- 1Instituto de la Grasa, Sevilla, Spain (lauragismerod@gmail.com)
- 2Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS -CSIC)
- 3University of Natural Resources and Applied Life Sciences Vienna (BOKU) - Institute of Soil Research, Vienna, Austria
- 4Department of Soil & Environment, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
- 5Wageningen University & Research, Wageningen Plant Research, Wageningen, Netherlands
- 6Thünen Institute of Climate-Smart Agriculture, Braunschweig
- 7Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC)
Crop diversification is hypothesized to enhance the diversity of soil organic matter (SOM) and its associated microbial communities. However, the specific impacts of crop diversification on SOM composition and its associated microbial communities remain poorly understood.
This study, conducted as part of the EJP Soil – Energylink project, investigates agricultural soils across Europe located along a pedo-climatic gradient. The studied locations include long-term field experiments in Sweden, the Netherlands, Austria, the Czech Republic, Slovenia, France, and Spain. To assess potential seasonal effects, multiple sampling campaigns were conducted at some sites. Topsoil (0-20 cm) bulk samples from all sites were analyzed for carbon (C), nitrogen (N), and phosphorus (P) contents. SOM diversity was evaluated using solid-state 13C NMR spectroscopy. Microbial communities were characterized via phospholipid fatty acid (PLFA) analysis, quantifying both the ratio fungi/bacteria (F/B) and the ratio Gram-positive / Gram-negative bacteria (G+/G-), and overall microbial biomass.
In general, trends for C, N or P contents in diversified plots compared to controls were no consistent across sites. Preliminary results suggest that crop diversification has a minimal effect on SOM diversity. In most countries, SOM composition showed little or no significant differences between plots with different levels of crop diversification. However, significantly lower humification indices (O-alkyl C / alkyl C) were detected in diversified plots from the Czech Republic and Slovenia in both studied seasons. In Spain and France, significant differences in this parameter were limited to seasonal variations. The most pronounced differences in SOM composition occurred at sites with strong contrasts in soil disturbance between control and treatment plots (e.g. bare soil vs. cover crops). Similar results were obtained for PLFA, indicating a higher microbial biomass with increasing diversity, although these differences were not statistically significant at most sites. Comparably, a higher fungal/bacterial ratio was generally observed in more diversified plots, but without significant variation. G+/G- did not appear to have a consistent trend across sites. In conclusion, crop diversification appears to have limited effects on SOM diversity and associated microbial communities. Further analysis is needed to confirm these preliminary results and to better understand the interactions between crop diversification practices and SOM.
Keywords: solid-state 13C NMR spectroscopy, PLFA, biodiversity, sustainable agriculture
Acknowledgments: This work is financed by the project EJP Soil/Energylink, which received funding through the European Union’s Horizon 2020 research and innovation programme under grant agreement N° 862695
How to cite: Gismero Rodríguez, L., Velasco-Molina, M., König, A., Inselsbacher, E., Herrmann, A., Hanegraaf, M., Schroeder, J., Valverde, A., and Knicker, H.: Effect of crop diversification on soil organic matter: a study along a pedo-climatic gradient in Europe, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1019, https://doi.org/10.5194/egusphere-egu25-1019, 2025.
