Articles | Volume 7, issue 1
https://doi.org/10.5194/soil-7-305-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/soil-7-305-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Original research article
| Highlight paper
| 
29 Jun 2021
Original research article | Highlight paper |
| 29 Jun 2021
| 29 Jun 2021
Continental-scale controls on soil organic carbon across sub-Saharan Africa
Sophie F. von Fromm
CORRESPONDING AUTHOR
Department of Biogeochemical Processes, Max Planck Institute for
Biogeochemistry, Jena, Germany
Department of Environmental Systems Science, ETH Zurich, Zurich,
Switzerland
Alison M. Hoyt
Department of Biogeochemical Processes, Max Planck Institute for
Biogeochemistry, Jena, Germany
Climate and Ecosystem Sciences Division, Lawrence Berkeley National
Laboratory, Berkeley, CA, USA
Markus Lange
Department of Biogeochemical Processes, Max Planck Institute for
Biogeochemistry, Jena, Germany
Gifty E. Acquah
Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, UK
Ermias Aynekulu
World Agroforestry Centre (ICRAF), Nairobi, Kenya
Asmeret Asefaw Berhe
Department of Live and Environmental Sciences, University of
California Merced, Merced, CA, USA
Stephan M. Haefele
Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, UK
Steve P. McGrath
Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, UK
Keith D. Shepherd
World Agroforestry Centre (ICRAF), Nairobi, Kenya
Andrew M. Sila
World Agroforestry Centre (ICRAF), Nairobi, Kenya
Johan Six
Department of Environmental Systems Science, ETH Zurich, Zurich,
Switzerland
Erick K. Towett
World Agroforestry Centre (ICRAF), Nairobi, Kenya
Susan E. Trumbore
Department of Biogeochemical Processes, Max Planck Institute for
Biogeochemistry, Jena, Germany
Tor-G. Vågen
World Agroforestry Centre (ICRAF), Nairobi, Kenya
Elvis Weullow
World Agroforestry Centre (ICRAF), Nairobi, Kenya
Leigh A. Winowiecki
World Agroforestry Centre (ICRAF), Nairobi, Kenya
Sebastian Doetterl
Department of Environmental Systems Science, ETH Zurich, Zurich,
Switzerland
Related authors
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
Short summary
Short summary
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.
Leila Maria Wahab, Sora L. Kim, and Asmeret Asefaw Berhe
Biogeosciences, 22, 3915–3930, https://doi.org/10.5194/bg-22-3915-2025, https://doi.org/10.5194/bg-22-3915-2025, 2025
Short summary
Short summary
Soils are a large reservoir of carbon (C) on land, and there is uncertainty regarding how this reservoir will be affected by climate change. Currently, active research on (1) how changing precipitation patterns, a key aspect of climate change, will affect soil C and (2) how vulnerable subsoils are to climate change is still being undertaken. In this study, we examined subsoils after 20 years of experimentally manipulated precipitation shifts to see whether increasing precipitation would affect C amounts and chemistry.
Antoine de Clippele, Astrid C. H. Jaeger, Simon Baumgartner, Marijn Bauters, Pascal Boeckx, Clement Botefa, Glenn Bush, Jessica Carilli, Travis W. Drake, Christian Ekamba, Gode Lompoko, Nivens Bey Mukwiele, Kristof Van Oost, Roland A. Werner, Joseph Zambo, Johan Six, and Matti Barthel
Biogeosciences, 22, 3011–3027, https://doi.org/10.5194/bg-22-3011-2025, https://doi.org/10.5194/bg-22-3011-2025, 2025
Short summary
Short summary
Tropical forest soils as a large terrestrial source of carbon dioxide (CO2) contribute to the global greenhouse gas budget. Despite this, carbon flux data from forested wetlands are scarce in tropical Africa. The study presents 3 years of semi-continuous measurements of surface CO2 fluxes within the Congo Basin. Although no seasonal patterns were evident, our results show a positive effect of soil temperature and moisture, while a quadratic relationship was observed with the water table.
Johanne Lebrun Thauront, Philippa Ascough, Sebastian Doetterl, Negar Haghipour, Pierre Barré, Christian Walter, and Samuel Abiven
EGUsphere, https://doi.org/10.5194/egusphere-2025-2693, https://doi.org/10.5194/egusphere-2025-2693, 2025
This preprint is open for discussion and under review for Biogeosciences (BG).
Short summary
Short summary
Fire-derived carbon is a form of organic carbon that has a long persistence in soils. However, its persistence at the landscape scale may be underestimated due to lateral and vertical redistribution. We measured fire-derived carbon in soils of a hilly agricultural watershed to identify the result of transport processes on the centennial time-scale. We show that the subsoil stores a large amount of fire-derived carbon and that erosion can redistribute it to localized accumulation zones.
Claude Raoul Müller, Johan Six, Daniel Mugendi Njiru, Bernard Vanlauwe, and Marijn Van de Broek
Biogeosciences, 22, 2733–2747, https://doi.org/10.5194/bg-22-2733-2025, https://doi.org/10.5194/bg-22-2733-2025, 2025
Short summary
Short summary
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 compared with the control, but mineral nitrogen had no significant effect. Manure was the organic treatment that significantly increased SOC at the deepest soil depths, 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.
Lei Zhang, Lin Yang, Thomas W. Crowther, Constantin M. Zohner, Sebastian Doetterl, Gerard B. M. Heuvelink, Alexandre M. J.-C. Wadoux, A.-Xing Zhu, Yue Pu, Feixue Shen, Haozhi Ma, Yibiao Zou, and Chenghu Zhou
Earth Syst. Sci. Data, 17, 2605–2623, https://doi.org/10.5194/essd-17-2605-2025, https://doi.org/10.5194/essd-17-2605-2025, 2025
Short summary
Short summary
Current understandings of depth-dependent variations and controls of soil organic carbon turnover time (τ) at global, biome, and local scales remain incomplete. We used the state-of-the-art soil and root profile databases and satellite observations to generate new spatially explicit global maps of topsoil and subsoil τ, with quantified uncertainties for better user applications. The new insights from the resulting maps will facilitate efforts to model the carbon cycle and will support effective carbon management.
Marijn Van de Broek, Fiona Stewart-Smith, Moritz Laub, Marc Corbeels, Monicah Wanjiku Mucheru-Muna, Daniel Mugendi, Wycliffe Waswa, Bernard Vanlauwe, and Johan Six
EGUsphere, https://doi.org/10.5194/egusphere-2025-2287, https://doi.org/10.5194/egusphere-2025-2287, 2025
This preprint is open for discussion and under review for SOIL (SOIL).
Short summary
Short summary
To improve soil health and increase crop yields, organic matter is commenly added to arable soils. Studying the effect of different organic amenmends on soil organic carbon sequestration in four long-term field trials in Kenya, we found that only a small portion (< 7 %) of added carbon was stabilised. Moreover, this was only observed in the top 15 cm of the soil. These results underline the challenges associated with increasing the organic carbon content of tropical arable soils.
Annina Maier, Maria E. Macfarlane, Marco Griepentrog, and Sebastian Doetterl
EGUsphere, https://doi.org/10.5194/egusphere-2025-2006, https://doi.org/10.5194/egusphere-2025-2006, 2025
Short summary
Short summary
A systematic analysis of the interaction between pedo- and biosphere in shaping alpine soil organic carbon (SOC) stocks remains missing. Our regional-scale study of alpine SOC stocks across five parent materials shows that plant biomass is not a strong control of SOC stocks. Rather, the greatest SOC stocks are linked to more weathered soil profiles with higher Fe and Al pedogenic oxide content, showing the importance of parent material weatherability and geochemistry for SOC stabilization.
Carlos A. Sierra, Ingrid Chanca, Meinrat Andreae, Alessandro Carioca de Araújo, Hella van Asperen, Lars Borchardt, Santiago Botía, Luiz Antonio Candido, Caio S. C. Correa, Cléo Quaresma Dias-Junior, Markus Eritt, Annica Fröhlich, Luciana V. Gatti, Marcus Guderle, Samuel Hammer, Martin Heimann, Viviana Horna, Armin Jordan, Steffen Knabe, Richard Kneißl, Jost Valentin Lavric, Ingeborg Levin, Kita Macario, Juliana Menger, Heiko Moossen, Carlos Alberto Quesada, Michael Rothe, Christian Rödenbeck, Yago Santos, Axel Steinhof, Bruno Takeshi, Susan Trumbore, and Sönke Zaehle
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2025-151, https://doi.org/10.5194/essd-2025-151, 2025
Preprint under review for ESSD
Short summary
Short summary
We present here a unique dataset of atmospheric observations of greenhouse gases and isotopes that provide key information on land-atmosphere interactions for the Amazon forests of central Brazil. The data show a relatively large level of variability, but also important trends in greenhouse gases, and signals from fires as well as seasonal biological activity.
