Abstract: The methane and nitrous oxide emissions from rice field which added biochar as fertilizer in South China were measured from field experiments, by using of static chambergas chromatography method. Six treatments including traditional farming (CK), BC1 (5t·ha-1 biochar), BC2 (10t·ha-1 biochar), BC3 (20t·ha-1 biochar), RS (rice straw return), and RI (rice straw return with inoculants) were designed. The results showed that compared to CK, RS and RI, the treatments with biochar incorporation inhibited the greenhouse gas (methane and nitrous oxide) emissions intensity significantly. The comprehensive emission intensity of BC3 was 0.98kg CO2eq·kg-1, which has the lowest emissions among all the treatments. According to this study, the more biochar added, the lowest average (22.11mg·m-2·h-1) and seasonal total methane emissions (93.21kg·ha-1) were found. While the emissions of nitrous oxide had the opposite trend, i.e. the lowest biochar application had the highest average and seasonal emissions which were respectively 285.65μg·m-2·h-1 and 1.07kg·ha-1. But this emission was still less than the CK treatment (368.13μg·m-2·h-1 and 1.13kg·ha-1). In addition, this study also found that the highest biochar application(BC3) had the highest rice yield, which stood at 7152.58kg·ha-1.In conclusion, BC3 was the optimal management which had the best effects on emission reduction and rice production.

Key words: Biochar, Methane, Nitrous oxide, Emission flux, Total emission, Emission intensity