Table 1 Annual change in biomass carbon and soil carbon, global warming potential (GWP) of annual soil N2O and CH4 emission, and annual net change in ecosystem carbon (Δ, megagrams of Ceq hectare−1year−1) (means ± SD; n = 3).

Different lowercase letters indicate significant differences among N addition rates for the same variable (P < 0.05).

TreatmentΔWoody biomass CΔSoil CNEP CGWPΔEcosystem COffset rate
(%)
AbovegroundBelowgroundSubtotalN2OCH4Subtotal
Control4.17 ± 0.18c3.11 ± 0.29c7.28 ± 0.46c−0.51 ± 0.32b6.77 ± 0.36c0.61 ± 0.10b−0.050 ± 0.007a0.56 ± 0.09b6.20 ± 0.28c8.32 ± 0.99
N305.46 ± 0.15ab4.34 ± 0.28ab9.80 ± 0.43ab−1.37 ± 0.12a8.43 ± 0.54ab0.81 ± 0.10a−0.045 ± 0.006ab0.77 ± 0.10a7.66 ± 0.64ab9.17 ± 1.78
N605.76 ± 0.05a4.33 ± 0.15a10.09 ± 0.18a−1.29 ± 0.08a8.80 ± 0.21a0.83 ± 0.10a−0.035 ± 0.006b0.79 ± 0.10a8.01 ± 0.11a8.97 ± 0.91
N905.08 ± 0.13b4.02 ± 0.22b9.10 ± 0.35b−1.09 ± 0.19a8.01 ± 0.28b0.73 ± 0.09ab−0.035 ± 0.006b0.70 ± 0.08ab7.31 ± 0.35b8.74 ± 1.29