Roxanne Daelman, Marijn Bauters, Matti Barthel, Emmanuel Bulonza, Lodewijk Lefevre, José Mbifo, Johan Six, Klaus Butterbach-Bahl, Benjamin Wolf, Ralf Kiese, and Pascal Boeckx
Biogeosciences, 22, 1529–1542, https://doi.org/10.5194/bg-22-1529-2025, https://doi.org/10.5194/bg-22-1529-2025, 2025
Short summary
Short summary
The increase in atmospheric concentrations of several greenhouse gases (GHGs) since 1750 is attributed to human activity. However, natural ecosystems, such as tropical forests, also contribute to GHG budgets. The Congo Basin hosts the second largest tropical forest and is understudied. In this study, measurements of soil GHG exchange were carried out during 16 months in a tropical forest in the Congo Basin. Overall, the soil acted as a major source of CO2 and N2O and a minor sink of CH4.
Marijn Van de Broek, Gerard Govers, Marion Schrumpf, and Johan Six
Biogeosciences, 22, 1427–1446, https://doi.org/10.5194/bg-22-1427-2025, https://doi.org/10.5194/bg-22-1427-2025, 2025
Short summary
Short summary
Soil organic carbon models are used to predict how soils affect the concentration of CO2 in the atmosphere. We show that equifinality – the phenomenon that different parameter values lead to correct overall model outputs, albeit with a different model behaviour – is an important source of model uncertainty. Our results imply that adding more complexity to soil organic carbon models is unlikely to lead to better predictions as long as more data to constrain model parameters are not available.
Mosisa Tujuba Wakjira, Nadav Peleg, Johan Six, and Peter Molnar
Hydrol. Earth Syst. Sci., 29, 863–886, https://doi.org/10.5194/hess-29-863-2025, https://doi.org/10.5194/hess-29-863-2025, 2025
Short summary
Short summary
In this study, we implement a climate, water, and crop interaction model to evaluate current conditions and project future changes in rainwater availability and its yield potential, with the goal of informing adaptation policies and strategies in Ethiopia. Although climate change is likely to increase rainfall in Ethiopia, our findings suggest that water-scarce croplands in Ethiopia are expected to face reduced crop yields during the main growing season due to increases in temperature.
Ingrid Chanca, Ingeborg Levin, Susan Trumbore, Kita Macario, Jost Lavric, Carlos Alberto Quesada, Alessandro Carioca de Araújo, Cléo Quaresma Dias Júnior, Hella van Asperen, Samuel Hammer, and Carlos A. Sierra
Biogeosciences, 22, 455–472, https://doi.org/10.5194/bg-22-455-2025, https://doi.org/10.5194/bg-22-455-2025, 2025
Short summary
Short summary
Assessing the net carbon (C) budget of the Amazon entails considering the magnitude and timing of C absorption and losses through respiration (transit time of C). Radiocarbon-based estimates of the transit time of C in the Amazon Tall Tower Observatory (ATTO) suggest a change in the transit time from 6 ± 2 years and 18 ± 4 years within 2 years (October 2019 and December 2021, respectively). This variability indicates that only a fraction of newly fixed C can be stored for decades or longer.
Luciano Emmert, Susan Trumbore, Joaquim dos Santos, Adriano Lima, Niro Higuchi, Robinson Negrón-Juárez, Cléo Dias-Júnior, Tarek El-Madany, Olaf Kolle, Gabriel Ribeiro, and Daniel Marra
EGUsphere, https://doi.org/10.5194/egusphere-2024-3234, https://doi.org/10.5194/egusphere-2024-3234, 2024
Preprint archived
Short summary
Short summary
For the first time, we documented wind gusts with the potential to damage trees in a forest in the Central Amazon. We used meteorological data collected at crown height over 24 months. We recorded 424 gusts, which occur more frequently and intensely in higher elevated areas and during the transition from the dry to the wet season. More intense rains showed the strongest relationship with extreme winds, highlighting the role of extreme events in tree mortality.
Vira Leng, Rémi Cardinael, Florent Tivet, Vang Seng, Phearum Mark, Pascal Lienhard, Titouan Filloux, Johan Six, Lyda Hok, Stéphane Boulakia, Clever Briedis, João Carlos de Moraes Sá, and Laurent Thuriès
SOIL, 10, 699–725, https://doi.org/10.5194/soil-10-699-2024, https://doi.org/10.5194/soil-10-699-2024, 2024
Short summary
Short summary
We assessed the long-term impacts of no-till cropping systems on soil organic carbon and nitrogen dynamics down to 1 m depth under the annual upland crop productions (cassava, maize, and soybean) in the tropical climate of Cambodia. We showed that no-till systems combined with rotations and cover crops could store large amounts of carbon in the top and subsoil in both the mineral organic matter and particulate organic matter fractions. We also question nitrogen management in these systems.
Moritz Laub, Magdalena Necpalova, Marijn Van de Broek, Marc Corbeels, Samuel Mathu Ndungu, Monicah Wanjiku Mucheru-Muna, Daniel Mugendi, Rebecca Yegon, Wycliffe Waswa, Bernard Vanlauwe, and Johan Six
Biogeosciences, 21, 3691–3716, https://doi.org/10.5194/bg-21-3691-2024, https://doi.org/10.5194/bg-21-3691-2024, 2024
Short summary
Short summary
We used the DayCent model to assess the potential impact of integrated soil fertility management (ISFM) on maize production, soil fertility, and greenhouse gas emission in Kenya. After adjustments, DayCent represented measured mean yields and soil carbon stock changes well and N2O emissions acceptably. Our results showed that soil fertility losses could be reduced but not completely eliminated with ISFM and that, while N2O emissions increased with ISFM, emissions per kilogram yield decreased.
Luiz A. T. Machado, Jürgen Kesselmeier, Santiago Botía, Hella van Asperen, Meinrat O. Andreae, Alessandro C. de Araújo, Paulo Artaxo, Achim Edtbauer, Rosaria R. Ferreira, Marco A. Franco, Hartwig Harder, Sam P. Jones, Cléo Q. Dias-Júnior, Guido G. Haytzmann, Carlos A. Quesada, Shujiro Komiya, Jost Lavric, Jos Lelieveld, Ingeborg Levin, Anke Nölscher, Eva Pfannerstill, Mira L. Pöhlker, Ulrich Pöschl, Akima Ringsdorf, Luciana Rizzo, Ana M. Yáñez-Serrano, Susan Trumbore, Wanda I. D. Valenti, Jordi Vila-Guerau de Arellano, David Walter, Jonathan Williams, Stefan Wolff, and Christopher Pöhlker
Atmos. Chem. Phys., 24, 8893–8910, https://doi.org/10.5194/acp-24-8893-2024, https://doi.org/10.5194/acp-24-8893-2024, 2024
Short summary
Short summary
Composite analysis of gas concentration before and after rainfall, during the day and night, gives insight into the complex relationship between trace gas variability and precipitation. The analysis helps us to understand the sources and sinks of trace gases within a forest ecosystem. It elucidates processes that are not discernible under undisturbed conditions and contributes to a deeper understanding of the trace gas life cycle and its intricate interactions with cloud dynamics in the Amazon.
Hella van Asperen, Thorsten Warneke, Alessandro Carioca de Araújo, Bruce Forsberg, Sávio José Filgueiras Ferreira, Thomas Röckmann, Carina van der Veen, Sipko Bulthuis, Leonardo Ramos de Oliveira, Thiago de Lima Xavier, Jailson da Mata, Marta de Oliveira Sá, Paulo Ricardo Teixeira, Julie Andrews de França e Silva, Susan Trumbore, and Justus Notholt
Biogeosciences, 21, 3183–3199, https://doi.org/10.5194/bg-21-3183-2024, https://doi.org/10.5194/bg-21-3183-2024, 2024
Short summary
Short summary
Carbon monoxide (CO) is regarded as an important indirect greenhouse gas. Soils can emit and take up CO, but, until now, uncertainty remains as to which process dominates in tropical rainforests. We present the first soil CO flux measurements from a tropical rainforest. Based on our observations, we report that tropical rainforest soils are a net source of CO. In addition, we show that valley streams and inundated areas are likely additional hot spots of CO in the ecosystem.
