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摘要
Here, we evaluated the effects of fulvic acid potassium on N transformation in and N2O emission from tobacco soil using a labora? tory static-culture method. The experiment included five treatments with an equivalent N basis：CK, ammonium nitrate（200 mg N·kg-1）; T1, ammonium nitrate + fulvic acid potassium（2.5 g·kg-1）; T2, ammonium nitrate + fulvic acid potassium（5 g·kg-1）; T3, ammonium ni? trate + fulvic acid potassium（10 g·kg-1）; and T4, ammonium nitrate + fulvic acid potassium（15 g·kg-1）. When compared with the CK treat? ment, the fulvic acid potassium treatments significantly decreased the soil concentration of inorganic N, but the T3 and T4 treatments signif? icantly increased the soil concentration of soluble organic N. Furthermore, the net mineralization and nitrification rates decreased with an increase in the addition rate of fulvic acid potassium, but they were significantly less than those of the CK treatment（P<0.05）. The fulvic acid potassium treatment significantly increased the N2O and CO2 emission rates and cumulative emission compared with those of the CK treatment, and its effect significantly increased with an increase in the addition rate of fulvic acid potassium（P<0.05）. In addition, there was a significant positive correlation between cumulative N2O emission and CO2 emission（R2=0.97, P<0.001）. In summary, the addition of fulvic acid potassium promoted the net microbial immobilization of inorganic N, which could significantly decrease the soil concentration of inorganic N. Moreover, the addition of fulvic acid potassium stimulated denitrification, causing a significant increase in cumulative N2O emission. Furthermore, a significant positive correlation between cumulative N2O emission and cumulative CO2 emission was observed, im? plying that cumulative CO2 emission can be used as a potential indicator to quantify cumulative N2O emission.
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单位南京师范大学; 土壤与农业可持续发展国家重点实验室
