A balancing act: nutrient enrichment and soil carbon stocks
IntroductionA fragile balance
As temperatures rise, microbial activity in the soil increases, leading to more respiration and accelerated loss of carbon into the atmosphere. This effect can accelerate climate change by up to 17 percent. However, scientists think that these losses could potentially be offset by global soil nutrient enrichment, frequently used in agriculture, for example, that could stimulate plant growth around the world.
Understanding how the human production of fossil fuels and farming fertilizers affects the fragile balance between carbon uptake and release is crucial to understanding the rate of climate change.
Our ResearchNutrient enrichment and soil carbon storage
In collaboration with the Nutrient Network, a unique project that brings together ecologists worldwide, the Crowther Lab analyzed the changes in soil carbon storage. For this, we compared control plots with plots that were enriched with nutrients to see if more carbon had accumulated over a 2 to 4-year period. In a second step, we used big-data modelling approaches to understand the particular environments that experienced gains or losses in carbon under nutrient enrichment
This approach will not only indicate which ecosystems are able to store more carbon under nutrient enrichment and which lose carbon, but also helps us improve Earth system models that allow us to predict the rate of climate change.
ResultsDiffering effects depending on the latitude
1. Nutrient mix: In isolation, adding nitrogen and phosphorus had a minimal impact on the amount of carbon stored in the soil. Only in combination with potassium did the soil carbon potential increase significantly.
2. Region specific: This positive effect only happens in dry and sandy regions, where there is less rain and vegetation. In high-latitude regions like Northern Scandinavia, Siberia, Alaska or Canada the opposite effect holds true as nutrient enrichment actually leads to the loss of carbon from those soils.
Our study provides important mechanistic insights into the sensitivity of carbon stocks to nutrient enrichment. With this knowledge Earth systems models can be improved, enabling us to better predict the dynamics of climate change and the impact of negative feedback loops.
Managing soils effectively and increasing plant cover across the globe may be critical for minimizing these dangerous effects that could accelerate climate change into the future.
Full paperFind out more
Want to learn more about how soil carbon loss can accelerate climate change? Read the full paper "Quantifying global soil carbon losses in response to warming" published in Nature here: