水分类型对土壤排放的温室气体组成和综合温室效应的影响

EFFECTS OF WATER REGIME ON CO_2, CH_4 AND N_2O EMISSIONS AND OVERALL POTENTIAL FOR GREENHOUSE EFFECT CAUSED BY EMITTED GASES

实验室研究表明，土壤排放出的温室气体（CO2、CH4和N2O）组成及总量显著地受土壤水分类型和施用秸秆的影响。连续淹水条件下，土壤仅排放微量的N2O，但排放出大量的CH4和CO2；好气条件下，土壤不排放CH4，但排放出大量的N2O；虽然淹水的土壤排水促进N2O排放，但显著抑制CH4的排放，淹水好气交替处理的土壤其排放的CO2、CH4和N2O均在好气和连续淹水之间。根据各种温室气体产生温室效应的相对潜力，计算土壤排放的温室气体的综合温室效应表明，连续淹水条件下，土壤产生的总温室效应最高，淹水好气交替处理的土壤产生的总温室效应最小。实验结果说明，人为因素对土壤的干扰可以显著地改变土壤排放的温室气体组成和产生的综合温室效应。

The results from a laboratory experiment showed that the composition and total amount of CO2, CH4 and N2O emitted from a clayey soil were affected significantly by water regime and amendment of wheat straw. Under the flooded conditions, the emission was small for N2O, but large for CH4 and CO2, in contrast under the aerobic conditions, the emission was not detectable for CH4, but large for N2O; the drainage of flooded water acceleseted N2O emission, but depressed CH4 emission. And the emissions of CO2, CH4 and N2O under the flooded/drained alternate conditions were the middles between those under flooded conditions and under aerobic conditions. The overall potential for greenhouse effect (OPGE) caused by the emitted greenhouse gases, calculated according to their potential in absorbing thermal radiation, was the highest under the flooded conditions and the lowest under the flooded/drained alternate conditions. It clearly demonstrated that the change in water regime would not only alter the composition of greenhouse gases emitted from soil but OPGE as well.