Articles | Volume 14, issue 9
Research article 12 May 2017
Research article | 12 May 2017
Modelling the genesis of equatorial podzols: age and implications for carbon fluxes
Cédric Doupoux et al.
No articles found.
Patricia Merdy, Yves Lucas, Bruno Coulomb, Adolpho J. Melfi, and Célia R. Montes
SOIL, 7, 585–594,Short summary
Transfer of organic C from topsoil to deeper horizons and the water table is little documented, especially in equatorial environments, despite high primary productivity in the evergreen forest. Using column experiments with podzol soil and a percolating solution sampled in an Amazonian podzol area, we show how the C-rich Bh horizon plays a role in natural organic matter transfer and Si, Fe and Al mobility after a kaolinitic layer transition, thus giving insight to the genesis of tropical podzol.
Arjun Chakrawal, Anke M. Herrmann, John Koestel, Jerker Jarsjö, Naoise Nunan, Thomas Kätterer, and Stefano Manzoni
Geosci. Model Dev., 13, 1399–1429,Short summary
Soils are heterogeneous, which results in a nonuniform spatial distribution of substrates and the microorganisms feeding on them. Our results show that the variability in the spatial distribution of substrates and microorganisms at the pore scale is crucial because it affects how fast substrates are used by microorganisms and thus the decomposition rate observed at the soil core scale. This work provides a methodology to include microscale heterogeneity in soil carbon cycling models.
Related subject area
Biogeochemistry: SoilsSoil profile connectivity can impact microbial substrate use, affecting how soil CO2 effluxes are controlled by temperatureAdditional carbon inputs to reach a 4 per 1000 objective in Europe: feasibility and projected impacts of climate change based on Century simulations of long-term arable experimentsCycling and retention of nitrogen in European beech (Fagus sylvatica L.) ecosystems under elevated fructification frequencyMercury mobility, colloid formation and methylation in a polluted Fluvisol as affected by manure application and flooding–draining cycleSimulating measurable ecosystem carbon and nitrogen dynamics with the mechanistically defined MEMS 2.0 modelSimilar importance of edaphic and climatic factors for controlling soil organic carbon stocks of the worldRepresenting methane emissions from wet tropical forest soils using microbial functional groups constrained by soil diffusivityLong-term bare-fallow soil fractions reveal thermo-chemical properties controlling soil organic carbon dynamicsGeochemical zones and environmental gradients for soils from the central Transantarctic Mountains, AntarcticaEffect of organic carbon addition on paddy soil organic carbon decomposition under different irrigation regimesAge distribution, extractability, and stability of mineral-bound organic carbon in central European soilsDenitrification in soil as a function of oxygen availability at the microscaleKey drivers of pyrogenic carbon redistribution during a simulated rainfall eventSubsurface flow and phosphorus dynamics in beech forest hillslopes during sprinkling experiments: how fast is phosphorus replenished?Estimating maximum fine-fraction organic carbon in UK grasslandsMillennial-age glycerol dialkyl glycerol tetraethers (GDGTs) in forested mineral soils: 14C-based evidence for stabilization of microbial necromassParticles under stress: ultrasonication causes size and recovery rate artifacts with soil-derived POM but not with microplasticsDeepening roots can enhance carbonate weathering by amplifying CO2-rich rechargeVertical mobility of pyrogenic organic matter in soils: a column experimentVertical partitioning of CO2 production in a forest soilInteractions between biogeochemical and management factors explain soil organic carbon in Pyrenean grasslandsReviews and syntheses: Ironing out wrinkles in the soil phosphorus cycling paradigmHerbicide weed control increases nutrient leaching compared to mechanical weeding in a large-scale oil palm plantationReviews and syntheses: The mechanisms underlying carbon storage in soilIdentification of lower-order inositol phosphates (IP5 and IP4) in soil extracts as determined by hypobromite oxidation and solution 31P NMR spectroscopyModelling dynamic interactions between soil structure and the storage and turnover of soil organic matterWarming increases soil respiration in a carbon-rich soil without changing microbial respiratory potentialReviews and syntheses: Soil responses to manipulated precipitation changes – an assessment of meta-analysesFrom fibrous plant residues to mineral-associated organic carbon – the fate of organic matter in Arctic permafrost soilsRelevance of aboveground litter for soil organic matter formation – a soil profile perspectiveA