A Study of Paddy CO2 Emissions under Long-Term Fertilizations and Associated Impact Factors

A field experiment was made using static chamber-GC theory to observe CO 2 emissions from rice paddy that have been fertilized for 25 consecutive years. Impact factors derived from the experiment were also studied. Seasonal variations of CO 2 flux presented a similar pattern, though they were different in treatment. CO 2 flux peaks appeared in the flooding season, with the bottom in the drainage. Seasonal trends of CO 2 flux went along with the air temperature near the ground. Chemical fertilizer applications produced more CO 2 flux, compared with other treatments, though there was no significant correlation between other treatments and the treatment with only chemical fertilizer. NPKS had the largest CO 2 flux, or 502.58 mgldrm -2 h -1 , and CK the lowest flux, or 249.16 mgldrm -2 h -1 . There was a significant negative correlation between CO 2 flux and water depth (p 2 flux. Temperature is another most important factor that controls CO 2 flux from rice-involved plots, in a range of 13.33degC~38.59degC. There is a significant exponential relationship between CO 2 flux and temperature, or F=20.1365e 0.088838T (p 2 flux (p<0.01), though further study is needed to clarify the mechanism.