中文摘要：

研究了发育于不同成土母质和不同土地利用方式下的45个亚热带土壤样本,在反硝化严格厌氧培养条件下（密闭、淹水、充N2）,加入KNO3的处理（加入N量为200 mg.kg^-1）和不加KNO3的空白对照对CH4产生和排放的影响.结果表明,厌氧培养条件下无论加入KNO3与否,CH4的产生和排放首先取决于土壤有机碳总量水平及其有效性.对照土壤中花岗岩母质发育的土壤和KNO3处理土壤中稻田利用方式下的土壤CH4排放量最高.加入KNO3显著抑制了CH4的产生和排放,NO3^--N对CH4产生的抑制效应可能较N2O对CH4产生的抑制效应更大.加入KNO3处理中厌氧培养第1周内的NO3^--反硝化量和降低速率是决定CH4排放量的关键因素.不加KNO3的对照土壤中,73%的土样表现为Fe^2＋的产生和CH4的排放之间呈指数关系增长,表明Fe^3＋和CO2的还原可同步进行.NO3^--N不仅显著抑制了CH4的产生和排放,也抑制了Fe^3＋的还原.

英文摘要：

Methane production and emission were investigated in 45 subtropical soil samples, collected from different land use and derived from different soil parent materials in Jiangxi province, by incubating flooded soil slurries in a closed system under N2 gas in the headspace after treatment with or without NO3^- -N （200 mg.kg^-1 ） for 28 days at 30℃. The results indicated that the content and availability of soil organic C were the dominant factors influencing CH4 production and emission whether NO3^--N was added or not under this anaerobic incubation condition. Methane emission was higher in the soils derived from granite in the unamended soils and used for rice cultivation in the amended soils. During the anaerobic incubation, the NO3^- -N added significantly inhibited the production and emission of CH4. The inhibitory effect of NO3^- -N on CH4 emission might be stronger than that of N20. The amount and rate of NO3^- -N deuitrified in the first 7 days of incubation determined the CH4 emission amount in the soils with NO3^- -N .The FeE＋ content increased exponentially with the CH4 emission in 73% of the control soils without NO3^- -N, which indicated that Fe^3＋ reduction processed simultaneously with CO2 reduction. Nitrate nitrogen inhibits not only the production and emission of CH4 but also the reduction of Fe^3＋ .