revised pan-Arctic permafrost soil Hg pool based on Western Siberian peat Hg and carbon observationsUsing respiration quotients to track changing sources of soil respiration seasonally and with experimental warmingThe soil organic carbon stabilization potential of old and new wheat cultivars: a 13CO2-labeling studyDrivers and modelling of blue carbon stock variability in sediments of southeastern AustraliaA comparison of patterns of microbial C : N : P stoichiometry between topsoil and subsoil along an aridity gradientSoil total phosphorus and nitrogen explain vegetation community composition in a northern forest ecosystem near a phosphate massifContrasting conifer species productivity in relation to soil carbon, nitrogen and phosphorus stoichiometry of British Columbia perhumid rainforestsIncreasing soil carbon stocks in eight permanent forest plots in ChinaEstimates of mean residence times of phosphorus in commonly considered inorganic soil phosphorus poolsLability classification of soil organic matter in the northern permafrost regionCurrent, steady-state and historical weathering rates of base cations at two forest sites in northern and southern Sweden: a comparison of three methodsAnoxic conditions maintained high phosphorus sorption in humid tropical forest soilsReviews and syntheses: Agropedogenesis – humankind as the sixth soil-forming factor and attractors of agricultural soil degradationWeathering rates in Swedish forest soilsExogenous phosphorus compounds interact with nitrogen availability to regulate dynamics of soil inorganic phosphorus fractions in a meadow steppeThe simulated N deposition accelerates net N mineralization and nitrification in a tropical forest soilSimulated wild boar bioturbation increases the stability of forest soil carbonSpatial changes in soil stable isotopic composition in response to carrion decompositionSpatial gradients in the characteristics of soil-carbon fractions are associated with abiotic features but not microbial communitiesPhysical constraints for respiration in microbial hotspots in soil and their importance for denitrification
Frances A. Podrebarac, Sharon A. Billings, Kate A. Edwards, Jérôme Laganière, Matthew J. Norwood, and Susan E. Ziegler
Biogeosciences, 18, 4755–4772,Short summary
Soil respiration is a large and temperature-responsive flux in the global carbon cycle. We found increases in microbial use of easy to degrade substrates enhanced the temperature response of respiration in soils layered as they are in situ. This enhanced response is consistent with soil composition differences in warm relative to cold climate forests. These results highlight the importance of the intact nature of soils rarely studied in regulating responses of CO2 fluxes to changing temperature.
Elisa Bruni, Bertrand Guenet, Yuanyuan Huang, Hugues Clivot, Iñigo Virto, Roberta Farina, Thomas Kätterer, Philippe Ciais, Manuel Martin, and Claire Chenu
Biogeosciences, 18, 3981–4004,Short summary
Increasing soil organic carbon (SOC) stocks is beneficial for climate change mitigation and food security. One way to enhance SOC stocks is to increase carbon input to the soil. We estimate the amount of carbon input required to reach a 4 % annual increase in SOC stocks in 14 long-term agricultural experiments around Europe. We found that annual carbon input should increase by 43 % under current temperature conditions, by 54 % for a 1 °C warming scenario and by 120 % for a 5 °C warming scenario.
Rainer Brumme, Bernd Ahrends, Joachim Block, Christoph Schulz, Henning Meesenburg, Uwe Klinck, Markus Wagner, and Partap K. Khanna
Biogeosciences, 18, 3763–3779,Short summary
In order to study the fate of litter nitrogen in forest soils, we combined a leaf litterfall exchange experiment using 15N-labeled leaf litter with long-term element budgets at seven European beech sites in Germany. It appears that fructification intensity, which has increased in recent decades, has a distinct impact on N retention in forest soils. Despite reduced nitrogen deposition, about 6 and 10 kg ha−1 of nitrogen were retained annually in the soils and in the forest stands, respectively.
Lorenz Gfeller, Andrea Weber, Isabelle Worms, Vera I. Slaveykova, and Adrien Mestrot
Biogeosciences, 18, 3445–3465,Short summary
Our incubation experiment shows that flooding of polluted floodplain soils may induce pulses of both mercury (Hg) and methylmercury to the soil solution and threaten downstream ecosystems. We demonstrate that mobilization of Hg bound to manganese oxides is a relevant process in organic-matter-poor soils. Addition of organic amendments accelerates this mobilization but also facilitates the formation of nanoparticulate Hg and the subsequent fixation of Hg from soil solution to the soil.