Maximiliano González-Sosa, Carlos A. Sierra, J. Andrés Quincke, Walter E. Baethgen, Susan Trumbore, and M. Virginia Pravia
SOIL, 10, 467–486, https://doi.org/10.5194/soil-10-467-2024, https://doi.org/10.5194/soil-10-467-2024, 2024
Short summary
Short summary
Based on an approach that involved soil organic carbon (SOC) monitoring, radiocarbon measurement in bulk soil, and incubations from a long-term 60-year experiment, it was concluded that the avoidance of old carbon losses in the integrated crop–pasture systems is the main reason that explains their greater carbon storage capacities compared to continuous cropping. A better understanding of these processes is essential for making agronomic decisions to increase the carbon sequestration capacity.
Claude Raoul Müller, Johan Six, Liesa Brosens, Philipp Baumann, Jean Paolo Gomes Minella, Gerard Govers, and Marijn Van de Broek
SOIL, 10, 349–365, https://doi.org/10.5194/soil-10-349-2024, https://doi.org/10.5194/soil-10-349-2024, 2024
Short summary
Short summary
Subsoils in the tropics are not as extensively studied as those in temperate regions. In this study, the conversion of forest to agriculture in a subtropical region affected the concentration of stabilized organic carbon (OC) down to 90 cm depth, while no significant differences between 90 cm and 300 cm were detected. Our results suggest that subsoils below 90 cm are unlikely to accumulate additional stabilized OC through reforestation over decadal periods due to declining OC input with depth.
Johan Six, Sebastian Doetterl, Moritz Laub, Claude R. Müller, and Marijn Van de Broek
SOIL, 10, 275–279, https://doi.org/10.5194/soil-10-275-2024, https://doi.org/10.5194/soil-10-275-2024, 2024
Short summary
Short summary
Soil C saturation has been tested in several recent studies and led to a debate about its existence. We argue that, to test C saturation, one should pay attention to six fundamental principles: the right measures, the right units, the right dispersive energy and application, the right soil type, the right clay type, and the right saturation level. Once we take care of those six rights across studies, we find support for a maximum of C stabilized by minerals and thus soil C saturation.
Armwell Shumba, Regis Chikowo, Christian Thierfelder, Marc Corbeels, Johan Six, and Rémi Cardinael
SOIL, 10, 151–165, https://doi.org/10.5194/soil-10-151-2024, https://doi.org/10.5194/soil-10-151-2024, 2024
Short summary
Short summary
Conservation agriculture (CA), combining reduced or no tillage, permanent soil cover, and improved rotations, is often promoted as a climate-smart practice. However, our knowledge of the impact of CA on top- and subsoil soil organic carbon (SOC) stocks in the low-input cropping systems of sub-Saharan Africa is rather limited. Using two long-term experimental sites with different soil types, we found that mulch could increase top SOC stocks, but no tillage alone had a slightly negative impact.
Moritz Laub, Sergey Blagodatsky, Marijn Van de Broek, Samuel Schlichenmaier, Benjapon Kunlanit, Johan Six, Patma Vityakon, and Georg Cadisch
Geosci. Model Dev., 17, 931–956, https://doi.org/10.5194/gmd-17-931-2024, https://doi.org/10.5194/gmd-17-931-2024, 2024
Short summary
Short summary
To manage soil organic matter (SOM) sustainably, we need a better understanding of the role that soil microbes play in aggregate protection. Here, we propose the SAMM model, which connects soil aggregate formation to microbial growth. We tested it against data from a tropical long-term experiment and show that SAMM effectively represents the microbial growth, SOM, and aggregate dynamics and that it can be used to explore the importance of aggregate formation in SOM stabilization.
Gina Garland, John Koestel, Alice Johannes, Olivier Heller, Sebastian Doetterl, Dani Or, and Thomas Keller
SOIL, 10, 23–31, https://doi.org/10.5194/soil-10-23-2024, https://doi.org/10.5194/soil-10-23-2024, 2024
Short summary
Short summary
The concept of soil aggregates is hotly debated, leading to confusion about their function or relevancy to soil processes. We propose that the use of conceptual figures showing detached and isolated aggregates can be misleading and has contributed to this skepticism. Here, we conceptually illustrate how aggregates can form and dissipate within the context of undisturbed soils, highlighting the fact that aggregates do not necessarily need to have distinct physical boundaries.
Adriana Simonetti, Raquel Fernandes Araujo, Carlos Henrique Souza Celes, Flávia Ranara da Silva e Silva, Joaquim dos Santos, Niro Higuchi, Susan Trumbore, and Daniel Magnabosco Marra
Biogeosciences, 20, 3651–3666, https://doi.org/10.5194/bg-20-3651-2023, https://doi.org/10.5194/bg-20-3651-2023, 2023
Short summary
Short summary
We combined 2 years of monthly drone-acquired RGB (red–green–blue) imagery with field surveys in a central Amazon forest. Our results indicate that small gaps associated with branch fall were the most frequent. Biomass losses were partially controlled by gap area, with branch fall and snapping contributing the least and greatest relative values, respectively. Our study highlights the potential of drone images for monitoring canopy dynamics in dense tropical forests.
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
Short summary
Short summary
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.
Moritz Laub, Marc Corbeels, Antoine Couëdel, Samuel Mathu Ndungu, Monicah Wanjiku Mucheru-Muna, Daniel Mugendi, Magdalena Necpalova, Wycliffe Waswa, Marijn Van de Broek, Bernard Vanlauwe, and Johan Six
SOIL, 9, 301–323, https://doi.org/10.5194/soil-9-301-2023, https://doi.org/10.5194/soil-9-301-2023, 2023
Short summary
Short summary
In sub-Saharan Africa, long-term low-input maize cropping threatens soil fertility. We studied how different quality organic inputs combined with mineral N fertilizer could counteract this. Farmyard manure was the best input to counteract soil carbon loss; mineral N fertilizer had no effect on carbon. Yet, the rates needed to offset soil carbon losses are unrealistic for farmers (>10 t of dry matter per hectare and year). Additional agronomic measures may be needed.
Kristof Van Oost and Johan Six
Biogeosciences, 20, 635–646, https://doi.org/10.5194/bg-20-635-2023, https://doi.org/10.5194/bg-20-635-2023, 2023
Short summary
Short summary
The direction and magnitude of the net erosion-induced land–atmosphere C exchange have been the topic of a big scientific debate for more than a decade now. Many have assumed that erosion leads to a loss of soil carbon to the atmosphere, whereas others have shown that erosion ultimately leads to a carbon sink. Here, we show that the soil carbon erosion source–sink paradox is reconciled when the broad range of temporal and spatial scales at which the underlying processes operate are considered.
Charlotte Decock, Juhwan Lee, Matti Barthel, Elizabeth Verhoeven, Franz Conen, and Johan Six
Biogeosciences Discuss., https://doi.org/10.5194/bg-2022-221, https://doi.org/10.5194/bg-2022-221, 2022
Preprint withdrawn
Short summary
Short summary
One of the least well understood processes in the nitrogen (N) cycle is the loss of nitrogen gas (N2), referred to as total denitrification. This is mainly due to the difficulty of quantifying total denitrification in situ. In this study, we developed and tested a novel modeling approach to estimate total denitrification over the depth profile, based on concentrations and isotope values of N2O. Our method will help close N budgets and identify management strategies that reduce N pollution.
Jeffrey Prescott Beem-Miller, Craig Rasmussen, Alison May Hoyt, Marion Schrumpf, Georg Guggenberger, and Susan Trumbore
EGUsphere, https://doi.org/10.5194/egusphere-2022-1083, https://doi.org/10.5194/egusphere-2022-1083, 2022
Preprint withdrawn
Short summary
Short summary
We compared the age of persistent soil organic matter as well as active emissions of carbon dioxide from soils across a gradient of climate and geology. We found that clay minerals are more important than mean annual temperature for both persistent and actively cycling soil carbon, and that they may attenuate the sensitivity of soil organic matter decomposition to temperature. Accounting for geology and soil development could therefore improve estimates of soil carbon stocks and changes.
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
Short summary
Short summary
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.
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
Short summary
Short summary
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.
