Articles | Volume 12, issue 2
https://doi.org/10.5194/soil-12-1035-2026
© Author(s) 2026. 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-12-1035-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Original research article
| 
26 Oct 2026
Original research article |
| 26 Oct 2026
| 26 Oct 2026
Soil health management outweighs edaphic properties in explaining soil organic matter across working organic farms
Kenzo E. Esquivel
CORRESPONDING AUTHOR
Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
Hannah Waterhouse
Environmental Studies, University of California Santa Cruz, Santa Cruz, CA, 95064, USA
Jennifer Thompson
Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, 15374, Germany
Daniel S. Karp
Wildlife, Fish, and Conservation Biology, Davis, CA, 95616, USA
Grace Santos
Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
Yordi Gil-Santos
Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
Patrick Baur
Fisheries, Animal, and Veterinary Sciences, University of Rhode Island, Rhode Island, RI, 02881, USA
Alastair Iles
Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
Timothy Bowles
Environmental Science, Policy, and Management, University of California Berkeley, Berkeley, CA, 94720, USA
Cited articles
Abbas, F., Hammad, H. M., Ishaq, W., Farooque, A. A., Bakhat, H. F., Zia, Z., Fahad, S., Farhad, W., and Cerdà, A.: A review of soil carbon dynamics resulting from agricultural practices, J. Environ. Manage., 268, 110319, https://doi.org/10.1016/j.jenvman.2020.110319, 2020.
Aguilera, E., Lassaletta, L., Gattinger, A., and Gimeno, B. S.: Managing soil carbon for climate change mitigation and adaptation in Mediterranean cropping systems: A meta-analysis, Agr. Ecosyst. Environ., 168, 25–36, https://doi.org/10.1016/j.agee.2013.02.003, 2013.
Angers, D. A. and Eriksen-Hamel, N. S.: Full-Inversion Tillage and Organic Carbon Distribution in Soil Profiles: A Meta-Analysis, Soil Sci. Soc. Am. J., 72, 1370–1374, https://doi.org/10.2136/sssaj2007.0342, 2008.
Angst, G., Mueller, K. E., Castellano, M. J., Vogel, C., Wiesmeier, M., and Mueller, C. W.: Unlocking complex soil systems as carbon sinks: Multi-pool management as the key, Nat. Commun., 14, 2967, https://doi.org/10.1038/s41467-023-38700-5, 2023.
Babin, N., Tan, J., Church, S. P., and Radulski, B.: Systemic change or input substitution? The impact of the Healthy Soils Program on agroecological transitions within California food systems, Agroecol. Sustain. Food Syst., 49, 1785–1828, https://doi.org/10.1080/21683565.2025.2472770, 2025.
Bach, C. E., Warnock, D. D., Van Horn, D. J., Weintraub, M. N., Sinsabaugh, R. L., Allison, S. D., and German, D. P.: Measuring phenol oxidase and peroxidase activities with pyrogallol, l-DOPA, and ABTS: Effect of assay conditions and soil type, Soil Biol. Biochem., 67, 183–191, https://doi.org/10.1016/j.soilbio.2013.08.022, 2013.
Bates, D., Maechler, M., Bolker, B., Walker, S., Christensen, R. H. B., Singmann, H., Dai, B., Scheipl, F., Grothendieck, G., Green, P., Fox, J., Bauer, A., Krivitsky, P. N., and Tanaka, E.: lme4: Linear Mixed-Effects Models using “Eigen” and S4 (Version 1.1-35.1) [computer software], https://cran.r-project.org/web/packages/lme4/index.html (last access: 2 September 2024), 2023.
Bian, Q., Zhao, L., Cheng, K., Jiang, Y., Li, D., Xie, Z., Sun, B., and Wang, X.: Divergent accumulation of microbe- and plant-derived carbon in different soil organic matter fractions in paddy soils under long-term organic amendments, Agr. Ecosyst. Environ., 366, 108934, https://doi.org/10.1016/j.agee.2024.108934, 2024.
Blanco-Canqui, H.: Cover crops and carbon sequestration: Lessons from U.S. studies, Soil Sci. Soc. Am. J., 86, 501–519, https://doi.org/10.1002/saj2.20378, 2022.
Bol, R., Poirier, N., Balesdent, J., and Gleixner, G.: Molecular turnover time of soil organic matter in particle-size fractions of an arable soil, Rapid Commun. Mass Spectrom., 23, 2551–2558, https://doi.org/10.1002/rcm.4124, 2009.
Bolinder, M. A., Crotty, F., Elsen, A., Frac, M., Kismányoky, T., Lipiec, J., Tits, M., Tóth, Z., and Kätterer, T.: The effect of crop residues, cover crops, manures and nitrogen fertilization on soil organic carbon changes in agroecosystems: A synthesis of reviews, Mitig. Adapt. Strateg. Glob. Change, 25, 929–952, https://doi.org/10.1007/s11027-020-09916-3, 2020.