Yao Zhang, Jocelyn M. Lavallee, Andy D. Robertson, Rebecca Even, Stephen M. Ogle, Keith Paustian, and M. Francesca Cotrufo
Biogeosciences, 18, 3147–3171,Short summary
Soil organic matter (SOM) is essential for the health of soils, and the accumulation of SOM helps removal of CO2 from the atmosphere. Here we present the result of the continued development of a mathematical model that simulates SOM and its measurable fractions. In this study, we simulated several grassland sites in the US, and the model generally captured the carbon and nitrogen amounts in SOM and their distribution between the measurable fractions throughout the entire soil profile.
Zhongkui Luo, Raphael A. Viscarra-Rossel, and Tian Qian
Biogeosciences, 18, 2063–2073,Short summary
Using the data from 141 584 whole-soil profiles across the globe, we disentangled the relative importance of biotic, climatic and edaphic variables in controlling global SOC stocks. The results suggested that soil properties and climate contributed similarly to the explained global variance of SOC in four sequential soil layers down to 2 m. However, the most important individual controls are consistently soil-related, challenging current climate-driven framework of SOC dynamics.
Debjani Sihi, Xiaofeng Xu, Mónica Salazar Ortiz, Christine S. O'Connell, Whendee L. Silver, Carla López-Lloreda, Julia M. Brenner, Ryan K. Quinn, Jana R. Phillips, Brent D. Newman, and Melanie A. Mayes
Biogeosciences, 18, 1769–1786,Short summary
Humid tropical soils are important sources and sinks of methane. We used model simulation to understand how different kinds of microbes and observed soil moisture and oxygen dynamics contribute to production and consumption of methane along a wet tropical hillslope during normal and drought conditions. Drought alters the diffusion of oxygen and microbial substrates into and out of soil microsites, resulting in enhanced methane release from the entire hillslope during drought recovery.
Mathieu Chassé, Suzanne Lutfalla, Lauric Cécillon, François Baudin, Samuel Abiven, Claire Chenu, and Pierre Barré
Biogeosciences, 18, 1703–1718,Short summary
Evolution of organic carbon content in soils could be a major driver of atmospheric greenhouse gas concentrations over the next century. Understanding factors controlling carbon persistence in soil is a challenge. Our study of unique long-term bare-fallow samples, depleted in labile organic carbon, helps improve the separation, evaluation and characterization of carbon pools with distinct residence time in soils and gives insight into the mechanisms explaining soil organic carbon persistence.
Melisa A. Diaz, Christopher B. Gardner, Susan A. Welch, W. Andrew Jackson, Byron J. Adams, Diana H. Wall, Ian D. Hogg, Noah Fierer, and W. Berry Lyons
Biogeosciences, 18, 1629–1644,Short summary
Water-soluble salt and nutrient concentrations of soils collected along the Shackleton Glacier, Antarctica, show distinct geochemical gradients related to latitude, longitude, elevation, soil moisture, and distance from coast and glacier. Machine learning algorithms were used to estimate geochemical gradients for the region given the relationship with geography. Geography and surface exposure age drive salt and nutrient abundances, influencing invertebrate habitat suitability and biogeography.
Heleen Deroo, Masuda Akter, Samuel Bodé, Orly Mendoza, Haichao Li, Pascal Boeckx, and Steven Sleutel
Revised manuscript accepted for BGShort summary
We wanted to assess if and how incorporation of exogenous organic carbon (OC) such as straw could affect decomposition of native soil organic carbon (SOC) under different irrigation regimes. Addition of exogenous OC promoted dissolution of native SOC, partly because of increased Fe reduction, leading to more net release of Fe-bound SOC. Yet, there was no proportionate priming of SOC-derived DOC mineralisation. Water-saving irrigation can retard both priming of SOC dissolution and mineralisation.
Marion Schrumpf, Klaus Kaiser, Allegra Mayer, Günter Hempel, and Susan Trumbore
Biogeosciences, 18, 1241–1257,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.
Lena Rohe, Bernd Apelt, Hans-Jörg Vogel, Reinhard Well, Gi-Mick Wu, and Steffen Schlüter
Biogeosciences, 18, 1185–1201,Short summary
Total denitrification, i.e. N2O and (N2O + N2) fluxes, of repacked soil cores were analysed for different combinations of soils and water contents. Prediction accuracy of (N2O + N2) fluxes was highest with combined proxies for oxygen demand (CO2 flux) and oxygen supply (anaerobic soil volume fraction). Knowledge of denitrification completeness (product ratio) improved N2O predictions. Substitutions with cheaper proxies (soil organic matter, empirical diffusivity) reduced prediction accuracy.
