Articles | Volume 11, issue 1
https://doi.org/10.5194/soil-11-17-2025
© Author(s) 2025. 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-11-17-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Original research article
| 
08 Jan 2025
Original research article |
| 08 Jan 2025
| 08 Jan 2025
Large errors in soil carbon measurements attributed to inconsistent sample processing
Rebecca J. Even
CORRESPONDING AUTHOR
Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, USA
Megan B. Machmuller
Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, USA
Soil Carbon Solutions Center, Colorado State University, Fort Collins, CO 80523, USA
Jocelyn M. Lavallee
Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, USA
Environmental Defense Fund, 257 Park Ave S, New York, NY 10010, USA
Tamara J. Zelikova
Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, USA
Soil Carbon Solutions Center, Colorado State University, Fort Collins, CO 80523, USA
M. Francesca Cotrufo
Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, USA
Soil Carbon Solutions Center, Colorado State University, Fort Collins, CO 80523, USA
Related authors
No articles found.
Stefano Manzoni and M. Francesca Cotrufo
Biogeosciences, 21, 4077–4098, https://doi.org/10.5194/bg-21-4077-2024, https://doi.org/10.5194/bg-21-4077-2024, 2024
Short summary
Short summary
Organic carbon and nitrogen are stabilized in soils via microbial assimilation and stabilization of necromass (in vivo pathway) or via adsorption of the products of extracellular decomposition (ex vivo pathway). Here we use a diagnostic model to quantify which stabilization pathway is prevalent using data on residue-derived carbon and nitrogen incorporation in mineral-associated organic matter. We find that the in vivo pathway is dominant in fine-textured soils with low organic matter content.
Sam J. Leuthold, Jocelyn M. Lavallee, Bruno Basso, William F. Brinton, and M. Francesca Cotrufo
SOIL, 10, 307–319, https://doi.org/10.5194/soil-10-307-2024, https://doi.org/10.5194/soil-10-307-2024, 2024
Short summary
Short summary
We examined physical soil organic matter fractions to understand their relationship to temporal variability in crop yield at field scale. We found that interactions between crop productivity, topography, and climate led to variability in soil organic matter stocks among different yield stability zones. Our results imply that linkages between soil organic matter and yield stability may be scale-dependent and that particulate organic matter may be an indicator of unstable areas within croplands.
Yao Zhang, Jocelyn M. Lavallee, Andy D. Robertson, Rebecca Even, Stephen M. Ogle, Keith Paustian, and M. Francesca Cotrufo
Biogeosciences, 18, 3147–3171, https://doi.org/10.5194/bg-18-3147-2021, https://doi.org/10.5194/bg-18-3147-2021, 2021
Short summary
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.
Jennifer M. Rhymes, Irene Cordero, Mathilde Chomel, Jocelyn M. Lavallee, Angela L. Straathof, Deborah Ashworth, Holly Langridge, Marina Semchenko, Franciska T. de Vries, David Johnson, and Richard D. Bardgett
SOIL, 7, 95–106, https://doi.org/10.5194/soil-7-95-2021, https://doi.org/10.5194/soil-7-95-2021, 2021
Andy D. Robertson, Keith Paustian, Stephen Ogle, Matthew D. Wallenstein, Emanuele Lugato, and M. Francesca Cotrufo
Biogeosciences, 16, 1225–1248, https://doi.org/10.5194/bg-16-1225-2019, https://doi.org/10.5194/bg-16-1225-2019, 2019
Short summary
Short summary
Predicting how soils respond to varying environmental conditions or land-use change is essential if we aim to promote sustainable management practices and help mitigate climate change. Here, we present a new ecosystem-scale soil model (MEMS v1) that is built upon recent, novel findings and can be run using very few inputs. The model accurately predicted soil carbon stocks for more than 8000 sites across Europe, ranging from cold, wet forests in sandy soils to hot, dry grasslands in clays.
E. Ashley Shaw, Karolien Denef, Cecilia Milano de Tomasel, M. Francesca Cotrufo, and Diana H. Wall
SOIL, 2, 199–210, https://doi.org/10.5194/soil-2-199-2016, https://doi.org/10.5194/soil-2-199-2016, 2016
Short summary
Short summary
We investigated fire's effects on root decomposition and carbon (C) flow to the soil food web. We used 13C-labeled dead roots buried in microcosms constructed from two burn treatment soils (annual and infrequent burn). Our results showed greater root decomposition and C flow to the soil food web for the annual burn compared to infrequent burn treatment. Thus, roots are a more important C source for decomposers in annually burned areas where surface plant litter is frequently removed by fire.
Related subject area
Soils and global change
Soil is a major contributor to global greenhouse gas emissions and climate change
Impact of crop type on the greenhouse gas (GHG) emissions of a rewetted cultivated peatland
Thermodynamic and hydrological drivers of the soil and bedrock thermal regimes in central Spain
The effect of different biopreparations on soil physical properties and CO2 emissions when growing winter wheat and oilseed rape
Earthworm-invaded boreal forest soils harbour distinct microbial communities
Back to the future? Conservative grassland management can preserve soil health in the changing landscapes of Uruguay
Effects of a warmer climate and forest composition on soil carbon cycling, soil organic matter stability and stocks in a humid boreal region
Effects of mild alternate wetting and drying irrigation and rice straw application on N2O emissions in rice cultivation
Whole-soil warming decreases abundance and modifies the community structure of microorganisms in the subsoil but not in surface soil
Short- and long-term temperature responses of soil denitrifier net N2O efflux rates, inter-profile N2O dynamics, and microbial genetic potentials
Acute glyphosate exposure does not condition the response of microbial communities to a dry–rewetting disturbance in a soil with a long history of glyphosate-based herbicides
Depletion of soil carbon and aggregation after strong warming of a subarctic Andosol under forest and grassland cover
Effect of deforestation and subsequent land use management on soil carbon stocks in the South American Chaco
The effects of worms, clay and biochar on CO2 emissions during production and soil application of co-composts
Climate and soil factors influencing seedling recruitment of plant species used for dryland restoration
A call for international soil experiment networks for studying, predicting, and managing global change impacts
Global distribution of soil organic carbon – Part 2: Certainty of changes related to land use and climate
The economics of soil C sequestration and agricultural emissions abatement
Peter M. Kopittke, Ram C. Dalal, Brigid A. McKenna, Pete Smith, Peng Wang, Zhe Weng, Frederik J. T. van der Bom, and Neal W. Menzies
SOIL, 10, 873–885, https://doi.org/10.5194/soil-10-873-2024, https://doi.org/10.5194/soil-10-873-2024, 2024
Short summary
Short summary
Soil produces 98.8 % of the calories consumed by humans, but the contribution that the anthropogenic use of soil makes to global warming is not clear. We show that soil has contributed 15 % of the total global warming caused by well-mixed greenhouse gases. Thus, our finding that soil is a substantial contributor to global anthropogenic greenhouse gas emissions represents a "wicked problem" – how do we continue to increase food production from soil whilst also decreasing emissions?
Kristiina Lång, Henri Honkanen, Jaakko Heikkinen, Sanna Saarnio, Tuula Larmola, and Hanna Kekkonen
SOIL, 10, 827–841, https://doi.org/10.5194/soil-10-827-2024, https://doi.org/10.5194/soil-10-827-2024, 2024
Short summary
Short summary
We studied greenhouse (GHG) gas fluxes at an agricultural peat soil site with willow, forage and set-aside. The mean annual water table rose from 80 to 30 cm in 2019–2022. Raising the water table slowed down annual CO2 emissions. CH4 fluxes changed from uptake to emissions, and nitrous oxide emissions decreased towards the end of the experiment. The total greenhouse gas balance was relatively high, highlighting the challenge in mitigating emissions from cultivated peatlands.
Félix García-Pereira, Jesús Fidel González-Rouco, Thomas Schmid, Camilo Melo-Aguilar, Cristina Vegas-Cañas, Norman Julius Steinert, Pedro José Roldán-Gómez, Francisco José Cuesta-Valero, Almudena García-García, Hugo Beltrami, and Philipp de Vrese
SOIL, 10, 1–21, https://doi.org/10.5194/soil-10-1-2024, https://doi.org/10.5194/soil-10-1-2024, 2024
Short summary
Short summary
This work addresses air–ground temperature coupling and propagation into the subsurface in a mountainous area in central Spain using surface and subsurface data from six meteorological stations. Heat transfer of temperature changes at the ground surface occurs mainly by conduction controlled by thermal diffusivity of the subsurface, which varies with depth and time. A new methodology shows that near-surface diffusivity and soil moisture content changes with time are closely related.
Sidona Buragienė, Egidijus Šarauskis, Aida Adamavičienė, Kęstutis Romaneckas, Kristina Lekavičienė, Daiva Rimkuvienė, and Vilma Naujokienė
SOIL, 9, 593–608, https://doi.org/10.5194/soil-9-593-2023, https://doi.org/10.5194/soil-9-593-2023, 2023
Short summary
Short summary
The aim of this study was to investigate the effects of different biopreparations on soil porosity, temperature, and CO2 emission from the soil in northeast Europe (Lithuania) when growing food-type crops. The application of the biopreparations showed a cumulative effect on the soil properties. In the third year of the study, the total porosity of the soil was higher in all scenarios compared to the control, ranging between 51% and 74%.
Justine Lejoly, Sylvie Quideau, Jérôme Laganière, Justine Karst, Christine Martineau, Mathew Swallow, Charlotte Norris, and Abdul Samad
SOIL, 9, 461–478, https://doi.org/10.5194/soil-9-461-2023, https://doi.org/10.5194/soil-9-461-2023, 2023
Short summary
Short summary
Earthworm invasion in North American forests can alter soil functioning. We investigated how the presence of invasive earthworms affected microbial communities, key drivers of soil biogeochemistry, across the major soil types of the Canadian boreal forest, which is a region largely understudied. Although total microbial biomass did not change, community composition shifted in earthworm-invaded mineral soils, where we also found higher fungal biomass and greater microbial species diversity.
