Soil Organic Carbon Increases With Decreasing Microbial Carbon Use Efficiency During Vegetation Restoration

Area of Science:

• Soil Science
• Microbiology
• Ecology

Background:

• Microbial carbon use efficiency (CUE) is the fraction of organic carbon used for microbial growth.
• Globally, CUE generally increases with soil organic carbon (SOC) content.
• The relationship between CUE and SOC during natural vegetation restoration is not well understood.

Purpose of the Study:

• To investigate CUE patterns during a 160-year vegetation restoration chronosequence.
• To examine the relationship between CUE and SOC content during restoration.
• To identify key drivers of CUE changes in terrestrial ecosystems.

Main Methods:

• Stoichiometric modeling to estimate CUE.
• Analysis of CUE and SOC content along a vegetation restoration chronosequence.
• Meta-analysis to synthesize findings.

Main Results:

• Vegetation restoration led to a decrease in CUE from 0.35 to 0.28.
• SOC content increased as CUE decreased during restoration.
• Soil pH was the primary predictor of CUE, with lower pH correlating with decreased CUE.
• Alkaline soil acidification was found to decrease CUE.

Conclusions:

• Natural vegetation restoration decreases microbial carbon use efficiency.
• Decreased CUE in mature forests, driven by soil pH, may limit expected carbon sequestration.
• Management strategies should focus on maintaining CUE in mature forests to enhance carbon sinks.