Plant diversity builds soil carbon via microbes
Higher plant species richness raises soil organic carbon by boosting microbial growth, biomass, and fungal necromass, not carbon-use efficiency.
Source
Increased microbial growth, biomass, and turnover drive soil organic carbon accumulation at higher plant diversity
What they did
Authors sampled 85 grassland plots in the Jena Experiment (1–60 plant species) and measured soil organic carbon, microbial biomass, growth, respiration, carbon-use efficiency, and fungal versus bacterial necromass, then linked those pools with path analysis.
What they found
SOC rose 29% from monocultures to 60-species plots. Microbial biomass rose 58% and growth about twofold while respiration rose only 1.5-fold. Carbon-use efficiency did not change; SOC tracked microbial biomass more than root carbon.
The limits
What it doesn't show
A single September 2015 snapshot in one German grassland cannot prove that the same microbial path operates in forests, croplands, or under future climate; CUE was statistically unchanged rather than shown to be irrelevant in all soils.
Key terms
- Plant species richness (PSR)
- Number of plant species sown in a plot, here ranging from 1 to 60.
- Soil organic carbon (SOC)
- Carbon stored in soil organic matter, a major terrestrial carbon pool.
- Microbial carbon-use efficiency (CUE)
- Fraction of carbon taken up by microbes that is allocated to biomass rather than respiration.
- Necromass
- Dead microbial residues, measured here via amino-sugar biomarkers for fungi versus bacteria.
- Jena Experiment
- Long-term grassland biodiversity experiment in Jena, Germany, manipulating plant species and functional-group richness.
Flashcards
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Quiz yourself
Main SOC pathway in this grassland experiment:
Common questions
Did more plant species raise soil carbon?
Yes—SOC was 29% higher in 60-species plots than in monocultures.
What microbial change was strongest?
Microbial biomass rose 58% from 1 to 60 species.
Did microbes use carbon more efficiently?
No significant CUE response to plant richness.
Which necromass increased?
Fungal necromass increased; bacterial necromass did not.
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