Bradford, M. A., Wood, S. A., Addicott, E. T., Fenichel, E. P., Fields, N., González-Rivero, J., Jevon, F. V., Maynard, D. S., Oldfield, E. E., Polussa, A., Ward, E. B., and Wieder, W. R.: Quantifying microbial control of soil organic matter dynamics at macrosystem scales, Biogeochemistry, 156, 19–40, https://doi.org/10.1007/s10533-021-00789-5, 2021.
Bramble, D. S. E., Ulrich, S., Schöning, I., Mikutta, R., Brandt, L., Poll, C., Kandeler, E., Mikutta, C., Konrad, A., Siemens, J., Yang, Y., Polle, A., Schall, P., Ammer, C., Kaiser, K., and Schrumpf, M.: Formation of mineral-associated organic matter in temperate soils is primarily controlled by mineral type and modified by land use and management intensity, Glob. Change Biol., 30, e17024, https://doi.org/10.1111/gcb.17024, 2024.
Bu, R., Lu, J., Ren, T., Liu, B., Li, X., and Cong, R.: Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems, PLOS ONE, 10, e0143835, https://doi.org/10.1371/journal.pone.0143835, 2015.
California Department of Food and Agriculture: Healthy Soils Program, https://www.cdfa.ca.gov/oefi/healthysoils/ (last access: 15 March 2024), 2021.
California Department of Food and Agriculture (CDFA): California Agricultural Statistics Review, California Department of Food and Agriculture, https://www.cdfa.ca.gov/Statistics/PDFs/2022_Ag_Stats_Review.pdf (last access: 15 April 2024), 2022a.
California Department of Food and Agriculture (CDFA): 2021 Healthy Soils Program – Incentives Program: Applications Selected For Award, https://www.cdfa.ca.gov/oefi/healthysoils/docs/2021-HSPIncentive-SelectedProjects.pdf (last access: 15 April 2024), 2022b.
Carlisle, L., Esquivel, K., Baur, P., Ichikawa, N. F., Olimpi, E. M., Ory, J., Waterhouse, H., Iles, A., Karp, D. S., Kremen, C., and Bowles, T. M.: Organic farmers face persistent barriers to adopting diversification practices in California's Central Coast, Agroecol. Sustain. Food Syst., 46, 1145–1172, https://doi.org/10.1080/21683565.2022.2104420, 2022.
Cenini, V. L., Fornara, D. A., McMullan, G., Ternan, N., Carolan, R., Crawley, M. J., Clément, J.-C., and Lavorel, S.: Linkages between extracellular enzyme activities and the carbon and nitrogen content of grassland soils, Soil Biol. Biochem., 96, 198–206, https://doi.org/10.1016/j.soilbio.2016.02.015, 2016.
Conceição, P. C., Dieckow, J., and Bayer, C.: Combined role of no-tillage and cropping systems in soil carbon stocks and stabilization, Soil Till. Res., 129, 40–47, https://doi.org/10.1016/j.still.2013.01.006, 2013.
Cotrufo, M. F. and Lavallee, J. M.: Chapter One – Soil organic matter formation, persistence, and functioning: A synthesis of current understanding to inform its conservation and regeneration, in: Advances in Agronomy, vol. 172, edited by: Sparks, D. L., Academic Press, 1–66, https://doi.org/10.1016/bs.agron.2021.11.002, 2022.
County of Monterey Agricultural Commissioner: 2021 Monterey County Crop & Livestock Report, County of Monterey, California, https://www.countyofmonterey.gov/home/showpublisheddocument/113214/638797995070170000 (last access: 20 April 2024), 2022.
Desjardins, R. L., Smith, W., Grant, B., Campbell, C., and Riznek, R.: Management Strategies to Sequester Carbon in Agricultural Soils and to Mitigate Greenhouse Gas Emissions, in: Increasing Climate Variability and Change: Reducing the Vulnerability of Agriculture and Forestry, edited by: Salinger, J., Sivakumar, M. V. K., and Motha, R. P., Springer Netherlands, 283–297, https://doi.org/10.1007/1-4020-4166-7_14, 2005.
Dominik, P. and Kaupenjohann, M.: Simple spectrophotometric determination of Fe in oxalate and HCl soil extracts, Talanta, 51, 701–707, https://doi.org/10.1016/s0039-9140(99)00324-0, 2000.
Dray, S., Dufour, A.-B., Thioulouse, J., Jombart, T., Pavoine, S., Lobry, J. R., Ollier, S., Borcard, D., Legendre, P., Bougeard, S., Siberchicot, A., and Chessel, D.: ade4: Analysis of Ecological Data: Exploratory and Euclidean Methods in Environmental Sciences (Version 1.7-22) [computer software], https://cran.r-project.org/web/packages/ade4/index.html (last access: 23 October 2023), 2023.