Ina Säumel, Leonardo R. Ramírez, Sarah Tietjen, Marcos Barra, and Erick Zagal
SOIL, 9, 425–442, https://doi.org/10.5194/soil-9-425-2023, https://doi.org/10.5194/soil-9-425-2023, 2023
Short summary
Short summary
We analyzed intensification of Uruguayan grasslands in a country-wide survey on fertility proxies, pH and trace metals in topsoils. We observed a loss of nutrients, trace metals and organic matter in grasslands, croplands and timber plantations and accumulation in riverine forests. This raises questions about the carrying capacity of Uruguayan soils with regard to currently implemented intensification strategies and supports more conservative forms of extensive grassland management.
David Paré, Jérôme Laganière, Guy R. Larocque, and Robert Boutin
SOIL, 8, 673–686, https://doi.org/10.5194/soil-8-673-2022, https://doi.org/10.5194/soil-8-673-2022, 2022
Short summary
Short summary
Major soil carbon pools and fluxes were assessed along a climatic gradient expanding 4 °C in mean annual temperature for two important boreal conifer forest stand types. Species and a warmer climate affected soil organic matter (SOM) cycling but not stocks. Contrarily to common hypotheses, SOM lability was not reduced by warmer climatic conditions and perhaps increased. Results apply to cold and wet conditions and a stable vegetation composition along the climate gradient.
Kaikuo Wu, Wentao Li, Zhanbo Wei, Zhi Dong, Yue Meng, Na Lv, and Lili Zhang
SOIL, 8, 645–654, https://doi.org/10.5194/soil-8-645-2022, https://doi.org/10.5194/soil-8-645-2022, 2022
Short summary
Short summary
We explored the effects of mild alternate wetting and drying (AWD) irrigation combined with rice straw return on N2O emissions and rice yield through rice pot experiments. Mild AWD irrigation significantly increased both N2O and yield-scaled N2O emissions. The addition of rice straw under mild AWD irrigation could promote N2O emissions. Mild AWD irrigation could reduce soil-nitrogen uptake by rice when urea was applied. Mild AWD irrigation reduced rice aboveground biomass but not rice yield.
Cyrill U. Zosso, Nicholas O. E. Ofiti, Jennifer L. Soong, Emily F. Solly, Margaret S. Torn, Arnaud Huguet, Guido L. B. Wiesenberg, and Michael W. I. Schmidt
SOIL, 7, 477–494, https://doi.org/10.5194/soil-7-477-2021, https://doi.org/10.5194/soil-7-477-2021, 2021
Short summary
Short summary
How subsoil microorganisms respond to warming is largely unknown, despite their crucial role in the soil organic carbon cycle. We observed that the subsoil microbial community composition was more responsive to warming compared to the topsoil community composition. Decreased microbial abundance in subsoils, as observed in this study, might reduce the magnitude of the respiration response over time, and a shift in the microbial community will likely affect the cycling of soil organic carbon.
Kate M. Buckeridge, Kate A. Edwards, Kyungjin Min, Susan E. Ziegler, and Sharon A. Billings
SOIL, 6, 399–412, https://doi.org/10.5194/soil-6-399-2020, https://doi.org/10.5194/soil-6-399-2020, 2020
Short summary
Short summary
We do not understand the short- and long-term temperature response of soil denitrifiers, which produce and consume N2O. Boreal forest soils from a long-term climate gradient were incubated in short-term warming experiments. We found stronger N2O consumption at depth, inconsistent microbial gene abundance and function, and consistent higher N2O emissions from warmer-climate soils at warmer temperatures. Consideration of our results in models will contribute to improved climate projections.
Marco Allegrini, Elena Gomez, and María Celina Zabaloy
SOIL, 6, 291–297, https://doi.org/10.5194/soil-6-291-2020, https://doi.org/10.5194/soil-6-291-2020, 2020
Short summary
Short summary
Research was conducted to assess the response of microbial communities in a soil with a long history of glyphosate-based herbicides to a secondary imposed perturbation (dry–rewetting event). Both perturbations could increase their frequency under current agricultural practices and climate change. The results of this study demonstrate that acute exposure to a glyphosate-based herbicide does not have a conditioning effect on the response of microbial communities to the dry–rewetting event.
