Diversified crop rotations and organic amendments as strategies for increasing soil carbon storage and stabilisation in UK arable systems

Summary

This long-term factorial field experiment evaluated how diverse crop rotations and grass-clover ley integration affect soil carbon accumulation and chemical stabilisation in UK arable systems. Diversified organic rotations with 3-year grass-clover leys significantly increased soil carbon stocks at both topsoil and subsoil depths, independent of fertilisation source. Advanced analytical methods revealed that whilst topsoil carbon stocks were higher under organic management, carbon stabilisation benefits were primarily observed in subsoil layers, suggesting differential mechanisms of carbon persistence across soil profiles.

UK applicability

The findings directly apply to UK arable farming practice and policy, demonstrating that adoption of diversified crop rotations with extended grass-clover leys can enhance soil carbon sequestration in British cereals-dominated systems. The results support organic and regenerative farming transitions as climate-change mitigation strategies within UK arable agriculture, though practitioners should note that carbon stabilisation patterns differ between topsoil and subsoil, with implications for long-term carbon durability.

Key measures

Soil carbon stocks (mg/g); carbon stabilisation assessed via physical fractionation, thermal analysis (TG-DSC-QMS), and pyrolysis-GC/MS; crop rotation type (cereal-intensive conventional vs. diversified legume-intensive organic); grass-clover ley duration (2 vs. 3 years); fertilisation source (mineral vs. compost); soil depth (0–0.30 m and 0.30–0.60 m)

Outcomes reported

The study measured soil carbon stocks and carbon stabilisation across different soil depths (0–0.30 m and 0.30–0.60 m) using physical fractionation, thermal analysis with differential scanning calorimetry, and pyrolysis-based molecular characterisation. Results indicated that diversified organic rotations with longer grass-clover ley periods accumulated higher soil carbon stocks at both depths.

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