Tegawende Léa Jeanne Ilboudo, Lucien NGuessan Diby, Delwendé Innocent Kiba, Tor Gunnar Vågen, Leigh Ann Winowiecki, Hassan Bismarck Nacro, Johan Six, and Emmanuel Frossard
EGUsphere, https://doi.org/10.5194/egusphere-2022-209, https://doi.org/10.5194/egusphere-2022-209, 2022
Preprint withdrawn
Short summary
Short summary
Our results showed that at landscape level SOC stock variability was mainly explained by clay content. We found significant linear positive relationships between VC and SOC stocks for the land uses annual croplands, perennial croplands, grasslands and bushlands without soil depth restrictions until 110 cm. We concluded that in the forest-savanna transition zone, soil properties and topography determine land use, which in turn affects the stocks of SOC and TN and to some extent the VC stocks.
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
Short summary
Short summary
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.
Daniel Rath, Nathaniel Bogie, Leonardo Deiss, Sanjai J. Parikh, Daoyuan Wang, Samantha Ying, Nicole Tautges, Asmeret Asefaw Berhe, Teamrat A. Ghezzehei, and Kate M. Scow
SOIL, 8, 59–83, https://doi.org/10.5194/soil-8-59-2022, https://doi.org/10.5194/soil-8-59-2022, 2022
Short summary
Short summary
Storing C in subsoils can help mitigate climate change, but this requires a better understanding of subsoil C dynamics. We investigated changes in subsoil C storage under a combination of compost, cover crops (WCC), and mineral fertilizer and found that systems with compost + WCC had ~19 Mg/ha more C after 25 years. This increase was attributed to increased transport of soluble C and nutrients via WCC root pores and demonstrates the potential for subsoil C storage in tilled agricultural systems.
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
Short summary
Short summary
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.
Leigh Ann Winowiecki, Aida Bargués-Tobella, Athanase Mukuralinda, Providence Mujawamariya, Elisée Bahati Ntawuhiganayo, Alex Billy Mugayi, Susan Chomba, and Tor-Gunnar Vågen
SOIL, 7, 767–783, https://doi.org/10.5194/soil-7-767-2021, https://doi.org/10.5194/soil-7-767-2021, 2021
Short summary
Short summary
Achieving global restoration targets requires scaling of context-specific restoration options on the ground. We implemented the Land Degradation Surveillance Framework in Rwanda to assess indicators of soil and land health, including soil organic carbon (SOC), erosion prevalence, infiltration capacity, and tree biodiversity. Maps of soil erosion and SOC were produced at 30 m resolution with high accuracy. These data provide a rigorous biophysical baseline for tracking changes over time.
Philipp Baumann, Juhwan Lee, Emmanuel Frossard, Laurie Paule Schönholzer, Lucien Diby, Valérie Kouamé Hgaza, Delwende Innocent Kiba, Andrew Sila, Keith Sheperd, and Johan Six
SOIL, 7, 717–731, https://doi.org/10.5194/soil-7-717-2021, https://doi.org/10.5194/soil-7-717-2021, 2021
Short summary
Short summary
This work delivers openly accessible and validated calibrations for diagnosing 26 soil properties based on mid-infrared spectroscopy. These were developed for four regions in Burkina Faso and Côte d'Ivoire, including 80 fields of smallholder farmers. The models can help to site-specifically and cost-efficiently monitor soil quality and fertility constraints to ameliorate soils and yields of yam or other staple crops in the four regions between the humid forest and the northern Guinean savanna.
Laura Summerauer, Philipp Baumann, Leonardo Ramirez-Lopez, Matti Barthel, Marijn Bauters, Benjamin Bukombe, Mario Reichenbach, Pascal Boeckx, Elizabeth Kearsley, Kristof Van Oost, Bernard Vanlauwe, Dieudonné Chiragaga, Aimé Bisimwa Heri-Kazi, Pieter Moonen, Andrew Sila, Keith Shepherd, Basile Bazirake Mujinya, Eric Van Ranst, Geert Baert, Sebastian Doetterl, and Johan Six
SOIL, 7, 693–715, https://doi.org/10.5194/soil-7-693-2021, https://doi.org/10.5194/soil-7-693-2021, 2021
Short summary
Short summary
We present a soil mid-infrared library with over 1800 samples from central Africa in order to facilitate soil analyses of this highly understudied yet critical area. Together with an existing continental library, we demonstrate a regional analysis and geographical extrapolation to predict total carbon and nitrogen. Our results show accurate predictions and highlight the value that the data contribute to existing libraries. Our library is openly available for public use and for expansion.
Benjamin Bukombe, Peter Fiener, Alison M. Hoyt, Laurent K. Kidinda, and Sebastian Doetterl
SOIL, 7, 639–659, https://doi.org/10.5194/soil-7-639-2021, https://doi.org/10.5194/soil-7-639-2021, 2021
Short summary
Short summary
Through a laboratory incubation experiment, we investigated the spatial patterns of specific maximum heterotrophic respiration in tropical African mountain forest soils developed from contrasting parent material along slope gradients. We found distinct differences in soil respiration between soil depths and geochemical regions related to soil fertility and the chemistry of the soil solution. The topographic origin of our samples was not a major determinant of the observed rates of respiration.
Sebastian Doetterl, Rodrigue K. Asifiwe, Geert Baert, Fernando Bamba, Marijn Bauters, Pascal Boeckx, Benjamin Bukombe, Georg Cadisch, Matthew Cooper, Landry N. Cizungu, Alison Hoyt, Clovis Kabaseke, Karsten Kalbitz, Laurent Kidinda, Annina Maier, Moritz Mainka, Julia Mayrock, Daniel Muhindo, Basile B. Mujinya, Serge M. Mukotanyi, Leon Nabahungu, Mario Reichenbach, Boris Rewald, Johan Six, Anna Stegmann, Laura Summerauer, Robin Unseld, Bernard Vanlauwe, Kristof Van Oost, Kris Verheyen, Cordula Vogel, Florian Wilken, and Peter Fiener
Earth Syst. Sci. Data, 13, 4133–4153, https://doi.org/10.5194/essd-13-4133-2021, https://doi.org/10.5194/essd-13-4133-2021, 2021
Short summary
Short summary
The African Tropics are hotspots of modern-day land use change and are of great relevance for the global carbon cycle. Here, we present data collected as part of the DFG-funded project TropSOC along topographic, land use, and geochemical gradients in the eastern Congo Basin and the Albertine Rift. Our database contains spatial and temporal data on soil, vegetation, environmental properties, and land management collected from 136 pristine tropical forest and cropland plots between 2017 and 2020.
Philipp Baumann, Anatol Helfenstein, Andreas Gubler, Armin Keller, Reto Giulio Meuli, Daniel Wächter, Juhwan Lee, Raphael Viscarra Rossel, and Johan Six
SOIL, 7, 525–546, https://doi.org/10.5194/soil-7-525-2021, https://doi.org/10.5194/soil-7-525-2021, 2021
Short summary
Short summary
We developed the Swiss mid-infrared spectral library and a statistical model collection across 4374 soil samples with reference measurements of 16 properties. Our library incorporates soil from 1094 grid locations and 71 long-term monitoring sites. This work confirms once again that nationwide spectral libraries with diverse soils can reliably feed information to a fast chemical diagnosis. Our data-driven reduction of the library has the potential to accurately monitor carbon at the plot scale.
Mario Reichenbach, Peter Fiener, Gina Garland, Marco Griepentrog, Johan Six, and Sebastian Doetterl
SOIL, 7, 453–475, https://doi.org/10.5194/soil-7-453-2021, https://doi.org/10.5194/soil-7-453-2021, 2021
Short summary
Short summary
In deeply weathered tropical rainforest soils of Africa, we found that patterns of soil organic carbon stocks differ between soils developed from geochemically contrasting parent material due to differences in the abundance of organo-mineral complexes, the presence/absence of chemical stabilization mechanisms of carbon with minerals and the presence of fossil organic carbon from sedimentary rocks. Physical stabilization mechanisms by aggregation provide additional protection of soil carbon.
Joseph Tamale, Roman Hüppi, Marco Griepentrog, Laban Frank Turyagyenda, Matti Barthel, Sebastian Doetterl, Peter Fiener, and Oliver van Straaten
SOIL, 7, 433–451, https://doi.org/10.5194/soil-7-433-2021, https://doi.org/10.5194/soil-7-433-2021, 2021
Short summary
Short summary
Soil greenhouse gas (GHG) fluxes were measured monthly from nitrogen (N), phosphorous (P), N and P, and control plots of the first nutrient manipulation experiment located in an African pristine tropical forest using static chambers. The results suggest (1) contrasting soil GHG responses to nutrient addition, hence highlighting the complexity of the tropical forests, and (2) that the feedback of tropical forests to the global soil GHG budget could be altered by changes in N and P availability.