Christopher Poeplau, Páll Sigurðsson, and Bjarni D. Sigurdsson
SOIL, 6, 115–129, https://doi.org/10.5194/soil-6-115-2020, https://doi.org/10.5194/soil-6-115-2020, 2020
Short summary
Short summary
Global warming leads to increased mineralisation of soil organic matter, inducing a positive climate–carbon cycle feedback loop. Loss of organic matter can be associated with loss of soil structure. Here we use a strong geothermal gradient to investigate soil warming effects on soil organic matter and structural parameters in subarctic forest and grassland soils. Strong depletion of organic matter caused a collapse of aggregates, highlighting the potential impact of warming on soil function.
Natalia Andrea Osinaga, Carina Rosa Álvarez, and Miguel Angel Taboada
SOIL, 4, 251–257, https://doi.org/10.5194/soil-4-251-2018, https://doi.org/10.5194/soil-4-251-2018, 2018
Short summary
Short summary
The sub-humid Argentine Chaco, originally covered by forest, has been subjected to clearing since the end of the 1970s and replacement of the forest by no-till farming. The organic carbon stock content up to 1 m depth varied as follows: forest > pasture > continuous cropping, with no impact of the number of years under cropping. The incorporation of pastures of warm-season grasses was able to mitigate the decrease of C stocks caused by cropping and so could be considered sustainable management.
Justine Barthod, Cornélia Rumpel, Remigio Paradelo, and Marie-France Dignac
SOIL, 2, 673–683, https://doi.org/10.5194/soil-2-673-2016, https://doi.org/10.5194/soil-2-673-2016, 2016
Short summary
Short summary
In this study we evaluated CO2 emissions during composting of green wastes with clay and/or biochar in the presence and absence of worms, as well as the effect of those amendments on carbon mineralization after application to soil. Our results indicated that the addition of clay or clay–biochar mixture reduced carbon mineralization during co-composting without worms by up to 44 %. In the presence of worms, CO2 emissions during composting increased for all treatments except for the low clay dose.
Miriam Muñoz-Rojas, Todd E. Erickson, Dylan C. Martini, Kingsley W. Dixon, and David J. Merritt
SOIL, 2, 287–298, https://doi.org/10.5194/soil-2-287-2016, https://doi.org/10.5194/soil-2-287-2016, 2016
M. S. Torn, A. Chabbi, P. Crill, P. J. Hanson, I. A. Janssens, Y. Luo, C. H. Pries, C. Rumpel, M. W. I. Schmidt, J. Six, M. Schrumpf, and B. Zhu
SOIL, 1, 575–582, https://doi.org/10.5194/soil-1-575-2015, https://doi.org/10.5194/soil-1-575-2015, 2015
M. Köchy, A. Don, M. K. van der Molen, and A. Freibauer
SOIL, 1, 367–380, https://doi.org/10.5194/soil-1-367-2015, https://doi.org/10.5194/soil-1-367-2015, 2015
Short summary
Short summary
Using ranges for variables in a model of organic C stocks of the top 1m of soil on a global 0.5° grid, we assessed the (un)certainty of changes in stocks over the next 75 years. Changes are more certain where land-use change strongly affects carbon inputs and where higher temperatures and adequate moisture favour decomposition, e.g. tropical mountain forests. Global stocks will increase by 1% with a certainty of 75% if inputs to the soil increase due to CO₂ fertilization of the vegetation.
P. Alexander, K. Paustian, P. Smith, and D. Moran
SOIL, 1, 331–339, https://doi.org/10.5194/soil-1-331-2015, https://doi.org/10.5194/soil-1-331-2015, 2015
Cited articles
Amooh, M. and Bonsu, M.: Effects of Soil Texture and Organic Matter on Evaporative Loss of Soil Moisture, Journal of Global Agriculture and Ecology, 3, 152–161, 2015.
Apesteguia, M., Plante, A. F., and Virto, I.: Methods assessment for organic and inorganic carbon quantification in calcareous soils of the Mediterranean region, Geoderma Regional, 12, 39–48, https://doi.org/10.1016/j.geodrs.2017.12.001, 2018.
Arnold, S. L. and Schepers, J. S.: A Simple Roller-Mill Grinding Procedure for Plant and Soil Samples, Commun. Soil Sci. Plan., 35, 537–545, https://doi.org/10.1081/CSS-120029730, 2004.
Arshad, M. A., Lowery, B., and Grossman, B.: Physical Tests for Monitoring Soil Quality, in: Methods for Assessing Soil Quality, John Wiley & Sons, Ltd, 123–141, https://doi.org/10.2136/sssaspecpub49.c7, 1997.
Bai, Y. and Cotrufo, M. F.: Grassland soil carbon sequestration: Current understanding, challenges, and solutions, Science, 377, 603–608, https://doi.org/10.1126/science.abo2380, 2022.
Bates, D., Mächler, M., Bolker, B., and Walker, S.: Fitting Linear Mixed-Effects Models Using lme4, J. Stat. Softw., 67, 1–48, https://doi.org/10.18637/jss.v067.i01, 2015.
