- 1CREAF, Cerdanyola del Vallès, Spain (c.lopez@creaf.cat)
- 2BABVE, Universitat Autònoma de Barcelona, Catalonia, Spain
- 3UNIBO- Department of Agricultural and Food sciences, University of Bologna
- 4State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China
- 5Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
- 6Institute for Environmental Genomics, University of Oklahoma, Norman, OK 73019
- 7Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK 73019
- 8CSIC, Global Ecology Unit CREAF-CSIC-UAB, Bellaterra, Catalonia, Spain
Forests are integral to maintaining planetary health, serving as biodiversity reservoirs, carbon sink, and regulators of nutrient cycles, yet their capacity to sustain these functions is increasingly disrupted by global changes. Among them, the rise in atmospheric nitrogen (N) deposition, resulting from anthropogenic emissions of reactive N compounds during fertilizer production and fossil fuel combustion, occurs across terrestrial ecosystems and can alter microbial communities’ functional composition and diversity.
In this study, we evaluate the effects of long-term N fertilisation (simulating an increase in N deposition) on the taxonomic and functional diversity of soil microbial communities in a mature beech forest in Northern Italy. The experiment started in 2015, and it includes control (only ambient deposition, N0) and soil N addition (30 kg ha-1 yr-1, N30) each replicated in 3 plots. Soil biochemical variables including Nitrogen (N), Carbon (C) and Phosphorus (P) content and soluble ions were characterized for both treatments. In addition, GeoChip 5.0S, a microarray technology, was used to characterize the taxonomic and functional diversity of microbial communities.
Although no changes were detected in soil physicochemical characteristics between N30 and N0, there was a significant increase in the taxonomic richness and diversity (Shannon-Weiver and Simpson indices) in the fertilized plots. Moreover, the relative abundance of some functional genes related to the N, C and sulphur (S) cycles were significantly increased in N30 plots, whereas P cycling genes showed no significant changes between treatments. Preliminary results suggest a probable increase in the denitrification and assimilatory and dissimilatory nitrate reduction processes of the N-added soil microbiome. In addition, the results suggest an increase of both the C fixation and C degradation pathways in N30 plots. The higher stimulation of C degradation cycling genes in comparison to C fixation cycling genes, could be explained by the promotion of plant growth and the consequent increase in rhizosphere secretions and C input to the soil after N addition.
This study contributes to the description of microbial community dynamics and the resulting changes in soil biogeochemical processes in forests under increased N deposition conditions.
How to cite: López Sánchez, C., Ribas, À., Guerreri, R., Lei, J., Yang, Y., Zhou, J., and Mattana, S.: Effects of long-term nitrogen addition on changes in the functional composition of microbial communities after long-term N addition in a temperate beech forest, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18703, https://doi.org/10.5194/egusphere-egu25-18703, 2025.
