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).