Grazing Impacts on Soil Carbon Dynamics in Grassland Ecosystems

Grassland ecosystems store a significant proportion of terrestrial carbon in soil organic matter. Livestock grazing influences carbon inputs and outputs through plant biomass removal, trampling, alteration of species composition and stimulation of soil microbial activity. Optimal grazing regimes can enhance root turnover and litter incorporation, thereby promoting the stabilisation of soil organic carbon (SOC). Conversely, excessive grazing intensity often leads to soil compaction, reduced vegetation cover and accelerated organic matter decomposition, resulting in net carbon loss. Spatial heterogeneity in grassland type, climate and soil texture interacts with grazing management to determine the direction and magnitude of SOC change. Across global biomes, a balance between disturbance and recovery—reflecting an intermediate disturbance hypothesis—emerges as a key principle for maintaining carbon sequestration potential. Understanding these dynamics is vital for mitigating climate change, sustaining rangeland productivity and informing restoration strategies.

Research from Nature Portfolio

Recent work in global land surface modelling has revealed that managed grasslands have shifted from a net sink to a source of greenhouse gases owing to intensified livestock densities and land‐use conversion, while concurrent climatic drivers such as elevated CO₂ concentrations and nitrogen deposition have partially offset emissions by enhancing soil carbon uptake. The overall balance of carbon fluxes in grazed systems has been shown to approach neutrality, underlining the critical role of sustainable grazing in preserving soil carbon storage.

A separate analysis of farms converted to management‐intensive grazing in the southeastern United States demonstrated rapid soil carbon accumulation, with rates approaching those of native forests within a decade. Enhanced cation exchange capacity and water retention were observed alongside annual sequestration rates of approximately 8 Mg ha⁻¹, illustrating the potential for targeted grazing management to drive short‐term carbon recovery and improve soil quality.

Grazing Impacts on Soil Carbon Dynamics in Grassland Ecosystems publication trend

The graph below shows the total number of articles in grazing impacts on soil carbon dynamics in grassland ecosystems across all publications each year (not limited to Nature Index journals).

Technical terms

Soil organic carbon (SOC): Carbon stored in soil organic matter, a key indicator of soil health and carbon sequestration potential.

Particulate organic matter (POM): Organic carbon fractions derived from plant and microbial residues, often labile and prone to rapid decomposition.

Mineral‐associated organic matter (MAOM): Organic carbon bound to soil minerals, typically more stable and resistant to microbial breakdown.

Grazing intensity: The pressure exerted by grazing animals, usually expressed as stocking rate or biomass removal per unit area.

Intermediate disturbance hypothesis: Ecological principle positing that moderate disturbance levels maximise biodiversity and ecosystem functioning, including carbon dynamics.

References

1. Climate warming from managed grasslands cancels the cooling effect of carbon sinks in sparsely grazed and natural grasslands. Nature Communications (2021).
2. Emerging land use practices rapidly increase soil organic matter. Nature Communications (2015).
3. Ruminating on soil carbon: Applying current understanding to inform grazing management. Global Change Biology (2024).
4. Carbon in Chinese grasslands: meta-analysis and theory of grazing effects. Carbon Research (2023).
5. Critical review of the impacts of grazing intensity on soil organic carbon storage and other soil quality indicators in extensively managed grasslands. Agriculture Ecosystems & Environment (2018).