Florian Wilken, Peter Fiener, Michael Ketterer, Katrin Meusburger, Daniel Iragi Muhindo, Kristof van Oost, and Sebastian Doetterl
SOIL, 7, 399–414, https://doi.org/10.5194/soil-7-399-2021, https://doi.org/10.5194/soil-7-399-2021, 2021
Short summary
Short summary
This study demonstrates the usability of fallout radionuclides 239Pu and 240Pu as a tool to assess soil degradation processes in tropical Africa, which is particularly valuable in regions with limited infrastructure and challenging monitoring conditions for landscape-scale soil degradation monitoring. The study shows no indication of soil redistribution in forest sites but substantial soil redistribution in cropland (sedimentation >40 cm in 55 years) with high variability.
Abdul-Wahab Mossa, Dawd Gashu, Martin R. Broadley, Sarah J. Dunham, Steve P. McGrath, Elizabeth H. Bailey, and Scott D. Young
SOIL, 7, 255–268, https://doi.org/10.5194/soil-7-255-2021, https://doi.org/10.5194/soil-7-255-2021, 2021
Short summary
Short summary
Zinc deficiency is a widespread nutritional problem in human populations, especially in sub-Saharan Africa (SSA). Crop Zn depends in part on soil Zn. The Zn status of soils from the Amahara region, Ethiopia, was quantified by measuring pseudo-total, available, soluble and isotopically exchangeable Zn, and soil geochemical properties were assessed. Widespread phyto-available Zn deficiency was observed. The results could be used to improve agronomic interventions to tackle Zn deficiency in SSA.
Anatol Helfenstein, Philipp Baumann, Raphael Viscarra Rossel, Andreas Gubler, Stefan Oechslin, and Johan Six
SOIL, 7, 193–215, https://doi.org/10.5194/soil-7-193-2021, https://doi.org/10.5194/soil-7-193-2021, 2021
Short summary
Short summary
In this study, we show that a soil spectral library (SSL) can be used to predict soil carbon at new and very different locations. The importance of this finding is that it requires less time-consuming lab work than calibrating a new model for every local application, while still remaining similar to or more accurate than local models. Furthermore, we show that this method even works for predicting (drained) peat soils, using a SSL with mostly mineral soils containing much less soil carbon.
Simon Baumgartner, Marijn Bauters, Matti Barthel, Travis W. Drake, Landry C. Ntaboba, Basile M. Bazirake, Johan Six, Pascal Boeckx, and Kristof Van Oost
SOIL, 7, 83–94, https://doi.org/10.5194/soil-7-83-2021, https://doi.org/10.5194/soil-7-83-2021, 2021
Short summary
Short summary
We compared stable isotope signatures of soil profiles in different forest ecosystems within the Congo Basin to assess ecosystem-level differences in N cycling, and we examined the local effect of topography on the isotopic signature of soil N. Soil δ15N profiles indicated that the N cycling in in the montane forest is more closed, whereas the lowland forest and Miombo woodland experienced a more open N cycle. Topography only alters soil δ15N values in forests with high erosional forces.
Marion Schrumpf, Klaus Kaiser, Allegra Mayer, Günter Hempel, and Susan Trumbore
Biogeosciences, 18, 1241–1257, https://doi.org/10.5194/bg-18-1241-2021, https://doi.org/10.5194/bg-18-1241-2021, 2021
Short summary
Short summary
A large amount of organic carbon (OC) in soil is protected against decay by bonding to minerals. We studied the release of mineral-bonded OC by NaF–NaOH extraction and H2O2 oxidation. Unexpectedly, extraction and oxidation removed mineral-bonded OC at roughly constant portions and of similar age distributions, irrespective of mineral composition, land use, and soil depth. The results suggest uniform modes of interactions between OC and minerals across soils in quasi-steady state with inputs.
Severin-Luca Bellè, Asmeret Asefaw Berhe, Frank Hagedorn, Cristina Santin, Marcus Schiedung, Ilja van Meerveld, and Samuel Abiven
Biogeosciences, 18, 1105–1126, https://doi.org/10.5194/bg-18-1105-2021, https://doi.org/10.5194/bg-18-1105-2021, 2021
Short summary
Short summary
Controls of pyrogenic carbon (PyC) redistribution under rainfall are largely unknown. However, PyC mobility can be substantial after initial rain in post-fire landscapes. We conducted a controlled simulation experiment on plots where PyC was applied on the soil surface. We identified redistribution of PyC by runoff and splash and vertical movement in the soil depending on soil texture and PyC characteristics (material and size). PyC also induced changes in exports of native soil organic carbon.
Simon Baumgartner, Matti Barthel, Travis William Drake, Marijn Bauters, Isaac Ahanamungu Makelele, John Kalume Mugula, Laura Summerauer, Nora Gallarotti, Landry Cizungu Ntaboba, Kristof Van Oost, Pascal Boeckx, Sebastian Doetterl, Roland Anton Werner, and Johan Six
Biogeosciences, 17, 6207–6218, https://doi.org/10.5194/bg-17-6207-2020, https://doi.org/10.5194/bg-17-6207-2020, 2020
Short summary
Short summary
Soil respiration is an important carbon flux and key process determining the net ecosystem production of terrestrial ecosystems. The Congo Basin lacks studies quantifying carbon fluxes. We measured soil CO2 fluxes from different forest types in the Congo Basin and were able to show that, even though soil CO2 fluxes are similarly high in lowland and montane forests, the drivers were different: soil moisture in montane forests and C availability in the lowland forests.
Laurent K. Kidinda, Folasade K. Olagoke, Cordula Vogel, Karsten Kalbitz, and Sebastian Doetterl
SOIL Discuss., https://doi.org/10.5194/soil-2020-80, https://doi.org/10.5194/soil-2020-80, 2020
Preprint withdrawn
Short summary
Short summary
In deeply weathered tropical rainforest soils of Africa, we found that patterns of microbial processes differ between soils developed from geochemically contrasting parent materials due to differences in resource availability. Across investigated geochemical regions and soil depths, soil microbes were P-limited rather than N-limited. Topsoil microbes were more C-limited than their subsoil counterparts but inversely P-limited.
Cited articles
Abegaz, A., Winowiecki, L. A., Vågen, T.-G., Langan, S., and Smith, J.
U.: Spatial and temporal dynamics of soil organic carbon in landscapes of
the upper Blue Nile Basin of the Ethiopian Highlands, Agr.
Ecosyst. Environ., 218, 190–208, https://doi.org/10.1016/j.agee.2015.11.019, 2016.
Albani, S., Mahowald, N. M., Winckler, G., Anderson, R. F., Bradtmiller, L.
I., Delmonte, B., François, R., Goman, M., Heavens, N. G., Hesse, P. P.,
Hovan, S. A., Kang, S. G., Kohfeld, K. E., Lu, H., Maggi, V., Mason, J. A.,
Mayewski, P. A., McGee, D., Miao, X., Otto-Bliesner, B. L., Perry, A. T.,
Pourmand, A., Roberts, H. M., Rosenbloom, N., Stevens, T., and Sun, J.:
Twelve thousand years of dust: the Holocene global dust cycle constrained by
natural archives, Clim. Past, 11, 869–903, https://doi.org/10.5194/cp-11-869-2015,
2015.
Amelung, W., Zech, W., Zhang, X., Follett, R. F., Tiessen, H., Knox, E., and
Flach, K.-W.: Carbon, Nitrogen, and Sulfur Pools in Particle-Size Fractions
as Influenced by Climate, Soil Sci. Soc. Am. J., 62,
172–181, https://doi.org/10.2136/sssaj1998.03615995006200010023x, 1998.
Barthès, B. G., Kouakoua, E., Larré-Larrouy, M.-C., Razafimbelo, T.
M., de Luca, E. F., Azontonde, A., Neves, C. S. V. J., de Freitas, P. L.,
and Feller, C. L.: Texture and sesquioxide effects on water-stable
aggregates and organic matter in some tropical soils, Geoderma, 143, 14–25,
https://doi.org/10.1016/j.geoderma.2007.10.003, 2008.
Barton, K.: MuMIn: Multi-Model Inference, available at: https://CRAN.R-project.org/package=MuMIn (last access: 3 June 2021), 2020.