Severin-Luca Bellè, Asmeret Asefaw Berhe, Frank Hagedorn, Cristina Santin, Marcus Schiedung, Ilja van Meerveld, and Samuel Abiven
Biogeosciences, 18, 1105–1126,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.
Michael Rinderer, Jaane Krüger, Friederike Lang, Heike Puhlmann, and Markus Weiler
Biogeosciences, 18, 1009–1027,Short summary
We quantified the lateral and vertical subsurface flow (SSF) and P concentrations of three beech forest plots with contrasting soil properties during sprinkling experiments. Vertical SSF was 2 orders of magnitude larger than lateral SSF, and both consisted mainly of pre-event water. P concentrations in SSF were high during the first 1 to 2 h (nutrient flushing) but nearly constant thereafter. This suggests that P in the soil solution was replenished fast by mineral or organic sources.
Kirsty C. Paterson, Joanna M. Cloy, Robert M. Rees, Elizabeth M. Baggs, Hugh Martineau, Dario Fornara, Andrew J. Macdonald, and Sarah Buckingham
Biogeosciences, 18, 605–620,Short summary
Soil organic carbon sequestration across agroecosystems worldwide can contribute to mitigating the effects of climate change by reducing levels of atmospheric carbon dioxide. The maximum carbon sequestration potential is frequently estimated using the linear regression equation developed by Hassink (1997). This work examines the suitability of this equation for use in grasslands across the United Kingdom. The results highlight the need to ensure the fit of equations to the soils being studied.
Hannah Gies, Frank Hagedorn, Maarten Lupker, Daniel Montluçon, Negar Haghipour, Tessa Sophia van der Voort, and Timothy Ian Eglinton
Biogeosciences, 18, 189–205,Short summary
Understanding controls on the persistence of organic matter in soils is essential to constrain its role in the carbon cycle. Emerging concepts suggest that the soil carbon pool is predominantly comprised of stabilized microbial residues. To test this hypothesis we isolated microbial membrane lipids from two Swiss soil profiles and measured their radiocarbon age. We find that the ages of these compounds are in the range of millenia and thus provide evidence for stabilized microbial mass in soils.
Frederick Büks, Gilles Kayser, Antonia Zieger, Friederike Lang, and Martin Kaupenjohann
Biogeosciences, 18, 159–167,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.
Hang Wen, Pamela L. Sullivan, Gwendolyn L. Macpherson, Sharon A. Billings, and Li Li
Biogeosciences, 18, 55–75,Short summary
Carbonate weathering is essential in regulating carbon cycle at the century timescale. Plant roots accelerate weathering by elevating soil CO2 via respiration. It however remains poorly understood how and how much rooting characteristics modify flow paths and weathering. This work indicates that deepening roots in woodlands can enhance carbonate weathering by promoting recharge and CO2–carbonate contact in the deep, carbonate-abundant subsurface.
Marcus Schiedung, Severin-Luca Bellè, Gabriel Sigmund, Karsten Kalbitz, and Samuel Abiven
Biogeosciences, 17, 6457–6474,Short summary
The mobility of pyrogenic organic matter (PyOM) in soils is largely unknow, while it is a major and persistent component of the soil organic matter. With a soil column experiment, we identified that only a small proportion of PyOM can migrate through the soil, but its export is continuous. Aging and associated oxidation increase its mobility but also its retention in soils. Further, PyOM can alter the vertical mobility of native soil organic carbon during its downward migration.
Patrick Wordell-Dietrich, Anja Wotte, Janet Rethemeyer, Jörg Bachmann, Mirjam Helfrich, Kristina Kirfel, Christoph Leuschner, and Axel Don
Biogeosciences, 17, 6341–6356,Short summary
The release of CO2 from soils, known as soil respiration, plays a major role in the global carbon cycle. However, the contributions of different soil depths or the sources of soil CO2 have hardly been studied. We quantified the CO2 production for different soil layers (up to 1.5 m) in three soil profiles for 2 years. We found that 90 % of CO2 production occurs in the first 30 cm of the soil profile, and that the CO2 originated from young carbon sources, as revealed by radiocarbon measurements.