Drinkwater, L. E. and Snapp, S. S.: Advancing the science and practice of ecological nutrient management for smallholder farmers, Front. Sustain. Food Syst., 6, 921216, https://doi.org/10.3389/fsufs.2022.921216, 2022.
Drinkwater, L. E., Midega, C. A. O., Awuor, R., Nyagol, D., and Khan, Z. R.: Perennial legume intercrops provide multiple belowground ecosystem services in smallholder farming systems, Agr. Ecosyst. Environ., 320, 107566, https://doi.org/10.1016/j.agee.2021.107566, 2021.
Esquivel, K., Carlisle, L., Ke, A., Olimpi, E., Baur, P., Ory, J., Waterhouse, H., Iles, A., Karp, D. S., Kremen, C., and Bowles, T. M.: The “sweet spot” in the middle: Why do mid-scale farms adopt diversification practices at higher rates?, Front. Sustain. Food Syst., 5, 734088, https://doi.org/10.3389/fsufs.2021.734088, 2021.
Esquivel, K., Thompson, J. B., Waterhouse, H., Gil-Santos, Y., Santos, G., Rutledge, J., Wang, T., Guzder-Williams, B., Carlisle, L., Baur, P., Iles, A., Kremen, C., Karp, D., and Bowles, T.: Continuous living cover outweighs other soil health practices and soil properties in predicting soil multifunctionality on working farms, SSRN [preprint], https://doi.org/10.2139/ssrn.7301425, 2026.
Geisseler, D. and Scow, K. M.: Long-term effects of mineral fertilizers on soil microorganisms – A review, Soil Biol. Biochem., 75, 54–63, https://doi.org/10.1016/j.soilbio.2014.03.023, 2014.
Gelman, A.: Scaling regression inputs by dividing by two standard deviations, Stat. Med., 27, 2865–2873, https://doi.org/10.1002/sim.3107, 2008.
Gentsch, N., Riechers, F. L., Boy, J., Schweneker, D., Feuerstein, U., Heuermann, D., and Guggenberger, G.: Cover crops improve soil structure and change organic carbon distribution in macroaggregate fractions, SOIL, 10, 139–150, https://doi.org/10.5194/soil-10-139-2024, 2024.
Georgiou, K., Jackson, R. B., Vindušková, O., Abramoff, R. Z., Ahlström, A., Feng, W., Harden, J. W., Pellegrini, A. F. A., Polley, H. W., Soong, J. L., Riley, W. J., and Torn, M. S.: Global stocks and capacity of mineral-associated soil organic carbon, Nat. Commun., 13, 3797, https://doi.org/10.1038/s41467-022-31540-9, 2022.
German, D. P., Weintraub, M. N., Grandy, A. S., Lauber, C. L., Rinkes, Z. L., and Allison, S. D.: Optimization of hydrolytic and oxidative enzyme methods for ecosystem studies, Soil Biol. Biochem., 43, 1387–1397, https://doi.org/10.1016/j.soilbio.2011.03.017, 2011.
Gorelick, N., Hancher, M., Dixon, M., Ilyushchenko, S., Thau, D., and Moore, R.: Google Earth Engine: Planetary-scale geospatial analysis for everyone, Remote Sens. Environ., 202, 18–27, https://doi.org/10.1016/j.rse.2017.06.031, 2017.
Grandy, A. S. and Robertson, G. P.: Land-Use Intensity Effects on Soil Organic Carbon Accumulation Rates and Mechanisms, Ecosystems, 10, 59–74, https://doi.org/10.1007/s10021-006-9010-y, 2007.
Grandy, A. S., Neff, J. C., and Weintraub, M. N.: Carbon structure and enzyme activities in alpine and forest ecosystems, Soil Biol. Biochem., 39, 2701–2711, https://doi.org/10.1016/j.soilbio.2007.05.009, 2007.
Haddix, M. L., Gregorich, E. G., Helgason, B. L., Janzen, H., Ellert, B. H., and Cotrufo, M. F.: Climate, carbon content, and soil texture control the independent formation and persistence of particulate and mineral-associated organic matter in soil, Geoderma, 363, 114160, https://doi.org/10.1016/j.geoderma.2019.114160, 2020.
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, https://doi.org/10.7717/peerj.4794, 2018.
Heckman, K., Lawrence, C. R., and Harden, J. W.: A sequential selective dissolution method to quantify storage and stability of organic carbon associated with Al and Fe hydroxide phases, Geoderma, 312, 24–35, https://doi.org/10.1016/j.geoderma.2017.09.043, 2018.