Berhe, A. A., Suttle, K. B., Burton, S. D., and Banfield, J. F.: Contingency
in the direction and mechanics of soil organic matter responses to increased
rainfall, Plant Soil, 358, 371–383, https://doi.org/10.1007/s11104-012-1156-0, 2012.
Bischl, B., Lang, M., Kotthoff, L., Schiffner, J., Richter, J., Studerus,
E., Casalicchio, G., and Jones, Z. M.: mlr: Machine Learning in R, J.
Mach. Learn. Res., 17, 1–5, 2016.
Blankinship, J. C., Berhe, A. A., Crow, S. E., Druhan, J. L., Heckman, K.
A., Keiluweit, M., Lawrence, C. R., Marín-Spiotta, E., Plante, A. F.,
Rasmussen, C., Schädel, C., Schimel, J. P., Sierra, C. A., Thompson, A.,
Wagai, R., and Wieder, W. R.: Improving understanding of soil organic matter
dynamics by triangulating theories, measurements, and models,
Biogeochemistry, 140, 1–13, https://doi.org/10.1007/s10533-018-0478-2, 2018.
Boehmke, B. and Greenwell, B. M.: Hands-On Machine Learning with R, The R
Series, Chapman and Hall/CRC, Boca Raton, Florida,2020.
Breiman, L., Friedman, J., Stone, C. J., and Olshen, R. A.: Classification
and Regression Trees, Taylor & Francis, Boca Raton, Florida, USA, 368 pp., 1984.
Brenning, A.: Spatial cross-validation and bootstrap for the assessment of
prediction rules in remote sensing: The R package sperrorest, 2012 IEEE
International Geoscience and Remote Sensing Symposium, 5372–5375, 2012.
Bruun, T. B., Elberling, B., and Christensen, B. T.: Lability of soil
organic carbon in tropical soils with different clay minerals, Soil Biol.
Biochem., 42, 888–895, https://doi.org/10.1016/j.soilbio.2010.01.009, 2010.
Budyko, M. I.: Climate and Life, Academic Press, New York, USA, 508 pp.,
1974.
Buringh, P.: Introduction to the study of soils in tropical and subtropical
regions, Centre for Agricultural Publishing and Documentation, Wageningen,
Netherlands, 99 pp., 1970.
Burnham, K. P. and Anderson, D. R.: Model Selection and Multimodel
Inference: A Practical Information-Theoretic Approach, Springer, New York,
USA, 488 pp., 2002.
Butler, B. M., Palarea-Albaladejo, J., Shepherd, K. D., Nyambura, K. M.,
Towett, E. K., Sila, A. M., and Hillier, S.: Mineral–nutrient relationships
in African soils assessed using cluster analysis of X-ray powder diffraction
patterns and compositional methods, Geoderma, 375, 114474,
https://doi.org/10.1016/j.geoderma.2020.114474, 2020.
Chen, C., Hall, S. J., Coward, E., and Thompson, A.: Iron-mediated organic
matter decomposition in humid soils can counteract protection, Nat.
Commun., 11, 2255, https://doi.org/10.1038/s41467-020-16071-5, 2020.
Doetterl, S., Stevens, A., Six, J., Merckx, R., van Oost, K., Casanova
Pinto, M., Casanova-Katny, A., Muñoz, C., Boudin, M., Zagal Venegas, E.,
and Boeckx, P.: Soil carbon storage controlled by interactions between
geochemistry and climate, Nat. Geosci., 8, 780–783, https://doi.org/10.1038/ngeo2516,
2015.
Dokuchaev, V. V.: Russian Chernozem. Report to the Imperial Free Economic
Society (Tipogr. Declerona i Evdokimova) St. Petersburg,
Russia, 1883 (in Russian).
ESA: Land Cover CCI Product User Guide Version 2, Tech. Rep., available at: http://2016africalandcover20m.esrin.esa.int/, 2017.
Eusterhues, K., Rumpel, C., Kleber, M., and Kögel-Knabner, I.:
Stabilisation of soil organic matter by interactions with minerals as
revealed by mineral dissolution and oxidative degradation, Org.
Geochem., 34, 1591–1600, https://doi.org/10.1016/j.orggeochem.2003.08.007, 2003.
Feller, C. and Beare, M. H.: Physical control of soil organic matter
dynamics in the tropics, Geoderma, 79, 69–116,
https://doi.org/10.1016/S0016-7061(97)00039-6, 1997.
Fick, S. E. and Hijmans, R. J.: WorldClim 2: new 1-km spatial resolution
climate surfaces for global land areas, Int. J.
Climatol., 37, 4302–4315, https://doi.org/10.1002/joc.5086, 2017.
Friedlingstein, P., Meinshausen, M., Arora, V. K., Jones, C. D., Anav, A.,
Liddicoat, S. K., and Knutti, R.: Uncertainties in CMIP5 Climate Projections
due to Carbon Cycle Feedbacks, J. Clim., 27, 511–526,
https://doi.org/10.1175/jcli-d-12-00579.1, 2014.
Friedman, J. H.: Greedy function approximation: A gradient boosting machine,
Ann. Stat., 29, 1189–1232, https://doi.org/10.1214/aos/1013203451, 2001.
Fujisaki, K., Chapuis-Lardy, L., Albrecht, A., Razafimbelo, T., Chotte,
J.-L., and Chevallier, T.: Data synthesis of carbon distribution in particle
size fractions of tropical soils: Implications for soil carbon storage
potential in croplands, Geoderma, 313, 41–51,
https://doi.org/10.1016/j.geoderma.2017.10.010, 2018a.
Fujisaki, K., Chevallier, T., Chapuis-Lardy, L., Albrecht, A., Razafimbelo,
T., Masse, D., Ndour, Y. B., and Chotte, J.-L.: Soil carbon stock changes in
tropical croplands are mainly driven by carbon inputs: A synthesis,
Agr. Ecosys. Environ., 259, 147–158,
https://doi.org/10.1016/j.agee.2017.12.008, 2018b.
Goudie, A. S. and Middleton, N. J.: Saharan dust storms: nature and
consequences, Earth-Sci. Rev., 56, 179–204,
https://doi.org/10.1016/S0012-8252(01)00067-8, 2001.
Greenland, D. J.: Interaction between clays and organic compounds in soils,
Part II: Adsorption of soil organic compounds and its effect on soil
properties, Soils and Fertilizers, 28, 415–425, 1965.
Greenwell, B. M.: pdp: An R Package for Constructing Partial Dependence
Plots, The R Journal, 9, 421–436, https://doi.org/10.32614/RJ-2017-016, 2017.
Harrison, X. A., Donaldson, L., Correa-Cano, M. E., Evans, J., Fisher, D.
N., Goodwin, C. E. D., Robinson, B. S., Hodgson, D. J., and Inger, R.: A
brief introduction to mixed effects modelling and multi-model inference in
ecology, PeerJ, 6, e4794–e4794, https://doi.org/10.7717/peerj.4794, 2018.
Hartmann, J. and Moosdorf, N.: The new global lithological map database
GLiM: A representation of rock properties at the Earth surface,
Geochem. Geophy. Geosy., 13, 1–37, https://doi.org/10.1029/2012gc004370, 2012.
Heimann, M. and Reichstein, M.: Terrestrial ecosystem carbon dynamics and
climate feedbacks, Nature, 451, 289–292, https://doi.org/10.1038/nature06591, 2008.
Holmes, K. W., Roberts, D. A., Sweeney, S., Numata, I., Matricardi, E.,
Biggs, T. W., Batista, G., and Chadwick, O. A.: Soil databases and the
problem of establishing regional biogeochemical trends, Glob. Change
Biol., 10, 796–814, https://doi.org/10.1111/j.1529-8817.2003.00753.x, 2004.
Holmes, K. W., Kyriakidis, P. C., Chadwick, O. A., Soares, J. V., and
Roberts, D. A.: Multi-scale variability in tropical soil nutrients following
land-cover change, Biogeochemistry, 74, 173–203, https://doi.org/10.1007/s10533-004-3544-x,
2005.
Inagaki, T. M., Possinger, A. R., Grant, K. E., Schweizer, S. A., Mueller,
C. W., Derry, L. A., Lehmann, J., and Kögel-Knabner, I.: Subsoil
organo-mineral associations under contrasting climate conditions, Geochim.
Cosmochim. Ac., 270, 244–263, https://doi.org/10.1016/j.gca.2019.11.030, 2020.
