Organic carbon and nitrogen accrual evidenced by the underpinning protection mechanisms in soil profile following contrasting 35-year fertilization regimes

Summary

This 35-year field experiment demonstrates that long-term accumulation and retention of organic carbon and nitrogen in arable soils are governed primarily by soil aggregation and mineral-organic complexation rather than by cumulative nutrient inputs alone. The study identifies specific protection mechanisms across the soil profile that stabilise carbon and nitrogen, with implications for soil carbon sequestration potential and nitrogen cycling efficiency under sustained fertilisation management. The findings provide empirical evidence on how multi-decadal management choices influence structural and chemical soil functioning.

UK applicability

Whilst conducted in China, the mechanistic insights into how soil structure and mineral-organic associations govern carbon and nitrogen retention are applicable to temperate arable systems in the UK. The findings may inform UK soil management policy and fertilisation guidance, particularly regarding the role of soil physical condition in sustaining soil carbon and nitrogen stocks under different input regimes.

Key measures

Soil organic carbon concentration and stocks; total nitrogen; soil aggregate stability; mineral-organic complex formation; vertical distribution across soil profile depths

Outcomes reported

The study measured organic carbon and nitrogen accumulation and retention across soil profile depths following 35 years of contrasting fertilisation treatments. It identified the specific soil protection mechanisms—aggregation and mineral-organic complexation—governing carbon and nitrogen stabilisation under sustained fertilisation management.

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