Influence of nematodes and earthworms on the emissions of soil trace gases (CO2, N2O)

To determine effects of soil fauna on greenhouse gas emissions, soil inoculated with different populations of nematodes and earthworms was incubated for 15 d. Soil with greater populations of nematodes and earthworms enhanced CO₂ and N₂O emissions. Cumulative emission fluxes of the two gases in the treatment of greater populations of nematodes and the treatment of greater populations of nematodes and earthworms were increased by 4.3 and 5.2 times for CO₂, 1.8 and 2.7 times for N₂O, respectively in comparison of the nematode-killed treatment. The emission fluxes of CO₂ and N₂O in soil treated with greater populations of nematodes were 19% for CO₂ and 21% for N₂O higher than those in soil treated with lower populations of nematodes. Meanwhile, the emission fluxes of the two gases in soil treated with greater populations of nematodes and earthworms were 12% for CO₂ and 27% for N₂O higher than those in soil treated with lower populations of nematodes and earthworms. The two gas fluxes were significantly correlated (R² = 0.9414; p < 0.001). Cumulative emissions of CO₂ and N₂O from soil treated with different populations of nematodes were positively correlated with DOC (dissolved organic carbon) concentration measured at the start of gas sampling (p < 0.05).