IPCC: Climate Change and Land, an IPCC special report on climate change,
desertification, land degradation, sustainable land management, food
security, and greenhouse gas fluxes in terrestrial ecosystems, edited by:
Arneth, A., Barbosa, H., Benton, T., Calvin, K., and Calvo, E., IPCC,
Geneva, Switzerland, 2019.
Jenny, H.: Factors of soil formation – a system of quantitative pedology,
McGraw-Hill, New York, USA, 1941.
Jobbágy, E. G. and Jackson, R. B.: The vertical distribution of soil
organic carbon and its relation to climate and vegetation, Ecol.
Appl., 10, 423–436, https://doi.org/10.1890/1051-0761(2000)010[0423:Tvdoso]2.0.Co;2,
2000.
Jones, A., Breuning-Madsen, H., Brossard, M., Dampha, A., Deckers, J.,
Dewitte, O., Gallali, T., Hallett, S., Jones, R., Kilasara, M., Le Roux, P.,
Michéli, E., Montanarella, L., Spaargaren, O., Thiombiano, L., van
Ranst, E., Yemefack, M., and Zougmore, R.: Soil Atlas of Africa, Commission,
Publications Office of the European Union, Luxembourg, 2013.
Kahle, M., Kleber, M., and Jahn, R.: Carbon storage in loess derived surface
soils from Central Germany: Influence of mineral phase variables, J.
Plant Nutr. Soil Sci., 165, 141–149,
https://doi.org/10.1002/1522-2624(200204)165:2<141::Aid-jpln141>3.0.Co;2-x, 2002.
Kennard, R. W. and Stone, L. A.: Computer Aided Design of Experiments,
Technometrics, 11, 137–148, https://doi.org/10.1080/00401706.1969.10490666, 1969.
Kramer, M. G. and Chadwick, O. A.: Climate-driven thresholds in reactive
mineral retention of soil carbon at the global scale, Nat. Clim. Change,
8, 1104–1108, https://doi.org/10.1038/s41558-018-0341-4, 2018.
Legendre, P. and Legendre, L.: Numerical Ecology, Elsevier Science,
Amsterdam, the Netherlands, 2006 pp., 2012.
Likens, G. E., Driscoll, C. T., Buso, D. C., Siccama, T. G., Johnson, C. E.,
Lovett, G. M., Fahey, T. J., Reiners, W. A., Ryan, D. F., Martin, C. W., and
Bailey, S. W.: The biogeochemistry of calcium at Hubbard Brook,
Biogeochemistry, 41, 89–173, https://doi.org/10.1023/A:1005984620681, 1998.
Lovelace, R., Nowosad, J., and Muenchow, J.: Geocomputation with R, Chapman
and Hall/CRC, Boca Raton, Florida, USA, 335 pp., 2019.
Luo, Z., Viscarra-Rossel, R. A., and Qian, T.: Similar importance of edaphic
and climatic factors for controlling soil organic carbon stocks of the
world, Biogeosciences, 18, 2063–2073, https://doi.org/10.5194/bg-18-2063-2021, 2021.
Malick, B. M. L. and Ishiga, H.: Geochemical Classification and
Determination of Maturity Source Weathering in Beach Sands of Eastern San'
in Coast, Tango Peninsula, and Wakasa Bay, Japan, Earth Sci. Res., 5,
44–56, https://doi.org/10.5539/esr.v5n1p44, 2016.
McGrath, S. P. and Cunliffe, C. H.: A simplified method for the extraction
of the metals Fe, Zn, Cu, Ni, Cd, Pb, Cr, Co and Mn from soils and sewage
sludges, J. Sci. Food Agr., 36, 794–798,
https://doi.org/10.1002/jsfa.2740360906, 1985.
McLennan, S. M.: Weathering and Global Denudation, J. Geol., 101, 295–303,
https://doi.org/10.1086/648222, 1993.
Milborrow, S.: rpart.plot: Plot “rpart” Models: An Enhanced Version of
“plot.rpart”, available at: https://CRAN.R-project.org/package=rpart.plot (last access: 3 June 2021), 2019.
Muneer, M. and Oades, J.: The role of Ca-organic interactions in soil
aggregate stability .III. Mechanisms and models, Soil Res., 27, 411–423,
https://doi.org/10.1071/SR9890411, 1989.
Nakagawa, S. and Schielzeth, H.: A general and simple method for obtaining
R2 from generalized linear mixed-effects models, Method. Ecol.
Evol., 4, 133–142, https://doi.org/10.1111/j.2041-210x.2012.00261.x, 2013.
Nave, L. E., Bowman, M., Gallo, A., Hatten, J. A., Heckman, K. A.,
Matosziuk, L., Possinger, A. R., SanClements, M., Sanderman, J., Strahm, B.
D., Weiglein, T. L., and Swanston, C. W.: Patterns and predictors of soil
organic carbon storage across a continental-scale network, Biogeochemistry,
https://doi.org/10.1007/s10533-020-00745-9, 2021.
Nesbit, H. W. and Young, G. M.: Early Proterozoic climates and plate
motions inferred from major element chemistry of lutites, Nature, 299,
715–717, https://doi.org/10.1038/299715a0, 1982.
Oades, J. M.: The retention of organic matter in soils, Biogeochemistry, 5,
35–70, https://doi.org/10.1007/BF02180317, 1988.
Olorunfemi, I. E., Fasinmirin, J. T., Olufayo, A. A., and Komolafe, A. A.:
Total carbon and nitrogen stocks under different land use/land cover types
in the Southwestern region of Nigeria, Geoderma Regional, 22, e00320,
https://doi.org/10.1016/j.geodrs.2020.e00320, 2020.
Parfitt, R. and Childs, C.: Estimation of forms of Fe and Al – a review,
and analysis of contrasting soils by dissolution and Mossbauer methods, Soil
Res., 26, 121–144, https://doi.org/10.1071/SR9880121, 1988.
Peterson, R. A. and Cavanaugh, J. E.: Ordered quantile normalization: a
semiparametric transformation built for the cross-validation era, J.
Appl. Stat., 47, 1–16, https://doi.org/10.1080/02664763.2019.1630372, 2019.
Pinheiro, J., Bates, D., DebRoy, S., Sarkar, D., and R Core Team: nlme:
Linear and Nonlinear Mixed Effects Models, available at: https://CRAN.R-project.org/package=nlme (last access: 24 April 2020), 2020.
Probst, P., Wright, M. N., and Boulesteix, A.-L.: Hyperparameters and tuning
strategies for random forest, WIREs Data Mining and Knowledge Discovery, 9,
e1301, https://doi.org/10.1002/widm.1301, 2019.
Prout, J. M., Shepherd, K. D., McGrath, S. P., Kirk, G. J. D., and Haefele,
S. M.: What is a good level of soil organic matter? An index based on
organic carbon to clay ratio, Europ. J. Soil Sci., 1–11,
https://doi.org/10.1111/ejss.13012, 2020.
Quesada, C. A., Paz, C., Oblitas Mendoza, E., Phillips, O. L., Saiz, G., and
Lloyd, J.: Variations in soil chemical and physical properties explain
basin-wide Amazon forest soil carbon concentrations, SOIL, 6, 53–88,
https://doi.org/10.5194/soil-6-53-2020, 2020.
R Core Team: R: A language and environment for statistical computing, R
Foundation for Statistical Computing, Vienna, Austria, available at: https://www.R-project.org/ (last access: 24 April 2020), 2020.
Rasmussen, C., Heckman, K., Wieder, W. R., Keiluweit, M., Lawrence, C. R.,
Berhe, A. A., Blankinship, J. C., Crow, S. E., Druhan, J. L., Hicks Pries,
C. E., Marin-Spiotta, E., Plante, A. F., Schädel, C., Schimel, J. P.,
Sierra, C. A., Thompson, A., and Wagai, R.: Beyond clay: towards an improved
set of variables for predicting soil organic matter content,
Biogeochemistry, 137, 297–306, https://doi.org/10.1007/s10533-018-0424-3, 2018.
Rimmer, D. L. and Greenland, D. J.: Effects of Calcium carbonate on the
swelling behaviour of a soil clay, J. Soil Sci., 27, 129–139,
https://doi.org/10.1111/j.1365-2389.1976.tb01983.x, 1976.
Rowley, M. C., Grand, S., and Verrecchia, É. P.: Calcium-mediated
stabilisation of soil organic carbon, Biogeochemistry, 137, 27–49,
https://doi.org/10.1007/s10533-017-0410-1, 2018.
Schlüter, T.: Geological Atlas of Africa, Springer, Heidelberg, Germany,
307 pp., 2008.