Bernoux, M. and Cerri, C. E. P.: GEOCHEMISTRY|Soil, Organic Components, in: Encyclopedia of Analytical Science, 2nd Edn., edited by: Worsfold, P., Townshend, A., and Poole, C., Elsevier, Oxford, 203–208, https://doi.org/10.1016/B0-12-369397-7/00245-4, 2005.
Bisutti, I., Hilke, I., and Raessler, M.: Determination of total organic carbon – an overview of current methods, TrAC-Trend. Anal.l Chem., 23, 716–726, https://doi.org/10.1016/j.trac.2004.09.003, 2004.
Bomgardner, M. M. and Erickson, B. E.: Carbon farming gets off the ground, C&EN Global Enterprise, 99, 22–28, https://doi.org/10.1021/cen-09918-cover, 2021.
Bossio, D. A., Cook-Patton, S. C., Ellis, P. W., Fargione, J., Sanderman, J., Smith, P., Wood, S., Zomer, R. J., von Unger, M., Emmer, I. M., and Griscom, B. W.: The role of soil carbon in natural climate solutions, Nat. Sustain., 3, 391–398, https://doi.org/10.1038/s41893-020-0491-z, 2020.
Bowman, R. A., Reeder, J. D., and Wienhold, B. J.: Quantifying laboratory and field variability to assess potential for carbon sequestration, Commun. Soil Sci. Plant, 33, 1629–1642, https://doi.org/10.1081/CSS-120004304, 2002.
Brady, N. C. and Weil, R. R.: The nature and properties of soils, No. Ed. 11, xi + 740 pp., Upper Saddle River, NJ, Prentice-Hall Inc, ISBN 978-0-13-243189-7, 1996.
Cihacek, L. J. and Jacobson, K. A.: Effects of Soil Sample Grinding Intensity on Carbon Determination by High-Temperature Combustion, Commun. Soil Sci. Plant, 38, 1733–1739, https://doi.org/10.1080/00103620701435506, 2007.
Clement, C. R. and Williams, T. E.: An Examination of the Method of Aggregate Analysis by Wet Sieving in Relation to the Influence of Diverse Leys on Arable Soils, J. Soil Sci., 9, 252–266, https://doi.org/10.1111/j.1365-2389.1958.tb01915.x, 1958.
Dias, R. M. S., Sempiterno, C. M., and Farropas, L.: Influence of soil grinding degree on the determination of total nitrogen, total carbon and organic carbon concentrations, Revista de Ciencias Agrarias (Portugal), 33, 88–95, 2010.
Díaz-Zorita, M., Grove, J., and Perfect, E.: Aggregation, fragmentation, and structural stability measurement, Encyclopedia of Soil Science, 1, 37–40, 2002.
Even, R.: Soil carbon measurements, Zenodo [data set, code], https://doi.org/10.5281/zenodo.14397267, 2024.
Fan, J., McConkey, B., Wang, H., and Janzen, H.: Root distribution by depth for temperate agricultural crops, Field Crop. Res., 189, 68–74, https://doi.org/10.1016/j.fcr.2016.02.013, 2016.
Farmer, J., Matthews, R., Smith, P., Langan, C., Hergoualc'h, K., Verchot, L., and Smith, J. U.: Comparison of methods for quantifying soil carbon in tropical peats, Geoderma, 214–215, 177–183, https://doi.org/10.1016/j.geoderma.2013.09.013, 2014.
Garcia, G. A., Warren, J. G., Abit, S., Garcia, C., and Flusche Ogden, G.: Sample processing impacts on single wet sieve aggregate stability analysis, Agr. Environ. Lett., 7, e20094, https://doi.org/10.1002/ael2.20094, 2022.
Goydaragh, M. G., Taghizadeh-Mehrjardi, R., Jafarzadeh, A. A., Triantafilis, J., and Lado, M.: Using environmental variables and Fourier Transform Infrared Spectroscopy to predict soil organic carbon, CATENA, 202, 105280, https://doi.org/10.1016/j.catena.2021.105280, 2021.
Harris, D., Horwáth, W. R., and van Kessel, C.: Acid fumigation of soils to remove carbonates prior to total organic carbon or CARBON-13 isotopic analysis, Soil Sci. Soc. Am. J., 65, 1853–1856, https://doi.org/10.2136/sssaj2001.1853, 2001.
Heiri, O., Lotter, A. F., and Lemcke, G.: Loss on ignition as a method for estimating organic and carbonate content in sediments: reproducibility and comparability of results, J. Paleolimnol., 25, 101–110, https://doi.org/10.1023/A:1008119611481, 2001.
International Organization for Standardization: Guidelines for the Determination of Organic Carbon and Nitrogen Stocks and Their Variations in Mineral Soils at Field Scale, ISO 23400:2021 en, Geneva, Switzerland, ISBN 978 0 539 05757 7, 2021.
