In the global carbon cycle, the soil is an essential player that stores more carbon in the atmosphere. Scientists in a new study studied how does carbon is stored in the soil.
The study by the Technical University of Munich (TUM) and other institutions reveals that plant residues play a crucial role in keeping carbon in the soil, which is important for reducing the planet’s CO2 emissions.
Kristina Witzgall, a scientist at the Chair of Soil Science at TUM, said, “Small pieces of dead plants are often seen as just fast food for bacteria and fungi in the soil. We have shown that plant residue plays a greater role in the formation and storage of carbon in the soil than previously thought.”
To study how carbon gets into the soil, scientists studied the natural decomposition process of plant residues in the laboratory. They did this by mixing plant residues into the soil material and then encapsulated them in small cylinders. The incubation period was of three months.
After three months, using a special imaging technique, scientists examined the chemical processes. They found the critical role of fungi in the decomposition of the added plant residues- more than bacteria.
Witzgall said, “We were able to see that there is a translocation of plant carbon deeper into the soil. This occurs as a result of the expansion of fungal hyphal networks.”
Carsten Müller, Professor at the University of Copenhagen and one of the study authors, said, “The fungi wrap their white filaments around the plant debris and ‘glue’ it to the soil. Then the fungi eat the carbon in the plants and store a lot of carbon in the soil.”
The new findings show that plant residues themselves can store carbon because critical processes occur directly on the surface of the plant residues.
Carsten Müller said, “Plant residues are central to carbon storage. They can help ensure that carbon is stored in the soil for longer. That’s why we should use them much more in the future.”
“Plant residues for storing carbon are an important factor for fertile and climate-friendly agricultural soils. In the future, we also plan to conduct experiments in which we place rotting plants deeper into the soil so that the carbon can be stored there for longer. If better conditions for carbon storage in the soil were created, this could store between 0.8 and 1.5 gigatons of carbon per year. By comparison, the world’s population has emitted 4.9 gigatons of carbon per year over the past ten years.”
Kristina Witzgall says, “To effectively increase soil organic carbon through soil management, a better understanding of the dynamics and complexity of soil carbon formation and persistence is needed.”
- Witzgall, K., Vidal, A., Schubert, D.I. et al. Particulate organic matter as a functional soil component for persistent soil organic carbon. Nat Commun 12, 4115 (2021). DOI: 10.1038/s41467-021-24192-8