Batch aerobic incubation experiment was conducted using an acidic loam soil for 110 days with five N treatments: no N [Control], $(NH_2)_2CO$ [U], $(NH_4)_2SO_4$ [AS], $KNO_3$ [PN], and $NH_4NO_3$ [AN]. Cumulative amount of $CO_2$ emission (mg C/kg) was 1066.5 [U], 951.4 [AS], 753.8 [PN] and 847.0 [AN] during the entire incubation period. Sensitivity of soil organic carbon (SOC) mineralization (expressed as the ratio of the amount of N fertilization-induced $CO_2$-C emission to a given amount of N addition) was greatest in U followed by AS, AN, and PN treatments, suggesting that application of $NO_3^-$-based fertilization would be helpful in reducing fertilizer-induced SOC mineralization in agricultural soils.