Soil Carbon Dynamics in Land Use Changes

Soil carbon dynamics encompass the processes by which carbon is stored, transformed and released in terrestrial soils under varying land-use regimes. Land-use changes such as deforestation, afforestation, agricultural conversion and ecosystem restoration alter the balance between carbon inputs from plant biomass and losses through microbial decomposition. The distribution of soil organic carbon (SOC) with depth, its interactions with soil nitrogen and the influence of heat and moisture regimes together determine the capacity of soils to act as carbon sinks or sources. Conversion of forests or grasslands to croplands often leads to abrupt SOC decline, whereas reverting croplands or degraded land to forests or grasslands can partially restore carbon stocks over decadal timescales. However, recovery is frequently incomplete owing to changes in soil structure, nutrient availability and microbial community composition. Understanding soil carbon dynamics under land-use change is critical for improving Earth system models, guiding restoration strategies and informing climate-mitigation policies that rely on soils as long-term carbon reservoirs.

Research from Nature Portfolio

Large-scale surveys in northern China have demonstrated that forestation yields both biomass and soil organic carbon sinks, but that increasing soil nitrogen supply can enhance biomass carbon uptake while simultaneously driving declines in SOC through accelerated decomposition. Paired comparisons of active restoration versus natural regeneration across diverse croplands reveal that active interventions enhance SOC more effectively in initially carbon-poor soils and predominantly in topsoil horizons, whereas natural regeneration may outperform active measures where soils already contain high organic carbon. A global synthesis of carbon-to-nitrogen ratios following afforestation indicates that C:N stoichiometry in organic horizons decreases over stand age while remaining stable in mineral horizons, suggesting a sustained coupling of carbon and nitrogen cycles during forest establishment across climatic zones and vegetation types.

Soil Carbon Dynamics in Land Use Changes publication trend

The graph below shows the total number of articles in soil carbon dynamics in land use changes across all publications each year (not limited to Nature Index journals).

Technical terms

Soil organic carbon: The carbon component of soil organic matter derived from plant and microbial residues, representing a major terrestrial carbon reservoir.

Land-use change: The alteration of natural or managed ecosystems to other land-cover types, such as conversion of forest to agriculture or restoration of cropland to grassland.

Carbon sequestration: The process by which atmospheric carbon dioxide is captured and stored in biological, chemical or physical pools, including soils and biomass.

Biomass carbon sink: The portion of carbon captured and stored in living plant tissues, contributing to net ecosystem carbon uptake.

Priming effect: A phenomenon in which fresh organic inputs or changes in root activity stimulate microbial decomposition of existing soil organic matter, potentially accelerating carbon loss.

References

1. Asymmetry of carbon sequestrations by plant and soil after forestation regulated by soil nitrogen. Nature Communications (2023).
2. Soil carbon sequestration benefits of active versus natural restoration vary with initial carbon content and soil layer. Communications Earth & Environment (2023).
3. Carbon: nitrogen stoichiometry following afforestation: a global synthesis. Scientific Reports (2016).
4. Land Use Change Alters Soil Organic Carbon: Constrained Global Patterns and Predictors. Earth's Future (2024).
5. Tree planting in organic soils does not result in net carbon sequestration on decadal timescales. Global Change Biology (2020).