[Effects of elevated atmospheric CO2 on CH4 and N2O emissions from paddy fields]

Effects of elevated atmospheric CO2 on CH4 and N2O emissions during the paddy rice-growing season were examined in a FACE (free-air carbon dioxide enrichment) study. The emission fluxes of CH4 and N2O from paddy rice fields were measured using methods based on static opaque-chamber and gas chromatography techniques. Synthetic fertilizer N was amended for the rice-growing season at two rates, 150 and 250 kgN.hm-2 and the atmospheric CO2 was enriched by 200 mumol.mol-1. At both N levels, the preliminary results indicate that no significant effect of CO2 enrichment on CH4 and N2O emissions from the rice paddy fields was detected. The result on CH4 emissions is inconsistent with the most literatures, and the result on N2O emissions is consistent with the most literatures.