Wang S.,Agrometeorological Experiment Station of Jiangxi Province |
Hu J.,Nanjing University of Information Science and Technology |
Wu G.,Agrometeorological Experiment Station of Jiangxi Province |
Zhang C.,Agrometeorological Experiment Station of Jiangxi Province |
And 4 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2011
In order to evaluate carbon source or sink strength, CO2 fluxes from a paddy ecosystem were continuously measured using the eddy covariance technique over the course of a year. During a cropping paddy season, the summation of CO2 fluxes from paddy ecosystem was negative and the paddy ecosystem was a carbon dioxide sink. Distinct CO2 fluxes characteristic of diurnal variation were observed. The net absorptive capacity of CO2 in the day was much more than CO2 release in the night. The absorbed efficiency of CO2 from rice elongating stage to milk stage was higher than other stages. The net carbon dioxide fixation from tillering stage to flowering stage was much more than other stages. During a non-cropping paddy season, i.e., from late October(after the rice harvest) to the following year in April, the paddy ecosystem absorbed a small quantity of CO2 only in March, while in other months it released CO2, becoming a carbon source. The paddy ecosystem absorbed 14.35 t · hm-2 of CO2 from the atmosphere over a year, including 8.81 t · hm-2 of CO2 absorbed by early season rice and 11.71 t · hm-2 by late season rice. Although the paddy ecosystem released 6.17 t · hm-2 of CO2 during a non-cropping paddy season, it was an overall carbon dioxide sink for the atmosphere.