Holland, P. W.: Statistics and Causal Inference, J. Am. Stat. Assoc., 81, 945–960, https://doi.org/10.1080/01621459.1986.10478354, 1986.
Hothorn, T., Hornik, K., Strobl, C., and Zeileis, A.: party: A Laboratory for Recursive Partytioning (Version 1.3-14) [computer software], https://cran.r-project.org/web/packages/party/index.html (last access: 25 March 2024), 2023.
Hu, Q., Thomas, B. W., Powlson, D., Hu, Y., Zhang, Y., Jun, X., Shi, X., and Zhang, Y.: Soil organic carbon fractions in response to soil, environmental and agronomic factors under cover cropping systems: A global meta-analysis, Agr. Ecosyst. Environ., 355, 108591, https://doi.org/10.1016/j.agee.2023.108591, 2023.
James, G., Witten, D., Hastie, T., Tibshirani, R., and Taylor, J.: An introduction to statistical learning: With applications in python, Springer Nature, https://doi.org/10.1007/978-3-031-38747-0, 2023.
Jilling, A., Keiluweit, M., Contosta, A. R., Frey, S., Schimel, J., Schnecker, J., Smith, R. G., Tiemann, L., and Grandy, A. S.: Minerals in the rhizosphere: overlooked mediators of soil nitrogen availability to plants and microbes, Biogeochemistry, 139, 103–122, https://doi.org/10.1007/s10533-018-0459-5, 2018.
Jilling, A., Kane, D., Williams, A., Yannarell, A. C., Davis, A., Jordan, N. R., Koide, R. T., Mortensen, D. A., Smith, R. G., Snapp, S. S., Spokas, K. A., and Grandy, A. S.: Rapid and distinct responses of particulate and mineral-associated organic nitrogen to conservation tillage and cover crops, Geoderma, 359, 114001, https://doi.org/10.1016/j.geoderma.2019.114001, 2020.
Jilling, A., Keiluweit, M., Gutknecht, J. L. M., and Grandy, A. S.: Priming mechanisms providing plants and microbes access to mineral-associated organic matter, Soil Biol. Biochem., 158, 108265, https://doi.org/10.1016/j.soilbio.2021.108265, 2021.
Jilling, A., Grandy, A. S., Daly, A. B., Hestrin, R., Possinger, A., Abramoff, R., Annis, M., Cates, A. M., Dynarski, K., Georgiou, K., Heckman, K., Keiluweit, M., Lang, A. K., Phillips, R. P., Rocci, K., Shabtai, I. A., Sokol, N. W., and Whalen, E. D.: Evidence for the existence and ecological relevance of fast-cycling mineral-associated organic matter, Commun. Earth Environ., 6, 690, https://doi.org/10.1038/s43247-025-02681-8, 2025.
Kallenbach, C. M., Frey, S. D., and Grandy, A. S.: Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls, Nat. Commun., 7, 13630, https://doi.org/10.1038/ncomms13630, 2016.
Karlen, D. L., Goeser, N. J., Veum, K. S., and Yost, M. A.: On-farm soil health evaluations: Challenges and opportunities, J. Soil Water Conserv., 72, 26A–31A, https://doi.org/10.2489/jswc.72.2.26A, 2017.
Kleber, M., Eusterhues, K., Keiluweit, M., Mikutta, C., Mikutta, R., and Nico, P. S.: Chapter One – Mineral–Organic Associations: Formation, Properties, and Relevance in Soil Environments, in: Advances in Agronomy, vol. 130, edited by: Sparks, D. L., Academic Press, 1–140, https://doi.org/10.1016/bs.agron.2014.10.005, 2015.
Klink, S., Keller, A. B., Wild, A. J., Baumert, V. L., Gube, M., Lehndorff, E., Meyer, N., Mueller, C. W., Phillips, R. P., and Pausch, J.: Stable isotopes reveal that fungal residues contribute more to mineral-associated organic matter pools than plant residues, Soil Biol. Biochem., 168, 108634, https://doi.org/10.1016/j.soilbio.2022.108634, 2022.
Kopittke, P. M., Berhe, A. A., Carrillo, Y., Cavagnaro, T. R., Chen, D., Chen, Q.-L., Román Dobarco, M., Dijkstra, F. A., Field, D. J., Grundy, M. J., He, J.-Z., Hoyle, F. C., Kögel-Knabner, I., Lam, S. K., Marschner, P., Martinez, C., McBratney, A. B., McDonald-Madden, E., Menzies, N. W., Mosley, L. M., Mueller, C. W., Murphy, D. V., Nielsen, U. N., O'Donnell, A. G., Pendall, E., Pett-Ridge, J., Rumpel, C., Young, I. M., and Minasny, B.: Ensuring planetary survival: The centrality of organic carbon in balancing the multifunctional nature of soils, Crit. Rev. Environ. Sci. Technol., 52, 4308–4324, https://doi.org/10.1080/10643389.2021.2024484, 2022.
