Does Arbuscular Mycorrhizal Fungi Inoculation Influence Soil Carbon Sequestration?

Whether arbuscular mycorrhizal fungi (AMF) inoculation promotes soil C sequestration is largely unknown. Here, meta-analysis and logistic regression were applied to study the ecological effects of AMF inoculation on soil organic C (SOC) turnover and plant growth under different inoculation manipulations, plant traits, and soil conditions. Results showed that AMF inoculation generally increased SOC stock and plant biomass accumulation. Soil sterilization, unsterilized inoculum wash (a filtrate of mycorrhizal inoculum excluding AMF) addition in non-mycorrhizal treatments, experimental type, and inoculated AMF species influenced soil microbial biomass C (MBC) but had no impact on SOC turnover. Plant root system, initial SOC content, and soil pH were the key factors that influenced the AMF-mediated SOC turnover. AMF inoculation in fertile or acidic soils might deplete SOC. The symbiosis between tap-rooted plants and AMF was more likely to sequestrate C into the soil compared to fibrous-rooted plants. Moreover, plant total dry biomass largely relied on its own photosynthetic pathway although AMF was introduced. Collectively, our results suggest that AMF inoculation is a promising approach for soil C sequestration.