Pulse Brain · Growing Health Evidence Index
Tier 3 — Observational / field trialPeer-reviewed

Balancing legume-cereal proportions in cover crop mixtures to minimize N2O emissions

Guillermo Guardia, Diego Ábalos, Emanuele Ribatti, Federico Ardenti, Federico Capra, Giacomo Mortella, Vincenzo Tabaglio, Miguel Ibáñez, Ji Chen, Andrea Fiorini

Geoderma · 2025

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Summary

This two-phase greenhouse mesocosm study evaluated how adjusting the proportions of rye and vetch in cover crop mixtures affects nitrous oxide emissions and nitrogen cycling. The authors found that most N₂O emissions occurred after cover crop incorporation, with roots contributing substantially more (57%) than shoots (31%) to total emissions. A mixture of 33% vetch and 66% rye maintained N₂O emissions as low as rye monoculture whilst providing agronomic benefits of legume inclusion, suggesting an optimised ratio for balancing environmental and productive outcomes.

Regional applicability

Although this study was conducted as a greenhouse experiment with European researchers across multiple institutions, the findings are potentially applicable to United Kingdom arable systems, where cover crop adoption is increasing as a soil health and nitrogen management tool. The transferability depends on whether UK soil conditions, temperatures, and management practices during incorporation align with the experimental conditions; field validation in UK temperate conditions would be warranted before making specific management recommendations.

Key measures

N₂O fluxes (emissions), soil mineral nitrogen content, root morphological traits (fine/very fine root proportion, root length density), root carbon-to-nitrogen ratio, total dry biomass, nitrogen yield, relative contribution of roots and shoots to total N₂O emissions

Outcomes reported

The study measured nitrous oxide (N₂O) emissions during cover crop growth and post-incorporation phases, and quantified the relative contribution of roots versus shoots to total emissions across different rye-vetch mixture ratios. It also assessed correlations between root morphological traits, biomass, mineral nitrogen content, and N₂O flux.

Theme
Climate & resilience
Subject
Climate & greenhouse gas mitigation
Study type
Research
Study design
Laboratory/greenhouse mesocosm experiment
Source type
Peer-reviewed study
Status
Published
Geography
International
System type
Arable cereals
DOI
10.1016/j.geoderma.2025.117195
Catalogue ID
SNmomgwbsa-go6ehb

Topic tags

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