Lal, R.: Soil health and carbon management, Food Energy Secur., 5, 212–222, https://doi.org/10.1002/fes3.96, 2016.
LaRose, J. and Myers, R.: Adoption of Soil Health Systems Based on Data from the 2017 U.S. Census of Agriculture, Soil Health Institute, https://soilhealthinstitute.org/app/uploads/2021/11/Soil-Health-Census-Report.pdf (last access: 15 February 2024), 2019.
Lavallee, J. M., Soong, J. L., and Cotrufo, M. F.: Conceptualizing soil organic matter into particulate and mineral-associated forms to address global change in the 21st century, Glob. Change Biol., 26, 261–273, https://doi.org/10.1111/gcb.14859, 2020.
Lehmann, J., Hansel, C. M., Kaiser, C., Kleber, M., Maher, K., Manzoni, S., Nunan, N., Reichstein, M., Schimel, J. P., Torn, M. S., Wieder, W. R., and Kögel-Knabner, I.: Persistence of soil organic carbon caused by functional complexity, Nat. Geosci., 13, 529–534, https://doi.org/10.1038/s41561-020-0612-3, 2020.
Lessmann, M., Ros, G. H., Young, M. D., and de Vries, W.: Global variation in soil carbon sequestration potential through improved cropland management, Glob. Change Biol., 28, 1162–1177, https://doi.org/10.1111/gcb.15954, 2022.
Li, G., Yu, C., Shen, P., Hou, Y., Ren, Z., Li, N., Liao, Y., Li, T., and Wen, X.: Crop diversification promotes soil aggregation and carbon accumulation in global agroecosystems: A meta-analysis, J. Environ. Manage., 350, 119661, https://doi.org/10.1016/j.jenvman.2023.119661, 2024.
Li, H., Bölscher, T., Winnick, M., Tfaily, M. M., Cardon, Z. G., and Keiluweit, M.: Simple Plant and Microbial Exudates Destabilize Mineral-Associated Organic Matter via Multiple Pathways, Environ. Sci. Technol., 55, 3389–3398, https://doi.org/10.1021/acs.est.0c04592, 2021.
Li, H., Van den Bulcke, J., Mendoza, O., Deroo, H., Haesaert, G., Dewitte, K., De Neve, S., and Sleutel, S.: Soil texture controls added organic matter mineralization by regulating soil moisture – Evidence from a field experiment in a maritime climate, Geoderma, 410, 115690, https://doi.org/10.1016/j.geoderma.2021.115690, 2022.
Liang, C., Schimel, J. P., and Jastrow, J. D.: The importance of anabolism in microbial control over soil carbon storage, Nat. Microbiol., 2, 1–6, https://doi.org/10.1038/nmicrobiol.2017.105, 2017.
Liang, G., Stark, J., and Waring, B. G.: Mineral reactivity determines root effects on soil organic carbon, Nat. Commun., 14, 4962, https://doi.org/10.1038/s41467-023-40768-y, 2023.
Liptzin, D. and Silver, W. L.: Effects of carbon additions on iron reduction and phosphorus availability in a humid tropical forest soil, Soil Biol. Biochem., 41, 1696–1702, https://doi.org/10.1016/j.soilbio.2009.05.013, 2009.
Liu, S., Ward, S. E., Wilby, A., Manning, P., Gong, M., Davies, J., Killick, R., Quinton, J. N., and Bardgett, R. D.: Multiple targeted grassland restoration interventions enhance ecosystem service multifunctionality, Nat. Commun., 16, 3971, https://doi.org/10.1038/s41467-025-59157-8, 2025.
Lorenz, K. and Lal, R.: Cropland Soil Carbon Dynamics, in: Recarbonization of the Biosphere: Ecosystems and the Global Carbon Cycle, edited by: Lal, R., Lorenz, K., Hüttl, R. F., Schneider, B. U., and von Braun, J., Springer Netherlands, 303–346, https://doi.org/10.1007/978-94-007-4159-1_14, 2012.
Lovley, D. R. and Phillips, E. J. P.: Rapid Assay for Microbially Reducible Ferric Iron in Aquatic Sediments, Appl. Environ. Microbiol., 53, 1536–1540, https://doi.org/10.1128/aem.53.7.1536-1540.1987, 1987.
Maat, H.: The history and future of agricultural experiments, NJAS-Wageningen J. Life Sci., 57, 187–195, https://doi.org/10.1016/j.njas.2010.11.001, 2011.
Marland, G., West, T. O., Schlamadinger, B., and Canella, L.: Managing soil organic carbon in agriculture: The net effect on greenhouse gas emissions, Tellus B, 55, 613–621, https://doi.org/10.3402/tellusb.v55i2.17042, 2003.
