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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Fe2+的产生和CH4的排放之间呈指数关系增长,表明Fe3+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Fe3+的还原.
45 subtropical soil samples developed under different soil parent materials and different land use types were studied under the conditions of strict anaerobic denitrification (closed, flooded, filled with N2) and KNO3 mg.kg-1) and blank control without KNO3 on CH4 production and emission.The results show that under the anaerobic culture, the production and emission of CH4 depend on the total amount of soil organic carbon The soil CH4 emission in the paddy field with the granite parent material and KNO3-treated soil in the control soil was the highest.The addition of KNO3 significantly inhibited the production and emission of CH4, and the inhibitory effect of NO3 - N on CH4 production was probably The inhibition effect of CH4 was greater than that of N2O.The addition of NO3 in the first week of anaerobic culture in KNO3 treatment - the amount of denitrification and the rate of decrease were the key factors to determine CH4 emissions.75 In control soil without KNO3, 73 % Of soil samples showed an exponential relationship between the production of Fe2 + and the emission of CH4, indicating that the reduction of Fe3 + and CO2 can be simultaneously carried out.NO3 - N not only significantly inhibited the production and emission of CH4, but also inhibited the reduction of Fe3 + .