# Linking Crop Diversification to Soil Microbial Decomposition and Organic Carbon Storage -Synthesis of the Pan-European Ejp Soil Project Energylink

Tobias Bölscher, Beatriz Andreo-Jimenez, Abad Chabbi, Luigi Paolo d'Acqui, Sara Di Lonardo, Laura Gismero Rodríguez, Anton Govednik, Marjoleine Hanegraaf, Erich Inselsbacher, Katharina Keiblinger, et al.

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Tobias Bölscher, Beatriz Andreo-Jimenez, Abad Chabbi, Luigi Paolo d'Acqui, Sara Di Lonardo, et al. Linking Crop Diversification to Soil Microbial Decomposition and Organic Carbon Storage -Synthesis of the Pan-European Ejp Soil Project Energylink. VII EUROSOIL 2025 & X Congreso Ibérico de la Ciencia del Suelo, Sep 2025, Seville, Spain. hal-05263558

HAL Id: hal-05263558

https://hal.science/hal-05263558v1

Submitted on 16 Sep 2025

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LINKING CROP DIVERSIFICATION TO SOIL MICROBIAL DECOMPOSITION AND ORGANIC CARBON STORAGE – SYNTHESIS OF THE PAN-EUROPEAN EJP SOIL PROJECT ENERGYLINK

GT 10. Soil Carbon Dynamics and Stabilization / GT 03. Soil Biogeochemistry & Global Change

**Tobias Bölscher**\*¹, Beatriz Andreo-Jimenez², Abad Chabbi³,¹, Luigi Paolo D'acqui⁴, Sara Di Lonardo ⁴,⁵, Laura Gismero-Rodríguez⁶,⁷, Anton Govednik⁸, Marjoleine Hanegraaf², Erich Inselsbacher⁹, Katharina M. Keiblinger⁹, Heike Knicker⁶,⁷, Alexander König⁹, Erica Lumini¹⁰, Anita Maienza¹¹, Annelein Meisner², Katharina H. E. Meurer¹², Rajasekaran Murugan⁹, Naoise Nunan¹²,¹³, Christopher Poeplau¹⁴, Julia Schroeder¹⁴, Marjetka Suhadolc⁸, Angel Valverde¹⁵, Sophie Zechmeister-Boltenstern⁹, Anke M. Herrmann¹²

1. Université Paris-Saclay, INRAE, AgroParisTech, UMR EcoSys, Palaiseau, France

2. Wageningen University & Research, Wageningen Plant Research, Wageningen, The Netherlands

3. INRAE Centre de Recherche Nouvelle-Aquitaine-Poitiers, Unité de Recherche Pluridisciplinaire Prairies & Plantes Fourragères, Lusignan, France

4. National Research Council-Research Institute on Terrestrial Ecosystems (CNR-IRET), Sesto Fiorentino, Italy

5. National Biodiversity Future Center (NBFC), Palermo, Italy

6. Instituto de la Grasa (IG-CSIC), Sevilla, Spain

7. Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC), Sevilla, Spain

8. University of Ljubljana, Biotechnical Faculty, Ljubljana, Slovenia

9. Institute of Soil Research, BOKU University, Vienna, Austria

10. National Research Council- Institute for Sustainable Plant Protection (CNR-IPSP), Torino, Italy

11. National Research Council-Research Insitute of Bioeconomy (CNR IBE), Sesto Fiorentino, Italy

12. Department of Soil & Environment, Swedish University of Agricultural Sciences - SLU, Uppsala, Sweden

13. Institute of Ecology and Environmental Sciences - Paris, Sorbonne Université, CNRS, IRD, INRAe, UPEC, Paris, France

14. Thünen Institute of Climate-Smart Agriculture, Braunschweig, Germany

15. Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), Salamanca, Spain

ABSTRACT TEXT

Crop diversification is regarded as a promising agricultural practice for enhancing soil organic carbon (SOC) storage, and it is actively promoted by the EU Common Agricultural Policy. It remains, however, unclear through which mechanisms diversified cropping systems influence SOC accumulation. The EJP Soil EnergyLink project aimed to elucidate the relationship between crop diversification and SOC stabilization across a pan-European pedo-climatic gradient. Specifically, we investigated whether increased above-ground crop diversity influences microbial compositional and functional diversity, carbon use efficiency (CUE), and necromass formation as well as organic matter stocks, stoichiometry, and chemical diversity. This research was driven by the notion that microbial-derived SOC constitutes a significant fraction of stabilized SOC, particularly through the so

<footnote>* tobias.boelscher@inrae.fr</footnote>
called in-vivo pathway of SOC stabilization. We hypothesized that greater crop diversity would enhance microbial diversity and CUE, leading to greater SOC stabilisation.

To test this hypothesis, we collected soil samples from eight field sites across Northern to Southern Europe: Sweden, Lithuania, Netherlands, Czech Republic, Austria, France, Slovenia, and Spain. The diversification strategies included cover cropping, ley farming, and the integration of vegetation strips into perennial cropping systems, representing common European agricultural practices.

Contrary to our initial hypothesis, our findings revealed that crop diversification had no consistent impact on SOC storage, molecular diversity of organic matter, or microbial CUE in bulk soils. Additionally, increased plant diversity did not translate into greater microbial compositional or functional diversity. However, we observed that the introduction of vegetation strips in perennial cropping systems lead to increased SOC, molecular diversity, and fungal richness. Interestingly, these changes did not affect microbial CUE, as microbial growth and respiration increased proportionally. Our results suggest that in perennial cropping systems, SOC accumulation is driven by the quantity of organic matter inputs, the acceleration of microbial turnover, and the contribution of necromass to SOC. Furthermore, while our data did not indicate broad-scale shifts in microbial pathways of SOC stabilization, changes in microbial parameters and necromass contribution to SOC point to the importance of the in vivo pathway. This suggests that microbial growth, biomass, and turnover—rather than microbial CUE—may be the primary drivers of microbial-derived SOC stabilization. Future research should further explore these mechanisms to refine our understanding of SOC dynamics in diversified cropping systems.

## ACKNOWLEDGEMENTS

This work was supported by European Union's Horizon 2020 research and innovation programme (grant number 862695).