Emissions of N2O following field incorporation of leguminous and non-leguminous cover crops

• Published in: Agriculture, ecosystems & environment Vol. 379; p. 109335
• Main Authors: Andersen, Maria Skovgaard, Engedal, Tine, Bruun, Sander, Jensen, Lars Stoumann, Hansen, Veronika
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 28.02.2025
• Subjects: agriculture; biomass; climate change; Cover crops; environment; field experimentation; nitrogen content; Nitrous oxide; oilseeds; radishes; Raphanus sativus; risk; Secale cereale; soil; soil carbon; species; spring; Spring emissions; Trifolium incarnatum; Vicia villosa; winter rye; Cover crops; Nitrous oxide; Spring emissions
• ISSN: 0167-8809
• DOI: 10.1016/j.agee.2024.109335

Cover crop (CC) cultivation can reduce N leaching from agricultural fields. It has also recently been proposed as a measure to mitigate climate change due to its potential for increasing soil carbon (C) stocks and reducing soil nitrous oxide (N2O) emissions during CC growth. However, the input of immature, low C/N ratio plant material to the soil can increase the risk of N2O emission upon CC termination. In a field trial under humid temperate conditions, N2O emissions from two leguminous CC species – hairy vetch (Vicia villosa) and crimson clover (Trifolium incarnatum) – and from two non-leguminous CC species – oilseed radish (Raphanus sativus) and winter rye (Secale cereale) – were measured in the spring from 24 days before to 54 days after incorporation. The vetch had a significantly higher shoot N concentration and consequently lower C/N ratio than the other three species, but this did not increase N2O emissions relative to the fallow control. Indeed, oilseed radish was the only cover crop to significantly increase N2O emissions by 290 g N2O-N ha−1 during the measurement period relative to the fallow control. These results suggest that factors other than the shoot C/N ratio, such as total biomass, N content or other biochemical parameters may be of greater importance for predicting N2O emissions from immature cover crop residues. [Display omitted] •Leguminous cover crops did not produce higher N2O emissions than oilseed radish.•Oilseed radish generated significantly higher N2O emissions than the fallow control.•Total shoot biomass and N were better predictors of N2O emissions than C/N ratio.