Paper from the Soil Gas Working Group

The study was part of the joint project "Climate-smart adaptation strategies for agriculture II". Our aim was to evaluate soil-atmosphere N₂O fluxes and their controlling factors, as well as NH₃ emissions and yields for two soils (silt loam and clay loam) over two years under subsequent wheat and maize cultivation. This was done in three management systems with (1.) mineral fertilization only (simulated "cashcrop farm"), (2.) with biogas residues incorporated prior to seeding of maize ("livestock farm") or (3.) with minimum tillage with application to the growing crop or before maize sowing with incorporation using the strip-till technique ("Optimized farm"). On both sites we obtained the highest N₂O fluxes on the optimized system. However, fertilization under tillage with strip till did not increase the N₂O fluxes. The use of mineral fertilizers for wheat did not differ from organic fertilization. The isotopic values of the emitted N₂O showed that bacterial denitrification dominated and that more N₂ was emitted than N₂O. With respect to NH₃ fluxes, we could confirm that the application of digestate application in growing crops without incorporation or late incorporation in fertilization before sowing induces high fluxes. The beneficial aspects of the optimized system including more stable soil structure and resource conservation, are thus potentially counteracted by increased N₂O and NH₃ emissions.

https://doi.org/10.1007/s00374-024-01843-8