|
CH4, CO2 and N2O are three major greenhouse gases in atmosphere, the study of which was always one of important research topics in ecological system and global climate change. Sanjiang plain is the most important grain production base in northeast. For Widespread wetland has been converted into farmland in recent decades, original greenhouse gases emissions pattern has been changed. In order to investigate greenhouse gases emission situation of this typical regional and accumulate data for food security and greenhouse gases decrease, three greenhouse missions regular pattern of different seasons, rice varieties (Ky131, Lj18, Kj6), influenced factors (air temperature,0-30cm temperature) and GWP was studied by using the method of static chamber and gas chromatography in growing season in Sanjiang plain of China.The result showed that:The average fluxes of CO2, CH4 and N2O emission from rice field of Kongyu131, Longjingl8 and Kenjiandao6 was distributed between 405.488～647.202,9.587～14.809 and 0.0041～0.0063 mg.m-2hr-1 in growing season respectively, the flux of CO2 or N2O from Kongyu131 increased by 48.6%～59.6% or 46.5%～53.7%, the flux of CH4 decreased by 32.5%～35.3% than that from Longjingl8 and Kenjiandao6. The seasonal dynamics of CO2 emission from Kongyu131 took on summer>spring>autumn, and that from others took on summer>autumn>spring; the seasonal dynamics of CH4 emission from Longjing18 took on summer>spring>autumn, and the others took on summer>autumn>spring; three rice varieties all emitted N2O in spring and summer, which fluxes of N2O were similar in two seasons, but Longjing18 emitted N2O, the others absorbed N2O in autumn. The fluxes of CO2 emission from Kongyul31 were correlated with air temperature and 10 cm soil temperature, but that from Longjingl8 were significant with air temperature and 20 cm soil temperature, from Kenjiandao6 were significant with 10 cm and 30 cm soil temperature; The fluxes of CH4 emission from Kongyu131, Longjingl8 and Kenjiandao6 were significantly correlated with 10 cm～20 cm、0 cm～20 cm and 0 cm～30 cm soil temperature successively. Three kinds of rice fields all were sources of CO2, CH4, N2O (14.598～23.299 t.hm-2.yr-1; 345.1～737.8 kg.hm-2.yr-1; 0.148～0.227 kg.hm-2.yr-1), the CO2 or N2O emission from Longjingl8 and Kenjiandao6 decreased by 32.7%～37.3% or 32.2%～34.8%, and CH4 emission increased by 54.5%～113.8%, than from Kongyu131.The global warming potential (GWP) of three rice fields distributed between 26.905～32.691 t CO2·hm-2·yr-1, GWP of Kenjiandao6 decrease by 14.0%～17.7% than that of Kongyu131 and Longjing18, which GWP mainly were composed of CO2 and CH4 emission (≥99.8%).
|