To evaluate soil CO₂ emission and relative contribution of rhizospheric and soil respiration during the maize growing season, a field experiment was carried out in Fengqiu State Key Agro-Ecological Experimental Station, Henan Province, China in 2004.The experiment included four treatments: bare soil fertilized with 150 kg N hm^-2 and maize-cropped soil amended with 0, 150, and 250 kg N hm-2. The cumulative amount of CO₂ emission in the bare soil fertilized with 150 kg N hm^-2 was 294 g C m^-2, about half of that from the soil fertilized with 150 kg N hm^-2 and planted. The mean ratio of rhizospheric respiration to total soil CO₂ emission measured by root exclusion method was 46%, but was below 20% at the seedling stage and fluctuated between 30% and 70% at the other stages. Total amount of CO2 released from soil organic matter during the maize growing season reached 2.94 Mg C hm^-2, equivalent to 8% of the total carbon content in surface soil (0—40 cm). Our estimates indicated that 7.35 Mg hm^-2 plant residue with 40% carbon content was needed to supplement carbon loss as CO₂, which was twice the magnitude of maize root biomass left in soil after harvest, but equaled to the amount of maize root biomass and root exudates. The application magnitude of N fertilizer did not affect soil CO2 emission. However, N addition strongly reduced soil CO2 emission in tested soil compared to treatments without N application. Soil CO2 emission was mainly affected by soil temperature rather than soil moisture with Q10 of 1.902.88.