Arbuscular mycorrhizal fungi mitigate earthworm-induced NO emissions without significantly reducing total nitrogen leaching losses in a subtropical soil

Qian, Ziyi

SOIL ECOLOGY LETTERS

2026

8

6

He, XX

Invasive earthworms can exacerbate soil N leaching and N2O emissions, particularly in disturbed habitats with high populations. While earthworms and arbuscular mycorrhizal fungi (AMF) can synergistically influence plant N uptake, it remains unclear whether AMF inoculation can mitigate earthworm-induced N loss. We conducted a two-way factorial microcosm experiment to evaluate the effects of the pantropical earthworm Pontoscolex corethrurus and AMF (Rhizophagus intraradices) on soil N leaching and N2O fluxes. We further employed 15NH4 15NO3 labeling and qPCR to assess associated changes in nitrification and denitrification processes. P. corethrurus increased both N leaching and N2O emissions, whereas AMF inoculation significantly reduced N2O emissions and NH4 + leaching. The 15N2O patterns matched total N2O fluxes, suggesting emissions primarily derived from nitrification and denitrification. Abundance of nitrification- (amoA, amoB,) and denitrification-related genes (nirK, nirS, nosZ) showed positive correlations with soil NH4 + concentration and N2O emissions, indicating that microbial functional potential is closely linked to inorganic N availability and N2O emissions. AMF reduced these gene abundances, particularly in the rhizosphere, consistent with decreased NH4 + leaching and N2O emissions. These findings highlight the ecosystem risks posed by P. corethrurus and suggest AMF inoculation represents a promising strategy to mitigate earthworm-induced N2O emissions in tropical and subtropical regions.