Martins, B. H., Cavigelli, M. A., Buyer, J. S., Maul, J. E., Reeves III, J. B., and Martin-Neto, L.: Chemical Evaluation of Soil Organic Matter Structure in Diverse Cropping Systems, in: Labile Organic Matter – Chemical Compositions, Function, and Significance in Soil and the Environment, John Wiley and Sons, Ltd, 195–217, https://doi.org/10.2136/sssaspecpub62.2014.0041, 2015.
Masiello, C. A., Chadwick, O. A., Southon, J., Torn, M. S., and Harden, J. W.: Weathering controls on mechanisms of carbon storage in grassland soils, Global Biogeochem. Cy., 18, https://doi.org/10.1029/2004GB002219, 2004.
McKeague, J. A.: An evaluation of 0.1 m pyrophosphate and pyrophosphate-dithionite in comparison with oxalate as extractants of the accumulation products in podzols and some other soils, Can. J. Soil Sci., 47, 95–99, https://doi.org/10.4141/cjss67-017, 1967.
Miller, R. O., Gavlak, R., and Horneck, D.: Soil, Plant and Water Reference Methods for the Western Region, 4th Edn., Western Coordinating Committee on Nutrient Management (WERA-103), https://www.naptprogram.org/files/napt/publications/method-papers/western-states-methods-manual-2013.pdf (last access: 24 January 2022), 2013.
Mitchell, J. P., Klonsky, K., Shrestha, A., Fry, R., DuSault, A., Beyer, J., and Harben, R.: Adoption of conservation tillage in California: Current status and future perspectives, Aust. J. Exp. Agric., 47, 1383–1388, https://doi.org/10.1071/EA07044, 2007.
Natural Resources Conservation Service (NRCS): Soil Health, https://www.nrcs.usda.gov/conservation-basics/natural-resource-concerns/soils/soil-health (last access: 15 October 2023), 2024.
Olimpi, E. M., Ke, A., Baur, P., Carlisle, L., Esquivel, K., Glaser, T., Snyder, W. E., Waterhouse, H., Bowles, T. M., Kremen, C., and Karp, D. S.: Ungrazed seminatural habitats around farms benefit bird conservation without enhancing food borne pathogen risks, Landsc. Ecol., https://doi.org/10.1007/s10980-024-01907-y, 2024.
Plante, A. F., Conant, R. T., Stewart, C. E., Paustian, K., and Six, J.: Impact of Soil Texture on the Distribution of Soil Organic Matter in Physical and Chemical Fractions, Soil Sci. Soc. Am. J., 70, 287–296, https://doi.org/10.2136/sssaj2004.0363, 2006.
Prairie, A. M., King, A. E., and Cotrufo, M. F.: Restoring particulate and mineral-associated organic carbon through regenerative agriculture, P. Natl. Acad. Sci. USA, 120, e2217481120, https://doi.org/10.1073/pnas.2217481120, 2023.
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.
Ren, L., Yang, H., Li, J., Zhang, N., Han, Y., Zou, H., and Zhang, Y.: Organic fertilizer enhances soil aggregate stability by altering greenhouse soil content of iron oxide and organic carbon, J. Integr. Agric., S209531192400217X, https://doi.org/10.1016/j.jia.2024.05.026, 2024.
Rennert, T.: Wet-chemical extractions to characterise pedogenic Al and Fe species – a critical review, Soil Res., 57, 1–16, https://doi.org/10.1071/SR18299, 2018.
Romero, C. M., Hao, X., Hazendonk, P., Schwinghamer, T., Chantigny, M., Fonteyne, S., and Verhulst, N.: Tillage-residues affect mineral-associated organic matter on Vertisols in northern Mexico, Geoderma Reg., 27, e00430, https://doi.org/10.1016/j.geodrs.2021.e00430, 2021.
Ryals, R. and Silver, W. L.: Effects of organic matter amendments on net primary productivity and greenhouse gas emissions in annual grasslands, Ecol. Appl., 23, 46–59, https://doi.org/10.1890/12-0620.1, 2013.
Salonen, A. R., Soinne, H., Creamer, R., Lemola, R., Ruoho, N., Uhlgren, O., de Goede, R., and Heinonsalo, J.: Assessing the effect of arable management practices on carbon storage and fractions after 24 years in boreal conditions of Finland, Geoderma Reg., 34, e00678, https://doi.org/10.1016/j.geodrs.2023.e00678, 2023.
Samson, M.-E., Chantigny, M. H., Vanasse, A., Menasseri-Aubry, S., Royer, I., and Angers, D. A.: Management practices differently affect particulate and mineral-associated organic matter and their precursors in arable soils, Soil Biol. Biochem., 148, 107867, https://doi.org/10.1016/j.soilbio.2020.107867, 2020.
