Temperature Sensitivity of Soil Organic Matter Decomposition

Soil organic matter decomposition is a fundamental process in the global carbon cycle, driven by microbial respiration and enzyme-catalysed reactions that release carbon dioxide as organic substrates are broken down. The rate at which this process responds to changes in temperature, commonly quantified by the Q₁₀ coefficient, influences predictions of soil carbon feedbacks under warming scenarios. Temperature sensitivity varies with soil depth, substrate quality and microbial community composition, as well as with moisture and nutrient availability. More labile fractions of organic matter tend to exhibit lower sensitivity, whereas more recalcitrant pools and deeper horizons often show higher Q₁₀ values. Understanding these variations is essential for refining Earth-system and land-surface models, improving forecasts of soil carbon storage, and informing land-management strategies aimed at mitigating climate change.

Research from Nature Portfolio

A global synthesis of field and laboratory observations has revealed that atmospheric nitrogen enrichment modifies the temperature sensitivity of soil respiration, with stronger effects at higher latitudes. Past climatic conditions, particularly temperature and precipitation during the Last Glacial Maximum, emerge as better predictors of current soil Q₁₀ responses to nitrogen inputs than contemporary climate, suggesting legacy effects shape soil carbon and nitrogen content.

Laboratory incubations comparing topsoil and subsoil layers across agricultural fields demonstrate that subsoil horizons exhibit significantly higher Q₁₀ values than surface soils. This pattern inversely correlates with the abundance of readily degradable carbon, emphasising the need to incorporate depth-dependent thermal responses into carbon models to avoid underestimating soil carbon losses.

Investigations in temperate forest ecosystems show that the organic surface layer consistently displays greater temperature sensitivity than the underlying mineral soil. Over the course of prolonged incubation, Q₁₀ in both layers increases as substrate quality declines, underscoring the role of organic horizon dynamics in driving carbon release under warming.

Temperature Sensitivity of Soil Organic Matter Decomposition publication trend

The graph below shows the total number of articles in temperature sensitivity of soil organic matter decomposition across all publications each year (not limited to Nature Index journals).

Technical terms

Q10: A factor expressing how much the rate of soil organic matter decomposition increases with a 10 °C rise in temperature.

Heterotrophic respiration: The process by which soil microorganisms consume organic matter and release carbon dioxide.

Labile carbon: Easily decomposed organic compounds that support rapid microbial respiration.

Recalcitrant carbon: Complex organic matter that resists microbial breakdown and decomposes more slowly.

References

1. Climate Change and Soil Health: Explainable Artificial Intelligence Reveals Microbiome Response to Warming. Machine Learning and Knowledge Extraction (2024).
2. Rising Temperature May Trigger Deep Soil Carbon Loss Across Forest Ecosystems. Advanced Science (2020).
3. The temperature sensitivity of soil organic carbon decomposition is greater in subsoil than in topsoil during laboratory incubation. Scientific Reports (2017).
4. Past climate conditions predict the influence of nitrogen enrichment on the temperature sensitivity of soil respiration. Communications Earth & Environment (2021).
5. Distinct temperature sensitivity of soil carbon decomposition in forest organic layer and mineral soil. Scientific Reports (2014).