High-frequency monitoring and model-assisted analysis of N2O emission pulses after cattle slurry application under contrasting soil management systems

Nitrous oxide (N 2 O) emissions from fertilised agricultural soils are often dominated by short-lived emission pulses, but their regulation under contrasting tillage systems remains uncertain. This study combined high-frequency automated chamber measurements, process-based estimates of mineral nitrogen availability and Random Forest analysis to investigate N 2 O emission dynamics after cattle slurry application under conventional tillage, minimum tillage and no-tillage. The experiment was conducted during a maize–barley sequence in northern Italy. Daily N 2 O fluxes, soil temperature, water-filled pore space, carbon dioxide fluxes and mineral nitrogen dynamics were analysed to identify the main controls of post-fertilisation emission pulses. Most crop-period N 2 O emissions occurred within the first 40 days after slurry application, accounting for 91–97% of total emissions during maize and 78–89% during barley. In absolute terms, cumulative N 2 O–N emissions averaged 4.68 ± 0.74 kg N ha -1 during maize and 2.04 ± 0.74 kg N ha -1 during barley. This difference was not explained by water-filled pore space alone, which was broadly comparable between crop periods, but by the interaction among soil temperature, slurry-derived ammonium and nitrate availability, microbial activity and tillage-related soil physical conditions. Random Forest models showed crop- and system-specific driver importance, with soil temperature dominant during barley and stronger roles of water-filled pore space and mineral nitrogen during maize. No-tillage reduced area-scaled emissions but caused a strong yield penalty during maize, whereas it showed a more favourable agro-environmental balance during barley. These findings highlight the need to evaluate slurry and tillage management through both emission intensity and crop productivity.