Kamau-Rewe, M., Rasche, F., Cobo, J. G., Dercon, G., Shepherd, K. D., and Cadisch, G.: Generic Prediction of Soil Organic Carbon in Alfisols Using Diffuse Reflectance Fourier-Transform Mid-Infrared Spectroscopy, Soil Sci. Soc. Am. J., 75, 2358–2360, https://doi.org/10.2136/sssaj2011.0106N, 2011.
Lal, R.: Soil organic matter and water retention, Agron. J., 112, 3265–3277, https://doi.org/10.1002/agj2.20282, 2020.
Lenth, R.: emmeans: Estimated Marginal Means, aka Least-Squares Means, R package version 1.10.4, https://rvlenth.github.io/emmeans/ (last access: 2 February 2024), 2024.
Leogrande, R., Vitti, C., Castellini, M., Mastrangelo, M., Pedrero, F., Vivaldi, G. A., and Stellacci, A. M.: Comparison of Two Methods for Total Inorganic Carbon Estimation in Three Soil Types in Mediterranean Area, Land, 10, 409, https://doi.org/10.3390/land10040409, 2021.
Leong, L. S. and Tanner, P. A.: Comparison of Methods for Determination of Organic Carbon in Marine Sediment, Mar. Pollut. Bull., 38, 875–879, https://doi.org/10.1016/S0025-326X(99)00013-2, 1999.
Leuthold, S., Lavallee, J. M., Haddix, M. L., and Cotrufo, M. F.: Contrasting properties of soil organic matter fractions isolated by different physical separation methodologies, Geoderma, 445, 116870, https://doi.org/10.1016/j.geoderma.2024.116870, 2024.
McCarty, G. W., Reeves III, J. B., Yost, R., Doraiswamy, P. C., and Doumbia, M.: Evaluation of methods for measuring soil organic carbon in West African soils, Afr. J. Agr. Res., 5, 2169–2177, 2010
McClelland, S. C., Cotrufo, M. F., Haddix, M. L., Paustian, K., and Schipanski, M. E.: Infrequent compost applications increased plant productivity and soil organic carbon in irrigated pasture but not degraded rangeland, Agr. Ecosyst. Environ., 333, 107969, https://doi.org/10.1016/j.agee.2022.107969, 2022.
Mills, G. L. and Quinn, J. G.: Determination of organic carbon in marine sediments by persulfate oxidation, Chem. Geol., 25, 155–162, https://doi.org/10.1016/0009-2541(79)90090-1, 1979.
Minasny, B., Malone, B. P., McBratney, A. B., Angers, D. A., Arrouays, D., Chambers, A., Chaplot, V., Chen, Z.-S., Cheng, K., Das, B. S., Field, D. J., Gimona, A., Hedley, C. B., Hong, S. Y., Mandal, B., Marchant, B. P., Martin, M., McConkey, B. G., Mulder, V. L., O'Rourke, S., Richer-de-Forges, A. C., Odeh, I., Padarian, J., Paustian, K., Pan, G., Poggio, L., Savin, I., Stolbovoy, V., Stockmann, U., Sulaeman, Y., Tsui, C.-C., Vågen, T.-G., van Wesemael, B., and Winowiecki, L.: Soil carbon 4 per mille, Geoderma, 292, 59–86, https://doi.org/10.1016/j.geoderma.2017.01.002, 2017.
Mosier, S., Apfelbaum, S., Byck, P., Calderon, F., Teague, R., Thompson, R., and Cotrufo, M. F.: Adaptive multi-paddock grazing enhances soil carbon and nitrogen stocks and stabilization through mineral association in southeastern U.S. grazing lands, J. Environ. Manage., 288, 112409, https://doi.org/10.1016/j.jenvman.2021.112409, 2021.
Nelson, D. W. and Sommers, L. E.: Total Carbon, Organic Carbon, and Organic Matter, in: Methods of Soil Analysis, John Wiley & Sons, Ltd, 961–1010, https://doi.org/10.2136/sssabookser5.3.c34, 1996.
Oldfield, E. E., Eagle, A. J., Rubin, R. L., Rudek, J., Sanderman, J., and Gordon, D. R.: Crediting agricultural soil carbon sequestration, Science, 375, 1222–1225, https://doi.org/10.1126/science.abl7991, 2022.
Oldfield, E. E., Lavallee, J. M., Blesh, J., Bradford, M. A., Cameron-Harp, M., Cotrufo, M. F., Eagle, A. J., Eash, L., Even, R. J., Kuebbing, S. E., Kort, E. A., Lark, T. J., Latka, C., Lin, Y., Machmuller, M. B., O'Neill, B., Raffeld, A. M., RoyChowdhury, T., Rudek, J., Sanderman, J., Sprunger, C. D., Toombs, T. P., Uludere Aragon, N., Vidal, M., Woolf, D., Zelikova, T. J., and Gordon, D. R.: Greenhouse gas mitigation on croplands: clarifying the debate on knowns, unknowns and risks to move forward with effective management interventions, Carbon Manage., 15, 2365896, https://doi.org/10.1080/17583004.2024.2365896, 2024.