Antonio Rodríguez, Rosa Maria Canals, Josefina Plaixats, Elena Albanell, Haifa Debouk, Jordi Garcia-Pausas, Leticia San Emeterio, Àngela Ribas, Juan José Jimenez, and M.-Teresa Sebastià
Biogeosciences, 17, 6033–6050,Short summary
The novelty of our work is that it presents a series of potential interactions between drivers of soil organic carbon at broad scales in temperate mountain grasslands. The most relevant contribution of our work is that it illustrates the importance of grazing management for soil carbon stocks, indicating that interactions between grazing species and soil nitrogen and herbage quality may be promising paths in order to design further management policies for palliating climate change.
Curt A. McConnell, Jason P. Kaye, and Armen R. Kemanian
Biogeosciences, 17, 5309–5333,Short summary
Soil phosphorus (P) management is a critical challenge for agriculture worldwide; yet, simulation models of soil P processes lag those of other essential nutrients. In this review, we identify hindrances to measuring and modeling soil P pools and fluxes. We highlight the need to clarify biological and mineral interactions by defining P pools explicitly and using evolving techniques, such as tracing P in phosphates using oxygen isotopes.
Greta Formaglio, Edzo Veldkamp, Xiaohong Duan, Aiyen Tjoa, and Marife D. Corre
Biogeosciences, 17, 5243–5262,Short summary
The intensive management of large-scale oil palm plantations may result in high nutrient leaching losses which reduce soil fertility and potentially pollute water bodies. The reduction in management intensity with lower fertilization rates and with mechanical weeding instead of the use of herbicide results in lower nutrient leaching losses while maintaining high yield. Lower leaching results from lower nutrient inputs from fertilizer and from higher retention by enhanced cover vegetation.
Isabelle Basile-Doelsch, Jérôme Balesdent, and Sylvain Pellerin
Biogeosciences, 17, 5223–5242,Short summary
The 4 per 1000 initiative aims to restore carbon storage in soils to both mitigate climate change and contribute to food security. The French National Institute for Agricultural Research conducted a study to determine the carbon storage potential in French soils and associated costs. This paper is a part of that study. It reviews recent advances concerning the mechanisms that controls C stabilization in soils. Synthetic figures integrating new concepts should be of pedagogical interest.
Jolanda E. Reusser, René Verel, Daniel Zindel, Emmanuel Frossard, and Timothy I. McLaren
Biogeosciences, 17, 5079–5095,Short summary
Inositol phosphates (IPs) are a major pool of organic P in soil. However, information on their diversity and abundance in soil is limited. We isolated IPs from soil and characterised them using solution nuclear magnetic resonance (NMR) spectroscopy. For the first time, we provide direct spectroscopic evidence for the existence of a multitude of lower-order IPs in soil extracts previously not detected with NMR. Our findings will help provide new insight into the cycling of IPs in ecosystems.
Katharina Hildegard Elisabeth Meurer, Claire Chenu, Elsa Coucheney, Anke Marianne Herrmann, Thomas Keller, Thomas Kätterer, David Nimblad Svensson, and Nicholas Jarvis
Biogeosciences, 17, 5025–5042,Short summary
We present a simple model that describes, for the first time, the dynamic two-way interactions between soil organic matter and soil physical properties (porosity, pore size distribution, bulk density and layer thickness). The model was able to accurately reproduce the changes in soil organic carbon, soil bulk density and surface elevation observed during 63 years in a field trial, as well as soil water retention curves measured at the end of the experimental period.
Marion Nyberg and Mark J. Hovenden
Biogeosciences, 17, 4405–4420,Short summary
Experimental warming increased soil respiration (RS) by more than 25 % in a Tasmanian C-rich soil, but there was no impact on microbial respiration in laboratory experiments. Plant community composition had no effect on RS, suggesting the response is likely due to enhanced belowground plant respiration and C supply through rhizodeposition and root exudates. Results imply we need studies of both C inputs and losses to model net ecosystem C exchange of these crucial, C-dense systems effectively.
Akane O. Abbasi, Alejandro Salazar, Youmi Oh, Sabine Reinsch, Maria del Rosario Uribe, Jianghanyang Li, Irfan Rashid, and Jeffrey S. Dukes
Biogeosciences, 17, 3859–3873,Short summary
In this study, we provide a holistic view of soil responses to precipitation changes. A total of 16 meta-analyses focusing on the effects of precipitation changes on 42 soil response variables were compared. A strong agreement was found that the belowground carbon and nitrogen cycling accelerate under increased precipitation and slow under decreased precipitation, while bacterial and fungal communities are relatively resistant to decreased precipitation. Knowledge gaps were also identified.