San Benito County Agricultural Commissioner: 2020 Annual Livestock and Crop Report, San Benito County Department of Agriculture, Weights and Measures, Hollister, CA, USA, https://www.sanbenitocountyca.gov/home/showpublisheddocument/7385/637693078344330000 (last access: 21 January 2023), 2021.
Santa Cruz County Agricultural Commissioner: Santa Cruz County Agricultural Crop and Livestock Report, Watsonville, CA, USA, https://www.agdept.com/Portals/10/pdf/Final%20Online%20-%202021%20Crop%20Report.pdf?ver=l87OElCLz3q_RcQe8X6GZw%3d%3d (last access: 21 January 2023), 2021.
Setia, R., Verma, S. L., and Marschner, P.: Measuring microbial biomass carbon by direct extraction – Comparison with chloroform fumigation-extraction, Eur. J. Soil Biol., 53, 103–106, https://doi.org/10.1016/j.ejsobi.2012.09.005, 2012.
Silva, L. C. R., Doane, T. A., Corrêa, R. S., Valverde, V., Pereira, E. I. P., and Horwath, W. R.: Iron-mediated stabilization of soil carbon amplifies the benefits of ecological restoration in degraded lands, Ecol. Appl., 25, 1226–1234, https://doi.org/10.1890/14-2151.1, 2015.
Singh, P., Kawa, N. C., and Sprunger, C. D.: “More questions than answers”: Ohio farmers' perceptions of novel soil health data and their utility for on-farm management, Agroecol. Sustain. Food Syst., 48, 74–92, https://doi.org/10.1080/21683565.2023.2270928, 2024.
Six, J., Bossuyt, H., Degryze, S., and Denef, K.: A history of research on the link between (micro)aggregates, soil biota, and soil organic matter dynamics, Soil Till. Res., 79, 7–31, https://doi.org/10.1016/j.still.2004.03.008, 2004.
Sobrino, J. A., Raissouni, N., and Li, Z.-L.: A Comparative Study of Land Surface Emissivity Retrieval from NOAA Data, Remote Sens. Environ., 75, 256–266, https://doi.org/10.1016/S0034-4257(00)00171-1, 2001.
Sokol, N. W., Sanderman, J., and Bradford, M. A.: Pathways of mineral-associated soil organic matter formation: Integrating the role of plant carbon source, chemistry, and point of entry, Glob. Change Biol., 25, 12–24, https://doi.org/10.1111/gcb.14482, 2019.
Spohn, M.: Preferential adsorption of nitrogen- and phosphorus-containing organic compounds to minerals in soils: A review, Soil Biol. Biochem., 194, 109428, https://doi.org/10.1016/j.soilbio.2024.109428, 2024.
Sprunger, C. D., Culman, S. W., Deiss, L., Brock, C., and Jackson-Smith, D.: Which management practices influence soil health in Midwest organic corn systems?, Agron. J., 113, 4201–4219, https://doi.org/10.1002/agj2.20786, 2021.
Stoffel, M. A., Nakagawa, S., and Schielzeth, H.: partR2: Partitioning R2 in GLMMs (Version 0.9.2) [computer software], https://cran.r-project.org/web/packages/partR2/index.html (last access: 15 March 2024), 2024.
Thompson, J. B., Symonds, J., Carlisle, L., Iles, A., Karp, D. S., Ory, J., and Bowles, T. M.: Remote sensing of hedgerows, windbreaks, and winter cover crops in California's Central Coast reveals low adoption but hotspots of use, Front. Sustain. Food Syst., 7, 1052029, https://doi.org/10.3389/fsufs.2023.1052029, 2023.
van Buuren, S. and Groothuis-Oudshoorn, K.: mice: Multivariate Imputation by Chained Equations in R, J. Stat. Softw., 45, 1–67, https://doi.org/10.18637/jss.v045.i03, 2011.
Vendig, I., Guzman, A., De La Cerda, G., Esquivel, K., Mayer, A. C., Ponisio, L., and Bowles, T. M.: Quantifying direct yield benefits of soil carbon increases from cover cropping, Nat. Sustain., 6, 1125–1134, https://doi.org/10.1038/s41893-023-01131-7, 2023.
Von Lützow, M., Kögel-Knabner, I., Ekschmitt, K., Flessa, H., Guggenberger, G., Matzner, E., and Marschner, B.: SOM fractionation methods: Relevance to functional pools and to stabilization mechanisms, Soil Biol. Biochem., 39, 2183–2207, https://doi.org/10.1016/j.soilbio.2007.03.007, 2007.
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.
