Microbial-derived carbon is a major contributor to rhizosphere soil
organic carbon accumulation in alpine coniferous forests
Abstract
Root activity creates a unique microbial hotspot in the rhizosphere and
profoundly regulates soil carbon (C) dynamics, but empirical assessments
of the soil microbial carbon pump (MCP) and associated ecological
consequences on soil C storage based on insight of the rhizosphere
remains lack, especially for different root functional modules. Based on
the assessment of MCP efficacy in the rhizosphere of absorptive and
transport roots, we found that rhizosphere MCP efficacy was
~ 60%. The RMCP-efficacy was 26.5% higher in the
rhizosphere of absorptive roots than in that of transport roots. The
plant-derived C contributed only 5.71 ~ 10.48% of the
increased SOC in the rhizosphere. These observations suggest that the
soil MCP is intensely stimulated in the rhizosphere, especially in the
rhizosphere of absorptive roots. Our study provides novel and direct
empirical evidence for the active soil MCP functions in SOC
sequestration from the perspective of the rhizosphere.