Isabel Prater, Sebastian Zubrzycki, Franz Buegger, Lena C. Zoor-Füllgraff, Gerrit Angst, Michael Dannenmann, and Carsten W. Mueller
Biogeosciences, 17, 3367–3383,Short summary
Large amounts of soil organic matter stored in permafrost-affected soils from Arctic Russia are present as undecomposed plant residues. This large fibrous organic matter might be highly vulnerable to microbial decay, while small mineral-associated organic matter can most probably attenuate carbon mineralization in a warmer future. Labile soil fractions also store large amounts of nitrogen, which might be lost during permafrost collapse while fostering the decomposition of soil organic matter.
Patrick Liebmann, Patrick Wordell-Dietrich, Karsten Kalbitz, Robert Mikutta, Fabian Kalks, Axel Don, Susanne K. Woche, Leena R. Dsilva, and Georg Guggenberger
Biogeosciences, 17, 3099–3113,Short summary
We studied the contribution of litter-derived carbon (C) in the formation of subsoil organic matter (OM). Soil core sampling, 13C field labeling, density fractionation, and water extractions were used to track its contribution to different functional OM fractions down to the deep subsoil. We show that while migrating down the soil profile, OM undergoes a sequence of repeated sorption, microbial processing, and desorption. However, the contribution of litter-derived C to subsoil OM is small.
Artem G. Lim, Martin Jiskra, Jeroen E. Sonke, Sergey V. Loiko, Natalia Kosykh, and Oleg S. Pokrovsky
Biogeosciences, 17, 3083–3097,Short summary
To better understand the mercury (Hg) content in northern soils, we measured Hg concentration in peat cores across a 1700 km permafrost gradient in Siberia. We demonstrated a northward increase in Hg concentration in peat and Hg pools in frozen peatlands. We revised the 0–30 cm northern soil Hg pool to be 72 Gg, which is 7 % of the global soil Hg pool of 1086 Gg. The results are important for understanding Hg exchange between soil, water, and the atmosphere under climate change in the Arctic.
Caitlin Hicks Pries, Alon Angert, Cristina Castanha, Boaz Hilman, and Margaret S. Torn
Biogeosciences, 17, 3045–3055,Short summary
The apparent respiration quotient (ARQ) changes according to which substrates microbes consume, allowing sources of soil respiration to be traced. In a forest soil warming experiment, ARQ had a strong seasonal pattern that reflected a shift from respiration being fueled by sugars and organic acids derived from roots during the growing season to respiration being fueled by dead microbes during winter. ARQ values also changed with experimental warming.
Marijn Van de Broek, Shiva Ghiasi, Charlotte Decock, Andreas Hund, Samuel Abiven, Cordula Friedli, Roland A. Werner, and Johan Six
Biogeosciences, 17, 2971–2986,Short summary
Four wheat cultivars were labeled with 13CO2 to quantify the effect of rooting depth and root biomass on the belowground transfer of organic carbon. We found no clear relation between the time since cultivar development and the amount of carbon inputs to the soil. Therefore, the hypothesis that wheat cultivars with a larger root biomass and deeper roots promote carbon stabilization was rejected. The amount of root biomass that will be stabilized in the soil on the long term is, however, unknown.
Carolyn J. Ewers Lewis, Mary A. Young, Daniel Ierodiaconou, Jeffrey A. Baldock, Bruce Hawke, Jonathan Sanderman, Paul E. Carnell, and Peter I. Macreadie
Biogeosciences, 17, 2041–2059,Short summary
Blue carbonecosystems – tidal marsh, mangrove, and seagrass – serve as important organic carbon sinks, mitigating impacts of climate change. We utilized a robust regional carbon stock dataset to identify ecological, geomorphological, and anthropogenic drivers of carbon stock variability and create high-spatial-resolution predictive carbon stock maps. This work facilitates strategic conservation and restoration of coastal blue carbon ecosystems to contribute to climate change mitigation.