Poeplau, C. and Don, A.: Carbon sequestration in agricultural soils via cultivation of cover crops – A meta-analysis, Agr. Ecosyst. Environ., 200, 33–41, https://doi.org/10.1016/j.agee.2014.10.024, 2015.
Poeplau, C., Eriksson, J., and Kätterer, T.: Estimating residual water content in air-dried soil from organic carbon and clay content, Soil Till. Res., 145, 181–183, https://doi.org/10.1016/j.still.2014.09.021, 2015.
Pribyl, D. W.: A critical review of the conventional SOC to SOM conversion factor, Geoderma, 156, 75–83, https://doi.org/10.1016/j.geoderma.2010.02.003, 2010.
Raffeld, A. M., Bradford, M. A., Jackson, R. D., Rath, D., Sanford, G. R., Tautges, N., and Oldfield, E. E.: The importance of accounting method and sampling depth to estimate changes in soil carbon stocks, Carbon Balance and Management, 19, 2, https://doi.org/10.1186/s13021-024-00249-1, 2024.
Rawlins, B. G., Scheib, A. J., Lark, R. M., and Lister, T. R.: Sampling and analytical plus subsampling variance components for five soil indicators observed at regional scale, Eur. J. Soil Sci., 60, 740–747, https://doi.org/10.1111/j.1365-2389.2009.01159.x, 2009.
R Core Team: R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria, https://www.R-project.org/ (last access: 11 December 2024), 2023.
Reeves, J. B.: Near- versus mid-infrared diffuse reflectance spectroscopy for soil analysis emphasizing carbon and laboratory versus on-site analysis: Where are we and what needs to be done?, Geoderma, 158, 3–14, https://doi.org/10.1016/j.geoderma.2009.04.005, 2010.
Rytter, R.-M.: Stone and gravel contents of arable soils influence estimates of C and N stocks, CATENA, 95, 153–159, https://doi.org/10.1016/j.catena.2012.02.015, 2012.
S890 North American Proficiency Testing program oversight committee: NAPT program.org, https://www.soils.org/membership/committees/view/get-file/S890/S890-guidelines.pdf (last access: 14 May 2024), 2020.
Safanelli, J. L., Sanderman, J., Bloom, D., Todd-Brown, K., Parente, L. L., Hengl, T., Adam, S., Albinet, F., Ben-Dor, E., Boot, C. M., Bridson, J. H., Chabrillat, S., Deiss, L., Demattê, J. A. M., Scott Demyan, M., Dercon, G., Doetterl, S., van Egmond, F., Ferguson, R., Garrett, L. G., Haddix, M. L., Haefele, S. M., Heiling, M., Hernandez-Allica, J., Huang, J., Jastrow, J. D., Karyotis, K., Machmuller, M. B., Khesuoe, M., Margenot, A., Matamala, R., Miesel, J. R., Mouazen, A. M., Nagel, P., Patel, S., Qaswar, M., Ramakhanna, S., Resch, C., Robertson, J., Roudier, P., Sabetizade, M., Shabtai, I., Sherif, F., Sinha, N., Six, J., Summerauer, L., Thomas, C. L., Toloza, A., Tomczyk-Wójtowicz, B., Tsakiridis, N. L., van Wesemael, B., Woodings, F., Zalidis, G. C., and Żelazny, W. R.: An interlaboratory comparison of mid-infrared spectra acquisition: Instruments and procedures matter, Geoderma, 440, 116724, https://doi.org/10.1016/j.geoderma.2023.116724, 2023.
Sanderman, J. and Baldock, J. A.: Accounting for soil carbon sequestration in national inventories: a soil scientist's perspective, Environ. Res. Lett., 5, 034003, https://doi.org/10.1088/1748-9326/5/3/034003, 2010.
Sanderman, J., Savage, K., and Dangal, S. R. S.: Mid-infrared spectroscopy for prediction of soil health indicators in the United States, Soil Sci. Soc. Am. J., 84, 251–261, https://doi.org/10.1002/saj2.20009, 2020.
Sanderman, J., Smith, C., Safanelli, J. L., Morgan, C. L. S., Ackerson, J., Looker, N., Mathers, C., Keating, R., and Kumar, A. A.: Diffuse reflectance mid-infrared spectroscopy is viable without fine milling, Soil Security, 13, 100104, https://doi.org/10.1016/j.soisec.2023.100104, 2023.
Seybold, C. A., Ferguson, R., Wysocki, D., Bailey, S., Anderson, J., Nester, B., Schoeneberger, P., Wills, S., Libohova, Z., Hoover, D., and Thomas, P.: Application of Mid-Infrared Spectroscopy in Soil Survey, Soil Sci. Soc. Am. J., 83, 1746–1759, https://doi.org/10.2136/sssaj2019.06.0205, 2019.
