Work

N2O flux dynamics and production pathways modulated by soil organic matter and litter turnover

Year: 2025

Type: article

Abstract: Addition of organic material, such as plant litter, can strongly alter C and N turnover in soils and promote CO 2 and N 2 O formation. This study aimed to elucidate the role of C availability on N turnover processes leading to N 2 O formation under moderately dry conditions. We measured CO 2 , NO, and N 2 O fluxes and contributing processes from an arable and a grassland soil with four different treatments: 50% water-filled pore space (WFPS), 50% WFPS + Maize litter, 60% WFPS, 60% WFPS + Maize litter. CO 2 fluxes were partitioned into SOM- and litter-derived, and N 2 O-forming processes were estimated applying a Bayesian mixing and fractionation model to infer source contributions and N 2 O reduction rates. Further, we quantified bacterial and fungal population size, as well as genes involved in nitrification and denitrification at the end of the experiment. N 2 O flux dynamics and contributing processes strongly differed between the C-limited arable soil and the C-rich grassland soil. In the arable soil, bacterial denitrification was consistently the main source of N 2 O and strongly increased with addition of maize litter. In contrast, nitrification accounted for 51% of N 2 O formation in the grassland soil without litter, while litter addition promoted fungal denitrification. We found higher N 2 O emissions with higher total and SOM-derived CO 2 emissions confirming that availability of organic C from SOM and litter are important controls of N 2 O losses. However, neither soil organic C content, nor litter addition, nor soil moisture alone were appropriate to predict the main N 2 O-forming process. Therefore, our study emphasizes the need to disentangle and quantify N 2 O-forming processes to develop successful mitigation strategies.

Source: Biology and Fertility of Soils

DOI: 10.1007/s00374-025-01925-1

Authors: Pauline Sophie Rummel, Paulina Englert, Lukas Beule, Johanna Pausch

Institutions: Aarhus University, University of Göttingen, University of Bonn, Julius Kühn-Institut, University of Bayreuth

Language: English

Topic: Soil Carbon and Nitrogen Dynamics

Subfield: Soil Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDGs: Life on land, Climate action, Zero hunger

Open Access status: hybrid

Estimated APC paid: $4,790