Schmidt, M. W. I., Torn, M. S., Abiven, S., Dittmar, T., Guggenberger, G.,
Janssens, I. A., Kleber, M., Kögel-Knabner, I., Lehmann, J., Manning, D.
A. C., Nannipieri, P., Rasse, D. P., Weiner, S., and Trumbore, S. E.:
Persistence of soil organic matter as an ecosystem property, Nature, 478,
49–56, https://doi.org/10.1038/nature10386, 2011.
Six, J., Conant, R. T., Paul, E. A., and Paustian, K.: Review: Stabilization
mechanisms of soil organic matter: Implications for C-saturation of soils,
Plant Soil, 241, 155–176, https://doi.org/10.1023/A:1016125726789, 2002a.
Six, J., Feller, C., Denef, K., Ogle, S. M., de Moraes Sa, J. C., and
Albrecht, A.: Soil organic matter, biota and aggregation in temperate and
tropical soils – Effects of no-tillage, Agronomie, 22, 755–775,
https://doi.org/10.1051/agro:2002043, 2002b.
Slessarev, E. W., Lin, Y., Bingham, N. L., Johnson, J. E., Dai, Y., Schimel,
J. P., and Chadwick, O. A.: Water balance creates a threshold in soil pH at
the global scale, Nature, 540, 567–569, https://doi.org/10.1038/nature20139, 2016.
Terhoeven-Urselmans, T., Vågen, T.-G., Spaargaren, O., and Shepherd, K.
D.: Prediction of Soil Fertility Properties from a Globally Distributed Soil
Mid-Infrared Spectral Library, Soil Sci. Soc. Am. J., 74,
1792–1799, https://doi.org/10.2136/sssaj2009.0218, 2010.
Therneau, T. and Atkinson, B.: rpart: Recursive Partitioning and Regression
Trees, available at: https://CRAN.R-project.org/package=rpart (last access: 3 June 2021),
2019.
Thompson, A., Rancourt, D. G., Chadwick, O. A., and Chorover, J.: Iron
solid-phase differentiation along a redox gradient in basaltic soils,
Geochim. Cosmochim. Ac., 75, 119–133, https://doi.org/10.1016/j.gca.2010.10.005,
2011.
Tifafi, M., Guenet, B., and Hatté, C.: Large Differences in Global and
Regional Total Soil Carbon Stock Estimates Based on SoilGrids, HWSD, and
NCSCD: Intercomparison and Evaluation Based on Field Data From USA, England,
Wales, and France, Global Biogeochem. Cy., 32, 42–56,
https://doi.org/10.1002/2017gb005678, 2018.
Tisdall, J. M. and Oades, J. M.: Organic matter and water-stable aggregates
in soils, J. Soil Sci., 33, 141–163,
https://doi.org/10.1111/j.1365-2389.1982.tb01755.x, 1982.
Towett, E. K., Shepherd, K. D., Tondoh, J. E., Winowiecki, L. A., Lulseged,
T., Nyambura, M., Sila, A., Vågen, T.-G., and Cadisch, G.: Total
elemental composition of soils in Sub-Saharan Africa and relationship with
soil forming factors, Geoderma Regional, 5, 157–168,
https://doi.org/10.1016/j.geodrs.2015.06.002, 2015.
Trabucco, A. and Zomer, R.: Global Aridity Index and Potential
Evapotranspiration (ET0) Climate Database v2. Figshare, 2019.
Vågen, T.-G., Walsh, M. G., and Shepherd, K. D.: Stable isotopes for
characterisation of trends in soil carbon following deforestation and land
use change in the highlands of Madagascar, Geoderma, 135, 133–139,
https://doi.org/10.1016/j.geoderma.2005.11.012, 2006.
Vågen, T.-G., Shepherd, K. D., Walsh, M. G., Winowiecki, L., Desta, L.
T., and Tondoh, J. E.: AfSIS Technical Specifications – Soil Health
Surveillance [Version 1.0], Nairobi, Kenya, 69 pp., 2010.
Vågen, T.-G., Winowiecki, L. A., Abegaz, A., and Hadgu, K. M.:
Landsat-based approaches for mapping of land degradation prevalence and soil
functional properties in Ethiopia, Remote Sens. Environ., 134,
266–275, https://doi.org/10.1016/j.rse.2013.03.006, 2013a.
Vågen, T.-G., Winowiecki, L. A., Tondoh, J. E., and Desta, L. T.: Africa
Soil Information Service (AfSIS) – Soil Health Mapping, Harvard Dataverse,
2013b.
Vågen, T.-G., Winowiecki, L. A., Tondoh, J. E., Desta, L. T., and
Gumbricht, T.: Mapping of soil properties and land degradation risk in
Africa using MODIS reflectance, Geoderma, 263, 216–225,
https://doi.org/10.1016/j.geoderma.2015.06.023, 2016.
Vågen, T.-G., Winowiecki, L. A., Desta, L., Tondoh, J., Weullow, E.,
Shepherd, K., Sila, A., Dunham, S., J., Hernández-Allica, J., Carter,
J., and McGrath, S. P.: Wet chemistry data for a subset of AfSIS: Phase I
archived soil samples, producers: Rothamsted Research,
World Agroforestry, and
Bill an Melinda Gates Foundation,
Biotechnology, UK, Biological Sciences Research, C., CGIAR Research
Program on Water, and Ecosystems, World Agroforestry – Research
Data Repository, available at: https://data.worldagroforestry.org/dataset.xhtml?persistentId=doi:10.34725/DVN/66BFOB, last access: 30 March 2021.
Vanlauwe, B., Descheemaeker, K., Giller, K. E., Huising, J., Merckx, R.,
Nziguheba, G., Wendt, J., and Zingore, S.: Integrated soil fertility
management in sub-Saharan Africa: unravelling local adaptation, SOIL, 1,
491–508, https://doi.org/10.5194/soil-1-491-2015, 2015.
Wagai, R., Kajiura, M., and Asano, M.: Iron and aluminum association with
microbially processed organic matter via meso-density aggregate formation
across soils: organo-metallic glue hypothesis, SOIL, 6, 597–627,
https://doi.org/10.5194/soil-6-597-2020, 2020.
Wiesmeier, M., Urbanski, L., Hobley, E., Lang, B., von Lützow, M.,
Marin-Spiotta, E., van Wesemael, B., Rabot, E., Ließ, M., Garcia-Franco,
N., Wollschläger, U., Vogel, H.-J., and Kögel-Knabner, I.: Soil
organic carbon storage as a key function of soils – A review of drivers and
indicators at various scales, Geoderma, 333, 149–162,
https://doi.org/10.1016/j.geoderma.2018.07.026, 2019.
Winowiecki, L. A., Vågen, T.-G., and Huising, J.: Effects of land cover
on ecosystem services in Tanzania: A spatial assessment of soil organic
carbon, Geoderma, 263, 274–283, https://doi.org/10.1016/j.geoderma.2015.03.010, 2016a.
Winowiecki, L. A., Vågen, T.-G., Massawe, B., Jelinski, N. A., Lyamchai,
C., Sayula, G., and Msoka, E.: Landscape-scale variability of soil health
indicators: effects of cultivation on soil organic carbon in the Usambara
Mountains of Tanzania, Nutr. Cycl. Agroecosystems, 105, 263–274,
https://doi.org/10.1007/s10705-015-9750-1, 2016b.
Winowiecki, L. A., Vågen, T.-G., Boeckx, P., and Dungait, J. A. J.:
Landscape-scale assessments of stable carbon isotopes in soil under diverse
vegetation classes in East Africa: application of near-infrared
spectroscopy, Plant Soil, 421, 259–272, https://doi.org/10.1007/s11104-017-3418-3, 2017.
Wright, M. N. and Ziegler, A.: ranger: A fast implementation fo random
forests for high dimensional data in C
Zuur, A. F., Ieno, E. N., and Elphick, C. S.: A protocol for data
exploration to avoid common statistical problems, Method. Ecol.
Evol., 1, 3–14, https://doi.org/10.1111/j.2041-210X.2009.00001.x, 2010.
Short summary
We investigated various soil and climate properties that influence soil organic carbon (SOC) concentrations in sub-Saharan Africa. Our findings indicate that climate and geochemistry are equally important for explaining SOC variations. The key SOC-controlling factors are broadly similar to those for temperate regions, despite differences in soil development history between the two regions.
We investigated various soil and climate properties that influence soil organic carbon (SOC)...
