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

Smart Mixture Design Can Steer the Fate of Root‐Derived Carbon Into Mineral‐Associated and Particulate Organic Matter in Intensively Managed Grasslands

Esben Øster Mortensen, Diego Ábalos, Tine Engedal, August Kau Lægsgaard, Kirsten Lønne Enggrob, Carsten W. Mueller, Jim Rasmussen

Global Change Biology · 2025

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Summary

This field trial demonstrates that plant community composition in intensively managed grasslands can be strategically designed to influence the fate of root-derived carbon into stable soil organic matter pools. Whilst pure perennial ryegrass stands accumulated more total rhizodeposited carbon in both MAOC and POC fractions compared to grass–legume–forb mixtures, the inclusion of legumes increased the proportion of carbon allocated to the more stable MAOC pool. The study identifies root length as a key driver of absolute carbon quantities in both pools, whilst root diameter and C:N ratio favour MAOC formation, providing practical guidance for species selection to enhance soil carbon storage.

Regional applicability

The study was conducted in Europe and examined intensively managed grasslands, a dominant system across the United Kingdom and Northern Europe. These findings are directly applicable to UK grassland management practices and policy objectives around soil carbon sequestration in agricultural soils, though the specific cultivar responses may require local validation.

Key measures

MAOC and POC quantities (g C kg−1 dry soil); proportion of MAOC relative to POC (%MAOC of net C rhizodeposition); root length, root diameter, root C:N ratio; total C rhizodeposition

Outcomes reported

The study measured net carbon rhizodeposition partitioned into mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) across different grass–legume–forb mixture treatments using 13C-CO2 labelling. Root traits including root length, diameter, and C:N ratio were related to these carbon fractionation outcomes.

Theme
Farming systems, soils & land use
Subject
Soil carbon & organic matter
Study type
Research
Study design
Field trial
Source type
Peer-reviewed study
Status
Published
Geography
Europe
System type
Pasture-based livestock
DOI
10.1111/gcb.70117
Catalogue ID
SNmomgwbsa-4gw8d0

Topic tags

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