添加生物炭对华南早稻田CH_4和N_2O排放的影响

Effect of Biochar on CH_4 and N_2O Emissions from Early Rice Field in South China

通过田间试验,采用静态箱-气象色谱法研究生物炭添加对华南早稻田甲烷(CH4)和氧化亚氮(N2O)排放的影响。试验设对照(CK),BC1、BC2、BC3(土壤中分别混入5、10、20t·hm-2生物炭)、RS(稻草直接还田)和RI(稻草加腐熟剂还田)6个处理。结果表明,与CK、RS和RI相比,生物炭处理能降低稻田CH4和N2O排放量及排放强度,综合排放强度最低的为BC3处理,值为0.98kgCO2-eq·kg-1。在本实验的处理范围内,生物炭添加量越高,CH4平均排放通量及其季节排放总量越低,最低值分别为22.11mg·m-2·h-1和93.21kg·hm-2;N2O排放通量和季节排放总量则随生物炭添加量的增加呈上升趋势,最高值分别为285.65μg·m-2·h-1和1.07kg·hm-2,但依然小于对照处理(368.13μg·m-2·h-1和1.13kg·hm-2)。此外,试验发现高用量的生物炭(即BC3)处理水稻产量最高,值为7152.58kg·hm-2。综合分析各处理,BC3对减缓温室效应和稳定水稻生产贡献最大。

The methane and nitrous oxide emissions from rice field which added bioehar 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）, BE2 （10t.ha^-1 bioehar）, 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 COz-eq. kg^-1, which has the lowest emissions among all the treatments. According to this study, the more biochar added, the lowest average （22. 11 mg. m z. 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.