Plant diversity increases soil microbial activity and soil carbon storage

Area of Science:

• Ecology
• Soil Science
• Biogeochemistry

Background:

• Plant diversity significantly impacts ecosystem functions, including soil carbon storage.
• The precise mechanisms linking plant diversity to enhanced soil carbon storage remain unclear.
• Understanding these mechanisms is crucial for predicting ecosystem responses to biodiversity changes.

Purpose of the Study:

• To investigate the relationship between plant diversity and soil carbon storage mechanisms.
• To determine how plant diversity influences carbon inputs, microbial activity, and decomposition rates.
• To elucidate the role of the soil microbial community in mediating plant diversity effects on carbon.

Main Methods:

• Utilized long-term data from the Jena Experiment, a grassland biodiversity experiment.
• Employed radiocarbon (14C) modeling to trace carbon flow and accumulation.
• Analyzed changes in rhizosphere carbon inputs, microbial activity, and decomposition rates across diverse plant communities.

Main Results:

• Higher plant diversity led to increased carbon inputs into the soil microbial community.
• Elevated plant diversity correlated with enhanced microbial activity and greater soil carbon storage.
• Increases in soil carbon were primarily due to the accumulation of recently fixed carbon, not increased decomposition.

Conclusions:

• Elevated soil carbon storage in high-diversity grasslands is a direct function of the soil microbial community.
• The integration of new carbon into the soil, driven by microbial processes, is the main limiting factor for carbon storage.
• Plant diversity enhances soil carbon sequestration by stimulating microbial carbon assimilation rather than reducing decomposition.