Yuqing Liu, Wenhong Ma, Dan Kou, Xiaxia Niu, Tian Wang, Yongliang Chen, Dima Chen, Xiaoqin Zhu, Mengying Zhao, Baihui Hao, Jinbo Zhang, Yuanhe Yang, and Huifeng Hu
Biogeosciences, 17, 2009–2019,Short summary
The microbial C : N ratio increased with aridity, while the microbial N : P ratio decreased with aridity, which implied that drought-stimulated microbes tend to be more N conservative. Among all examined ecological factors, substrate supply and microbial structure together controlled the microbial stoichiometry. Overall, these results illustrated N and P limitation in microbial biomass at deeper soil depths along the aridity gradient and limited responses to ecological factors in the subsoil.
Laura Matkala, Maija Salemaa, and Jaana Bäck
Biogeosciences, 17, 1535–1556,Short summary
We studied how species number and abundance of the understorey vegetation correlates with nutrient contents of soil and tree leaves at a northern boreal forest site. The phosphorus (P) content of the humus layer showed higher correlation with vegetation than the nitrogen (N) content. Usually N is considered more important in boreal forests. The plots with high P content in humus had birch as the dominant tree species, implying that birch leaf litter is an important source of P to the plants.
John Marty Kranabetter, Ariana Sholinder, and Louise de Montigny
Biogeosciences, 17, 1247–1260,Short summary
Temperate rainforests of the Pacific Northwest often have productive soils with high levels of organic matter. We describe the nitrogen and phosphorus attributes of this soil organic matter in relation to the growth of four conifer species. Sitka spruce thrived on high-nitrogen soils, more so than the other conifer species, but productivity overall is likely constrained by phosphorus deficiencies. Study results will guide wood production, carbon sequestration and conservation priorities.
Jianxiao Zhu, Chuankuan Wang, Zhang Zhou, Guoyi Zhou, Xueyang Hu, Lai Jiang, Yide Li, Guohua Liu, Chengjun Ji, Shuqing Zhao, Peng Li, Jiangling Zhu, Zhiyao Tang, Chengyang Zheng, Richard A. Birdsey, Yude Pan, and Jingyun Fang
Biogeosciences, 17, 715–726,Short summary
Soil is the largest carbon pool in forests. Whether forest soils function as a sink or source of atmospheric carbon remains controversial. Here, we investigated the 20-year changes in the soil organic carbon pool at eight permanent forest plots in China. Our results revealed that the soils sequestered 3.6–16.3 % of the annual net primary production across the investigated sites, demonstrating that these forest soils have functioned as an important C sink during the past 2 decades.
Julian Helfenstein, Chiara Pistocchi, Astrid Oberson, Federica Tamburini, Daniel S. Goll, and Emmanuel Frossard
Biogeosciences, 17, 441–454,Short summary
In this article we provide estimates of mean residence times of phosphorus in inorganic soil phosphorus pools. These values improve our understanding of the dynamics of phosphorus cycling and can be used to improve global land surface models.
Peter Kuhry, Jiří Bárta, Daan Blok, Bo Elberling, Samuel Faucherre, Gustaf Hugelius, Christian J. Jørgensen, Andreas Richter, Hana Šantrůčková, and Niels Weiss
Biogeosciences, 17, 361–379,
Sophie Casetou-Gustafson, Harald Grip, Stephen Hillier, Sune Linder, Bengt A. Olsson, Magnus Simonsson, and Johan Stendahl
Biogeosciences, 17, 281–304,Short summary
Reliable methods are required for estimating mineral supply rates to forest growth from weathering. We applied the depletion method, the PROFILE model and the base cation budget method to two forest sites in Sweden. The highest weathering rate was obtained from the budget method and the lowest from the depletion method. The high rate by the budget method suggests that there were additional sources for tree uptake not captured by measurements.
Yang Lin, Avner Gross, Christine S. O'Connell, and Whendee L. Silver
Biogeosciences, 17, 89–101,Short summary
Phosphorus (P) is an important soil nutrient that often limits plant growth and microbial activity in humid tropical forests. These ecosystems receive a large amount of rainfall that helps create frequent anoxic events in soils. Our results show that anoxic conditions reduced the strength of soil minerals to bind P even though a large amount of P was still bound to minerals. Our study suggests that anoxic events might serve as hot moments for plants and microbes to acquire P.
Yakov Kuzyakov and Kazem Zamanian
Biogeosciences, 16, 4783–4803,Short summary
Agropedogenesis, i.e. soil development under agricultural use, is the anthropogenic modification of soil and environmental factors for optimization of crop production. Maximization of only this function, crop production, leads to declines in all other soil functions and consequently promotes uniformity in soil properties around the globe. Here we developed a new scientific background for the theory of agropedogenesis and the identification of soil degradation stages.
