand Guenet, Charlotte Blasi, Olivier Crouzet, Jean-Christophe Lata, and Isabelle Lamy
Biogeosciences, 19, 2953–2968, https://doi.org/10.5194/bg-19-2953-2022, https://doi.org/10.5194/bg-19-2953-2022, 2022
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This study focused on the modellisation of two important drivers of soil greenhouse gas emissions: soil contamination and soil moisture change. The aim was to include a Cu function in the soil biogeochemical model DNDC for different soil moisture conditions and then to estimate variation in N2O, NO2 or NOx emissions. Our results show a larger effect of Cu on N2 and N2O emissions than on the other nitrogen species and a higher effect for the soils incubated under constant constant moisture.
Marie Spohn and Johan Stendahl
Biogeosciences, 19, 2171–2186, https://doi.org/10.5194/bg-19-2171-2022, https://doi.org/10.5194/bg-19-2171-2022, 2022
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We explored the ratios of carbon (C), nitrogen (N), and phosphorus (P) of organic matter in Swedish forest soils. The N : P ratio of the organic layer was most strongly related to the mean annual temperature, while the C : N ratios of the organic layer and mineral soil were strongly related to tree species even in the subsoil. The organic P concentration in the mineral soil was strongly affected by soil texture, which diminished the effect of tree species on the C to organic P (C : OP) ratio.
Moritz Mainka, Laura Summerauer, Daniel Wasner, Gina Garland, Marco Griepentrog, Asmeret Asefaw Berhe, and Sebastian Doetterl
Biogeosciences, 19, 1675–1689, https://doi.org/10.5194/bg-19-1675-2022, https://doi.org/10.5194/bg-19-1675-2022, 2022
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The largest share of terrestrial carbon is stored in soils, making them highly relevant as regards global change. Yet, the mechanisms governing soil carbon stabilization are not well understood. The present study contributes to a better understanding of these processes. We show that qualitative changes in soil organic matter (SOM) co-vary with alterations of the soil matrix following soil weathering. Hence, the type of SOM that is stabilized in soils might change as soils develop.
Jasmin Fetzer, Emmanuel Frossard, Klaus Kaiser, and Frank Hagedorn
Biogeosciences, 19, 1527–1546, https://doi.org/10.5194/bg-19-1527-2022, https://doi.org/10.5194/bg-19-1527-2022, 2022
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As leaching is a major pathway of nitrogen and phosphorus loss in forest soils, we investigated several potential drivers in two contrasting beech forests. The composition of leachates, obtained by zero-tension lysimeters, varied by season, and climatic extremes influenced the magnitude of leaching. Effects of nitrogen and phosphorus fertilization varied with soil nutrient status and sorption properties, and leaching from the low-nutrient soil was more sensitive to environmental factors.
Karis J. McFarlane, Heather M. Throckmorton, Jeffrey M. Heikoop, Brent D. Newman, Alexandra L. Hedgpeth, Marisa N. Repasch, Thomas P. Guilderson, and Cathy J. Wilson
Biogeosciences, 19, 1211–1223, https://doi.org/10.5194/bg-19-1211-2022, https://doi.org/10.5194/bg-19-1211-2022, 2022
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Planetary warming is increasing seasonal thaw of permafrost, making this extensive old carbon stock vulnerable. In northern Alaska, we found more and older dissolved organic carbon in small drainages later in summer as more permafrost was exposed by deepening thaw. Younger and older carbon did not differ in chemical indicators related to biological lability suggesting this carbon can cycle through aquatic systems and contribute to greenhouse gas emissions as warming increases permafrost thaw.
Pengzhi Zhao, Daniel Joseph Fallu, Sara Cucchiaro, Paolo Tarolli, Clive Waddington, David Cockcroft, Lisa Snape, Andreas Lang, Sebastian Doetterl, Antony G. Brown, and Kristof Van Oost
Biogeosciences, 18, 6301–6312, https://doi.org/10.5194/bg-18-6301-2021, https://doi.org/10.5194/bg-18-6301-2021, 2021
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We investigate the factors controlling the soil organic carbon (SOC) stability and temperature sensitivity of abandoned prehistoric agricultural terrace soils. Results suggest that the burial of former topsoil due to terracing provided an SOC stabilization mechanism. Both the soil C : N ratio and SOC mineral protection regulate soil SOC temperature sensitivity. However, which mechanism predominantly controls SOC temperature sensitivity depends on the age of the buried terrace soils.
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Short summary
Ultrasonication with density fractionation of soils is a commonly used method to separate soil organic matter pools, which is, e.g., important to calculate carbon turnover in landscapes. It is shown that the approach that merges soil and dense solution without mixing has a low recovery rate and causes co-extraction of parts of the retained labile pool along with the intermediate pool. An alternative method with high recovery rates and no cross-contamination was recommended.
Ultrasonication with density fractionation of soils is a commonly used method to separate soil...
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