Wang, P., Wang, J., Zhang, H., Dong, Y., and Zhang, Y.: The role of iron oxides in the preservation of soil organic matter under long-term fertilization, J. Soils Sediments, 19, 588–598, https://doi.org/10.1007/s11368-018-2085-1, 2019.
Wang, T., Tian, Z., Bengtson, P., Tunlid, A., and Persson, P.: Mineral surface-reactive metabolites secreted during fungal decomposition contribute to the formation of soil organic matter, Environ. Microbiol., 19, 5117–5129, https://doi.org/10.1111/1462-2920.13990, 2017.
Warton, D. I. and Hui, F. K. C.: The arcsine is asinine: The analysis of proportions in ecology, Ecology, 92, 3–10, https://doi.org/10.1890/10-0340.1, 2011.
Wasserstein, R. L. and Lazar, N. A.: The ASA Statement on p-Values: Context, Process, and Purpose, Am. Stat., 70, 129–133, https://doi.org/10.1080/00031305.2016.1154108, 2016.
Wasserstein, R. L., Schirm, A. L., and Lazar, N. A.: Moving to a World Beyond “p < 0.05”, Am. Stat., 73, 1–19, https://doi.org/10.1080/00031305.2019.1583913, 2019.
Whalen, E. D., Grandy, A. S., Sokol, N. W., Keiluweit, M., Ernakovich, J., Smith, R. G., and Frey, S. D.: Clarifying the evidence for microbial- and plant-derived soil organic matter, and the path toward a more quantitative understanding, Glob. Change Biol., 28, 7167–7185, https://doi.org/10.1111/gcb.16413, 2022.
White, K. E., Brennan, E. B., Cavigelli, M. A., and Smith, R. F.: Winter cover crops increase readily decomposable soil carbon, but compost drives total soil carbon during eight years of intensive, organic vegetable production in California, PLOS ONE, 15, e0228677, https://doi.org/10.1371/journal.pone.0228677, 2020.
Williams, H., Colombi, T., and Keller, T.: The influence of soil management on soil health: An on-farm study in southern Sweden, Geoderma, 360, 114010, https://doi.org/10.1016/j.geoderma.2019.114010, 2020.
Wooliver, R. and Jagadamma, S.: Response of soil organic carbon fractions to cover cropping: A meta-analysis of agroecosystems, Agr. Ecosyst. Environ., 351, 108497, https://doi.org/10.1016/j.agee.2023.108497, 2023.
Wu, S., Konhauser, K. O., Chen, B., and Huang, L.: “Reactive Mineral Sink” drives soil organic matter dynamics and stabilization, npj Mater. Sustain., 1, 3, https://doi.org/10.1038/s44296-023-00003-7, 2023.
Ye, C., Huang, W., Hall, S. J., and Hu, S.: Association of Organic Carbon With Reactive Iron Oxides Driven by Soil pH at the Global Scale, Global Biogeochem. Cy., 36, e2021GB007128, https://doi.org/10.1029/2021GB007128, 2022.
Yu, G., Xiao, J., Hu, S., Polizzotto, M. L., Zhao, F., McGrath, S. P., Li, H., Ran, W., and Shen, Q.: Mineral availability as a key regulator of soil carbon storage, Environ. Sci. Technol., 51, 4960–4969, https://doi.org/10.1021/acs.est.7b00305, 2017.
Yu, W., Huang, W., Weintraub-Leff, S. R., and Hall, S. J.: Where and why do particulate organic matter (POM) and mineral-associated organic matter (MAOM) differ among diverse soils?, Soil Biol. Biochem., 172, 108756, https://doi.org/10.1016/j.soilbio.2022.108756, 2022.
Zhang, Z., Kaye, J. P., Bradley, B. A., Amsili, J. P., and Suseela, V.: Cover crop functional types differentially alter the content and composition of soil organic carbon in particulate and mineral-associated fractions, Glob. Change Biol., 28, 5831–5848, https://doi.org/10.1111/gcb.16296, 2022.
Zuur, A. F., Ieno, E. N., Walker, N. J., Saveliev, A. A., and Smith, G. M.: Mixed Effects Modelling for Nested Data, in: Mixed effects models and extensions in ecology with R, edited by: Zuur, A. F., Ieno, E. N., Walker, N., Saveliev, A. A., and Smith, G. M., Springer, 101–142, https://doi.org/10.1007/978-0-387-87458-6_5, 2009.
Short summary
We studied how farming practices like cover cropping, reduced tillage, and crop diversity relate to soil carbon on 28 California organic farms. Fields with more continuous plant cover and less tillage tended to have more particulate organic carbon, with weaker but positive signals for slower-cycling mineral-associated carbon. Management explained trends in particulate and mineral-associated carbon more than soil properties, suggesting that farming practices could help build soil carbon.
We studied how farming practices like cover cropping, reduced tillage, and crop diversity relate...