Cecilia Akselsson, Salim Belyazid, Johan Stendahl, Roger Finlay, Bengt A. Olsson, Martin Erlandsson Lampa, Håkan Wallander, Jon Petter Gustafsson, and Kevin Bishop
Biogeosciences, 16, 4429–4450,Short summary
The release of elements from soil through weathering is an important process, controlling nutrient availability for plants and recovery from acidification. However, direct measurements cannot be done, and present estimates are burdened with high uncertainties. In this paper we use different approaches to quantify weathering rates in different scales in Sweden and discuss the pros and cons. The study contributes to more robust assessments of sustainable harvesting of forest biomass.
Heyong Liu, Ruzhen Wang, Hongyi Wang, Yanzhuo Cao, Feike A. Dijkstra, Zhan Shi, Jiangping Cai, Zhengwen Wang, Hongtao Zou, and Yong Jiang
Biogeosciences, 16, 4293–4306,
Yanxia Nie, Xiaoge Han, Jie Chen, Mengcen Wang, and Weijun Shen
Biogeosciences, 16, 4277–4291,Short summary
The N–transformation rates and N–related functional gene abundance were surveyed in a tropical forest soil with experimental N additions. The C : N ratio was the determinant factor for N transformations in the dry season while the microbial biomass was the one in the wet season. This study also found that high N addition imposed significant positive effects on the functional gene abundance of AOA amoA and nirK but negative effects on that of AOB amoA and nosZ.
Axel Don, Christina Hagen, Erik Grüneberg, and Cora Vos
Biogeosciences, 16, 4145–4155,Short summary
Forest soils have a steep carbon gradient from the forest floor to the mineral soil, indicating that carbon is prevented from entry into the soil. Wild boar are effective in mixing the soil when searching for food. In a 6–year field study, we found no significant changes in soil organic carbon stocks in the wild boar treatment plots. However, around 50 % of forest floor carbon was transferred with mixing into mineral soil carbon and increased the stabilised fraction of soil organic carbon.
Sarah W. Keenan, Sean M. Schaeffer, and Jennifer M. DeBruyn
Biogeosciences, 16, 3929–3939,Short summary
Decaying animals perturb soil biogeochemical cycles. Stable δ15N composition, which reflects the sum of all biogeochemical processes, increases during decay and persists for years. Enrichment following beaver decay persisted after at least 1 year, and was evident up to 10 cm depth and 60 cm from the decaying animals, beyond where soils were visibly impacted by decomposition. Nutrients sourced from decaying animals represent an integral and long–lived component of nitrogen cycling in soils.
Aditi Sengupta, Julia Indivero, Cailene Gunn, Malak M. Tfaily, Rosalie K. Chu, Jason Toyoda, Vanessa L. Bailey, Nicholas D. Ward, and James C. Stegen
Biogeosciences, 16, 3911–3928,Short summary
Coastal terrestrial–aquatic interfaces represent dynamic yet poorly understood zones of biogeochemical cycles. We evaluated associations between the soil salinity gradient, molecular-level soil-C chemistry, and microbial community assembly processes in a coastal watershed on the Olympic Peninsula in Washington, USA. Results revealed salinity-driven gradients in molecular-level C chemistry, with little evidence of an association between C chemistry and microbial community assembly processes.
Steffen Schlüter, Jan Zawallich, Hans-Jörg Vogel, and Peter Dörsch
Biogeosciences, 16, 3665–3678,Short summary
A combination of gas chromatography and X-ray CT reveals the microscale processes that govern soil respiration. Aerobic and anaerobic respiration in microbial hotspots depends not only on the quality and quantity of soil organic matter, but also on the spatial distribution of hotspots. Denitrification kinetics are mainly governed by hotspot architecture due to local competition for oxygen during growth. Cumulative behavior is mainly governed by water saturation due to the overall supply with O2.
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Amazonian podzol soils store huge amounts of carbon and play a key role in transferring organic matter to the Amazon River. We modelled their formation by constraining both total carbon and radiocarbon. We found that the most waterlogged zones of the podzolized areas are the main source of dissolved organic matter found in the river network. The genesis time calculated considering the more likely settings runs to around 15–25 and 150–250 kyr for young and old podzols, respectively.
Amazonian podzol soils store huge amounts of carbon and play a key role in transferring organic...