Sherrod, L. A., Dunn, G., Peterson, G. A., and Kolberg, R. L.: Inorganic Carbon Analysis by Modified Pressure-Calcimeter Method, Soil Sci. Soc. Am. J., 66, 299–305, https://doi.org/10.2136/sssaj2002.2990, 2002.
Sleutel, S., De Neve, S., Singier, B., and Hofman, G.: Quantification of Organic Carbon in Soils: A Comparison of Methodologies and Assessment of the Carbon Content of Organic Matter, Commun. Soil Sci. Plant, 38, 2647–2657, https://doi.org/10.1080/00103620701662877, 2007.
Smith, P., Soussana, J.-F., Angers, D., Schipper, L., Chenu, C., Rasse, D. P., Batjes, N. H., van Egmond, F., McNeill, S., Kuhnert, M., Arias-Navarro, C., Olesen, J. E., Chirinda, N., Fornara, D., Wollenberg, E., Álvaro-Fuentes, J., Sanz-Cobena, A., and Klumpp, K.: How to measure, report and verify soil carbon change to realize the potential of soil carbon sequestration for atmospheric greenhouse gas removal, Glob. Change Biol., 26, 219–241, https://doi.org/10.1111/gcb.14815, 2020.
Soil Survey Staff: Kellogg, Soil Survey Laboratory methods manual, Soil Survey Investigations Report No. 42, Version 6.0, U.S. Department of Agriculture, Natural Resources Conservation Service, 2022.
Stanley, P., Spertus, J., Chiartas, J., Stark, P. B., and Bowles, T.: Valid inferences about soil carbon in heterogeneous landscapes, Geoderma, 430, 116323, https://doi.org/10.1016/j.geoderma.2022.116323, 2023.
Storer, D. A.: A simple high sample volume ashing procedure for determination of soil organic matter, Commun. Soil Sci. Plant, 15, 759–772, https://doi.org/10.1080/00103628409367515, 1984.
Syswerda, S. P., Corbin, A. T., Mokma, D. L., Kravchenko, A. N., and Robertson, G. P.: Agricultural Management and Soil Carbon Storage in Surface vs. Deep Layers, Soil Sci. Soc. Am. J., 75, 92–101, https://doi.org/10.2136/sssaj2009.0414, 2011.
Theocharopoulos, S. P., Mitsios, I. K., and Arvanitoyannis, I.: Traceability of environmental soil measurements, TrAC-Trend. Anal. Chem., 23, 237–251, https://doi.org/10.1016/S0165-9936(04)00317-6, 2004.
Von Unger, M. and Emmer, I.: Carbon Market Incentives to Conserve, Restore and Enhance Soil Carbon, Silvestrum and The Nature Conservancy, https://www.nature.org/content/dam/tnc/nature/en/documents/Carbon-Market-Incentives-Report.pdf (last access: 20 April 2024), 2018.
Wang, X., Wang, J., and Zhang, J.: Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China, PLOS ONE, 7, e44334, https://doi.org/10.1371/journal.pone.0044334, 2012.
Wang, Y., Lu, S., Ren, T., and Baoguo, L.: Bound Water Content of Air-Dry Soils Measured by Thermal Analysis, Soil Sci. Soc. Am. J., 75, 481–487, https://doi.org/10.2136/sssaj2010.0065, 2011.
Wijewardane, N. K., Ge, Y., Sanderman, J., and Ferguson, R.: Fine grinding is needed to maintain the high accuracy of mid-infrared diffuse reflectance spectroscopy for soil property estimation, Soil Sci. Soc. Am. J., 85, 263–272, https://doi.org/10.1002/saj2.20194, 2021.
World Data Center for Meteorology: Annual Average Humidity in Colorado, https://www.currentresults.com/Weather/Colorado/humidity-annual.php (last access: 16 May 2024), 2024.
Yeomans, J. C. and Bremner, J. M.: A rapid and precise method for routine determination of organic carbon in soil, Commun. Soil Sci. Plant, 19, 1467–1476, https://doi.org/10.1080/00103628809368027, 1988.
Zelikova, J., Chay, F., Freeman, J., and Cullenward, D.: A buyer's guide to soil carbon offsets, CarbonPlan, https://carbonplan.org/research/soil-protocols-explainer (last access: 14 March 2024), 2021.
Zimmermann, M., Leifeld, J., and Fuhrer, J.: Quantifying soil organic carbon fractions by infrared-spectroscopy, Soil Biol. Biochem., 39, 224–231, https://doi.org/10.1016/j.soilbio.2006.07.010, 2007.
Short summary
We conducted a service soil laboratory comparison study and tested the individual effect of common sieving, grinding, drying, and quantification methods on total, inorganic, and organic soil carbon (C) measurements. We found that inter-lab variability is large and each soil processing step impacts C measurement accuracy and/or precision. Standardizing soil processing methods is needed to ensure C measurements are accurate and precise, especially for C credit allocation and model calibration.
We conducted a service soil laboratory comparison study and tested the individual effect of...
