Dual effects of vegetation restoration models and soil depth on the soil
microbial residue carbon accumulation in a red soil erosion area of
southern China
Abstract
Microbial residue carbon (MRC) is an important source of soil organic
carbon (SOC) formation and plays a vital role in the accumulation and
retention of SOC. Vegetation restoration is an effective strategy to
restore degraded lands. However, there are no studies on how MRC in the
profile changes with vegetation restoration. We evaluated MRC (using
amino sugars) accumulation and its contribution to SOC in different soil
depths (0-20, 20-50, and 50-100 cm) during vegetation restoration in a
severely eroded forest (CK), a restored forest (as ecological
restoration management), an orchard (as development management model),
and a secondary forest (as ideal control). Microbial biomarkers were
extracted from soil profiles and used to measure microbial diversity and
microbial community composition (using 16S rRNA). Vegetation
restoration, soil depth, and their interaction with each other
significantly affected MRC, fungal residue carbon (FRC), and bacterial
residue carbon (BRC) contents. The MRC content showed an increasing
trend for the four vegetation restoration models in the following order:
CK < orchard < restored forest < secondary
forest. Furthermore, the contribution of MRC to SOC increased with the
increasing soil depth for the restored forest. The rapid accumulation of
MRC was substantially influenced by SOC, total nitrogen content, soil
pH, bacterial and fungal diversity, bacterial phylum, and fungal phylum.
In conclusion, the model of vegetation restoration and soil depth play
important roles in the accumulation of soil microbial residue carbon in
a red soil erosion area. These findings are pivotal for improving our
mechanistic understanding of microbial regulation of SOC preservation
during vegetation restoration of a degraded ecosystem.